agar and Tuberculosis--Pulmonary

To evaluate the concordance and safety of induced sputum (IS) and spontaneous sputum (SS), and estimate concordance and time to detection of M. tuberculosis between Lowenstein-Jensen (LJ), thin-layer agar (TLA), and the Mycobacteria Growth Indicator Tube system (MGIT).. This was a cohort study. Prisoners with pulmonary tuberculosis (PTB) were followed for 2 years. At baseline and every follow-up visit, three sputum samples were taken on consecutive days (one IS and two SS) and adverse events occurring before, during, and 30 min after IS were registered. All sputum samples were stained with auramine and cultured in LJ, TLA (to test resistance), and MGIT.. Five hundred eighty-six IS and 532 SS were performed on 64 PTB patients. Breathlessness (1.6%), cough (1.2%), hemoptysis (0.3%), and cyanosis (0.2%) were the only complications. Concordance between IS and SS was 0.78 (95% confidence interval 0.69-0.87); 11 positive cultures from IS samples were negative in SS, and 11 positive cultures from SS samples were negative in IS. One hundred seventy-eight cultures were positive by any technique: MGIT 95%, LJ 73%, and TLA 57%. Time to detection of M. tuberculosis in LJ, TLA, and MGIT was 31, 18, and 11 days, respectively.. The IS procedure is safe in prisons. The MGIT system is better and faster than LJ and TLA in the diagnosis of M. tuberculosis.

Topics: Agar; Bacteriological Techniques; Benzophenoneidum; Cohort Studies; Coloring Agents; Culture Media; Diagnostic Techniques, Respiratory System; Female; Humans; Male; Mycobacterium tuberculosis; Prisoners; Prospective Studies; Sputum; Time Factors; Tuberculosis, Pulmonary

Tuberculosis (TB) diagnostic laboratories in Latin America.. Evaluation of thin-layer agar (TLA) compared to Löwenstein-Jensen (LJ) culture for the diagnosis of TB.. Phase II prospective study in six laboratories. Samples included sputum and extra-pulmonary specimens from patients with a clinical diagnosis of TB. Respiratory samples were decontaminated using NaOH/ NALC; all samples were centrifuged, stained with Ziehl-Neelsen for acid-fast bacilli (AFB), cultured on LJ and TLA and identified according to recommended procedures. Sensitivity and likelihood ratios (LR), growth detection time and contamination rate were calculated for both media.. A total of 1118 clinical specimens were studied. Cultures detected Mycobacterium tuberculosis in all AFB-positive samples, whereas for AFB-negative specimens LJ detected 3.2% and TLA 4.4%. Sensitivity was 92.6% (95%CI 87.9-95.9) and 84.7% (95%CI 78.8-89.0) for TLA and LJ, respectively. Positive and negative LRs were similar. Contamination was 5.1% for TLA and 3.0% for LJ. Median time to detection of a positive culture was 11.5 days (95%CI 9.3-15.0) for TLA and 30.5 days (95%CI 26.9-39.0) for LJ (P < 0.0001).. Difference in the characteristics of the participating laboratories, the disease prevalence and the number and type of specimens processed did not affect the overall performance of TLA as compared to LJ, supporting the robustness of the method and its feasibility in different laboratory settings.

Topics: Agar; Bacteriological Techniques; Humans; Latin America; Mycobacterium tuberculosis; Prospective Studies; Time Factors; Tuberculosis, Pulmonary

"Mycobacterium canettii" is responsible for non-transmissible lymph node and pulmonary tuberculosis in persons exposed in the Horn of Africa. In the absence of direct human transmission, contaminated water and foodstuffs could be sources of contamination. We investigated the dry-heat inactivation of "M. canettii" alone and mixed into mock-infected foodstuffs by inoculating agar cylinders and milk with 10. Exposed to 35 °C, M. tuberculosis H37Rv, "M canettii" CIPT140010059 and "M. canettii" 157 exhibited a survival rate of 108, 95 and 81%, which is significantly higher than that of "M. canettii" 173. However, all tested mycobacteria tolerated a 90-min exposure at 45 °C. In the foodstuff models set at 70 °C, no growing mycobacteria were visualized. This study supports the premise that "M. canettii" may survive up to 45 °C; and suggests that contaminated raw drinks and foodstuffs but not cooked ones may be sources of infection for populations.

Topics: Agar; Animals; Hot Temperature; Humans; Microbial Viability; Milk; Mycobacterium; Mycobacterium tuberculosis; Species Specificity; Time Factors; Tuberculosis, Pulmonary

We compared the sensitivity and time to detection of growth of Mycobacterium tuberculosis in the thin layer agar (TLA) compared to BACTEC MGIT960. The average time for growth of M. tuberculosis in TLA and BACTEC MGIT960 was 10.6 and 9.6 days, respectively. The sensitivity of detection of M. tuberculosis was 97.3% on TLA and 97% on BACTEC MGIT960 for smear positive samples. TLA showed comparable results to BACTEC MGIT960 and could be an alternative method for low-income countries.

Topics: Agar; Bacteriological Techniques; Culture Techniques; Humans; Mycobacterium tuberculosis; Tuberculosis, Pulmonary

The objective of this study was to evaluate the performance of a low-cost method, the thin layer agar (TLA) method, for the diagnosis of smear-negative patients. This prospective study was performed in Homa Bay District Hospital in Kenya. Out of 1,584 smear-negative sputum samples, 212 (13.5%) were positive by culture in Löwenstein-Jensen medium (LJ) and 220 (14%) were positive by the TLA method. The sensitivities of LJ and TLA were 71% and 74%, respectively. TLA could become an affordable method for the diagnosis of smear-negative tuberculosis in resource-limited settings, with results available within 2 weeks.

Topics: Agar; Bacteriological Techniques; Clinical Laboratory Techniques; Culture Media; HIV Infections; Humans; Kenya; Mycobacterium tuberculosis; Prospective Studies; Sensitivity and Specificity; Sputum; Tuberculosis, Pulmonary

Quantitation of bacterial load in tissues is essential for experimental investigation of Mycobacterium tuberculosis infection and immunity. We have used an automated liquid culture system to determine the number of colony forming units (CFU) in murine tissues and compared the results to those obtained by conventional plating on Middlebrook agar. There is an overall good correlation between results obtained by the two methods. Although less consistency and more contamination was observed in the automated liquid culture, the method is more sensitive, less labour intensive and allows the processing of large numbers of samples.

Topics: Agar; Animals; Bacteriological Techniques; Colony Count, Microbial; Culture Media; Disease Models, Animal; Female; Humans; Lung; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mycobacterium tuberculosis; Sensitivity and Specificity; Spleen; Tuberculosis, Pulmonary

In this study, blood agar was used instead of 7H10 agar for the susceptibility testing of 34 clinical isolates of Mycobacterium tuberculosis to isoniazid (INH) and rifampin (RIF) in accordance with the NCCLS. The BACTEC 460 TB system (Becton Dickinson, Sparks, Md.) was used as a "gold standard." Results for both media were in agreement for RIF and INH at 100 and 94.1%, respectively. For INH, the specificity, sensitivity, positive predictive value, and negative predictive value were found to be 71.4, 100, 93.1, and 100%, respectively, while these values were 100% for RIF. In addition, the results of the susceptibility test performed with blood agar were obtained on day 14 of incubation. In conclusion, results were obtained much earlier with blood agar (2 weeks) than with 7H10 agar (3 weeks), and the results of this study suggest that blood agar may be used as an alternative medium for the susceptibility testing of M. tuberculosis to INH and RIF.

Topics: Agar; Antitubercular Agents; Blood; Culture Media; Humans; Isoniazid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Predictive Value of Tests; Rifampin; Sensitivity and Specificity; Tuberculosis, Multidrug-Resistant; Tuberculosis, Pulmonary

Mycobacterial diseases continue to cause high morbidity and mortality. Isolation, identification and sensitivity testing form the backbone of laboratory investigations. M. tuberculosis isolation needs 6-8 weeks on conventional egg containing media. For rapid isolation various methods have been evaluated. We evaluated biphasic system (Middlebrook 7H11 agar slant+Middlebrook 9H broth) in comparison with Lowenstein-Jensen (LJ) medium. In smear positive cases biphasic system showed the recovery rate of 97.05% as against 79.41% on LJ on incubation for 21+/-4.44 and 28+/-3.76 days respectively. In smear negative and culture positive cases biphasic system and LJ showed isolation rates of 91.66% and 66.6% after 36+/-3.44 and 41+/- 4.09 days respectively. Biphasic system showed lower contamination rate (1.33%). Biphasic medium is superior to LJ medium in isolation of M. tuberculosis.

Topics: Agar; Colony Count, Microbial; Humans; Mycobacterium tuberculosis; Sputum; Tuberculosis, Pulmonary

Levofloxacin, the active l-isomer of the quinolone ofloxacin, is now widely accepted for treatment of multidrug-resistant tuberculosis. Because the drug is now widely used, we sought to establish susceptibility test conditions for Mycobacterium tuberculosis against levofloxacin by the traditional reference method, agar proportion (AP), the commonly used BACTEC 460 radiometric system, and the newer BACTEC MGIT 960 method. To determine the stability of levofloxacin in the two newer test systems (BACTEC 460 and BACTEC MGIT 960), media containing subinhibitory levels of levofloxacin were prepared and stored at 4 and 37 degrees C for 14 days. The stored media were inoculated with H37Rv, and the drug activity was compared to freshly prepared media. Results show that levofloxacin is stable over the course of testing. Next, optimum levofloxacin test concentrations were determined for AP, BACTEC 460, and BACTEC MGIT 960 methods. MICs were determined for 32 pan-susceptible isolates of M. tuberculosis obtained from presumably untreated patients and 14 quinolone-resistant isolates. The levofloxacin-resistant strains either were isolated from patients who remained culture-positive despite treatment with a quinolone agent (six strains) or contained known mutations in gyrA (eight strains). Levofloxacin MICs resulted in a bimodal pattern with values for resistant strains consistently higher than those for pan-susceptible strains. Results show that levofloxacin concentrations of 2 microg/ml (BACTEC 460 and BACTEC MGIT 960) and 1 microg/ml (AP) inhibited the growth of all pan-susceptible strains while permitting the growth of all levofloxacin-resistant strains. Confirmatory tests with a subset of pan-susceptible and levofloxacin-resistant isolates validated the selected test concentrations.

Topics: Agar; Anti-Bacterial Agents; Bacteriological Techniques; Culture Media; Drug Resistance, Bacterial; Humans; Levofloxacin; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Ofloxacin; Tuberculosis, Pulmonary

A new rapid microdilution method, employing the dye resazurin as an indicator of mycobacterial growth, was developed to evaluate drug susceptibility of Mycobacterium tuberculosis reference strain H37Rv and of 13 M. tuberculosis susceptible or multidrug-resistant clinical strains. Different growth conditions were evaluated. The MICs of isoniazid, rifampicin, streptomycin and ethambutol were determined by the Microdilution Resazurin Assay (MRA) and the results compared with those obtained by the agar proportion method; complete agreement was always obtained. MRA resulted in a rapid, reliable, simple and inexpensive coloured method suitable for testing the susceptibility of M. tuberculosis clinical strains to first-line drugs; its employment in evaluating new antibacterial molecules is also suggested.

Topics: Agar; Antitubercular Agents; Colony Count, Microbial; Culture Media; Humans; Indicators and Reagents; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Oxazines; Tuberculosis, Pulmonary; Xanthenes

Topics: Agar; Animals; Anthrax; Bacillus anthracis; Bacteriological Techniques; Bacteriology; Cattle; Cholera; Cricetinae; Germany; Guinea Pigs; History, 19th Century; Humans; Lung; Mycobacterium tuberculosis; Spores, Bacterial; Tuberculosis, Pulmonary; Vibrio cholerae

Topics: Agar; Cerebral Infarction; Chronic Disease; Humans; Leukocyte Migration-Inhibitory Factors; Lymphokines; Methods; Multiple Sclerosis; Nephritis; Tuberculosis, Pulmonary

Topics: Agar; Animals; Cell Migration Inhibition; Evaluation Studies as Topic; Humans; Hypersensitivity, Delayed; Leukocytes; Male; Mice; Tuberculosis, Pulmonary

Topics: Agar; Animals; Culture Media; Culture Techniques; Humans; Immune Sera; Immunodiffusion; Mycobacterium; Mycobacterium tuberculosis; Rabbits; Serotyping; Tuberculosis, Pulmonary

Topics: Agar; Aminohydrolases; Diagnosis, Differential; Electrophoresis; Gels; Humans; Lung Neoplasms; Methods; Tuberculosis, Pulmonary

Topics: Agar; Amyloid; Amyloidosis; Animals; Antigens; Arthritis, Rheumatoid; Fluorescent Antibody Technique; gamma-Globulins; Humans; Immunodiffusion; Methods; Osteomyelitis; Pyelonephritis; Rabbits; Tuberculosis, Osteoarticular; Tuberculosis, Pulmonary