rifampin and Extensively-Drug-Resistant-Tuberculosis

In December 2022 World Health Organization released a new treatment for multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB) guideline. The main novelty of this update is two new recommendations (i) a 6-month treatment regimen composed of bedaquiline, pretomanid, linezolid (600 mg), and moxifloxacin (BPaLM) is recommended in place of the 9-month or longer (18-month) regimens in MDR/RR-TB patients, now including extensive pulmonary TB and extrapulmonary TB (except TB involving central nervous system, miliary TB and osteoarticular TB); (ii) the use of the 9-month all-oral regimen rather than longer (18-months) regimen is suggested in patients with MDR/RR-TB and in whom resistance to fluoroquinolones has been excluded. Longer (18-month) treatments remain a valid option in all cases in which shorter regimens cannot be implemented due to intolerance, drug-drug interactions, extensively drug-resistant tuberculosis, extensive forms of extrapulmonary TB, or previous failure. The new guidelines represent a milestone in MDR/RR-TB treatment landscape, setting the basis for a shorter, all-oral, more acceptable, equitable, and patient-centered model for MDR/RR-TB management. However, some challenges remain to be addressed to allow full implementation of the new recommendations.

Topics: Antitubercular Agents; Extensively Drug-Resistant Tuberculosis; Humans; Rifampin; Tuberculosis, Multidrug-Resistant; Tuberculosis, Pulmonary

The emergence of drug resistance continues to afflict TB control where drug resistant strains have become a global health concern. Contrary to drug-sensitive TB, the treatment of MDR/XDR-TB is more complicated requiring the administration of second-line drugs that are inefficient than the first line drugs and are associated with greater side effects. The emergence of drug resistant Mtb strains had coincided with an innovation void in the field of drug discovery of anti-mycobacterials. However, the approval of bedaquiline and delamanid recently for use in MDR/XDR-TB has given an impetus to the TB drug discovery. The review discusses the drug discovery efforts in the field of tuberculosis with a focus on the strategies adopted and challenges confronted by TB research community. Here, we discuss the diverse clinical candidates in the current TB drug discovery pipeline. There is an urgent need to combat the current TB menace through multidisciplinary approaches and strategies making use of the recent advances in understanding the molecular biology and pathogenesis of Mtb. The review highlights the recent advances in drug discovery, with the host directed therapeutics and nanoparticles-drug delivery coming up as important tools to fight tuberculosis in the future.

Topics: Antitubercular Agents; Diarylquinolines; Drug Therapy, Combination; Ethambutol; Extensively Drug-Resistant Tuberculosis; Humans; Isoniazid; Mycobacterium tuberculosis; Nitroimidazoles; Oxazoles; Pyrazinamide; Rifampin

The aim of this review is to inform the reader on the latest developments in epidemiology, diagnostics and management.. Drug-resistant Tuberculosis (DR-TB) continues to be a current global health threat, and is defined by higher morbidity and mortality, sequelae, higher cost and complexity. The WHO classifies drug-resistant TB into 5 categories: isoniazid-resistant TB, rifampicin resistant (RR)-TB and MDR-TB, (TB resistant to isoniazid and rifampicin), pre-extensively drug-resistant TB (pre-XDR-TB) which is MDR-TB with resistance to a fluoroquinolone and finally XDR-TB that is TB resistant to rifampicin, plus any fluoroquinolone, plus at least one further priority A drug (bedaquiline or linezolid). Of 500,000 estimated new cases of RR-TB in 2020, only 157 903 cases are notified. Only about a third of cases are detected and treated annually.. Recently newer rapid diagnostic methods like the GeneXpert, whole genome sequencing and Myc-TB offer solutions for rapid detection of resistance.. The availability of new TB drugs and shorter treatment regimens have been recommended for the management of DR-TB.. Despite advances in diagnostics and treatments we still have to find and treat two thirds of the drug resistant cases that go undetected and therefore go untreated each year. Control of TB and elimination will only occur if cases are detected, diagnosed and treated promptly.

Topics: Antitubercular Agents; Extensively Drug-Resistant Tuberculosis; Humans; Isoniazid; Mycobacterium tuberculosis; Rifampin; Tuberculosis, Multidrug-Resistant

Line probe assays (LPAs) are PCR-based assays used for the rapid diagnosis of Mycobacterium tuberculosis (MTB) and drug-resistant tuberculosis (DR-TB). But studies on its performance are insufficient. Thus, in this study, we conducted a systematic review and meta-analysis to evaluate the effect of LPAs in the detection of MTB and drug-resistant TB in comparison with the traditional culture and DST methods.. A systemic literature search was conducted on the Web of Science, Embase, PubMed, the Cochrane Library, Scopus, and OVID databases. All the included studies were classified according to different detecting objects. Sensitivity, specificity, Positive Likely Ratio (PLR), Negative Likely Ratio (NLR), Diagnostic Odds Ratio (DOR), corresponding 95% confidence interval, Area Under Curve (AUC), Deeks' funnel plot, and Bivariate Boxplot was used to do the evaluation.. 147 studies included 491 datasets, with 182,448 samples, were incorporated into our analysis. The sensitivity (95% CI), specificity (95% CI), PLR, NLR, DOR and AUC for MTB were 0.89 (0.86 to 0.92), 0.94 (0.90 to 0.97), 15.70, 0.11, 139 and 0.96, respectively; for rifampicin-resistant TB were 0.96 (0.95 to 0.97), 0.99 (0.98 to 0.99), 82.9, 0.04, 1994 and 1.00, respectively; for isoniazid-resistant TB were 0.91 (0.89 to 0.93), 0.99 (0.98 to 0.99), 83.4, 0.09, (0.99 to 1.00), 195.7, 0.07, 2783 and 1.00, respectively; for Multi-drug resistant TB (MDR-TB) were 0.93 (0.90 to 0.95), 1.00 (0.99 to 1.00), 195.7, 0.07, 2783 and 1.00, respectively; for extensively drug-resistant TB (XDR-TB) were 0.60 (0.33 to 0.82), 1.00 (0.95 to 1.00), 291.3, 0.4, 726 and 0.95, respectively; for (second-line drug-resistant TB) SLID-TB were 0.83 (0.78 to 0.87), 0.98 (0.97 to 0.99), 44.6, 0.17, 262 and 0.98, respectively. Sensitivity in pre-extensively drug-resistant TB (Pre-XDR-TB) was 0.67, specificity was 0.91. No publication bias existed according to Deeks' funnel plot.. High diagnosis performance was confirmed in LPAs for the diagnosis of MTB and drug-resistant TB. LPAs might be a good alternative to culture and DST in detecting MTB, RR-TB, INH-TB, XDR-TB, SLID-TB, and MDR-TB. While more studies were still needed to explore the diagnosis performance of LPAs for Pre-XDR TB.

Topics: Antitubercular Agents; Extensively Drug-Resistant Tuberculosis; Humans; Isoniazid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Rifampin; Sensitivity and Specificity; Tuberculosis, Multidrug-Resistant

No previous systematic reviews have comprehensively investigated the features of Xpert MTB/XDR and other rapid tests to diagnose pre-XDR/XDR-TB. The aim of this systematic review is to assess existing rapid diagnostics for pre-XDR/XDR-TB from a point-of-care perspective and describe their technical characteristics (i.e., sensitivity, specificity, positive and negative predictive values).. Embase, PubMed, Scopus, and Web of Science were searched to detect the articles focused on the accuracy of commercially available rapid molecular diagnostic tests for XDR-TB according to PRISMA guidelines. The analysis compared the diagnostic techniques and approaches in terms of sensitivity, specificity, laboratory complexity, time to confirmed diagnosis.. Of 1298 records identified, after valuating article titles and abstracts, 97 (7.5%) records underwent full-text evaluation and 38 records met the inclusion criteria. Two rapid World Health Organization (WHO)-endorsed tests are available: Xpert MTB/XDR and GenoType MTBDRsl (VER1.0 and VER 2.0). Both tests had similar performance, slightly favouring Xpert, although only 2 studies were available (sensitivity 91.4-94; specificity 98.5-99; accuracy 97.2-97.7; PPV 88.9-99.1; NPV 95.8-98.9).. Xpert MTB/XDR could be suggested at near-point-of-care settings to be used primarily as a follow-on test for laboratory-confirmed TB, complementing existing rapid tests detecting at least rifampicin-resistance. Both Xpert MTB/XDR and GenoType MTBDRsl are presently diagnosing what WHO defined, in 2021, as pre-XDR-TB.

Topics: Extensively Drug-Resistant Tuberculosis; Genotype; Humans; Mycobacterium tuberculosis; Predictive Value of Tests; Rifampin; Sensitivity and Specificity; Tuberculosis, Multidrug-Resistant

Drug-resistant tuberculosis, especially those with resistance to rifampicin (RR-TB), has become one of the main obstacles to achieving the dream of eradicating tuberculosis. Furthermore, it is necessary to combine three or four different drugs in the attempt to cure TB, however, unfortunately, there are few available that can be considered genuinely effective. Fortunately, the notable worldwide increase in RR-TB in recent years has led to the investment of resources in the development of new drugs for TB, and other drugs investigated for other diseases have been successfully tested on TB. This has resulted in a clear change in the clinical management of these patients over the last 3-4 years, and it is now easier to design therapeutic regimens and achieve higher success rates. All these changes are updated in this review.

Topics: Antitubercular Agents; Extensively Drug-Resistant Tuberculosis; Humans; Mycobacterium tuberculosis; Rifampin; Tuberculosis, Multidrug-Resistant

Xpert MTB/RIF and Xpert MTB/RIF Ultra (Xpert Ultra) are World Health Organization (WHO)-recommended rapid tests that simultaneously detect tuberculosis and rifampicin resistance in people with signs and symptoms of tuberculosis. This review builds on our recent extensive Cochrane Review of Xpert MTB/RIF accuracy.. To compare the diagnostic accuracy of Xpert Ultra and Xpert MTB/RIF for the detection of pulmonary tuberculosis and detection of rifampicin resistance in adults with presumptive pulmonary tuberculosis. For pulmonary tuberculosis and rifampicin resistance, we also investigated potential sources of heterogeneity. We also summarized the frequency of Xpert Ultra trace-positive results, and estimated the accuracy of Xpert Ultra after repeat testing in those with trace-positive results.. We searched the Cochrane Infectious Diseases Group Specialized Register, MEDLINE, Embase, Science Citation Index, Web of Science, LILACS, Scopus, the WHO ICTRP, the ISRCTN registry, and ProQuest to 28 January 2020 with no language restriction.. We included diagnostic accuracy studies using respiratory specimens in adults with presumptive pulmonary tuberculosis that directly compared the index tests. For pulmonary tuberculosis detection, the reference standards were culture and a composite reference standard. For rifampicin resistance, the reference standards were culture-based drug susceptibility testing and line probe assays.. Two review authors independently extracted data using a standardized form, including data by smear and HIV status. We assessed risk of bias using QUADAS-2 and QUADAS-C. We performed meta-analyses comparing pooled sensitivities and specificities, separately for pulmonary tuberculosis detection and rifampicin resistance detection, and separately by reference standard. Most analyses used a bivariate random-effects model. For tuberculosis detection, we estimated accuracy in studies in participants who were not selected based on prior microscopy testing or history of tuberculosis. We performed subgroup analyses by smear status, HIV status, and history of tuberculosis. We summarized Xpert Ultra trace results.. We identified nine studies (3500 participants): seven had unselected participants (2834 participants). All compared Xpert Ultra and Xpert MTB/RIF for pulmonary tuberculosis detection; seven studies used a paired comparative accuracy design, and two studies used a randomized design. Five studies compared Xpert Ultra and Xpert MTB/RIF for rifampicin resistance detection; four studies used a paired design, and one study used a randomized design. Of the nine included studies, seven (78%) were mainly or exclusively in high tuberculosis burden countries. For pulmonary tuberculosis detection, most studies had low risk of bias in all domains. Pulmonary tuberculosis detection Xpert Ultra pooled sensitivity and specificity (95% credible interval) against culture were 90.9% (86.2 to 94.7) and 95.6% (93.0 to 97.4) (7 studies, 2834 participants; high-certainty evidence) versus Xpert MTB/RIF pooled sensitivity and specificity of 84.7% (78.6 to 89.9) and 98.4% (97.0 to 99.3) (7 studies, 2835 participants; high-certainty evidence). The difference in the accuracy of Xpert Ultra minus Xpert MTB/RIF was estimated at 6.3% (0.1 to 12.8) for sensitivity and -2.7% (-5.7 to -0.5) for specificity. If the point estimates for Xpert Ultra and Xpert MTB/RIF are applied to a hypothetical cohort of 1000 patients, where 10% of those presenting with symptoms have pulmonary tuberculosis, Xpert Ultra will miss 9 cases, and Xpert MTB/RIF will miss 15 cases. The number of people wrongly diagnosed with pulmonary tuberculosis would be 40 with Xpert Ultra and 14 with Xpert MTB/RIF. In smear-negative, culture-positive participants, pooled sensitivity was 77.5% (67.6 to 85.6) for Xpert Ultra versus 60.6% (48.4 to 71.7) for Xpert MTB/RIF; pooled specificity was 95.8% (92.9 to 97.7) for Xpert Ultra versus 98.8% (97.7 to 99.5) for Xpert MTB/RIF (6 studies). In people living with HIV, pooled sensitivity was 87.6% (75.4 to 94.1) for Xpert Ultra versus 74.9% (58.7 to 86.2) for Xpert MTB/RIF; pooled specificity was 92.8% (82.3 to 97.0) for Xpert Ultra versus 99.7% (98.6 to 100.0) for Xpert MTB/RIF (3 studies). In participants with a history of tuberculosis, pooled sensitivity was 84.2% (72.5 to 91.7) for Xpert Ultra versus 81.8% (68.7 to 90.0) for Xpert MTB/RIF; pooled specificity was 88.2% (70.5 to 96.6) for Xpert Ultra versus 97.4% (91.7 to 99.5) for Xpert MTB/RIF (4 studies). The proportion of Ultra trace-positive results ranged from 3.0% to 30.4%. Data were insufficient to estimate the accuracy of X. Xpert Ultra has higher sensitivity and lower specificity than Xpert MTB/RIF for pulmonary tuberculosis, especially in smear-negative participants and people living with HIV. Xpert Ultra specificity was lower than that of Xpert MTB/RIF in participants with a history of tuberculosis. The sensitivity and specificity trade-off would be expected to vary by setting. For detection of rifampicin resistance, Xpert Ultra and Xpert MTB/RIF had similar sensitivity and specificity. Ultra trace-positive results were common. Xpert Ultra and Xpert MTB/RIF provide accurate results and can allow rapid initiation of treatment for rifampicin-resistant and multidrug-resistant tuberculosis.

Topics: Antibiotics, Antitubercular; Diagnostic Errors; Drug Resistance, Bacterial; Extensively Drug-Resistant Tuberculosis; False Negative Reactions; False Positive Reactions; Humans; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Rifampin; Sensitivity and Specificity; Tuberculosis, Pulmonary

For tuberculosis to be eradicated, the transmission of Multi-Drug-Resistant and eXtensively Drug Resistant strains of Mycobacterium tuberculosis (MDR and XDR-TB) must be considerably reduced. Drug resistant strains were initially thought to have reduced fitness, and the majority of resistant strains may actually have compromised fitness because they are found in only one or a few patients. In contrast, some MDR/XDR-TB strains are highly transmitted and cause large outbreaks. Most antibiotics target essential bacterial functions and the mutations that confer resistance to anti-TB drugs can incur fitness costs manifested as slower growth and reduced viability. The fitness costs vary with different resistance mutations and the bacilli can also accumulate secondary mutations that compensate for the compromised functions and partially or fully restore lost fitness. The compensatory mutations (CM) are different for each antibiotic, as they mitigate the deleterious effects of the specific functions compromised by the resistance mutations. CM are generally more common in strains with resistance mutations incurring the greatest fitness costs, but for RIF resistance, CM are most frequent in strains with the mutation carrying the least fitness cost, Ser450Leu. Here, we review what is known about fitness costs, CM and mechanisms of resistance to the drugs that define a strain as MDR or XDR-TB. The relative fitness costs of the resistance mutations and the mitigating effects of CM largely explain why certain mutations are frequently found in highly transmitted clusters while others are less frequently, rarely or never found in clinical isolates. The CM illustrate how drug resistance affects bacteria and how bacteria evolve to overcome the effects of the antibiotics, and thus a paradigm for how mycobacteria can evolve in response to stress.

Topics: Antitubercular Agents; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Genetic Fitness; Isoniazid; Mutation; Mycobacterium tuberculosis; Rifampin; Streptomycin; Tuberculosis, Multidrug-Resistant

Despite broad uptake of antiretroviral therapy (ART), tuberculosis (TB) incidence and mortality among people with HIV remain unacceptably high. Short-course regimens for TB, incorporating both novel and established drugs, offer the potential to enhance adherence and completion rates, thereby reducing the global TB burden. This review will outline short-course regimens for TB among patients with HIV.. After many years without new agents, there is now active testing of many novel drugs to treat TB, both for latent infection and active disease. Though not all studies have included patients with HIV, many have, and there are ongoing trials to address key implementation challenges such as potent drug-drug interactions with ART. The goal of short-course regimens for TB is to enhance treatment completion without compromising efficacy. Particularly among patients with HIV, studying these shortened regimens and integrating them into clinical care are of urgent importance. There are now multiple short-course regimens for latent infection and active disease that are safe and effective among patients with HIV.

Topics: Anti-HIV Agents; Antitubercular Agents; Drug Interactions; Extensively Drug-Resistant Tuberculosis; HIV Infections; Humans; Isoniazid; Pyrazinamide; Rifampin; Tuberculosis, Pulmonary

As we move into the era of the Sustainable Development Goals (SDGs), the World Health Organization (WHO) has developed the End TB strategy 2016-2035 with a goal to end the global epidemic of tuberculosis (TB) by 2035. Achieving the targets laid out in the Strategy will require strengthening of the whole TB diagnosis and treatment cascade, including improved case detection, the establishment of universal drug susceptibility testing and rapid treatment initiation. An estimated 3.9% of new TB cases and 21% of previously treated cases had rifampicin-resistant (RR) or multidrug-resistant (MDR) TB in 2015. These levels have remained stable over time, although limited data are available from major high burden settings. In addition to the emergence of drug resistance due to inadequate treatment, there is growing evidence that direct transmission is a large contributor to the RR/MDR-TB epidemic. Only 340,000 of the estimated 580,000 incident cases of RR/MDR-TB were notified to WHO in 2015. Among these, only 125,000 were initiated on second-line treatment. RR/MDR-TB epidemics are likely to be driven by direct transmission. The most important risk factor for MDR-TB is a history of previous treatment. Other risk factors vary according to setting but can include hospitalisation, incarceration and HIV infection. Children have the same risk of MDR-TB as adults and represent a diagnostic and treatment challenge. Rapid molecular technologies have revolutionized the diagnosis of drug-resistant TB. Until capacity can be established to test every TB patient for rifampicin resistance, countries should focus on gradually expanding their coverage of testing. DNA sequencing technologies are being increasingly incorporated into patient management and drug resistance surveillance. They offer additional benefits over conventional culture-based phenotypic testing, including a faster turn-around time for results, assessment of resistance patterns to a range of drugs, and investigation of strain clustering and transmission.

Topics: Adult; Antitubercular Agents; Child; Drug Resistance, Multiple, Bacterial; Epidemics; Extensively Drug-Resistant Tuberculosis; Hospitalization; Humans; Mycobacterium tuberculosis; Rifampin; Risk Factors; Sequence Analysis, DNA; Tuberculosis, Pulmonary; World Health Organization

The continuing spread of drug-resistant tuberculosis (TB) is one of the most urgent and difficult challenges facing global TB control. Patients who are infected with strains resistant to isoniazid and rifampicin, called multidrug-resistant (MDR) TB, are practically incurable by standard first-line treatment. In 2012, there were approximately 450,000 new cases and 170,000 deaths because of MDR-TB. Extensively drug-resistant (XDR) TB refers to MDR-TB strains that are resistant to fluoroquinolones and second-line injectable drugs. The main causes of the spread of resistant TB are weak medical systems, amplification of resistance patterns through incorrect treatment, and transmission in communities and facilities. Although patients harboring MDR and XDR strains present a formidable challenge for treatment, cure is often possible with early identification of resistance and use of a properly designed regimen. Community-based programs can improve treatment outcomes by allowing patients to be treated in their homes and addressing socioeconomic barriers to adherence.

Topics: Antitubercular Agents; Child; Coinfection; Community Health Services; Drug Administration Schedule; Drug Design; Drug Therapy, Combination; Extensively Drug-Resistant Tuberculosis; Female; Fluoroquinolones; Global Health; HIV Infections; Humans; Isoniazid; Pregnancy; Pregnancy Complications, Infectious; Rifampin; Tuberculosis, Multidrug-Resistant

After the introduction of isoniazid and rifampicin, the second one discovered in the Lepetit Research Laboratories (Milan, Italy), under the supervision of Professor Piero Sensi, tuberculosis (TB) was considered an illness of the past. Unfortunately, this infectious disease is still a global health fear, due to the multidrug-resistant Mycobacterium tuberculosis and extensively circulating drug-resistant strains, as well as the unrecognized TB transmission, especially in regions with high HIV incidence. In the last few years, new antitubercular molecules appeared on the horizon both in preclinical and clinical stage of evaluation. In this review, we focus on a few of them and on their mechanism of action. Two new promising drug targets, DprE1 and MmpL3, are also discussed.

Topics: Alcohol Oxidoreductases; Animals; Antitubercular Agents; Bacterial Proteins; Drug Discovery; Extensively Drug-Resistant Tuberculosis; Humans; Isoniazid; Mycobacterium tuberculosis; Rifampin; Tuberculosis; Tuberculosis, Multidrug-Resistant

To review the latest information about levels of anti-tuberculosis (TB) drug resistance in the European Region of the World Health Organization (WHO) and time-trends in multidrug-resistant TB (resistance to isoniazid and rifampicin; MDR-TB) over the past fifteen years. We analysed data on drug resistance among new and previously treated TB cases reported from 1997 to 2012. Data are collected in surveys of representative samples of TB patients or from surveillance systems based on diagnostic drug susceptibility testing. A total of 15.7% (95% confidence limits (CI): 9.5-21.9) of new and 45.3% (95%CI: 39.2-51.5) of previously treated TB cases are estimated to have MDR-TB in the Region. Extensively drug-resistant TB (MDR-TB and resistance to fluoroquinolones and second-line injectables; XDR-TB) had been reported by 38 of the 53 countries of the region (72%). The proportion of MDR-TB cases with XDR-TB is 11.4% (95%CI: 8.6-14.2). Between 1997 and 2012, population rates of MDR-TB declined in Estonia, Latvia and Germany and increased in the United Kingdom, Sweden and Tomsk Oblasts of the Russian Federation. Surveillance of drug resistance has been strengthened in the WHO European Region, which has the highest proportions of MDR-TB and XDR-TB ever reported globally. More complete data are needed particularly from the Russian Federation.

Topics: Antitubercular Agents; Europe; Extensively Drug-Resistant Tuberculosis; Humans; Isoniazid; Microbial Sensitivity Tests; Population Surveillance; Rifampin; Time Factors; Tuberculosis, Multidrug-Resistant; World Health Organization

Tuberculosis (TB) remains a global emergency and is responsible for 1.7 million deaths annually. Widespread global misuse of isoniazid and rifampicin over three decades has resulted in emergence of the ominous spread of multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) globally. These difficult to treat resistant forms of TB are increasingly seen in Asia, Eastern Europe, South America and sub-Saharan Africa, disrupting TB and HIV control programmes. We review the latest available global epidemiological and clinical evidence on drug-resistant TB in HIV-infected and uninfected populations, with focus on Africa where data are scanty because of poor diagnostic and reporting facilities. The difficult management and infection control problems posed by drug-resistant TB in HIV-infected patients are discussed. Given the increasing current global trends in MDR-TB, aggressive preventive and management strategies are urgently required to avoid disruption of global TB control efforts. The data suggest that existing interventions, public health systems and TB and HIV programmes must be strengthened significantly. Political and funder commitment is essential to curb the spread of drug-resistant TB.

Topics: Africa South of the Sahara; Antitubercular Agents; Asia; Europe, Eastern; Extensively Drug-Resistant Tuberculosis; HIV Infections; Humans; Isoniazid; Rifampin; South America; Tuberculosis, Multidrug-Resistant

The current 6-month tuberculosis (TB) therapy is suboptimal with significant side effects and a poor patient compliance problem that frequently selects drug-resistant organisms. The increasing drug-resistant TB problem highlights the need to develop new and more effective drugs. Significant progress has been made recently with several new drug candidates currently in clinical trials. Improved understanding of persister biology and development of persister drugs are likely to be important for developing a more effective therapy.

Topics: Adamantane; AIDS-Related Opportunistic Infections; Animals; Anti-Bacterial Agents; Antitubercular Agents; Drug Administration Schedule; Drug Resistance, Bacterial; Drug Therapy, Combination; Drugs, Investigational; Ethylenediamines; Extensively Drug-Resistant Tuberculosis; Fluoroquinolones; Humans; Isoniazid; Mycobacterium tuberculosis; Nitroimidazoles; Oxazoles; Pyrazinamide; Rifampin; Treatment Refusal; Tuberculosis, Multidrug-Resistant; Tuberculosis, Pulmonary

While the goal of universal drug susceptibility testing has been a key component of the WHO End TB Strategy, in practice, this remains inaccessible to many. Rapid molecular tests for tuberculosis (TB) and antituberculosis drug resistance could significantly improve access to testing. In this study, we evaluated the accuracy of the Akonni Biosystems XDR-TB (extensively drug-resistant TB) TruArray and lateral-flow-cell (XDR-LFC) assay (Akonni Biosystems, Inc., Frederick, MD, USA), a novel assay that detects mutations in seven genes associated with resistance to antituberculosis drugs:

Topics: Amikacin; Antitubercular Agents; Bacterial Proteins; Capreomycin; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Fluoroquinolones; Humans; Isoniazid; Kanamycin; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Prospective Studies; Rifampin; Tuberculosis, Multidrug-Resistant

Multidrug resistant (MDR) and extensively drug-resistant (XDR) tuberculosis (TB) are major public health threats that are significant causes of physical sequelae and financial consequences for infected people. Treatment for MDR- and XDR-TB are more toxic and take longer duration than for drug-susceptible-TB. As a result, the long-term sequelae are thought to be more common among patients with MDR- and XDR-TB than drug-susceptible-TB, but this is yet to be quantified. Hence, the aim of this systematic review and meta-analysis is to quantify the global burden and types of long-term physical sequelae and financial burden associated with both MDR- and XDR-TB.. We will search CINHAL, MEDLINE, Embase, Scopus, and Web of science for studies that report physical and financial sequelae associated with rifampicin-resistant (RR), MDR- and XDR-TB or their treatments. The search will be conducted without time, language, and place restrictions. A random-effects meta-analysis will be conducted to estimate the pooled prevalence of each physical sequela. Heterogeneity will be measured using the Higgins I2 statistics. We will assess publication bias visually using the funnel plot and statistically using Egger's test. Adjustments for publication basis will be made using Tweedie's and Duval Trim and Fill analysis.. Since the study is based on published evidence, ethics approval is not required. The findings of the systematic review will be presented at various conferences and will be published in a peer-reviewed journal.. The protocol is published in the PROSPERO with registration number CRD42021250909.

Topics: Antitubercular Agents; Extensively Drug-Resistant Tuberculosis; Financial Stress; Humans; Meta-Analysis as Topic; Rifampin; Risk Factors; Systematic Reviews as Topic; Tuberculosis, Multidrug-Resistant

Topics: Antitubercular Agents; Emigrants and Immigrants; Extensively Drug-Resistant Tuberculosis; Humans; Isoniazid; Mycobacterium tuberculosis; Refugees; Rifampin; Tuberculosis, Multidrug-Resistant; United States

Extensively drug-resistant tuberculosis (XDR-TB), defined as resistance to at least isoniazid (INH), rifampicin (RIF), a fluoroquinolone (FQ) and a second-line injectable drug (SLID), is difficult to treat and poses a major threat to TB control. The transmission dynamics and distribution of XDR

Topics: Antitubercular Agents; Drug Resistance; Extensively Drug-Resistant Tuberculosis; Fluoroquinolones; Humans; Mutation; Rifampin; South Africa

Uganda remains one of the countries with the highest burden of TB/HIV. Drug-resistant TB remains a substantial challenge to TB control globally and requires new strategic effective control approaches. Drug resistance usually develops due to inadequate management of TB patients including improper treatment regimens and failure to complete the treatment course which may be due to an unstable supply or a lack of access to treatment, as well as patient noncompliance.. Two sputa samples were collected from Xpert MTB/RIF® assay-diagnosed multi-drug resistant tuberculosis (MDR-TB) patient at Lira regional referral hospital in northern Uganda between 2020 and 2021 for comprehensive routine mycobacterial species identification and drug susceptibility testing using culture-based methods. Detection of drug resistance-conferring genes was subsequently performed using whole-genome sequencing with Illumina MiSeq platform at the TB Supranational Reference Laboratory in Uganda.. In both isolates, extensively drug-resistant TB (XDR-TB) was identified including resistance to Isoniazid (katG p.Ser315Thr), Rifampicin (rpoB p.Ser450Leu), Moxifloxacin (gyrA p.Asp94Gly), Bedaquiline (Rv0678 Glu49fs), Clofazimine (Rv0678 Glu49fs), Linezolid (rplC Cys154Arg), and Ethionamide (ethA c.477del). Further analysis of these two high quality genomes revealed that this 32 years-old patient was infected with the Latin American Mediterranean TB strain (LAM).. This is the first identification of extensively drug-resistant Mycobacterium tuberculosis clinical isolates with bedaquiline, linezolid and clofazimine resistance from Uganda. These acquired resistances were because of non-adherence as seen in the patient's clinical history. Our study also strongly highlights the importance of combating DR-TB in Africa through implementing next generation sequencing that can test resistance to all drugs while providing a faster turnaround time. This can facilitate timely clinical decisions in managing MDR-TB patients with non-adherence or lost to follow-up.

Topics: Adult; Antitubercular Agents; Clofazimine; Diarylquinolines; Extensively Drug-Resistant Tuberculosis; Humans; Linezolid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Rifampin; Tuberculosis, Multidrug-Resistant; Uganda

The Comprehensive Resistance Prediction for Tuberculosis: an International Consortium (CRyPTIC) presents here a data compendium of 12,289 Mycobacterium tuberculosis global clinical isolates, all of which have undergone whole-genome sequencing and have had their minimum inhibitory concentrations to 13 antitubercular drugs measured in a single assay. It is the largest matched phenotypic and genotypic dataset for M. tuberculosis to date. Here, we provide a summary detailing the breadth of data collected, along with a description of how the isolates were selected, collected, and uniformly processed in CRyPTIC partner laboratories across 23 countries. The compendium contains 6,814 isolates resistant to at least 1 drug, including 2,129 samples that fully satisfy the clinical definitions of rifampicin resistant (RR), multidrug resistant (MDR), pre-extensively drug resistant (pre-XDR), or extensively drug resistant (XDR). The data are enriched for rare resistance-associated variants, and the current limits of genotypic prediction of resistance status (sensitive/resistant) are presented by using a genetic mutation catalogue, along with the presence of suspected resistance-conferring mutations for isolates resistant to the newly introduced drugs bedaquiline, clofazimine, delamanid, and linezolid. Finally, a case study of rifampicin monoresistance demonstrates how this compendium could be used to advance our genetic understanding of rare resistance phenotypes. The data compendium is fully open source and it is hoped that it will facilitate and inspire future research for years to come.

Topics: Antitubercular Agents; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Humans; Microbial Sensitivity Tests; Mutation; Mycobacterium tuberculosis; Phenotype; Rifampin; Tuberculosis, Multidrug-Resistant

Topics: Antitubercular Agents; Extensively Drug-Resistant Tuberculosis; Fluoroquinolones; Humans; Isoniazid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Rifampin; Tuberculosis, Multidrug-Resistant

Refractory rifampicin-resistant/multidrug resistant/extensively-drug resistant tuberculosis (RR/MDR/XDR-TB) were defined as patients infected with Mycobacterium tuberculosis (MTB) resistant to rifampicin(RR-TB), or at least resistant to rifampicin and isoniazid (MDR-TB) or added resistant to fluoroquinolones (FQs) and one of second line injectable agents (XDR-TB), a patient for whom an effective regimen (fewer than 4 effective agents due to adverse events (AEs) or multiple drug resistances) cannot be developed. To compare the effectiveness and safety of bedaquiline (BDQ)-containing and BDQ-free regimens for treatment of patients with refractory RR/MDR/XDR-TB.. Patients with refractory RR/MDR/XDR-TB receiving BDQ-containing regimens (BDQ group, n = 102) and BDQ-free regimens (non-BDQ group, n = 100) satisfied with included criteria were strictly included in this retrospective historical control study across East China. Culture conversion, treatment outcome, cavity closing rate, and AEs were compared between two groups.. The baseline characteristics involved all possible aspects of patients were well balanced between two groups (p > 0.05). Culture conversion rates in the BDQ group at month 3 (89.2% vs. 66.0%), month 6 (90.2% vs 72.0%), month 9 (91.2% vs. 66.0%), and month 12 (94.1% vs 65.0%) were all significantly higher than those in non-BDQ group (p < 0.001). Similar results were observed in the cavity closing rate at month 9 (19.6% vs 8.0%, p = 0.0) and month 12 (39.2% vs 15.0%, p < 0.001). Patients receiving BDQ-containing regimens had more treatment success than those receiving BDQ-free regimens (p < 0.001; cure rate, 69.6% vs. 45.0%; complete the treatment, 22.5% vs. 18.0%; treatment success, 92.2% vs. 63.0%); the use of BDQ and combined with Linezolid or Clofazimine or Cycloserine were identified as independent predictors of treatment success and no culture reversion (P < 0.05). AEs were similarly reported in 26.5% of patients in the BDQ group and 19.0% in the non-BDQ group (p = 0.2).. BDQ-containing regimens resulted in better treatment outcomes and similar safety relative to BDQ-free regimens for patients with refractory pulmonary RR/MDR/XDR-TB.

Topics: Antitubercular Agents; Diarylquinolines; Extensively Drug-Resistant Tuberculosis; Humans; Retrospective Studies; Rifampin; Tuberculosis, Multidrug-Resistant; Tuberculosis, Pulmonary

To determine the levels and patterns of resistance to first- and second-line anti-tuberculosis (TB) drugs among new and previously treated sputum smear positive pulmonary TB (PTB) patients.. We conducted a nationally representative cross-sectional facility-based survey in June 2017-July 2018 involving 45 clusters selected based on probability proportional to size. The survey aimed to determine the prevalence of anti-TB drug resistance and associated risk factors among smear positive PTB patients in Tanzania. Sputum samples were examined using smear microscopy, Xpert MTB/RIF, culture and drug susceptibility testing (DST). Logistic regression was used to account for missing data and sampling design effects on the estimates and their standard errors.. We enrolled 1557 TB patients, including 1408 (90.4%) newly diagnosed and 149 (9.6%) previously treated patients. The prevalence of multidrug-resistant TB (MDR-TB) was 0.85% [95% confidence interval (CI): 0.4-1.3] among new cases and 4.6% (95% CI: 1.1-8.2) among previously treated cases. The prevalence of Mycobacterium tuberculosis strains resistant to any of the four first-line anti-TB drugs (isoniazid, rifampicin, streptomycin and ethambutol) was 1.7% among new TB patients and 6.5% among those previously treated. Drug resistance to all first-line drugs was similar (0.1%) in new and previously treated patients. None of the isolates displayed poly-resistance or extensively drug-resistant TB (XDR-TB). The only risk factor for MDR-TB was history of previous TB treatment (odds ratio = 5.7, 95% CI: 1.9-17.2).. The burden of MDR-TB in the country was relatively low with no evidence of XDR-TB. Given the overall small number of MDR-TB cases in this survey, it will be beneficial focusing efforts on intensified case detection including universal DST.

Topics: Antitubercular Agents; Cross-Sectional Studies; Ethambutol; Extensively Drug-Resistant Tuberculosis; Humans; Isoniazid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Rifampin; Streptomycin; Tanzania; Tuberculosis, Multidrug-Resistant

Drug resistant tuberculosis (DR-TB), particularly multidrug resistance (MDR-TB) and extensive drug resistance (XDR-TB) pose a serious threat to public health. This study aimed to identify drug resistance in pulmonary tuberculosis patients and to see their association with diabetes, human immunodeficiency virus (HIV), previous history of tuberculosis (TB) and family history of TB.. Sputum specimens obtained from 11,874 pulmonary tuberculosis patients were subjected to smear microscopy, cartridge based nucleic acid amplification test (CBNAAT) and liquid culture (LC). Smear positive isolates were subjected to first line Line probe assay (FL-LPA) for isoniazid and rifampicin resistance. FL- LPA positive isolates were subjected to second line Line probe assay (SL-LPA) for fluoroquinolones and second line injectable drug resistance.. Out of 11,874 microbiologically confirmed cases of pulmonary tuberculosis, 976 (8.2%) had a drug resistant tuberculosis. Five patterns of drug resistance were identified monoisoniazid; 394 (3.32%), rifampicin; 461 (3.88%) (monorifampicin; 383 (3.22%)), multidrug; 73 (0.61), extensivedrug; 11 (0.09) and others; 37 (0.31). Previous history of tuberculosis was significantly associated with rifampicin resistance and MDR-TB. Family history of tuberculosis contact was strongly associated with rifampicin resistance, MDR-TB and XDR-TB.. There has been an increasing trend in drug resistance in the recent years, particularly in retreatment cases. This study highlights the pattern of drug resistance and need to detect resistance among all tuberculosis cases, in order to interrupt transmission and control this emerging epidemic.

Topics: Drug Resistance; Extensively Drug-Resistant Tuberculosis; Humans; Rifampin; Tuberculosis, Multidrug-Resistant; Tuberculosis, Pulmonary

Multi-drug (MDR) and extensively drug-resistant (XDR) tuberculosis (TB) continues to be a global public health problem especially in high TB burden countries like Nigeria. Many of these cases are undetected and go on to infect high risk individuals. Clinical samples from positive rifampicin resistant Xpert®MTB/Rif assay were subjected to direct whole genome sequencing and bioinformatics analysis to identify the full antibiotics resistance and lineage profile. We report two (2) XDR TB samples also belonging to the East-Asian/Beijing family of lineage 2 Mycobacterium tuberculosis complex from clinical samples in Nigeria. Our findings further reveal the presence of mutations that confer resistance to first-line drugs (rifampicin, isoniazid, ethambutol and pyrazanimide), second-line injectables (capreomycin, streptomycin, kanamycin and/or amikacin) and at least one of the fluoroquinolones (ofloxacin, moxifloxacin, levofloxacin and/or ciprofloxacin) in both samples. The genomic sequence data from this study not only provide the first evidence of XDR TB in Nigeria and West Africa, but also emphasize the importance of WGS in accurately detecting MDR and XDR TB, to ensure adequate and proper management treatment regimens for affected individuals. This will greatly aid in preventing the spread of drug resistance TB in high burden countries.

Topics: Adult; Antitubercular Agents; Capreomycin; DNA, Bacterial; Extensively Drug-Resistant Tuberculosis; Female; Fluoroquinolones; HIV Infections; Humans; Male; Microbial Sensitivity Tests; Middle Aged; Mycobacterium tuberculosis; Nigeria; Phylogeny; Rifampin; Whole Genome Sequencing; Young Adult

Multidrug-resistant tuberculosis (MDR-TB) has become a major threat to the control of tuberculosis globally. Uganda is among the countries with a relatively high prevalence of tuberculosis despite significant control efforts. In this study, the drug resistance of Mycobacterium tuberculosis to rifampicin (RIF) and isoniazid (INH) was investigated among patients diagnosed with pulmonary tuberculosis in Southwestern Uganda. A total of 283 sputum samples (266 from newly diagnosed and 17 from previously treated patients), collected between May 2018 and April 2019 at four different TB diagnostic centres, were assessed for RIF and INH resistance using high-resolution melt curve analysis. The overall prevalence of monoresistance to INH and RIF was 8.5% and 11% respectively, while the prevalence of MDR-TB was 6.7%. Bivariate analysis showed that patients aged 25 to 44 years were at a higher risk of developing MDR-TB (cOR 0.253). Furthermore, among the newly diagnosed patients, the prevalence of monoresistance to INH, RIF and MDR-TB was 8.6%, 10.2% and 6.4% respectively; while among the previously treated cases, these prevalence rates were 5.9%, 23.5% and 11.8%. These rates are higher than those reported previously indicating a rise in MTB drug resistance and may call for measures used to prevent a further rise in drug resistance. There is also a need to conduct frequent drug resistance surveys, to monitor and curtail the development and spread of drug-resistant TB.

Topics: Adult; Aged; Antitubercular Agents; Extensively Drug-Resistant Tuberculosis; Female; Humans; Isoniazid; Male; Middle Aged; Rifampin; Uganda

There is paucity of data on the prevalence and distribution of multidrug- Resistant-Tuberculosis (MDR-TB) in the Republic of Congo. Among the challenges resides the implementation of a robust TB resistance diagnostic program using molecular tools. In resource limited settings there is a need to gather data to enable prioritization of actions. The objective of this study was is to implement molecular tools as a best of diagnosing MDR and XDR-TB among presumptive tuberculosis patients referred to reference hospital of Makelekele in Brazzaville, Republic of the Congo.. We have conducted a cross-sectional study, including a total of 92 presumptive pulmonary tuberculosis patients and who had never received treatment recruited at the reference hospital of Makelekele from October 2018 to October 2019. The socio-demographic and clinical data were collected as well as sputum samples. Rifampicin resistance was investigated using Xpert (Cepheid) and second-line TB drugs Susceptibility testing were performed by the Brucker HAIN Line Probe Assay (GenoType MTBDRsl VER 2.0 assay) method.. From the 92 recruited patients, 57 (62%) were found positive for the Mycobacterium tuberculosis complex. The prevalence of rifampicin-resistant tuberculosis (RR-TB) was 9.8% (9/92) and importantly 2.2% were pre-XDR/XDR.. This study showed a high rate of rifampicin resistance and the presence of extensively drug-resistant tuberculosis in the study area in new patients. This study highlights the need for further studies of TB drug resistance in the country.

Topics: Adolescent; Adult; Antitubercular Agents; Congo; Cross-Sectional Studies; Extensively Drug-Resistant Tuberculosis; Female; Humans; Male; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Rifampin; Sputum; Tuberculosis, Multidrug-Resistant; Young Adult

Rifampicin is one of the key drugs used to treat tuberculosis and is currently used orally. The use of higher oral doses of rifampicin is desired for better therapeutic efficacy, but this is accompanied by increased risk of systemic toxicity thus limiting its recommended oral dose to 10 mg/kg per day. Inhaled delivery of rifampicin is a potential alternative mode of delivery, to achieve high drug concentrations in both the lung and potentially the systemic circulation. In addition, rifampicin exists either as amorphous or crystalline particles, which may show different pharmacokinetic behaviour. However, disposition behaviour of amorphous and crystalline rifampicin formulations after inhaled high-dose delivery is unknown. In this study, rifampicin pharmacokinetics after intra-tracheal administration of carrier-free, amorphous and crystalline powder formulations to Sprague Dawley rats were evaluated. The formulations were administered once daily for seven days by oral, intra-tracheal and oral plus intra-tracheal delivery, and the pharmacokinetics were studied on day 0 and day 6. Intra-tracheal administration of the amorphous formulation resulted in a higher area under the plasma concentration curve (AUC) compared to the crystalline formulation. For both formulations, the intra-tracheal delivery led to significantly higher AUC compared to the oral delivery at the same dose suggesting higher rifampicin bioavailability from the inhaled route. Increasing the intra-tracheal dose resulted in a more than dose proportional AUC suggesting non-linear pharmacokinetics of rifampicin from the inhaled route. Upon repeated administration for seven days, no significant decrease in the AUCs were observed suggesting the absence of rifampicin induced enzyme auto-induction in this study. The present study suggests an advantage of inhaled delivery of rifampicin in achieving higher drug bioavailability compared to the oral route.

Topics: Administration, Inhalation; Administration, Oral; Animals; Antibiotics, Antitubercular; Area Under Curve; Biological Availability; Dry Powder Inhalers; Extensively Drug-Resistant Tuberculosis; Humans; Male; Models, Animal; Powders; Rats; Rats, Sprague-Dawley; Rifampin; Tuberculosis, Pulmonary

Delays in seeking and accessing treatment for rifampicin-resistant tuberculosis (RR-TB) and multi-drug resistant (MDR-TB) are major impediments to TB control in high-burden, resource-limited settings.. We prospectively determined health-seeking behavioural patterns and associations with treatment outcomes and costs among 68 RR-TB patients attending conveniently selected facilities in a decentralised system in Harare, Zimbabwe.. From initial symptoms to initiation of effective treatment, patients made a median number of three health care visits (IQR 2-4 visits) at a median cost of 13% (IQR 6-31%) of their total annual household income (mean cost, US$410). Cumulatively, RR-TB patients most frequently first visited private facilities, i.e., private pharmacies (30%) and other private health care providers (24%) combined. Median patient delay was 26 days (IQR 14-42 days); median health system delay was 97 days (IQR 30-215 days) and median total delay from symptom onset to initiation of effective treatment was 132 days (IQR 51-287 days). The majority of patients (88%) attributed initial delay in seeking care to "not feeling sick enough." Total delay, total cost and number of health care visits were not associated with treatment or clinical outcomes, though our study was not adequately powered for these determinations.. Despite the public availability of rapid molecular TB tests, patients experienced significant delays and high costs in accessing RR-TB treatment. Active case finding, integration of private health care providers and enhanced service delivery may reduce treatment delay and TB associated costs.

Topics: Adult; Antitubercular Agents; Cost of Illness; Extensively Drug-Resistant Tuberculosis; Female; Humans; Male; Patient Acceptance of Health Care; Rifampin; Zimbabwe

Appropriate technology tests are needed for Mycobacterium tuberculosis drug-susceptibility testing (DST) in resource-constrained settings. This study was performed to evaluate the MDR/XDR-TB Colour Test (a colour platethin-layer agar test; TB-CX) for M. tuberculosis DST by directly testing sputum at University of Gondar Hospital.. Sputum samples were each divided into two aliquots. One aliquot was mixed with disinfectant and applied directly to the TB-CX quadrant petri-plate containing culture medium with and without isoniazid, rifampicin, or ciprofloxacin. Concurrently, the other aliquot was decontaminated with sodium hydroxide, centrifuged, and cultured on Lӧwenstein-Jensen medium; the stored M. tuberculosis isolates were then sub-cultured in BACTEC Mycobacteria Growth Indicator Tube (MGIT) 960 for reference DST.. The TB-CX test yielded DST results for 94% (123/131) of positive samples. For paired DST results, the median number of days from sputum processing to DST was 12 for TB-CX versus 35 for LJ-MGIT (p<0.001). Compared with LJ-MGIT for isoniazid, rifampicin, and multidrug-resistant tuberculosis, TB-CX had 59%, 96%, and 95% sensitivity; 96%, 94%, and 98% specificity; and 85%, 94%, and 98% agreement, respectively. All ciprofloxacin DST results were susceptible by both methods.. The TB-CX test was simple and rapid for M. tuberculosis DST. Discordant DST results may have resulted from sub-optimal storage and different isoniazid concentrations used in TB-CX versus the reference standard test.

Topics: Adolescent; Adult; Antitubercular Agents; Ciprofloxacin; Culture Media; Ethiopia; Extensively Drug-Resistant Tuberculosis; Female; Health Resources; Humans; Isoniazid; Male; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Rifampin; Sensitivity and Specificity; Sputum; Tuberculosis, Multidrug-Resistant; Young Adult

Tuberculosis (TB) remains a main hurdle for national programs due to increase in drug resistance to antitubercular drugs. World Health Organization (WHO)-endorsed Line Probe Assay, Genotype MTBDRsl Ver 2.0, gives opportunity for rapid diagnosis and molecular characterization of different mutations in drug targets of fluoroquinolone (FQ) and second-line injectable drugs (SLID). We, retrospectively, analyzed the data of Genotype MTBDRsl Ver 2.0 from January 2018 to June 2018. A total of 863 isolates of

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Antitubercular Agents; Child; Extensively Drug-Resistant Tuberculosis; Female; Genotype; Humans; India; Isoniazid; Male; Microbial Sensitivity Tests; Middle Aged; Mycobacterium tuberculosis; Retrospective Studies; Rifampin; Sensitivity and Specificity; Tuberculosis, Multidrug-Resistant; Young Adult

Tuberculosis treatment includes broad-spectrum antibiotics such as rifampicin, streptomycin and fluoroquinolones, which are also used against other pathogenic bacteria. We developed Drug Resistance Associated Genes database (DRAGdb), a manually curated repository of mutational data of drug resistance associated genes (DRAGs) across ESKAPE (i.e. Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) pathogens, and other bacteria with a special focus on Mycobacterium tuberculosis (MTB). Analysis of mutations in drug-resistant genes listed in DRAGdb suggested both homoplasy and pleiotropy to be associated with resistance. Homoplasy was observed in six genes namely gidB, gyrA, gyrB, rpoB, rpsL and rrs. For these genes, drug resistance-associated mutations at codon level were conserved in MTB, ESKAPE and many other bacteria. Pleiotropy was exemplified by a single nucleotide mutation that was associated with resistance to amikacin, gentamycin, rifampicin and vancomycin in Staphylococcus aureus. DRAGdb data also revealed that mutations in some genes such as pncA, inhA, katG and embA,B,C were specific to Mycobacterium species. For inhA and pncA, the mutations in the promoter region along with those in coding regions were associated with resistance to isoniazid and pyrazinamide respectively. In summary, the DRAGdb database is a compilation of all the major MTB drug resistance genes across bacterial species, which allows identification of homoplasy and pleiotropy phenomena of DRAGs.

Topics: Antitubercular Agents; Bacterial Proteins; Data Curation; Databases, Genetic; DNA, Bacterial; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Fluoroquinolones; Isoniazid; Microbial Sensitivity Tests; Mutation; Mycobacterium tuberculosis; Pyrazinamide; Rifampin; Sequence Analysis, DNA; Tuberculosis, Multidrug-Resistant

A population pharmacokinetic (PopPK) model for pretomanid was developed using data from 14 studies in the pretomanid development program: six phase 1 studies, six phase 2 studies, and two phase 3 studies. The final analysis data set contained 17,725 observations from 1,054 subjects, including healthy subjects and subjects with drug-sensitive, multidrug-resistant, or extensively drug-resistant pulmonary tuberculosis dosed pretomanid in monotherapy or combination therapy for up to 6 months. Pretomanid pharmacokinetic behavior was described by a one-compartment model that at a given dose was linear in its absorption and clearance processes but where the rate of absorption and extent of bioavailability changed with dose. Clearance and volume of distribution scaled allometrically with weight. Apparent clearance in females was 18% less than in males. Among HIV-positive subjects, absent the effect of CYP3A4-inducing antiretrovirals, apparent clearance was 6% higher. Some effects of total bilirubin and albumin were found, but the impacts on exposure were small. Bioavailability in the fasted condition was about half that in the fed condition. Relative bioavailability decreased with increasing dose in the fasted condition, but not for doses of ≤200 mg in the fed condition. HIV-positive subjects taking efavirenz and lopinavir/ritonavir had exposures that were reduced by 46 and 17%, respectively. There was little evidence for noteworthy effects of regimen partners on pretomanid. Standard diagnostics indicated that the model described the voluminous, diverse data well, so that the model could be used to generate exposure metrics for exposure/response analyses to be reported elsewhere.

Topics: Antitubercular Agents; Biological Availability; Clinical Trials as Topic; Extensively Drug-Resistant Tuberculosis; Female; HIV Infections; Humans; Lopinavir; Male; Nitroimidazoles; Rifampin; Ritonavir; Tuberculosis, Multidrug-Resistant; Tuberculosis, Pulmonary

South Africa ranks among the highest drug-resistant tuberculosis (DR-TB) burdened countries in the world. This study assessed the changes in resistance levels in culture confirmed. This study was conducted at the central academic laboratory of the KwaZulu-Natal province of South Africa.. We analysed data for all MTB cultures performed in the KwaZulu-Natal province between 2011 and 2014. The data were collected from the laboratory information system.. Out of 88 559 drug susceptibility results analysed, 18 352 (20.7%) were resistant to rifampicin (RIF) and 19 190 (21.7%) showed resistance to isoniazid (INH). The proportion of rifampicin resistant cases that were mono-resistant increased from 15.3% in 2011 to 21.4% in 2014 while INH mono-resistance (IMR) showed a range between 13.8% and 21.1%. The multidrug-resistant tuberculosis (MDR-TB) rates increased from 18.8% to 23.9% and the proportion of MDR-TB cases that had extensively drug-resistant tuberculosis remained between 10.2% and 11.1%. Most drug resistance was found in females between the ages of 15 and 44 years and the northern districts bordering high MDR-TB regions had the highest MDR-TB rates.. Our findings show increasing RIF mono-resistance (RMR) and a substantial amount of IMR. This highlights a need for an initial test that detects resistance to both these drugs so as to avoid using RIF monotherapy during continuous phase of treatment in patients with IMR. Furthermore, addition of INH will benefit patients with RMR. Although DR-TB is widespread, HIV and migration influence its distribution; therefore, TB control strategies should include interventions that target these aspects.

Topics: Adolescent; Adult; Antitubercular Agents; Extensively Drug-Resistant Tuberculosis; Female; Humans; Isoniazid; Male; Mycobacterium tuberculosis; Retrospective Studies; Rifampin; South Africa; Tuberculosis, Multidrug-Resistant; Young Adult

Active extrusion of antituberculosis drugs via efflux pumps (EPs) has been suggested as contributing to drug resistance in Mycobacterium tuberculosis. This study was conducted to determine the role of 10 drug efflux transporters in the development of drug resistance in a series of clinical M. tuberculosis isolates.. A total of 31 clinical M. tuberculosis isolates without drug exposure [21 multi/extensively drug-resistant (M/XDR-TB) and 10 drug-susceptible isolates] were studied. The expression profile of 10 EP genes, including efpA, mmr, stp, drrA, drrB, mmpL7, Rv1250, Rv1634, Rv2994 and Rv1258c, was investigated against the H37Rv standard strain by quantitative reverse transcription PCR (RT-qPCR).. Among the 21M/XDR-TB isolates, 10 showed significantly increased levels of gene expression (>4-fold) for at least one of the studied EPs. Moreover, of the isolates with overexpressed genes, three and seven lacked genetic alterations in the surveyed regions of the rpoB+katG+inhA and katG+inhA genes, respectively. Whilst no elevation was observed in the expression of mmr, Rv1250, Rv1634 and Rv1258c genes in any of the isolates, drrA, stp and drrB were found to be the most commonly overexpressed, being overexpressed in seven, five and three isolates, respectively. Decreased minimum inhibitory concentrations (MICs) of rifampicin, but not isoniazid, were observed in the presence of the efflux pump inhibitor carbonyl cyanide 3-chlorophenylhydrazone (CCCP).. Overexpression of EP genes can contribute to the emergence of a MDR phenotype in M. tuberculosis. Inhibition of EPs may provide a promising strategy for improving tuberculosis treatment outcomes in patients infected with M/XDR-TB isolates.

Topics: Antitubercular Agents; Bacterial Proteins; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Gene Expression Regulation, Bacterial; Humans; Hydrazones; Isoniazid; Membrane Transport Proteins; Microbial Sensitivity Tests; Mutation; Mycobacterium tuberculosis; Rifampin; Transcriptome

Tajikistan is among the 30 countries with the highest multidrug-resistant tuberculosis (MDR-TB) burden.. To investigate the risk factors for unfavourable treatment outcomes among rifampicin-resistant (RR)/MDR-TB patients.. Retrospective medical chart review of RR/MDR-TB patients enrolled for treatment in 2012-2013.. Of 601 RR/MDR-TB patients, 58 (9.7%) had pre-extensively drug-resistant TB (pre-XDR-TB; i.e., MDR-TB with additional resistance to a fluoroquinolone or second-line injectable agent) and 45 (8%) had XDR-TB (MDR-TB with additional resistance to both). Treatment failure and death were reported in respectively 40 (7%) and 89 (15%) cases; 60 (10%) patients were lost to follow-up (LTFU). In multivariable analysis, treatment failure was associated with pre-XDR-TB (adjusted odds ratio [aOR] 3.67, 95%CI 1.47-9.18) or XDR-TB (aOR 8.61, 95%CI 3.48-21.34). Death was associated with age >45 years vs. <25 years (aOR 3.47, 95%CI 1.68-7.19) and no record of any adverse event during treatment (aOR 2.55, 95%CI 1.48-4.39). Changing place of residence during treatment was an independent predictor of LTFU (aOR 4.61, 95%CI 2.41-8.8).. Our findings highlight the need for 1) the use of regimens with new anti-tuberculosis drugs; 2) good handover of TB patients and 3) effective tracing mechanisms if patients change a place of residence to prevent LTFU.

Topics: Adult; Antitubercular Agents; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Female; Humans; Male; Middle Aged; Retrospective Studies; Rifampin; Risk Factors; Tajikistan; Treatment Failure; Treatment Outcome; Tuberculosis, Multidrug-Resistant; Young Adult

Understanding why some multidrug-resistant tuberculosis cases are not detected by rapid phenotypic and genotypic routine clinical tests is essential to improve diagnostic assays and advance toward personalized tuberculosis treatment. Here, we combine whole-genome sequencing with single-colony phenotyping to identify a multidrug-resistant strain that had infected a patient for 9 years. Our investigation revealed the failure of rapid testing and genome-based prediction tools to identify the multidrug-resistant strain. The false-negative findings were caused by uncommon rifampicin and isoniazid resistance mutations. Although whole-genome sequencing data helped to personalize treatment, the patient developed extensively drug-resistant tuberculosis, highlighting the importance of coupling new diagnostic methods with appropriate treatment regimens.

Topics: Antitubercular Agents; Bacterial Proteins; Diagnostic Errors; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Genome, Bacterial; Genotype; Humans; Isoniazid; Microbial Sensitivity Tests; Mutation; Mycobacterium tuberculosis; Rifampin; Sequence Analysis, DNA; Tuberculosis, Multidrug-Resistant; Whole Genome Sequencing

Topics: Antitubercular Agents; Bacterial Typing Techniques; Cohort Studies; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Genome, Bacterial; Genotype; Humans; Kanamycin; Levofloxacin; Microbial Sensitivity Tests; Moxifloxacin; Mycobacterium tuberculosis; Phenotype; Rifampin; Tuberculosis, Multidrug-Resistant; Whole Genome Sequencing

To evaluate the performance of nitrate reductase assay on smear positive pulmonary specimens for detection of multi and extensively drug resistant tuberculosis simultaneously.. Cross-sectional analytical study.. Microbiology Department, Armed Forces Institute of Pathology, Rawalpindi from June to December 2016.. Smear positive pulmonary samples were processed both by nitrate reductase method on Lowenstein Jenson medium and also inoculated on gold standard Bactec MGIT 960 TB system. All the specimens were first digested and decontaminated according to standard protocol before inoculation.. Out of total 76 samples, three did not give color and, therefore, were excluded from the final data analysis. Among the remaining 73 samples, mycobacterial index was: 28 specimens were having 1+ (1-9 bacilli/100 fields), 26 samples were 2+ (1-9 bacilli/ field), and 19 samples were having 3+ index (>9 bacilli/field). The respective sensitivity and specificity were 84% and 100% for isoniazid (INH); 82% and 100% for rifampin (RIF); 67% and 100% for amikacin (AK); and both 100% for ofloxacin (OFX). Overall agreement in case of INH, RIF, AK, and OFX was 94.5%, 97.2%, 98.6% and100%, respectively. Overall average agreement was 97.5%.. Nitrate reductase assay is a reliable, low cost and accurate method that can be used for early for diagnosis of multi and extensively drug resistant tuberculosis.

Topics: Amikacin; Antitubercular Agents; Cross-Sectional Studies; Drug Resistance, Multiple, Bacterial; Early Diagnosis; Extensively Drug-Resistant Tuberculosis; Humans; Isoniazid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Nitrate Reductase; Predictive Value of Tests; Rifampin; Sensitivity and Specificity; Sputum; Tuberculosis, Multidrug-Resistant

This study aimed to describe trends in antituberculosis drug prescribing for inpatients from 2011-2015 in a Chinese national tuberculosis (TB) hospital.. This retrospective study, performed in March 2016, reviewed the medical records of all inpatients from Beijing Chest Hospital diagnosed with TB between 2011-2015. Medication used for TB treatment during the inpatient period was recorded.. A total of 11465 inpatients were enrolled in the study. The most frequently prescribed drug for inpatients was isoniazid (71.2%; 8164/11465), followed by ethambutol (67.5%; 7738/11465), pyrazinamide (59.7%; 6839/11465) and rifampicin (40.0%; 4589/11465). In addition, amikacin (16.5%; 1889/11465), levofloxacin (33.0%; 3789/11465), para-aminosalicylic acid (12.4%; 1422/11465) and clarithromycin (3.5%; 406/11465) were the most common drugs used in the treatment of inpatients for Group II, III, IV and V drugs, respectively. A significant increasing trend in prescribing was found for rifampicin, pyrazinamide, capreomycin, moxifloxacin, prothionamide, para-aminosalicylic acid, cycloserine, clofazimine and linezolid, respectively, whilst there was a significant decreasing trend in the rate of prescribing of ethambutol, amikacin, levofloxacin, amoxicillin/clavulanic acid and clarithromycin during the 5-year study period (P. These data demonstrate that prescription of anti-TB drugs varied greatly across clinical diagnostic categories, treatment history and drug susceptibility profiles of TB patients. The World Health Organization (WHO)-endorsed standard regimen should be more extensively employed under conditions where drug susceptibility testing is unavailable in order to guide clinicians to formulate a suitable treatment regimen for TB patients.

Topics: Antitubercular Agents; China; Drug Prescriptions; Extensively Drug-Resistant Tuberculosis; Hospitals, Chronic Disease; Humans; Inpatients; Isoniazid; Linezolid; Medical Records; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Retrospective Studies; Rifampin

Topics: Antitubercular Agents; Emigrants and Immigrants; Extensively Drug-Resistant Tuberculosis; Humans; Italy; Mycobacterium tuberculosis; Rifampin; Tuberculosis, Multidrug-Resistant

Topics: Antibiotics, Antitubercular; Antitubercular Agents; Extensively Drug-Resistant Tuberculosis; Humans; Isoniazid; Mycobacterium tuberculosis; Rifampin; Tuberculosis, Multidrug-Resistant

Emergence of multidrug- and extensively drug-resistant tuberculosis (M/XDR-TB) is a major hurdle for TB control programs especially in developing countries like China. Resistance to fluoroquinolones is high among MDR-TB patients. Early diagnosis of MDR/pre-XDR-TB is essential for lowering transmission of drug-resistant TB and adjusting the treatment regimen.. Smear-positive sputum specimens (n = 186) were collected from Wuhan Institute for Tuberculosis Control. The DNA was extracted from the specimens and run through a Sanger sequencing assay to detect mutations associated with MDR/pre-XDR-TB including the rpoB core region for rifampicin (RIF) resistance; katG and inhA promoter for isoniazid (INH) resistance; and gyrA for fluoroquinolone (FQ) resistance. Sequencing data were compared to phenotypic Lowenstein-Jensen (L-J) proportion method drug susceptibility testing (DST) results for performance analysis.. By comparing the mutation data with phenotypic results, the detection rates of MDR-TB and pre-XDR-TB were 84.31% (43/51) and 83.33% (20/24), respectively. The sequencing assay illustrated good sensitivity for the detection of resistance to RIF (96.92%), INH (86.89%), FQ (77.50%). The specificities of the assay were 98.35% for RIF, 99.20% for INH, and 97.26% for FQ.. The sequencing assay is an efficient, accurate method for detection of MDR-TB and pre-XDR-TB from clinical smear-positive sputum specimens, should be considered as a supplemental method for obtaining early DST results before the availability of phenotypic DST results. This could be of benefit to early diagnosis, adjusting the treatment regimen and controlling transmission of drug-resistant TB.

Topics: Amino Acid Substitution; Antitubercular Agents; Bacterial Proteins; China; Early Diagnosis; Extensively Drug-Resistant Tuberculosis; Fluoroquinolones; Humans; Isoniazid; Microbial Sensitivity Tests; Mutation; Mycobacterium tuberculosis; Promoter Regions, Genetic; Rifampin; Sensitivity and Specificity; Sequence Analysis, DNA; Sputum; Tuberculosis, Multidrug-Resistant

The worldwide emergence of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) has posed additional challenges for global tuberculosis (TB) control efforts, as limited treatment options are available and treatment outcomes are often sub-optimal. This study determined treatment outcomes among a cohort of MDR-TB and XDR-TB patients in Hunan Province, China, and identified factors associated with poor treatment outcomes.. We conducted a retrospective study using data obtained from medical records of TB patients in Hunan Chest Hospital, and from the internet-based TB management information system managed by the Tuberculosis Control Institute of Hunan Province, for the period 2011 to 2014. Treatment outcomes were assessed for patients diagnosed with MDR-TB (TB resistant to at least isoniazid and rifampicin) and XDR-TB (MDR-TB plus resistance to any fluoroquinolone and at least 1 second-line injectable drug). Cumulative incidence functions were used to estimate time to events (i.e. poor treatment outcomes, loss to follow-up, and unfavourable treatment outcomes); and a competing-risks survival regression model was used to identify predictors of treatment outcomes.. Of 481 bacteriologically-confirmed patients, with a mean age of 40 years (standard deviation SD ± 13 years), 10 (2%) had XDR-TB and the remainder (471; 98%) had MDR-TB. For the entire cohort, treatment success was 57% (n = 275); 58% (n = 272) for MDR-TB and 30% (n = 3) for XDR-TB. Overall, 27% were lost to follow-up (n = 130), 27% (n = 126) for MDR-TB and 40% (n = 4) for XDR-TB; and 16% had a poor treatment outcome (n = 76), 15% for MDR-TB and 30% (n = 3) for XDR-TB. Of the 10 XDR-TB patients, 3 (30%) completed treatment, 3 (30%) died and 4 (40%) were lost to follow-up. Of the 471 MDR-TB patients, 258 (57%) were cured, 16 (3%) completed treatment, 13 (3%) died, 60 (13%) experienced treatment failure, and 126 (27%) were lost to follow-up. Resistance to ofloxacin was an independent predictor of poor (AHR = 3.1; 95%CI = 1.5, 6.3), and unfavourable (AHR = 1.7; 95%CI = 1.07, 2.9) treatment outcomes. Patients who started treatment during 2011-2012 (AHR = 2.8; 95% CI = 1.5, 5.3) and 2013 (AHR = 2.1; 95% CI = 1.2, 3.9) had poorer treatment outcomes compared to patients who started treatment during 2014.. Patients with MDR-TB and XDR-TB had low rates of treatment success in Hunan Province, especially among patients who started treatment during 2011 to 2013, with evidence of improved treatment outcomes in 2014. Resistance to ofloxacin was an independent predictor of poor treatment outcomes.

Topics: Adult; Antitubercular Agents; China; Cohort Studies; Extensively Drug-Resistant Tuberculosis; Female; Fluoroquinolones; Humans; Isoniazid; Lost to Follow-Up; Male; Middle Aged; Ofloxacin; Retrospective Studies; Rifampin; Treatment Failure; Treatment Outcome; Tuberculosis, Multidrug-Resistant

xtra-pulmonary tuberculosis (EPTB) is a growing public health concern, and data on drug resistance are limited.. Specimens from 2468 clinically diagnosed EPTB patients received at the Intermediate Reference Laboratory (IRL) of a tertiary centre in India were subjected to Ziehl-Neelsen staining, Xpert® MTB/RIF testing, liquid culture and drug susceptibility testing (DST) using automated BACTEC MGIT™ 960™. Line-probe assay (LPA) was performed on all culture-positive isolates. Gene sequencing was performed on rifampicin-resistant/multidrug-resistant TB (RR/MDR-TB) and phenotypic/genotypic discrepant isolates.. The culture positivity rate was 18.9% (483/2553). The sensitivity and specificity of Xpert in diagnosing EPTB were respectively 70.8% (95%CI 66.5-74.8) and 97.7% (95%CI 96.9-98.3), with liquid culture as the reference standard. Prevalence of RR/MDR-TB was 10.1% (49/483). Prevalence of pre-extensively drug-resistant TB (pre-XDR-TB) was 18.4% (09/49), whereas the prevalence of XDR-TB among MDR-TB patients was 2% (01/49). The sensitivity of genotypic DST for the detection of rifampicin resistance was 92.7% (95%CI 81.1-98.5) and specificity was 99.3% (95%CI 97.5-99.9), with 100% concordance between Xpert and LPA.. The burden of drug resistance, including M/XDR-TB, among EPTB patients is high. Novel molecular tests can help in early diagnosis and treatment to prevent disease progression and amplification of resistance.

Topics: Adult; Antitubercular Agents; Drug Resistance, Bacterial; Early Diagnosis; Extensively Drug-Resistant Tuberculosis; Female; Genotype; Humans; India; Male; Microbial Sensitivity Tests; Middle Aged; Mycobacterium tuberculosis; Prevalence; Rifampin; Sensitivity and Specificity; Tertiary Care Centers; Tuberculosis, Multidrug-Resistant; Young Adult

We evaluated the performance of two multiplex, real-time PCR tests (Anyplex II MTB/MDR and MTB/XDR; Seegene, Seoul, Korea), designed to detect the Mycobacterium tuberculosis complex (MTC) and drug-resistance mutations associated with isoniazid, rifampicin, fluoroquinolones, and second-line injectable drugs. We analyzed 122 clinical isolates with the Anyplex II MTB/MDR test, 68 of which were also tested with the Anyplex II MTB/XDR test. The Anyplex II MTB/MDR and MTB/XDR tests showed the following respective sensitivities and specificities: 68.8% and 100% for detecting isoniazid resistance, 93.8% and 100% for rifampicin, 82.8% and 100% for levofloxacin, 75.0% and 100% for kanamycin, and 92.6% and 100% for MTC identification. These kits correctly identified 61.8% of multi-drug resistant M. tuberculosis isolates and 64.7% of extensively drug-resistant M. tuberculosis isolates, and enabled semi-automatic detection of drug-resistant MTC in 3 hours. The Anyplex II kits could be useful as rule-in tests for detecting MTC and drug resistance.

Topics: Antitubercular Agents; DNA, Bacterial; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Fluoroquinolones; Humans; Isoniazid; Kanamycin; Levofloxacin; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Reagent Kits, Diagnostic; Real-Time Polymerase Chain Reaction; Rifampin; Sensitivity and Specificity; Seoul; Sequence Analysis, DNA; Tuberculosis, Multidrug-Resistant

Europe has the highest documented caseload and greatest increase in multidrug and extensively drug-resistant tuberculosis (M/XDR-TB) of all World Health Organization (WHO) regions. This survey examines how recommendations for M/XDR-TB management are being implemented.. TBNET is a pan-European clinical research collaboration for tuberculosis. An email survey of TBNET members collected data in relation to infection control, access to molecular tests and basic microbiology with drug sensitivity testing.. 68/105 responses gave valid information and were from countries within the WHO European Region. Inpatient beds matched demand, but single rooms with negative pressure were only available in low incidence countries; ultraviolet decontamination was used in 5 sites, all with >10 patients with M/XDR-TB per year. Molecular tests for mutations associated with rifampicin resistance were widely available (88%), even in lower income and especially in high incidence countries. Molecular tests for other first line and second line drugs were less accessible (76 and 52% respectively). A third of physicians considered that drug susceptibility results were delayed by > 2 months.. Infection control for inpatients with M/XDR-TB remains a problem in high incidence countries. Rifampicin resistance is readily detected, but tests to plan regimens tailored to the drug susceptibilities of the strain of Mycobacterium tuberculosis are significantly delayed, allowing for further drug resistance to develop.

Topics: Antitubercular Agents; Decontamination; Developing Countries; Drug Resistance, Bacterial; Europe; Extensively Drug-Resistant Tuberculosis; Humans; Infection Control; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Patient Isolation; Rifampin; Surveys and Questionnaires; Tuberculosis, Multidrug-Resistant; Ultraviolet Rays

Several infectious diseases of global importance-e.g., HIV infection and tuberculosis (TB)-require prolonged treatment with combination antimicrobial regimens typically involving high-potency core agents coupled with additional companion drugs that protect against the

Topics: Antitubercular Agents; Bayes Theorem; Biological Availability; Computer Simulation; Drug Administration Schedule; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Fluoroquinolones; Humans; Microbial Sensitivity Tests; Models, Statistical; Mycobacterium tuberculosis; Pyrazinamide; Rifampin; Tuberculosis, Pulmonary

Rifampin has been a cornerstone of tuberculosis (TB) treatment since its introduction. The rise of multidrug-resistant and extensively drug-resistant TB makes the development of novel therapeutics effective against these strains an urgent need. Site-specific mutations in the target enzyme of rifampin, RNA polymerase (RNAP) comprises the majority (~97%) of rifamycin-resistant (Rif

Topics: Antitubercular Agents; Aptamers, Nucleotide; Bacterial Proteins; Biological Assay; DNA-Directed RNA Polymerases; Drug Discovery; Drug Resistance, Bacterial; Escherichia coli; Extensively Drug-Resistant Tuberculosis; Gene Expression; High-Throughput Screening Assays; Humans; Microbial Sensitivity Tests; Mutation; Mycobacterium tuberculosis; Plasmids; Rifampin; Rifamycins; Small Molecule Libraries; Structure-Activity Relationship

Topics: Anti-Retroviral Agents; Antitubercular Agents; Communicable Disease Control; Drug Interactions; Drug Therapy, Combination; Extensively Drug-Resistant Tuberculosis; Humans; Infectious Disease Medicine; Models, Theoretical; Pulmonary Medicine; Rifampin; Tuberculosis; Tuberculosis, Pulmonary

In Vietnam, a country with high tuberculosis (137/100.000 population) and multidrug-resistant (MDR)-TB burdens (7.8/100.000 population), little is known about the molecular signatures of drug resistance in general and more particularly of second line drug (SLD) resistance. This study is specifically focused on Mycobacterium tuberculosis isolates resistant to four first-line drugs (FLDs) that make TB much more difficult to treat. The aim is to determine the proportion of SLD resistance in these quadruple drug resistant isolates and the genetic determinants linked to drug resistance to better understand the genetic processes leading to quadruple and extremely drug resistance (XDR). 91 quadruple (rifampicin, isoniazid, ethambutol and streptomycin) FLD resistant and 55 susceptible isolates were included. Spoligotyping and 24-locus MIRU-VNTR techniques were performed and 9 genes and promoters linked to FLD and SLD resistance were sequenced. SLD susceptibility testing was carried out on a subsample of isolates. High proportion of quadruple-FLD resistant isolates was resistant to fluoroquinolones (27%) and second-line injectable drugs (30.2%) by drug susceptibility testing. The sequencing revealed high mutation diversity with prevailing mutations at positions katG315, inhA-15, rpoB531, embB306, rrs1401, rpsL43 and gyrA94. The sensitivity and specificity were high for most drug resistances (>86%), but the sensitivity was lower for injectable drug resistances (<69%). The mutation patterns revealed 23.1% of pre-XDR and 7.7% of XDR isolates, mostly belonging to Beijing family. The genotypic diversity and the variety of mutations reflect the existence of various evolutionary paths leading to FLD and SLD resistance. Nevertheless, particular mutation patterns linked to high-level resistance and low fitness costs seem to be favored.

Topics: Antitubercular Agents; Bacterial Proteins; Bacterial Typing Techniques; Catalase; DNA Gyrase; DNA-Directed RNA Polymerases; Drug Resistance, Multiple, Bacterial; Ethambutol; Extensively Drug-Resistant Tuberculosis; Gene Expression; Genetic Fitness; Genetic Variation; Humans; Isoniazid; Mutation; Mycobacterium tuberculosis; Oxidoreductases; Pentosyltransferases; Ribosomal Proteins; Rifampin; Streptomycin; Vietnam

Current diagnostic tools for Mycobacterium tuberculosis (Mtb) have many disadvantages including low sensitivity, slow turnaround times, or high cost. Accurate, easy to use, and inexpensive point of care molecular diagnostic tests are urgently needed for the analysis of multidrug resistant (MDR) and extensively drug resistant (XDR) Mtb strains that emerge globally as a public health threat. In this study, we established proof-of-concept for a novel diagnostic platform (TB-DzT) for Mtb detection and the identification of drug resistant mutants using binary deoxyribozyme sensors (BiDz). TB-DzT combines a multiplex PCR with single nucleotide polymorphism (SNP) detection using highly selective BiDz sensors targeting loci associated with species typing and resistance to rifampin, isoniazid and fluoroquinolone antibiotics. Using the TB-DzT assay, we demonstrated accurate detection of Mtb and 5 mutations associated with resistance to three anti-TB drugs in clinical isolates. The assay also enables detection of a minority population of drug resistant Mtb, a clinically relevant scenario referred to as heteroresistance. Additionally, we show that TB-DzT can detect the presence of unknown mutations at target loci using combinatorial BiDz sensors. This diagnostic platform provides the foundation for the development of cost-effective, accurate and sensitive alternatives for molecular diagnostics of MDR- and XDR-TB.

Topics: Biosensing Techniques; DNA, Catalytic; Extensively Drug-Resistant Tuberculosis; Humans; Isoniazid; Microbial Sensitivity Tests; Multiplex Polymerase Chain Reaction; Mutation; Mycobacterium tuberculosis; Polymorphism, Single Nucleotide; Rifampin; Tuberculosis, Multidrug-Resistant

Efflux inhibition is proven bacterial machinery responsible for removal of bacterial wastage including antibiotics. Recently, efflux inhibitors (EI) have been tested with encouraging results as an adjuvant therapy for treatment of tuberculosis (TB). Although, EI have emerged as innovative approach of treatment for multi drug resistant (MDR) & extensively drug resistant tuberculosis (XDR-TB), toxicity profile limits their wider use. To address this issue, we have attempted synthesizing hybrid molecules those results by combining known EI and triazole. This synthesis was aimed to arrive at structure that possesses pharmacophore from known EI. Synthesized molecules were evaluated as growth inhibitors (GI) and Efflux inhibitor of TB initially against Mycobacterium smegmatis mc(2)155. Pharmacologically active compounds were then tested for their cytotoxicity to further narrow down search. Most active compounds 144, 145, 154 and 163 were then tested for their GEI action against Mycobacterium tuberculosis (Mtb). Synthesized compounds were also tested for their synergistic action with first line and second line anti-TB drugs and ethidium bromide (EtBr). We arrived at compound 135 as most potent dual inhibitor of tuberculosis.

Topics: Antitubercular Agents; Cells, Cultured; Chemistry Techniques, Synthetic; Drug Design; Drug Evaluation, Preclinical; Drug Synergism; Extensively Drug-Resistant Tuberculosis; Humans; Macrophages; Microbial Sensitivity Tests; Mycobacterium smegmatis; Mycobacterium tuberculosis; Triazoles

To identify the mutations in multi- and extensively drug-resistant tuberculosis isolates and to evaluate the use of molecular markers of resistance, we analyzed 257 multi- and extensively drug-resistant isolates and 64 pan-sensitive isolates from 23 provinces in China. Seven loci associated with drug resistance, including rpoB for rifampin (RIF), katG, inhA and oxyR-ahpC for isoniazid (INH), gyrA and gyrB for ofloxacin (OFX), and rrs for kanmycin (KAN), were examined by DNA sequencing. Compared with the phenotypic data, the sensitivity and specificity for DNA sequencing were 91.1% and 98.4% for RIF, 80.2% and 98.4% for INH, 72.2% and 98.3% for OFX and 40% and 98.2% for KAN, respectively. The most common mutations found in RIF, INH, OFX and KAN resistance were Ser531Leu (48.2%) in rpoB, Ser315Thr (49.8%) in katG, C(-15)T (10.5%) in inhA, Asp94Gly (20.3%), Asp94Ala (12.7%) and Ala90Val (21.5%) in gyrA, and A1401G (40%) in rrs. This molecular information will be helpful to establish new molecular biology-based methods for diagnosing multi- and extensively drug-resistant tuberculosis in China.

Topics: Antitubercular Agents; Bacterial Proteins; Catalase; China; DNA-Directed RNA Polymerases; DNA, Bacterial; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Genes, Bacterial; Genetic Loci; Humans; Isoniazid; Mycobacterium tuberculosis; Ofloxacin; Oxidoreductases; Rifampin; Sequence Analysis, DNA

Developing a fast, inexpensive, and specific test that reflects the mutations present in Mycobacterium tuberculosis isolates according to geographic region is the main challenge for drug-resistant tuberculosis (TB) control. The objective of this study was to develop a molecular platform to make a rapid diagnosis of multidrug-resistant (MDR) and extensively drug-resistant TB based on single nucleotide polymorphism (SNP) mutations present in therpoB, katG, inhA,ahpC, and gyrA genes from Colombian M. tuberculosis isolates. The amplification and sequencing of each target gene was performed. Capture oligonucleotides, which were tested before being used with isolates to assess the performance, were designed for wild type and mutated codons, and the platform was standardised based on the reverse hybridisation principle. This method was tested on DNA samples extracted from clinical isolates from 160 Colombian patients who were previously phenotypically and genotypically characterised as having susceptible or MDR M. tuberculosis. For our method, the kappa index of the sequencing results was 0,966, 0,825, 0,766, 0,740, and 0,625 forrpoB, katG, inhA,ahpC, and gyrA, respectively. Sensitivity and specificity were ranked between 90-100% compared with those of phenotypic drug susceptibility testing. Our assay helps to pave the way for implementation locally and for specifically adapted methods that can simultaneously detect drug resistance mutations to first and second-line drugs within a few hours.

Topics: Antibiotics, Antitubercular; Colombia; DNA, Bacterial; Extensively Drug-Resistant Tuberculosis; Fluoroquinolones; Gene Amplification; Humans; Isoniazid; Molecular Diagnostic Techniques; Mutation; Mycobacterium tuberculosis; Nucleic Acid Hybridization; Polymorphism, Single Nucleotide; Rifampin; Sequence Analysis, DNA; Tuberculosis, Multidrug-Resistant

Although molecular tests for drug-resistant TB perform well on culture isolates, their accuracy using clinical samples, particularly from TB and HIV-endemic settings, requires clarification. The MTBDRplus and MTBDRsl line probe assays were evaluated in 181 sputum samples and 270 isolates from patients with culture-confirmed drug-sensitive-TB, MDR-TB, or XDR-TB. Phenotypic culture-based testing was the reference standard. Using sputum, the sensitivities for resistance was 97.7%, 95.4%, 58.9%, 61.6% for rifampicin, isoniazid, ofloxacin, and amikacin, respectively, whereas the specificities were 91.8%, 89%, 100%, and 100%, respectively. MTBDRsl sensitivity differed in smear-positive vs. smear-negative samples (79.2% vs. 20%, p < 0.0001 for ofloxacin; 72.9% vs. 37%, p = 0.0023 for amikacin) but not by HIV status. If used sequentially, MTBDRplus and MTBDRsl could rule-in XDR-TB in 78.5% (22/28) and 10.5% (2/19) of smear-positive and smear-negative samples, respectively. On culture isolates, the sensitivity for resistance to rifampicin, isoniazid, ofloxacin, and amikacin was 95.1%, 96.1%, 72.3% and 76.6%, respectively, whereas the specificities exceeded 96%. Using a sequential testing approach, rapid sputum-based diagnosis of fluoroquinolone or aminoglycoside-resistant TB is feasible only in smear-positive samples, where rule-in value is good. Further investigation is required in samples that test susceptible in order to rule-out second-line drug resistance.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Antitubercular Agents; Biological Assay; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Female; Follow-Up Studies; Humans; Male; Middle Aged; Mycobacterium tuberculosis; Prognosis; Rifampin; Sputum; Young Adult

Topics: Amikacin; Antitubercular Agents; Capreomycin; Extensively Drug-Resistant Tuberculosis; Fluoroquinolones; Humans; India; Isoniazid; Kanamycin; Medication Adherence; Mycobacterium tuberculosis; Nonprescription Drugs; Rifampin; Tuberculosis, Multidrug-Resistant

Jiangxi, China.. To evaluate the performance of the direct nitrate reductase assay (D-NRA) for rapid, low-cost detection of multidrug-resistant (MDR-) and extensively drug-resistant tuberculosis (XDR-TB) in high-burden, resource-limited settings.. A total of 225 smear-positive sputum samples were collected from consecutive drug-resistant TB subjects. Samples were processed at the Province TB Reference Laboratory and tested for susceptibility to rifampicin (RMP), isoniazid (INH), ofloxacin (OFX), kanamycin (KM) and capreomycin (CPM) by D-NRA, using the indirect Löwenstein-Jensen proportion method (LJ-PM) as reference.. Of the 225 smear-positive sputum samples, 214 isolates were identified as Mycobacterium tuberculosis and analysed for further comparison. The sensitivity of the D-NRA in the detection of resistance to RMP, INH, OFX, KM and CPM was respectively 95.1% (97/102), 93.1% (135/145), 97.4% (76/78), 88.9% (40/45) and 90.6% (29/32); specificity was respectively 100% (112/112), 97.1% (67/69), 100% (136/136), 98.8% (167/169) and 96.7% (176/182). The median time to culture positivity was significantly shorter for NRA than for the indirect LJ-PM (14 days vs. 70 days, P < 0.001).. D-NRA showed high sensitivity and specificity in the rapid diagnosis of MDR- and XDR-TB in a high-burden, resource-limited setting.

Topics: Adult; Capreomycin; China; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Female; Humans; Isoniazid; Kanamycin; Male; Middle Aged; Mycobacterium tuberculosis; Nitrate Reductase; Ofloxacin; Prospective Studies; Rifampin; Sensitivity and Specificity; Sputum

GeneXpert MTB/RIF (Xpert) and Genotype MTBDRplus (DRplus) are two World Health Organization (WHO) endorsed probe based molecular drug susceptibility testing (DST) methods for rapid diagnosis of drug resistant tuberculosis. Both methods target the same 81 bp Rifampicin Resistance Determining Region (RRDR) of bacterial RNA polymerase β subunit (rpoB) for detection of Rifampicin (RIF) resistance associated mutations using DNA probes. So there is a correspondence of the probes of each other and expected similarity of probe binding.. We analyzed 92 sputum specimens by Xpert, DRplus and LJ proportion method (LJ-DST). We compared molecular DSTs with gold standard LJ-DST. We wanted to see the agreement level of two molecular methods for detection of RIF resistance associated mutations. The 81bp RRDR region of rpoB gene of discrepant cases between the two molecular methods was sequenced by Sanger sequencing.. The agreement of Xpert and DRplus with LJ-DST for detection of RIF susceptibility was found to be 93.5% and 92.4%, respectively. We also found 92.4% overall agreement of two molecular methods for the detection of RIF susceptibility. A total of 84 out of 92 samples (91.3%) had agreement on the molecular locus of RRDR mutation by DRplus and Xpert. Sanger sequencing of 81bp RRDR revealed that Xpert probes detected seven of eight discrepant cases correctly and DRplus was erroneous in all the eight cases.. Although the overall concordance with LJ-DST was similar for both Xpert and DRplus assay, Xpert demonstrated more accuracy in the detection of RIF susceptibility for discrepant isolates compared with DRplus. This observation would be helpful for the improvement of probe based detection of drug resistance associated mutations especially rpoB mutation in M. tuberculosis.

Topics: Antitubercular Agents; Bacterial Proteins; DNA Mutational Analysis; DNA Probes; DNA-Directed RNA Polymerases; Drug Resistance, Bacterial; Extensively Drug-Resistant Tuberculosis; Humans; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Rifampin; Sputum

The increasing incidence of multidrug-resistant tuberculosis (MDR-TB) infections has created a need for new effective drugs that also target extensively drug-resistant tuberculosis (XDR-TB) and/or augment the activities of existing drugs against tuberculosis.. This study searched natural products for a new lead compound that targets MDR/XDR-TB.. An active compound was purified from the roots of Cynanchum atratum Bunge (Asclepiadaceae) after screening 1640 plant extracts, and its inhibitory effects against MDR/XDR strains and synergistic effects with existing anti-TB drugs were assessed using the resazurin, MGIT, and checkboard assays.. (-)-Deoxypergularinine, purified from the roots of C. atratum, inhibited not only M. tuberculosis but also MDR/XDR strains. The minimum inhibitory concentrations (MICs) of (-)-deoxypergularinine for H37Ra, H37Rv, MDR, and XDR strains were all about 12.5 µg/ml. Moreover, combinations of (-)-deoxypergularinine with the first-line standard drugs rifampicin or isoniazid afforded six- and eight-fold reductions in drug MIC values, respectively, against strain H37Ra.. (-)-Deoxypergularinine exerts anti-tubercular activities not only against normal tuberculosis strains but also MDR/XDR strains, and synergic effects with rifampicin and isoniazid for the H37Ra strain. The alkaloid may be valuable for targeting M/XDR M. tuberculosis.

Topics: Antitubercular Agents; Cynanchum; Drug Resistance, Multiple, Bacterial; Drug Synergism; Extensively Drug-Resistant Tuberculosis; Isoniazid; Isoquinolines; Microbial Sensitivity Tests; Molecular Structure; Mycobacterium tuberculosis; Plant Extracts; Plant Roots; Rifampin

New diagnostic methods have provided a promising solution for rapid and reliable detection of drug-resistant TB strains. The aim of this study was to evaluate the performance of the MeltPro TB assay in identifying multidrug-resistant (MDR-) and extensively drug-resistant tuberculosis (XDR-TB) patients from sputum samples. The MeltPro TB assay was evaluated using sputum samples from 2057 smear-positive TB patients. Phenotypic Mycobacterial Growth Indicator Tube (MGIT) 960 drug susceptibility testing served as a reference standard. The sensitivity of the MeltPro TB assay was 94.2% for detecting resistance to rifampicin and 84.9% for detecting resistance to isoniazid. For second-line drugs, the assay showed a sensitivity of 83.3% for ofloxacin resistance, 75.0% for amikacin resistance, and 63.5% for kanamycin resistance. However, there was a significant difference for detecting kanamycin resistance between the two pilot sites in sensitivity, which was 53.2% in Guangdong and 81.5% in Shandong (P = 0.015). Overall, the MeltPro TB assay demonstrated good performance for the detection of MDR- and XDR-TB, with a sensitivity of 86.7% and 71.4%, respectively. The MeltPro TB assay is an excellent alternative for the detection of MDR- and XDR-TB cases in China, with high accuracy, short testing turn-around time, and low unit price compared with other tests.

Topics: Amikacin; China; Extensively Drug-Resistant Tuberculosis; Humans; Kanamycin; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Ofloxacin; Rifampin; Sensitivity and Specificity; Sputum; Tuberculosis, Multidrug-Resistant

Pre-extensively drug resistant (pre-XDR) and extensively drug resistant tuberculosis (XDR-TB) have been areas of growing concern, and are posing threat to global efforts of TB control. The present study was planned to study the presence of pre-XDR and XDR Mycobacterium tuberculosis and their genotypes in clinical isolates obtained from previously treated cases of pulmonary TB.. A total of 219 isolates obtained from previously treated cases of pulmonary TB were subjected to first-line (streptomycin, isoniazid, rifampicin and ethambutol) and second-line (ofloxacin, kanamycin, capreomycin and amikacin) drug susceptibility testing on solid Lowenstein-Jensen medium by proportion method. Genotyping was done for pre-XDR and XDR-TB isolates using 12 loci Mycobacterial Interspersed Repetitive Units-Variable Number Tandem Repeats (MIRU-VNTR).. Multi-drug resistance was observed in 39.7 per cent (87/219) isolates. pre-XDR and XDR M. tuberculosis isolates amongst 87 multi-drug resistant (MDR) TB isolates were 43 (49.4%) and 10 (11.4%), respectively. Two most dominant genotypes among pre-XDR and XDR M. tuberculosis isolates were Beijing and Delhi/CAS types.. Resistance to second-line anti-tubercular drugs should be routinely assessed in areas endemic for TB. Similar genotype patterns were seen in pre-XDR and XDR-TB isolates. Beijing and Delhi/CAS were predominant genotypes.

Topics: Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Genotype; Humans; India; Isoniazid; Kanamycin; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Ofloxacin; Rifampin; Tuberculosis, Multidrug-Resistant

In order to detect the in vitro synergistic effect of 4 drugs-pasiniazid (PA), moxifloxacin, rifabutin and rifapentini on multidrug-resistant mycobacterium tuberculosis (MDR-MTB) and extensively drug-resistant mycobacterium tuberculosis(XDR-MTB), which were core drugs of"The program of retreatment research of tuberculosis".. The checkerboard method was used to detect the minimum inhibitory concentration (MIC) of antituberculosis drug combination schemes (moxifloxacin-PA, moxifloxacin-PA-rifabutin and moxifloxacin-PA-rifapentini) to 40 strains of clinical drug resistant MTB(20 strains of MDR-MTB and 20 XDR-MTB) and the standard strain H37Rv, by calculating the fractional inhibitory concentration index of joint action in vitro to judge the combined effect, with fractional inhibitory concentration index(FICI)≤0.5 and FICI≤0.75 as the basis of 2 drugs and 3 drugs showing synergy.. The FICI of moxifloxacin-PA scheme for DR-MTB was 0.125 to 1.000, only 5 strains with a FICI ≤0.5, showing synergistic effect. The FICI of moxifloxacin-Pa-rifabutin scheme with 20 strains of MDR-MTB ranged from 0.310 to 1.260, 10 strains with a FICI≤0.75, showing synergistic effect. The FICI of moxifloxacin-PA-rifabutin scheme with 20 strains of XDR-MTB ranged from 0.215 to 1.250, 11 strains with a FICI≤0.75, showing synergistic effect. The FICI of moxifloxacin-PA-rifapentini scheme with 20 strains of MDR-MTB ranged from 0.150 to 0.780, 19 strains with a FICI≤0.75, showing synergistic effect. The FICI of moxifloxacin-PA-rifapentini scheme with 20 strains of XDR-MTB ranged from 0.200 to 1.280, 16 strains with a FICI≤0.75, showing synergistic effect.. The synergistic effect of moxifloxacin-PA scheme was poor, but showing better synergy when further combined with rifabutin or rifapentini. Rifabutin showed better effect than rifapentini, but the synergistic effect of moxifloxacin-PA-rifabutin combination scheme was poor than that of moxifloxacin-PA-rifapentini combination scheme.

Topics: Aminosalicylic Acids; Antibiotics, Antitubercular; Drug Synergism; Drug Therapy, Combination; Extensively Drug-Resistant Tuberculosis; Fluoroquinolones; Isoniazid; Microbial Sensitivity Tests; Moxifloxacin; Mycobacterium tuberculosis; Retreatment; Rifabutin; Rifampin; Tuberculosis, Multidrug-Resistant

Topics: Adolescent; Antitubercular Agents; Bacteriological Techniques; Child; Child, Preschool; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Humans; India; Infant; Mycobacterium tuberculosis; Rifampin; Sensitivity and Specificity

Genotypic molecular testing may be very helpful for tuberculosis (TB) drug-resistance surveillance and for treatment guidance in low resource settings.. Descriptive analysis of M. tuberculosis isolates from Beira Central Hospital, Mozambique, during 2014-2015. Genotype MTBDRplus and MTBDRsl were used and patient medical records reviewed. To explore genotypic susceptibility profile of Mycobacterium tuberculosis, to first and second line drugs (SLD) in Beira Mozambique.. Of 155 isolates, 16.1 % (25) were multidrug resistant (MDR), 8.4 % (13) isoniazid-monoresistant and 1.3 % (2) rifampicin-monoresistant. Among MDR-TB, 22.2 % showed primary and 77.8 % represented acquired resistance. The majority of patients with drug resistance had a history of previous TB treatment. Among 125 isolates tested for ethambutol and SLD, 7.2 % (9) were resistant to ethambutol, 4.8 % (6) to fluoroquinolones and 0.8 % (1) to ethambutol and fluoroquinolones. Resistance to injectable SLD was not detected.. As far as we know this is the first report of a genotypic testing used to provide information about SLD resistance in Mozambique, where phenotypic susceptibility testing is usually unavailable. Extensively drug resistant TB was not detected in this isolates from Beira Mozambique.

Topics: Adult; Antitubercular Agents; Drug Resistance, Bacterial; Ethambutol; Extensively Drug-Resistant Tuberculosis; Female; Fluoroquinolones; Genotype; Humans; Isoniazid; Male; Microbial Sensitivity Tests; Mozambique; Mycobacterium tuberculosis; Rifampin; Tuberculosis, Multidrug-Resistant; Tuberculosis, Pulmonary

Rapid molecular diagnostics, with their ability to quickly identify genetic mutations associated with drug resistance in Mycobacterium tuberculosis clinical specimens, have great potential as tools to control multi- and extensively drug-resistant tuberculosis (M/XDR-TB). The Qiagen PyroMark Q96 ID system is a commercially available pyrosequencing (PSQ) platform that has been validated for rapid M/XDR-TB diagnosis. However, the details of the assay's diagnostic and technical performance have yet to be thoroughly investigated in diverse clinical environments.. This study evaluates the diagnostic performance of the PSQ assay for 1128 clinical specimens from patients from three areas of high TB burden. We report on the diagnostic performance of the PSQ assay between the three sites and identify variables associated with poor PSQ technical performance.. In India, the sensitivity of the PSQ assay ranged from 89 to 98 % for the detection of phenotypic resistance to isoniazid, rifampicin, fluoroquinolones, and the injectables. In Moldova, assay sensitivity ranged from 7 to 94 %, and in South Africa, assay sensitivity ranged from 71 to 92 %. Specificity was high (94-100 %) across all sites. The addition of eis promoter sequencing information greatly improved the sensitivity of kanamycin resistance detection in Moldova (7 % to 79 %). Nearly all (89.4 %) sequencing reactions conducted on smear-positive, culture-positive specimens and most (70.8 %) reactions conducted on smear-negative, culture-positive specimens yielded valid PSQ reads. An investigation into the variables influencing sequencing failures indicated smear negativity, culture negativity, site (Moldova), and sequencing of the rpoB, gyrA, and rrs genes were highly associated with poor PSQ technical performance (adj. OR > 2.0).. This study has important implications for the global implementation of PSQ as a molecular TB diagnostic, as it demonstrates how regional factors may impact PSQ diagnostic performance, while underscoring potential gene targets for optimization to improve overall PSQ assay technical performance.. ClinicalTrials.gov ( #NCT02170441 ). Registered 12 June 2014.

Topics: Antitubercular Agents; Extensively Drug-Resistant Tuberculosis; Fluoroquinolones; Genes, Bacterial; Humans; Isoniazid; Kanamycin; Kanamycin Resistance; Microbial Sensitivity Tests; Molecular Diagnostic Techniques; Molecular Typing; Mutation; Mycobacterium tuberculosis; Promoter Regions, Genetic; Rifampin; Sensitivity and Specificity; Sequence Analysis, DNA

Topics: Adult; Amikacin; Aminosalicylic Acid; Anti-Bacterial Agents; Antitubercular Agents; Bronchoscopy; Clofazimine; Depression; Drug Costs; Emigrants and Immigrants; Ethambutol; Extensively Drug-Resistant Tuberculosis; Fluoroquinolones; Health Care Costs; Humans; India; Isoniazid; Linezolid; Male; Mediastinum; Microbial Sensitivity Tests; Moxifloxacin; New Zealand; Pyrazinamide; Radiography, Thoracic; Rifampin; Schizophrenia, Paranoid; Tuberculosis, Lymph Node; Tuberculosis, Multidrug-Resistant; Tuberculosis, Pleural; Tuberculosis, Pulmonary

In South Africa, drug resistant tuberculosis is a major public health crisis in the face of the colossal HIV pandemic.. In an attempt to understand the distribution of drug resistance in our setting, we analysed the rpoB, katG, inhA, pncA and embB genes associated with resistance to key drugs used in the treatment of tuberculosis in clinical isolates of Mycobacterium tuberculosis in the KwaZulu-Natal province.. Classical mutations were detected in the katG, inhA and embB genes associated with resistance to isoniazid and ethambutol. Diverse mutations were recorded in the multidrug resistant (MDR) and extensively drug resistant (XDR) isolates for the rpoB and pncA gene associated with resistance to rifampicin and pyrazinamide.. M.tuberculosis strains circulating in our setting display a combination of previously observed mutations, each mediating resistance to a different drug. The MDR and XDR TB isolates analysed in this study displayed classical mutations linked to INH and EMB resistance, whilst diverse mutations were linked to RIF and PZA resistance. The similarity of the XDR strains confirms reports of the clonality of the XDR epidemic. The successful dissemination of the drug resistant strains in the province underscores the need for rapid diagnostics to effectively diagnose drug resistance and guide treatment.

Topics: Amidohydrolases; Antitubercular Agents; Bacterial Proteins; Catalase; Drug Resistance, Multiple, Bacterial; Ethambutol; Extensively Drug-Resistant Tuberculosis; Humans; Isoniazid; Mutation; Mycobacterium tuberculosis; Oxidoreductases; Pentosyltransferases; Polymorphism, Restriction Fragment Length; Pyrazinamide; Rifampin; South Africa; Tuberculosis, Multidrug-Resistant

Direct sputum smear microscopy is commonly used for diagnosing tuberculosis (TB). The objectives of the study were first, to determine the recovery of Mycobacterium tuberculosis in smear-negative sputum samples through liquid culture (using MGIT 960) and solid culture (using LJ slant) and second, to screen multidrug-resistant isolates through line probe assay and further third, to identify XDR isolates through MGIT second-line DST from these positive MDR cultures in Delhi region.. In this study, the sample size was 717 (sputum smear AFB negative and culture positive for M. tuberculosis complex by both solid and liquid culture methods) MDRTB suspects who were enrolled from January 2014 to December 2014 at the Intermediate Reference Laboratory in New Delhi Tuberculosis Centre, New Delhi. Rapid line probe assay was performed on all culture-positive samples, which were direct smear-negative specimens, and LPA-confirmed MDR samples were tested on MGIT 960 second-line DST for identification of XDR strains.. An overall increase in the culture positivity (9.4%) among these smear-negative cases shows a good sign of recovery from M. tuberculosis infection in these samples. 717 (9.4%) positive cultures (MGIT+LJ) were subjected to line probe assay. Out of these 717 cultures, 9 (1.2%) were confirmed as NTM, 50 (7%) were MDR, 4 (0.6%) were mono-rifampicin resistant and 654 (91.2%) cultures were sensitive to both drugs Rif and Inh, respectively. Out of these 54 (50 MDR +4 mono-RIF resistant) cultures as screened by LPA, 1 (1.8%) was XDR, 10 (18.6%) were mono-ofloxacin resistant and 1 (1.8%) was mono-Kanamycin resistant. Sensitivity to both drugs KAN and OFX was seen in 42 (77.8%) cultures.. Since the bacterial load in direct smear-negative suspected MDR samples is less, it is important to recover mycobacteria by rapid liquid culture method in such samples. Initial screening for MDRTB is to be done in such cases by performing rapid molecular genotypic drug susceptibility test such as LPA. Baseline second-line DST is also done to rule out the XDR cases among them for rapid and better management of XDRTB patients.

Topics: Antitubercular Agents; Bacterial Typing Techniques; Extensively Drug-Resistant Tuberculosis; Humans; India; Isoniazid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Rifampin; Sputum

The recent approval of new tuberculosis (TB) drugs raises hope for new and more effective anti-tuberculosis treatment regimens. The Global Alliance for TB Drug Development (TB Alliance) is committed to ensuring that new anti-tuberculosis drugs fulfill the needs of patients, their families and the local health services that serve the communities. Here we present highlights of the TB Alliance's pipeline of regimen development, with novel regimens for patients with drug-susceptible, multidrug-resistant and extensively drug-resistant TB. The ongoing clinical trials (STAND, NC-005, Nix-TB and LIN-CL001) are outlined and their rationale and goals presented.

Topics: Antitubercular Agents; Clinical Protocols; Diarylquinolines; Dose-Response Relationship, Drug; Ethambutol; Extensively Drug-Resistant Tuberculosis; Fluoroquinolones; Humans; Isoniazid; Linezolid; Moxifloxacin; Nitroimidazoles; Pyrazinamide; Randomized Controlled Trials as Topic; Research Design; Rifampin; Tuberculosis, Multidrug-Resistant

A high-throughput screening effort on 45,000 compounds resulted in the discovery of a disubstituted oxazole as a new structural class inhibitor of Mycobacterium tuberculosis (Mtb). In order to improve the activity and investigate the SAR of this scaffold, a series of disubstituted azole analogues have been designed and synthesized. The newly synthesized compounds 1a-y were evaluated for their in vitro anti-TB activity versus replicating, multi- and extensive drug resistant Mtb strains. All the compounds, except 1o, 1p and 1q, showed potent anti-TB activity with MIC of 1-64 mg/L. The test of broad spectrum panel revealed that this series are specific to Mtb. The cytotoxicity assessment indicated that the compounds were not cytotoxic against HEK 293 cells. The compounds could have a novel mechanism to anti-Mtb as they can inhibit drug sensitive and drug resistant Mtb.

Topics: Antitubercular Agents; Dioxanes; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; HEK293 Cells; Humans; Mycobacterium tuberculosis; Oxazoles; Structure-Activity Relationship

Tuberculosis currently belongs to rare respiratory diseases in Slovakia. However, the emergence and spread of multi-drug resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) are major challenges for global tuberculosis control, since the treatment of resistant forms creates both medical and financial problems. Cultivation methods of diagnosis are time-consuming, many times exceeding the time of the initial phase of tuberculosis treatment. Therefore, in the presented study we compared the standard procedures, based on the cultivation of mycobacteria and subsequent drug susceptibility testing to antituberculotics, with molecular-genetic methods using PCR diagnostic kits. The molecular-genetic testing enables to obtain direct and fast evidence of Mycobacterium tuberculosis, with genomic verification of resistance to the most important anti-tuberculosis drugs - isoniazid and rifampicin in MDR-TB, and ethambutol, aminoglycosides, and fluoroquinolones in XDR-TB. In 2012-2013, we confirmed 19 cases of drug-resistant tuberculosis in Slovakia. The resistance to rifampicin was confirmed in all strains with both methods. In two cases, the molecular-genetic testing did not show resistance to isoniazid, as confirmed by conventional cultivation. Furthermore, two strains demonstrating susceptibility in conventional microbiological testing to ethambutol and five strains to fluoroquinolones were verified as actually being resistant using a PCR method. Rapid diagnosis and identification of MDR-TB or XDR-TB strains using molecular-genetic testing is an essential tool for the timely and appropriate drug treatment and prevention of spread of drug resistant strains.

Topics: Aminoglycosides; Antitubercular Agents; Culture Media; DNA, Bacterial; Drug Resistance, Multiple, Bacterial; Ethambutol; Extensively Drug-Resistant Tuberculosis; Fluoroquinolones; Genotype; Humans; Isoniazid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Polymerase Chain Reaction; Rifampin; Slovakia; Tuberculosis, Pulmonary

Tuberculosis (TB) is a devastating infectious disease causing high mortality and morbidity worldwide. The most serious threat related to tuberculosis control is the recent emergence of drug-resistant tuberculosis strains. The aim of the present study was to identify various types of mutations in the rpoB region in rifampicin-resistant strains isolated from sputum of tuberculosis patients.. Drug susceptibility of 125 Mycobacterium tuberculosis isolates was determined using the CDC standard conventional proportional method. Target DNA of M. tuberculosis was amplified by polymerase chain reaction, hybridized, and scanned. We used the low cost density array (LCD-array) to detect mutations within the 90-bp rpoB region. Each array is a transparent, prestructured polymer support using a nonfluorescent detection principle based on the precipitation of a clearly visible dark substrate.. Of the 125 M. tuberculosis isolates, 35 (28%) were found to be rifampicin-resistant and using the LCD array revealed point mutations at nine different codons as follows: S512T (AGC→ACC) (20%), D516V (GAC→GTC) (20%), H526D (CAC→GAC) (6%), H526R (CAC→CGC) (20%), H526Y (CAC→TAC) (23%), and S531W (TCG→TGG) (8%), and the most frequent site mutations were L511P (CCG→CTG) (46%), followed by S531l (TCG→TTG) (40%) and D516Y (GAC→TAC) (26%).. Our data significantly differs from previously reported mutation frequencies for codon 526 (CAC to GAC) among Italian isolates (40.1%) and Greek isolates (17.6%). Phenotypic testing is time-consuming and requires laboratory resources. Microarray rpoB is useful in detecting rifampicin resistance-determining region-associated site mutations of rifampicin-resistant M. tuberculosis isolates.

Topics: Adult; Antitubercular Agents; Bacterial Proteins; Codon; DNA-Directed RNA Polymerases; Drug Resistance, Bacterial; Extensively Drug-Resistant Tuberculosis; Female; Gene Expression; Humans; Incidence; Iran; Male; Microbial Sensitivity Tests; Middle Aged; Mutation Rate; Mycobacterium tuberculosis; Oligonucleotide Array Sequence Analysis; Polymerase Chain Reaction; Rifampin; Sputum; Tuberculosis, Pulmonary

Extensively drug-resistant tuberculosis (XDR-TB) is a serious worldwide problem. The REBA MTB-XDR (REBA-XDR) was recently developed in Korea to detect resistance to ofloxacin, kanamycin, and streptomycin. The aim of this study is to evaluate the diagnostic accuracy of the REBA-XDR. We prospectively enrolled 104 patients with acid-fast bacilli smear-positive specimens between July 2010 and January 2013. Performance characteristics were compared between REBA-XDR and conventional drug-susceptibility testing. The sensitivity values of REBA-XDR for detecting resistance to ofloxacin, kanamycin, and streptomycin were 66.7%, 90.9%, and 60.0%, and the specificity values were 93.3%, 93.5%, and 85.4%, respectively. The positive predictive values were 62.5%, 62.5%, and 40.9%, and the negative predictive values were 94.3%, 98.9%, and 92.7%, respectively. Accuracy was 89.4%, 93.3%, and 81.7%, respectively. REBA-XDR seems to be a useful kit for "ruling in" XDR-TB in intermediate-burden countries, and especially useful for detecting kanamycin resistance.

Topics: Adult; Anti-Bacterial Agents; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Female; Genes, MDR; Humans; Isoniazid; Kanamycin; Male; Microbial Sensitivity Tests; Middle Aged; Mycobacterium tuberculosis; Ofloxacin; Predictive Value of Tests; Republic of Korea; Rifampin; Sputum; Streptomycin

Multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of Mycobacterium tuberculosis (TB) constitute a major public health concern.. To determine the timing of pncA mutations that confer pyrazinamide (PZA) resistance in relation to mutations conferring resistance to isoniazid (INH) and rifampicin (RMP).. Isolates from two major urban centres--Paris (101 strains) and Shanghai (171 strains)--were investigated for the association of pncA mutations with resistance to drugs other than PZA.. The proportion of pncA mutations found in INH-monoresistant strains was not increased.. pncA mutations associated with PZA resistance were found almost exclusively in MDR-TB strains, underlining the importance of determining PZA resistance when treating MDR- or XDR-TB.

Topics: Amidohydrolases; Antitubercular Agents; China; DNA Mutational Analysis; DNA, Bacterial; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Fluoroquinolones; Gene Frequency; Genotype; Humans; Microbial Sensitivity Tests; Mutation; Mycobacterium tuberculosis; Paris; Phenotype; Pyrazinamide; Rifampin; Tuberculosis, Multidrug-Resistant

The Supranational Tuberculosis Reference Laboratory (NTRL), Bangkok, and Chiangrai Prachanukroh Hospital, Chiangrai, Thailand. To evaluate the diagnostic performance of newly developed line-probe assay (LiPA) kits in tuberculosis (TB) endemic settings.. LiPA kits were used to evaluate 404 clinical isolates of Mycobacterium species and 163 sputum samples in Thailand.. LiPA kits were able to identify M. tuberculosis, M. avium, M. intracellulare and M. kansasii with 100% sensitivity and specificity when compared with the commercially available AccuProbe assay. Testing of the LiPA kits for their ability to detect mutations in clinical isolates resistant to anti-tuberculosis drugs such as rifampicin, isoniazid, pyrazinamide and fluoroquinolones showed that the assay had very high sensitivity (65.9-100%) and specificity (98.2-100%) compared with drug susceptibility testing and DNA sequencing. LiPA had a sensitivity of 75.0-85.7% and a specificity of 96.4-100% in testing clinical sputum samples.. The novel LiPA kits have high sensitivity and specificity, and may enhance the rapid detection of first- and second-line anti-tuberculosis drug resistance, improving the selection of suitable chemotherapy agents to treat multidrug-resistant and extensively drug-resistant TB.

Topics: Antibiotics, Antitubercular; Extensively Drug-Resistant Tuberculosis; Fluoroquinolones; Genotype; Humans; Isoniazid; Microbial Sensitivity Tests; Mutation; Mycobacterium tuberculosis; Pyrazinamide; Reagent Kits, Diagnostic; Rifampin; Sensitivity and Specificity; Sputum; Thailand

Rifampicin (RMP) has been reported to reduce moxifloxacin (MFX) levels, which may interfere with the effectiveness of MFX in treating tuberculosis (TB).. To study the MFX-RMP interaction in patients receiving MFX with or without RMP as part of their anti-tuberculosis treatment regimen.. Patients with pulmonary TB followed up by the Tuberculosis Out-patient Clinic of the Pulmonary Department, Aristotle University of Thessaloniki, Greece, who underwent treatment with MFX during the periods 1 May 2012-30 April 2014 and 1 January-31 March 2015, were included in the study. MFX levels were compared between 12 patients who were receiving RMP (Group 1) and 10 who were not (Group 2).. The participants did not significantly differ in body mass index, days of MFX treatment or MFX dose/kg. Neither the peak concentration (Cmax) nor the 24 h area under the curve (AUC24) differed significantly between the two groups (Group 1, Cmax median 3.9 [range 1.9-4.5] mg/l; AUC24 29.1 [10-47.4] mg·h/l and Group 2, Cmax 4.1 [2-6.4] mg/l; AUC24 36.5 [14.6-54.2] mg·h/l).. Although a decrease in MFX exposure was observed in the RMP-treated group, the effect was lower than previously reported in a real-life setting. The large variability observed in MFX pharmacokinetics in both groups may suggest the need for dose readjustment in some patients, regardless of RMP co-administration.

Topics: Adult; Aged; Antitubercular Agents; Drug Interactions; Drug Therapy, Combination; Extensively Drug-Resistant Tuberculosis; Female; Fluoroquinolones; Greece; Humans; Isoniazid; Male; Middle Aged; Moxifloxacin; Outpatients; Rifampin; Tuberculosis, Pulmonary

Rifampicin (RIF) and isoniazid (INH) Mycobacterium tuberculosis isolates were characterized from south-central China and transmission patterns within the Beijing genotype were detected in multidrug-resistant isolates. Six genetic regions, including rpoB for RIF, and katG, inhA, ahpC, mabA-inhA promoter and oxyR-ahpC intergenic region for INH were analyzed by DNA sequencing in 60 multidrug-resistant isolates, including 7 extensively drug-resistant isolates. The genomic deletion RD105 was characterized by genotyping. The results showed that 91.7% of MDR isolates carried mutations in the rpoB gene and 85.0% of the MDR isolates had at least one mutation in the INH resistance-associated loci detected. In total, these six genetic regions are responsible for 95.0% of MDR isolates. Mutations in the XDR isolates were focused on rpoB 531 or rpoB 526, and katG 315, correlating to a higher frequency level of resistance to RIF MIC ⩾8 μg ml⁻¹ and INH MIC ⩾4 μg m⁻¹. Three novel katG mutants (G273S, I266T and P232S) and three new alleles (E458A, S509R and P535S) in the rpoB gene were identified. Among the 85 clinical isolates, 78 are Beijing genotypes and the other 7 are non-Beijing genotypes. The results present the identification of genetic markers in M. tuberculosis isolates, some of which may be unique to this particular geographic niche. An understanding of the mutations in these drug-resistant strains may aid in choosing the appropriate chemotherapy regimens on the pharmacogenetic properties of the mutations for the prevention and control of tuberculosis.

Topics: Academic Medical Centers; Alleles; Amino Acid Substitution; Antitubercular Agents; Bacterial Proteins; Catalase; China; DNA-Directed RNA Polymerases; DNA, Intergenic; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Humans; Isoniazid; Microbial Sensitivity Tests; Molecular Typing; Mutation; Mycobacterium tuberculosis; Prevalence; Promoter Regions, Genetic; Rifampin; Tuberculosis, Pulmonary

The First Affiliated Hospital of Nanchang University and the Chest Hospital of Jiangxi Province, Jiangxi, China.. To assess the performance and feasibility of the microscopic observation drug susceptibility (MODS) assay for the simultaneous detection of multidrug-resistant (MDR) and extensively drug-resistant tuberculosis (XDR-TB) in a high-burden, resource-limited setting.. A total of 208 archived clinical isolates of Mycobacterium tuberculosis were used to compare MODS with the conventional proportion method for the rapid detection of resistance to rifampicin (RMP) and isoniazid (INH), as well as to the second-line drugs ofloxacin (OFX) and kanamycin (KM).. Sensitivity was respectively 94.5%, 91%, 96.2% and 91.5% for RMP, INH, OFX and KM, and specificity was respectively 97.5%, 96%, 100% and 98.7%. Results for MODS were obtained in a median time of 7 days (range 5-17).. The MODS assay offers a simple, rapid, economical and feasible method for the detection of M. tuberculosis resistance to first- and second-line drugs in resource-limited settings.

Topics: Antitubercular Agents; Bacteriological Techniques; China; DNA Mutational Analysis; DNA, Bacterial; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Feasibility Studies; Humans; Kanamycin; Microbial Sensitivity Tests; Microscopy; Mutation; Mycobacterium tuberculosis; Ofloxacin; Patient Selection; Predictive Value of Tests; Rifampin; Time Factors

The spread of multidrug-resistant (MDR) and extensively drug-resistant (XDR) Mycobacterium tuberculosis compromises effective control of tuberculosis (TB) in Siberia. Early identification of drug-resistant isolates is, therefore, crucial for effective treatment of this disease. The aim of this study was to conduct drug susceptibility testing and identify mutations in drug resistance genes in clinical isolates of M. tuberculosis from some TB patients presenting for treatment in Siberia.. Thirty randomly selected clinical isolates of M. tuberculosis were obtained from the Novosibirsk Research Institute of Tuberculosis, Russia. Isolates were screened for drug resistance and characterized by variable number of tandem repeats (VNTR)-typing using 15 standard and four additional loci. Deligotyping on multiple large sequences was performed using 10 loci.. Twenty-nine of the isolates were assigned XDR status. Twenty-eight isolates belonged to the M. tuberculosis Beijing family, from which 11 isolates were considered the M11 type (39%), two the M2 type (7%), and one the M33 type (3%). Seventeen isolates (60.7%) from this family exhibited unique genetic patterns. The remaining two isolates belonged to the Latino-American Mediterranean family. Gene sequences (rpoB, katG, rrs, rpsL, tlyA, gidB, gyrA, gyrB) were analyzed to identify mutations that confer resistance to rifampicin, isoniazid, amikacin, kanamycin, capreomycin, and ofloxacin. The most common mutations among the XDR isolates were S531L in RpoB, S315T in KatG, various codon 94 mutations in gyrA, A90V in GyrA, K43R in RpsL, and 1401 A → G in rrs; these confer resistance to rifampicin, isoniazid, ofloxacin, streptomycin and kanamycin/capreomycin, respectively. There was high congruence between the two typing methods (VNTR typing and deligotyping) and RD105, RD149, RD152, RD181, and RD207 regions of difference were absent from the 28 Beijing family isolates.. Deligotyping can be used for rapid and reliable screening of M. tuberculosis isolates, followed by more in-depth genotyping. Identification of Beijing family isolates with extensive drug resistance confirms that such strains have epidemiological importance in Siberia. Rapid detection of mutations that lead to drug resistance should facilitate selection of effective drug therapies, and the development of early prevention strategies to combat this infection.

Topics: Adult; Amikacin; Antitubercular Agents; Capreomycin; Cross-Sectional Studies; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Female; Genotype; Humans; Isoniazid; Male; Microbial Sensitivity Tests; Middle Aged; Minisatellite Repeats; Mutation; Mycobacterium tuberculosis; Ofloxacin; Rifampin; Siberia; Tuberculosis; Young Adult

Dr Cetrángolo Hospital, Buenos Aires, Argentina.. To characterise drug-resistant (DR), multidrug-resistant (MDR-) and extensively drug-resistant (XDR-) Mycobacterium tuberculosis isolates, and identify their genetic profiles, drug resistance levels and resistance-conferring mutations.. Phenotypic drug susceptibility testing methods were used to determine drug resistance profiles. Minimal inhibitory concentrations (MICs) of isoniazid (INH), rifampicin (RMP) and levofloxacin (LVX) from 169 DR tuberculosis (TB) isolates, 78 of them monoresistant to INH, 13 to RMP, 7 to LVX, and 71 MDR-TB, were determined. Multiplex allele-specific polymerase chain reaction and DNA sequencing were used to detect mutations in katG, rpoB and gyrA/B genes. Genotyping was performed using spoligotyping and insertion sequence 6110 restriction fragment length polymorphism.. In total, 38.9% of the INH-resistant (INH(R)) isolates had an MIC ≥ 32 g/ml; 61.3% of RMP-resistant (RMP(R)) isolates had an MIC ≥ 64 g/ml and 55.6% of the LVX-resistant (LVX(R)) isolates had an MIC 4 ≥ 16 g/ml. The main mutations found in INH(R) isolates were katG315 (53.7%) and inhAP-15 (25.5%), whereas in RMP(R) isolates the main mutations were rpoB531 (61.9%), followed by rpoB526 (16.7%). LVX(R) isolates showed mutations in gyrA94/90. Haarlem, LAM and T were the main spoligotyping families found. katG315 was mainly associated with Haarlem and LAM, whereas inhAP-15 was associated with T.. Several isolates showed an association between high INH(R) levels and katG mutation; others from the Haarlem family were prone to becoming MDR-TB and continue to circulate in the community.

Topics: Antitubercular Agents; Argentina; Bacterial Typing Techniques; DNA, Bacterial; Drug Resistance, Bacterial; Extensively Drug-Resistant Tuberculosis; Genotype; Humans; Isoniazid; Levofloxacin; Microbial Sensitivity Tests; Mutation; Mycobacterium tuberculosis; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Rifampin; Sequence Analysis, DNA; Tuberculosis; Tuberculosis, Multidrug-Resistant

Multidrug-resistant tuberculosis (MDR-TB) is posing a great threat to global TB control. The burden in Zambia is not well defined because routine surveillance data are scarce. We reviewed national MDR-TB data for the last decade to inform future public health policy with respect to MDR-TB in Zambia.. Retrospective review of national surveillance of MDR-TB data, TB programme and laboratory reports between 2000 and 2011.. The total number of DSTs performed during this 11-year period was 2,038 and accounted for 2.6% (2,038/78,639) of all the retreatment cases notified. The total number of diagnosed MDR-TB cases for this period was 446, of which 56.3% (251/446) were male and 41.7% (186/446) female. Only one child was found to have MDR-TB. Poly-drug resistance accounted for 18.9% (172/911) of the DR-TB cases and 8.4% of the total DSTs. 8.8% (80/911) of the DR-TB cases showed either rifampicin mono- or poly-resistance other than MDR-TB. No XDR-TB was reported. There were no data available on DR-TB and HIV co-infection. Only 65 MDR-TB patients were notified and put on second-line treatment according to WHO guidelines.. Multidrug-resistant tuberculosis may be an emerging challenge in Zambia. There is a need to invest in improving the capacity of the TB programme to detect and manage MDR-TB.

Topics: Adult; Antibiotics, Antitubercular; Antitubercular Agents; Child; Disease Management; Extensively Drug-Resistant Tuberculosis; Female; HIV Infections; Humans; Incidence; Male; Population Surveillance; Retrospective Studies; Rifampin; Sex Factors; Tuberculosis, Multidrug-Resistant; Zambia

Extensively drug-resistant tuberculosis (XDR-tuberculosis) is a global public health threat, but few data exist elucidating factors driving this epidemic. The initial XDR-tuberculosis report from South Africa suggested transmission is an important factor, but detailed epidemiologic and molecular analyses were not available for further characterization.. We performed a retrospective, observational study among XDR-tuberculosis patients to identify hospital-associated epidemiologic links. We used spoligotyping, IS6110-based restriction fragment-length polymorphism analysis, and sequencing of resistance-determining regions to identify clusters. Social network analysis was used to construct transmission networks among genotypically clustered patients.. Among 148 XDR-tuberculosis patients, 98% were infected with human immunodeficiency virus (HIV), and 59% had smear-positive tuberculosis. Nearly all (93%) were hospitalized while infectious with XDR-tuberculosis (median duration, 15 days; interquartile range: 10-25 days). Genotyping identified a predominant cluster comprising 96% of isolates. Epidemiologic links were identified for 82% of patients; social network analysis demonstrated multiple generations of transmission across a highly interconnected network.. The XDR-tuberculosis epidemic in Tugela Ferry, South Africa, has been highly clonal. However, the epidemic is not the result of a point-source outbreak; rather, a high degree of interconnectedness allowed multiple generations of nosocomial transmission. Similar to the outbreaks of multidrug-resistant tuberculosis in the 1990s, poor infection control, delayed diagnosis, and a high HIV prevalence facilitated transmission. Important lessons from those outbreaks must be applied to stem further expansion of this epidemic.

Topics: Adult; Antitubercular Agents; Cluster Analysis; Cross Infection; Drug Therapy, Combination; Ethambutol; Extensively Drug-Resistant Tuberculosis; Female; Genotype; HIV Infections; Hospitals, Rural; Humans; Isoniazid; Male; Mutation; Mycobacterium tuberculosis; Polymorphism, Restriction Fragment Length; Prevalence; Pyrazinamide; Retrospective Studies; Rifampin; Sequence Analysis, DNA; South Africa

India with a major burden of multidrug-resistant tuberculosis (MDR-TB) does not have national level data on this hazardous disease. Since 2006, emergence of extensively drug-resistant TB (XDR-TB) is considered a serious threat to global TB control. This study highlights the demographic and clinical risk factors associated with XDR-TB in Delhi.. The study was conducted during April 2007 to May 2010. Six hundred eleven MDR-TB suspects were enrolled from four tertiary care hospitals, treating TB patients in Delhi and the demographic details recorded. Sputum samples were cultured using rapid, automated liquid culture system (MGIT 960). Drug susceptibility testing (DST) for Rifampicin (RIF) and Isoniazid (INH) was performed for all positive M. tuberculosis (M.tb) cultures. All MDR-TB isolates were tested for sensitivity to second-line drugs [Amikacin (AMK), Capreomycin (CAP), Ofloxacin (OFX), Ethionamide (ETA)].. Of 611, 483 patients were infected with MDR M. tuberculosis (M.tb) strains. Eighteen MDR-TB isolates (3.7%) were XDR M.tb strains. Family history of TB (p 0.045), socioeconomic status (p 0.013), concomitant illness (p 0.001) and previous intake of 2(nd) line injectable drugs (p 0.001) were significantly associated with occurrence of XDR-TB. Only two of the patients enrolled were HIV seropositive, but had a negative culture for M. tuberculosis. 56/483 isolates were pre-XDR M. tuberculosis, though the occurrence of pre-XDR-TB did not show any significant demographical associations.. The actual incidence and prevalence rate of XDR-TB in India is not available, although some scattered data is available. This study raises a concern about existence of XDR-TB in India, though small, signaling a need to strengthen the TB control program for early diagnosis of both tuberculosis and drug resistance in order to break the chains of transmission.

Topics: Adult; Amikacin; Antitubercular Agents; Capreomycin; Ethionamide; Extensively Drug-Resistant Tuberculosis; Female; Humans; Incidence; India; Isoniazid; Male; Mycobacterium tuberculosis; Ofloxacin; Prevalence; Rifampin; Risk Factors; Sputum; Tuberculosis, Pulmonary

It currently takes 2-3 months to obtain a diagnosis for multidrug-resistant (MDR-) and extensively drug-resistant tuberculosis (XDR-TB). We evaluated the rapid non-commercial nitrate reductase assay (NRA), which is capable of the simultaneous detection of MDR- and XDR-TB, and compared the results with the proportion method (PM). The sensitivity was respectively 97%, 99%, 100% and 94.6% for rifampicin (RMP), isoniazid (INH), ofloxacin (OFX) and kanamycin (KM). The specificity was respectively 100%, 95%, 95.7% and 99% for RMP, INH, OFX and KM. The turnaround time for NRA was 10-14 days, compared to 4-6 weeks for the PM. Our study showed that NRA provided sensitive and specific detection of resistance to first- and second-line drugs.

Topics: Antitubercular Agents; Colorimetry; DNA Mutational Analysis; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Humans; Isoniazid; Kanamycin; Kanamycin Resistance; Microbial Sensitivity Tests; Mutation; Mycobacterium tuberculosis; Nitrate Reductase; Ofloxacin; Predictive Value of Tests; Rifampin; Sensitivity and Specificity; Time Factors; Tuberculosis, Multidrug-Resistant

Tartu, Estonia.. To assess the performance and feasibility of the introduction of the thin-layer agar MDR/XDR-TB Colour Test (Colour Test) as a non-commercial method of drug susceptibility testing (DST).. The Colour Test combines the thin-layer agar technique with a simple colour-coded quadrant format, selective medium to reduce contamination and colorimetric indication of bacterial growth to simplify interpretation. DST patterns for isoniazid (INH), rifampicin (RMP) and ciprofloxacin (CFX) were determined using the Colour Test for 201 archived Mycobacterium tuberculosis isolates. Susceptibilities were compared to blinded DST results obtained routinely using the BACTEC™ Mycobacteria Growth Indicator Tube™ (MGIT) 960 to assess performance characteristics.. In all, 98% of the isolates produced interpretable results. The average time to positivity was 13 days, and all results were interpretable. The Colour Test detected drug resistance with 98% sensitivity for INH, RMP and CFX and 99% for multidrug-resistant tuberculosis. Specificities were respectively 100% (95%CI 82-100), 88% (95%CI 69-97) and 91% (95%CI 83-96) and 90% (95%CI 74-98). Agreement between the Colour Test and BACTEC MGIT 960 were respectively 98%, 96%, 94% and 97%.. The Colour Test could be an economical, accurate and simple technique for testing tuberculosis strains for drug resistance. As it requires little specialist equipment, it may be particularly useful in resource-constrained settings with growing drug resistance rates.

Topics: Antitubercular Agents; Ciprofloxacin; Color; Drug Resistance, Multiple, Bacterial; Estonia; Extensively Drug-Resistant Tuberculosis; Feasibility Studies; Humans; Isoniazid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Predictive Value of Tests; Rifampin; Sensitivity and Specificity; Time Factors; Tuberculosis, Multidrug-Resistant

Conventional culture-based drug susceptibility testing (DST) for the second-line antituberculosis drugs is slow, leading to diagnostic delay with associated exacerbation of transmission, amplification of resistance, and increased mortality.. To assess the diagnostic performance of the GenoType MTBDRsl line probe assay (LPA) for the rapid detection of mutations conferring resistance to ofloxacin (OFX), amikacin (AMK), and ethambutol and to determine the impact of implementation on the turnaround time in a high-throughput diagnostic laboratory.. Six hundred and fifty-seven direct patient acid-fast bacilli smear-positive specimens resistant to isoniazid, rifampin, or both according to the GenoType MTBDRplus assay were consecutively tested, using the GenoType MTBDRsl LPA. The diagnostic performance was assessed relative to the "gold standard" culture-based method, and the laboratory turnaround times for both methods were determined.. A total of 516 of 657 patient specimens had valid results for both tests. The sensitivity for detecting OFX, AMK, and extensive drug resistance, using the GenoType MTBDRsl LPA, was 90.7% (95% confidence interval [CI], 80.1-96.0%), 100% (95% CI, 91.8-100%), and 92.3% (95% CI, 75.9-97.9%), respectively, and the specificity for detection was 98.1% (95% CI, 96.3-99.0%), 99.4% (95% CI, 98.2-99.8%), and 99.6% (95% CI, 98.5-99.9%), respectively. Implementation of this test significantly reduced the turnaround time by 93.3% (P < 0.001), calculated from the date that the specimen was received at the laboratory to reporting second-line results. In addition, a significant increase in diagnostic yield of 20.1% and 19.3% (P < 0.001) for OFX and AMK resistance, respectively, was obtained for isolates that were either contaminated or had lost viability.. The GenoType MTBDRsl LPA is a rapid and reliable DST that can be easily incorporated into the diagnostic algorithm. This assay significantly improved diagnostic yield (P < 0.001) while simultaneously decreasing diagnostic delay for reporting second-line DST. The rapid dissemination of second-line DST results will guide initiation of appropriate treatment, thereby reducing transmission and improving treatment outcome.

Topics: Amikacin; Antitubercular Agents; Drug Resistance, Multiple, Bacterial; Ethambutol; Extensively Drug-Resistant Tuberculosis; Genetic Markers; Genotype; Humans; Microbial Sensitivity Tests; Molecular Diagnostic Techniques; Mycobacterium tuberculosis; Ofloxacin; Pentosyltransferases; Rifampin; Sensitivity and Specificity; South Africa; Sputum; Time Factors

In 2005 a cluster of 53 HIV-infected patients with extensively drug-resistant tuberculosis (XDR-TB) was detected in the Msinga sub-district, the catchment area for the Church of Scotland Hospital (CoSH) in Tugela Ferry, in KwaZulu-Natal province (KZN), South Africa. KZN is divided into 11 healthcare districts. We sought to determine the distribution of XDR TB cases in the province in relation to population density.. In this cross-sectional study, the KZN tuberculosis laboratory database was analysed. Results of all patients with a sputum culture positive for Mycobacterium tuberculosis from January 2006 to June 2007 were included. Drug-susceptibility test results for isoniazid, rifampicin, ethambutol, streptomycin, kanamycin and ofloxacin were available for all patients as well as the location of the hospital where their clinical diagnosis was made.. In total, 20858 patients attending one of 73 hospitals or their adjacent clinics had cultures positive for M. tuberculosis. Of these, 4170 (20%) were MDR-TB cases. Four hundred and forty three (11%) of the MDR tuberculosis cases displayed the XDR tuberculosis susceptibility profile. Only 1429 (34%) of the MDR-TB patients were seen at the provincial referral hospital for treatment. The proportion of XDR-TB amongst culture-confirmed cases was highest in the Msinga sub-district (19.6%), followed by the remaining part of the Umzinyati district (5.9%) and the other 10 districts (1.1%). The number of hospitals with at least one XDR-TB case increased from 18 (25%) to 58 (80%) during the study period.. XDR-TB is present throughout KZN. More than 65% of all diagnosed MDR-TB cases, including XDR-TB patients, were left untreated and likely remained in the community as a source of infection.

Topics: Antitubercular Agents; Cross-Sectional Studies; Ethambutol; Extensively Drug-Resistant Tuberculosis; Humans; Isoniazid; Kanamycin; Microbial Sensitivity Tests; Ofloxacin; Rifampin; South Africa; Streptomycin

Multidrug-resistant and extensively drug-resistant tuberculosis (MDR/XDR-TB) is an emerging global health threat. Proper management of close contacts of infectious patients is increasingly important. However, no evidence-based recommendations for treating latent TB infection (LTBI) after MDR/XDR-TB exposure (DR-LTBI) exist. An ultrashort regimen for LTBI caused by drug-susceptible strains (DS-LTBI) is also desirable. TMC207 has bactericidal and sterilizing activity in animal models of TB and improves the activity of current MDR-TB therapy in patients.. The objective of this study was to determine whether TMC207 might enable short-course treatment of DR-LTBI and ultrashort treatment of DS-LTBI.. Using an established experimental model of LTBI chemotherapy in which mice are aerosol-immunized with a recombinant bacillus Calmette-Guérin vaccine before low-dose aerosol infection with Mycobacterium tuberculosis, the efficacy of TMC207 alone and in combination with rifapentine was compared with currently recommended control regimens as well as once-weekly rifapentine + isoniazid and daily rifapentine ± isoniazid.. Outcomes included monthly lung colony-forming unit counts and relapse rates.. Lung colony-forming unit counts were stable at about 3.75 log(10) for up to 7.5 months postinfection in untreated mice. Rifamycin-containing regimens were superior to isoniazid monotherapy. TMC207 exhibited sterilizing activity at least as strong as that of rifampin alone and similar to that of rifampin + isoniazid, but daily rifapentine +/- isoniazid was superior to TMC207. Addition of TMC207 to rifapentine did not improve the sterilizing activity of rifapentine in this model.. TMC207 has substantial sterilizing activity and may enable treatment of DR-LTBI in 3-4 months.

Topics: Animals; Antibiotics, Antitubercular; Antitubercular Agents; Diarylquinolines; Disease Models, Animal; Drug Administration Schedule; Drug Therapy, Combination; Extensively Drug-Resistant Tuberculosis; Female; Latent Tuberculosis; Lung; Mice; Mice, Inbred BALB C; Mycobacterium tuberculosis; Quinolines; Rifampin; Stem Cells; Treatment Outcome

Topics: Acetamides; Adult; Amikacin; Antitubercular Agents; Capreomycin; Drug-Related Side Effects and Adverse Reactions; Extensively Drug-Resistant Tuberculosis; Female; Fluoroquinolones; Humans; Infectious Disease Medicine; Isoniazid; Kanamycin; Linezolid; Male; Middle Aged; Oxazolidinones; Rifampin

We screened 194 Mycobacterium tuberculosis strains isolated from tuberculosis (TB) patients in Delhi and neighboring regions in India to identify the prevalence of extensive drug resistance (XDR) in clinical isolates. Among these, 104 isolates were found to be multidrug resistant (MDR), and 6 were identified as XDR isolates, which was later confirmed by antimicrobial susceptibility testing against the respective drug screening panel. Genotyping was carried out by amplifying and sequencing the following genes: rpoB (rifampin), katG (isoniazid), gyrA (fluoroquinolones), and rrs (amikacin, kanamycin, and capreomycin). Our analyses indicated that mutations at the hot spots of these genes were positively correlated with drug resistance in clinical isolates. The key mutation observed for rpoB was in the codon for amino acid position 531 (S531L), and other mutations were seen in the hot spot, including those encoding Q510P, L511H, D516V, and H526Y mutations. We identified S315T and R463L substitutions encoded in the katG locus. An S95T substitution encoded in the gyrA locus was the most common mutation observed in fluoroquinolone-resistant isolates. In addition, we saw D94G and D94N mutations encoded in the QRDR region. The 16S rRNA (rrs) gene encoded mainly the A1401G mutation and an additional mutation, G1484T, resulting in ribosomal modifications. Taken together, the data in this report clearly establish the presence of phenotypically distinct XDR strains in India by molecular profiling and further identify specific mutational hot spots within key genes of XDR-TB strains.

Topics: Amikacin; Antitubercular Agents; Bacterial Proteins; Capreomycin; DNA Gyrase; DNA Mutational Analysis; DNA-Directed RNA Polymerases; Extensively Drug-Resistant Tuberculosis; Fluoroquinolones; India; Isoniazid; Kanamycin; Microbial Sensitivity Tests; Mutation; Mycobacterium tuberculosis; Point Mutation; Polymerase Chain Reaction; Rifampin

To determine the drug resistance spectrum and resistance levels of extensively drug-resistant (XDR-) and multidrug-resistant tuberculosis (MDR-TB) and TB resistant to either rifampicin (RMP, R) or isoniazid (INH, H; R/H-DR).. Of 142 drug-resistant clinical isolates examined, 13 were XDR-TB, 66 were MDR-TB and 63 were R/H-DR. The drug resistance spectrum was tested by the absolute two-concentration method. Minimum inhibitory concentrations (MICs) were determined for the strains by agar dilution method on Löwenstein-Jensen slants.. The drug resistance spectrum of XDR-TB, MDR-TB and R/H-DR TB isolates ranged from 4 to 9, 2 to 6 and 1 to 5 drugs, respectively. Over half of all XDR-TB (53.8%), MDR-TB (66.7%) and R/H-DR (54.0%) isolates were resistant to two other anti-tuberculosis drugs; 38.5% of XDR-TB, 24.2% of MDR-TB and 28.6% of R/H-DR TB isolates were resistant to ≥ 3 additional anti-tuberculosis drugs in addition to those originally defined, demonstrating that the MIC values and the proportions of strains with higher MICs followed a trend of XDR-TB > MDR-TB > R/H-DR for INH, RMP, ofloxacin and ethambutol.. XDR-TB, MDR-TB and R/H-DR TB isolates exhibited both increasingly broader resistance spectra and a higher percentage of strains with high MICs to more frequently resistant drugs, which might be related to patterns of TB chemotherapy.

Topics: Antitubercular Agents; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Humans; Isoniazid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Rifampin; Tuberculosis, Multidrug-Resistant

To evaluate the clinical efficacy of pulmonary resection and postoperative use of a first-line drug regimen for patients with well-localized, cavitary pulmonary multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB).. This was a prospective case study set in the National Masan Tuberculosis Hospital in Masan, Republic of Korea. From February 1998 to May 2004, 19 patients with well-localized, cavitary pulmonary MDR-TB or XDR-TB were enrolled and followed prospectively through April 2007. After radical surgical resection, patients were treated with anti-tuberculous therapy consisting of isoniazid (H), rifampin (R), ethambutol (E), pyrazinamide (Z), and streptomycin (S) (3HREZS/3HRES/6HRE).. All recovered isolates of Mycobacterium tuberculosis were resistant to isoniazid and rifampin, and to a mean of 4.7 anti-tuberculous drugs (range 2-8 drugs). Seventeen patients had MDR-TB and two had XDR-TB. Surgical procedures included: lobectomy (14 patients), lobectomy plus segmentectomy or wedge resection (four patients), and pneumonectomy (one patient). The median time to postoperative sputum smear and culture conversion was 2 days (range 1-23 days). Fifteen (78.9%) subjects, including both with XDR-TB, had durable cures (mean follow-up period 53.2 months). One patient failed to convert her sputum and was successfully switched to second-line therapy. Another patient developed active disease again 68 months after cure, likely due to re-infection with a new M. tuberculosis strain. Two patients were lost to follow-up after hospital discharge.. Resectional lung surgery combined with isoniazid- and rifampin-based anti-tuberculous chemotherapy can be an effective treatment strategy for patients with well-localized, cavitary pulmonary MDR-TB and XDR-TB.

Topics: Adult; Antitubercular Agents; Combined Modality Therapy; Drug Administration Schedule; Drug Resistance, Multiple, Bacterial; Drug Therapy, Combination; Extensively Drug-Resistant Tuberculosis; Female; Humans; Isoniazid; Korea; Lung; Male; Middle Aged; Mycobacterium tuberculosis; Pneumonectomy; Pulmonary Surgical Procedures; Rifampin; Treatment Outcome; Tuberculosis, Multidrug-Resistant; Tuberculosis, Pulmonary; Young Adult

Rise in prevalence of multi-drug resistance (MDR) in tubercle bacilli is a serious cause of concern. As mutations with two house keeping genes rpoB and katG are associated with resistance to two important anti-tubercular drugs rifampicin and isoniazid respectively, there is a need to understand the growth kinetics of organisms with such mutated genes in experimental animals. This study was undertaken to study the growth kinetics of susceptible as well multi-drug resistance Mycobacterium tuberculosis isolates in mice.. Two MDR (having mutations in rpoB and catG) and two drug susceptible isolates of M. tuberculosis along with H37Rv were grown in mice after aerogenic infection.. The MDR isolates grew slowly up to 3 wk though the growth was significantly different from sensitive strains. However, after 3 wk, the growth in sensitive as well MDR strains was similar, suggesting that even the mutations in the MDR strains did not have any impact on the growth kinetics.. The effect of mutations in other parts of these genes need to be studied. Retention of property of MDR strains to establish infection after aerogenic infection has epidemiological significance in terms of the transmission of MDR tuberculosis.

Topics: Animals; Antitubercular Agents; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Humans; Lung; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Rifampin; Tuberculosis, Multidrug-Resistant

Limited information about the prevalence of drug-resistant tuberculosis (TB) has been reported from India, the country with the world's highest burden of TB. We conducted a representative state-wide survey in the state of Gujarat (2005 population: 56 million).. Mycobacterium tuberculosis isolates from a representative sample of new and previously treated smear-positive pulmonary TB (PTB) cases were subjected to drug susceptibility testing (DST) against first-line drugs at a World Health Organization supranational reference laboratory. Isolates found to have at least both isoniazid (INH) and rifampicin (RMP) resistance (i.e., multidrug-resistant TB [MDR-TB]) were subjected to second-line DST.. Of 1571 isolates from new patients, 1236 (78.7%) were susceptible to all first-line drugs, 173 (11%) had any INH resistance and MDR-TB was found in 37 (2.4%, 95%CI 1.6-3.1). Of 1047 isolates from previously treated patients, 564 (54%) were susceptible to all first-line drugs, 387 (37%) had any INH resistance and MDR-TB was found in 182 (17.4%, 95%CI 15.0-19.7%). Among 216 MDR-TB isolates, 52 (24%) were ofloxacin (OFX) resistant; seven cases of extensively drug-resistant TB (XDR-TB) were found, all of whom were previously treated cases.. MDR-TB prevalence remains low among new TB patients in Gujarat, but is more common among previously treated patients. Among MDR-TB isolates, the alarmingly high prevalence of OFX resistance may threaten the success of the expanding efforts to treat and control MDR-TB.

Topics: Antitubercular Agents; Bacteriological Techniques; Colony Count, Microbial; Drug Resistance, Multiple, Bacterial; Ethionamide; Extensively Drug-Resistant Tuberculosis; Female; Humans; India; Isoniazid; Kanamycin; Male; Microscopy, Fluorescence; Mycobacterium tuberculosis; Ofloxacin; Population Surveillance; Prevalence; Rifampin; Sputum; Tuberculosis, Multidrug-Resistant

Topics: Antitubercular Agents; Communicable Diseases; Drug Resistance, Multiple, Bacterial; Extensively Drug-Resistant Tuberculosis; Humans; Infectious Disease Medicine; Public Health; Pulmonary Medicine; Rifampin; Treatment Failure; Treatment Outcome

Currently, no information is available on the effect of resistance/susceptibility to first-line drugs different from isoniazid and rifampicin in determining the outcome of extensively drug-resistant tuberculosis (XDR-TB) patients, and whether being XDR-TB is a more accurate indicator of poor clinical outcome than being resistant to all first-line anti-tuberculosis (TB) drugs. To investigate this issue, a large series of multidrug-resistant TB (MDR-TB) and XDR-TB cases diagnosed in Estonia, Germany, Italy and the Russian Federation during the period 1999-2006 were analysed. Drug-susceptibility testing for first- and second-line anti-TB drugs, quality assurance and treatment delivery was performed according to World Health Organization recommendations in all study sites. Out of 4,583 culture-positive TB cases analysed, 361 (7.9%) were MDR and 64 (1.4%) were XDR. XDR-TB cases had a relative risk (RR) of 1.58 to have an unfavourable outcome compared with MDR-TB cases resistant to all first-line drugs (isoniazid, rifampicin ethambutol, streptomycin and, when tested, pyrazinamide), and an RR of 2.61 compared with "other" MDR-TB cases (those susceptible to at least one first-line anti-TB drug among ethambutol, pyrazinamide and streptomycin, regardless of resistance to the second-line drugs not defining XDR-TB). The emergence of extensively drug-resistant tuberculosis confirms that problems in tuberculosis management are still present in Europe. While waiting for new tools which will facilitate management of extensively drug-resistant tuberculosis, accessibility to quality diagnostic and treatment services should be urgently ensured and adequate public health policies should be rapidly implemented to prevent further development of drug resistance.

Topics: Antitubercular Agents; Communicable Diseases; Drug Resistance, Multiple; Extensively Drug-Resistant Tuberculosis; Global Health; Humans; Isoniazid; Population Surveillance; Public Health; Rifampin; Risk; Russia; Time Factors; Treatment Outcome