rifampin and resazurin

Actinomycetoma is a chronic granulomatous disease affecting skin, subcutaneous tissue, fascia, muscle and bones. With increasing resistance against commonly used treatment regimens, susceptibility testing is urgently needed.. We developed an in vitro susceptibility assay for Actinomadura madurae, one of the common causative agents of actinomycetoma, employing resazurin for endpoint reading. Using this assay, reproducible MICs were determined for the most commonly used antibacterial agents for actinomycetoma treatment. The tested antibacterial agents included trimethoprim/sulfamethoxazole, amikacin, streptomycin, amoxicillin, ceftriaxone, gentamicin, ciprofloxacin, doxycycline, imipenem, linezolid, penicillin G and rifampicin.. Following the clinical breakpoints as stated by CLSI, 100% of the tested strains were susceptible to trimethoprim/sulfamethoxazole (MIC 0.03/0.59-1/19 mg/L), amikacin (MIC 0.0078-0.25 mg/L), doxycycline (MIC <0.25-1 mg/L) and linezolid (MIC <0.25-2 mg/L), 90% to ciprofloxacin (MIC <0.25-2 mg/L), 80% to ceftriaxone (MIC <0.5 to >64 mg/L) and imipenem (MIC <0.25-32 mg/L) and only 20% to amoxicillin (MIC <0.5 to >64 mg/L) and rifampicin (MIC 0.5 to >32 mg/L).. Determinations of MICs by visual readings of colour changes versus spectrophotometric readings were comparable. This convenient visual reading has the advantage of feasible implementation in endemic settings.

Topics: Amikacin; Amoxicillin; Anti-Bacterial Agents; Ceftriaxone; Ciprofloxacin; Doxycycline; Humans; Ifosfamide; Imipenem; Linezolid; Microbial Sensitivity Tests; Mycetoma; Rifampin; Trimethoprim, Sulfamethoxazole Drug Combination

Central nervous system tuberculosis (CNS-TB) is a devastating manifestation of TB. The most common form of CNS-TB is tuberculous meningitis. Drug-resistant TB poses a major threat to the control of TB worldwide. Timely treatment dramatically improves the outcome. Colorimetric techniques for drug susceptibility testing based on the oxidation-reduction principle give results quick and are less expensive. The objectives of this study were to compare the susceptibility of Mycobacterium tuberculosis isolated from cerebrospinal fluid to four first-line drugs using the MGIT automated mycobacterial detection system and the resazurin assay (RA) as well as to estimate the minimum inhibitory concentrations (MICs) by RA.. A total of 42 M. tuberculosis isolates were analysed for their susceptibilities by MGIT and RA.. Of the 42 isolates, 35 gave concordant results with both methods. Agreement between the two tests for streptomycin and rifampicin was 100% with a Fleiss' kappa (κ) value of 1, whereas for isoniazid and ethambutol agreement was 92.86% and 90.48%, respectively, with κ values of 0.853 and 0.738.. The RA appears to be a good alternative to the automated MGIT technique in resource-limited settings.

Topics: Antitubercular Agents; Cerebrospinal Fluid; Ethambutol; Humans; Isoniazid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Oxazines; Rifampin; Streptomycin; Tuberculosis, Meningeal; Xanthenes

We report the in vitro drugs interaction by the resazurin drugs combination microtiter assay (REDCA) of amoxicillin (AMO)/clavulanate (CLAV) with isoniazid (INH), ethambutol (EMB), and rifampicin (RIF) against susceptible and resistant Mycobacterium tuberculosis isolates. The addition of AMO/CLAV to classical antituberculosis drugs should be explored as a promising alternative for the treatment of resistant tuberculosis (TB).

Topics: Amoxicillin; Antitubercular Agents; Clavulanic Acid; Drug Resistance, Multiple, Bacterial; Ethambutol; Humans; Isoniazid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Oxazines; Rifampin; Xanthenes

A microemulsion has been formulated to coencapsulate antituberculosis drugs to solve the issue of stability of rifampicin (RIF) in the presence of isoniazid (INH) and pyrazinamide (PZA). The structural transition, solubilization locus, and quantitative release of drugs without interference have been estimated. Derivative absorbance spectroscopy, especially ratio derivative and double divisor ratio derivative methods, has been employed for estimating the release. The coencapsulation of the anti-tuberculosis drugs were carried out in single, binary, or ternary mixtures and occupy the same solubilization sites in multiple drugs microemulsion systems as in the case of single drug-loaded systems. INH and PZA obey the diffusional (Fickian) release mechanism, whereas RIF shows anomalous release. Resazurin assay and agar well diffusion method were adopted for cytotoxicity analysis and antimicrobial activity, respectively. Cytotoxicity was found to be dependent on concentration and on colloidal structure of microemulsion.

Topics: Animals; Antitubercular Agents; Cell Line; Chemistry, Pharmaceutical; Chlorocebus aethiops; Emulsions; Hydrophobic and Hydrophilic Interactions; Isoniazid; Oxazines; Plant Oils; Polyethylene Glycols; Pyrazinamide; Rifampin; Solubility; Vero Cells; Xanthenes

The resazurin microtiter assay (classic REMA), a colorimetric liquid culture-based drug susceptibility assay for Mycobacterium tuberculosis (MTB), has been endorsed by the World Health Organization. The assay requires 8-16 days to obtain results, delaying management of drug resistant tuberculosis patients. A modified REMA which allows results in as little as 24 hours for bacterial strains, has been developed and validated using Staphylococcus aureus, but has not yet been evaluated for MTB. Therefore we assessed the performance of the modified REMA for rifampicin (RIF) and isoniazid (INH) susceptibility, using the classic REMA as the reference standard. We also compared simplicity (from the technicians' point of view), time taken to obtain results (rank-sum testing), specificity and Kappa statistics of the two methods.. The modified REMA, which is a one-step procedure, was found to be simpler to perform and results were obtained in a significantly shorter time (5 versus 9 days, p < 0.0001) compared to the classic REMA due to addition of indicator and strain at the same time. The specificity of the modified REMA was low {46.8% (35.5% - 58.4%) for RIF and 13.9% (7.2% - 23.5%) for INH}. Kappa statistics were 16.0% for RIF and 2.0% for INH. Low specificity and kappa statistics are due to indicator reduction by the strains before complete drug activity.. Although modified REMA is faster and simpler compared to classic REMA, it is not reliable for MTB drug susceptibility testing.

Topics: Antitubercular Agents; Colorimetry; Humans; Isoniazid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Oxazines; Rifampin; Tuberculosis; Xanthenes

The microplate nitrate reductase assay (MNRA) and the rezasurin microtitre assay (REMA) were used for the susceptibility testing of 73 clinical isolates and the results were compared with those that were obtained using the Bactec 460 TB and Bactec MGIT 960 systems. The REMA and the MNRA were performed in 96-well plates. For the REMA, the concentrations of isoniazid (INH) and rifampicin (RIF) ranged from 1.0-0.01 µg/mL and 2.0-0.03 µg/mL, respectively. For the MNRA, the INH concentration was between 1.0-0.03 µg/mL and the RIF concentration was between 2.0-0.06 µg/mL. For the MNRA, the sensitivity, specificity, positive predictive value, negative predictive value and INH/RIF agreement were 100/95.6, 97.6/100, 96.8/100, 100/98 and 98.6/98.6, respectively, and for the REMA, they were 100/91.3, 90.4/100, 88.5/100, 100/96.1 and 94.5/97.2, respectively. Our data suggest that these two rapid, low-cost methods may be inexpensive, alternative assays for the rapid detection of multidrug resistant tuberculosis in low-income countries.

Topics: Antitubercular Agents; Drug Resistance, Multiple, Bacterial; Humans; Isoniazid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Nitrate Reductase; Oxazines; Predictive Value of Tests; Reagent Kits, Diagnostic; Rifampin; Sensitivity and Specificity; Tuberculosis, Multidrug-Resistant; Xanthenes

Mycobacterium tuberculosis 18b, a streptomycin (STR)-dependent mutant that enters a viable but nonreplicating state in the absence of STR, has been developed as a simple model for drug testing against dormant bacilli. Here, we further evaluated the STR-starved 18b (SS18b) model both in vitro and in vivo by comparing the behavior of 22 approved and experimental tuberculosis drugs. Using the resazurin reduction microplate assay (REMA), rifampin (RIF), rifapentine (RPT), TMC207, clofazimine (CFM), and linezolid (LIN) were found to be active against SS18b in vitro, and their bactericidal activity was confirmed by determining the number of CFU. A latent 18b infection was established in mice, and some of the above-mentioned drugs were used for treatment, either alone or in combination with RIF. RIF, RPT, TMC207, CFM, and pyrazinamide (PZA) were all active in vivo, while cell wall inhibitors were not. A comparative kinetic study of rifamycin efficacy was then undertaken, and the results indicated that RPT clears latent 18b infection in mice faster than RIF. Intrigued by the opposing responses of live and dormant 18b cells to cell wall inhibitors, we conducted a systematic analysis of 14 such inhibitors using REMA. This uncovered an SS18b signature (CWPRED) that accurately predicted the activities of cell wall inhibitors and performed well in a blind study. CWPRED will be useful for establishing the mode of action of compounds with unknown targets, while the SS18b system should facilitate the discovery of drugs for treating latent tuberculosis.

Topics: Acetamides; Amino Acid Sequence; Animals; Antitubercular Agents; Clofazimine; Diarylquinolines; Disease Models, Animal; Drug Discovery; Drugs, Investigational; Female; Genetic Engineering; Latent Tuberculosis; Linezolid; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Molecular Sequence Data; Mycobacterium tuberculosis; Oxazines; Oxazolidinones; Quinolines; Rifampin; Streptomycin; Structure-Activity Relationship; Xanthenes

Globospiramine (1), a new spirobisindole alkaloid possessing an Aspidosperma-Aspidosperma skeleton, together with deoxyvobtusine (2), deoxyvobtusine lactone (3), vobtusine lactone (4) and lupeol (5), were isolated and identified from Voacanga globosa through a bioassay-guided purification. The gross structure and absolute stereochemistry of 1 were established by circular dichroism spectroscopy, HR-MS and unambiguous NMR spectroscopic experiments. In addition, a new biogenetic pathway for the formation of the spiro-Aspidosperma-Aspidosperma skeleton is proposed. Alkaloid 1 showed potent antituberculosis activity against Mycobacterium tuberculosis H(37)Rv as evidenced in microplate Alamar blue assay (MIC = 4 μg/mL) and low-oxygen recovery assay (LORA (MIC = 5.2 μg/mL). The bisindole alkaloids also exhibited promising activity against acetylcholinesterase and, especially butyrylcholinesterase, with deoxyvobtusine (2) (IC(50) = 6.2 μM) as the most strongly inhibiting compound. This study extends the variety of alkaloid structural platforms which exhibit antimycobacterial and anticholinesterase activity.

Topics: Acetylcholinesterase; Alkaloids; Animals; Antitubercular Agents; Butyrylcholinesterase; Cholinesterase Inhibitors; Electrophorus; Horses; Indole Alkaloids; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Oxazines; Pentacyclic Triterpenes; Plant Extracts; Plant Leaves; Spiro Compounds; Structure-Activity Relationship; Voacanga; Xanthenes

A series of 4-alkyl/aryl-2,4-dihydro-5-((6-(4-bromophenyl)imidazo[2,1-b]thiazol-3-yl)methyl)-3H-1,2,4-triazole-3-thiones (3a-i) and 2-alkyl/arylamino-5-((6-(4-bromophenyl)imidazo[2,1-b]thiazol-3-yl)methyl)-1,3,4-thiadiazoles (4a-c) were synthesized starting from 6-(4-bromophenyl)imidazo[2,1-b]thiazole-3-acetic acid hydrazide. The newly synthesized compounds were characterized by IR, (1)H NMR, mass and elemental analysis. All compounds were tested for antibacterial and antifungal activities. The antimicrobial activities of the compounds were assessed by the microbroth dilution technique. The compounds were also evaluated for antituberculosis activity against Mycobacterium tuberculosis H37Rv (ATCC 27294). The preliminary results revealed that some of the compounds exhibited promising antimicrobial activities.

Topics: Anti-Infective Agents; Fungi; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Oxazines; Radiometry; Thiadiazoles; Triazoles; Xanthenes

The present article describes a facile one-pot synthesis of a series of eight pyrazolo[3,4-d]pyrimidines 4a-h which were evaluated for their in-vitro antibacterial activity against Mycobacterium tuberculosis H37Rv using the Alamar-Blue susceptibility test and the activity expressed as the minimum inhibitory concentration (MIC) in mg/mL. The compounds 4b, 4c, 4d, and 4g exhibited the best results (1.2 microg/mL) when compared with first-line drugs such as isoniazid (INH) and rifampicin (RIP). Therefore, this class of compounds could be a good starting point to develop new lead compounds in the treatment of multidrug-resistant tuberculosis.

Topics: Antitubercular Agents; Isoniazid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Oxazines; Pyrimidines; Rifampin; Structure-Activity Relationship; Tuberculosis, Multidrug-Resistant; Xanthenes

If tuberculosis therapy is to be shortened it is imperative that the sterilising activity of current and future anti-tuberculosis drugs is enhanced. Intracellular Mycobacterium tuberculosis (MTB) phagocytosed by macrophages may be a key subpopulation of bacteria that are less readily eliminated by therapy. Here we investigate whether macrophages provide MTB with a pharmacological sanctuary site, making them less susceptible to chemotherapy than extracellular bacilli. Intracellular drug activity was determined by a novel colorimetric method that measures the ability of a drug to protect A-THP1 cells from infection-mediated cell death by H37Rv. Extracellular bactericidal activity was determined by the microplate alamar blue assay (MABA). Further, the effect of P-glycoprotein (P-gp) expressed on macrophages on the intracellular kill of H37Rv was assessed. To screen the anti-tuberculosis drugs for P-gp substrate specificity, their toxicity and cellular accumulation were determined in CEM and CEM(VBL100) cells. Intracellular and extracellular anti-tuberculosis drug activity following 7-day treatment with isoniazid (mean EC(50)+/-SD: 36.7+/-2.2 and 57.2+/-2.5 ng/mL, respectively) and ethambutol (243+/-95 and 263+/-12 ng/mL, respectively) were similar. However, for rifampicin a higher concentration was required to kill intracellular (148+/-32 ng/mL) versus extracellular (1.27+/-0.02 ng/mL) bacilli. The P-gp inhibitor tariquidar, significantly increased intracellular kill of H37Rv by ethambutol and rifampicin and both of these drugs were shown to be substrates for P-gp using the P-gp overexpressing CEM(VBL100) cells. We observed a large discrepancy between intracellular and extracellular activity of rifampicin (but not with isoniazid or ethambutol). Several factors could have accounted for this including inoculum size, media and cell-mediated metabolism. These factors make the comparison of intracellular and extracellular drug activity complex. However, the intracellular assay described here has potential for studying the impact of host proteins (such as drug transporters) on the intracellular activity of drugs, and has been used successfully here to demonstrate that both rifampicin and ethambutol are substrates for P-gp.

Topics: Antitubercular Agents; ATP Binding Cassette Transporter, Subfamily B, Member 1; Cell Line, Tumor; Cell Survival; Cells, Cultured; Colorimetry; Drug Resistance, Bacterial; Drug Resistance, Multiple, Bacterial; Ethambutol; Humans; Indicators and Reagents; Isoniazid; Macrophages; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Oxazines; Phagocytosis; Quinolines; Rifampin; Spectrometry, Fluorescence; Tuberculosis; Xanthenes

Multidrug-resistant (MDR) tuberculosis (TB) can jeopardise the success of national TB control programmes. Rapid, simple drug susceptibility tests applicable in developing countries would allow earlier treatment of patients with MDR infections.. To test the feasibility and performance of the resazurin microtitre assay (REMA) as an indirect test for detecting isoniazid (INH) and rifampicin (RMP) resistance of Mycobacterium tuberculosis strains in Madagascar.. Study comparing the sensitivity and specificity of the REMA plate test with the Löwenstein-Jensen proportion method for determining the resistance of M. tuberculosis strains to INH and RMP.. The sensitivity and specificity of the resazurin test were studied in 77 strains and were respectively 95% and 97.3% for the detection of INH resistance, and 95% and 100% for the detection of RMP resistance. The sensitivity and specificity for the identification of MDR strains were respectively 89% and 100%.. The resazurin test is sensitive and specific enough for the detection of INH- and RMP-resistant strains. It is also easy to use, rapid and inexpensive, making it suitable for developing countries. Its usefulness for national drug resistance surveys should be assessed.

Topics: Antitubercular Agents; Colorimetry; Feasibility Studies; Humans; Indicators and Reagents; Isoniazid; Madagascar; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Oxazines; Predictive Value of Tests; Reproducibility of Results; Rifampin; Sensitivity and Specificity; Tuberculosis, Multidrug-Resistant; Xanthenes

Rapid, accurate and inexpensive methods are essential to detect drug-resistant Mycobacterium tuberculosis and allow timely application of effective treatment and precautions to prevent transmission. The proportion method, the MTT and Alamar Blue redox methods, and the D29 mycobacteriophage assay, were compared for their ability to detect resistance to isoniazid and rifampicin. When tested against a panel of known M. tuberculosis strains, the redox methods and the D29 assay showed good sensitivity and specificity compared to the proportion method, suggesting that they could be useful alternatives for identifying multidrug resistance in M. tuberculosis.

Topics: Antitubercular Agents; Costs and Cost Analysis; Drug Resistance, Bacterial; Isoniazid; Microbial Sensitivity Tests; Mycobacteriophages; Mycobacterium tuberculosis; Oxazines; Oxidation-Reduction; Rifampin; Sensitivity and Specificity; Tetrazolium Salts; Thiazoles; Xanthenes

Multi-drug resistant (MDR) Mycobacterium tuberculosis is still a serious public health problem all over the world. MDR tuberculosis (MDR-TB) caused by these strains has emerged within the last decade and rapid detection is critical for the effective treatment of patients. Recently, a resazurin microtiter assay plate for detecting MDR strains was developed. In this study, it was adapted to screw-cap tubes and the activity of isoniazid (INH) and rifampin (RIF) to 50 M. tuberculosis clinical isolates was tested by this method for the first time. Results were compared with the radiometric reference method for the susceptibility testing of M. tuberculosis complex. The results of both methods were in 100% and 96% agreement for RIF and INH, respectively. Specificity, sensitivity, positive predictive value and negative predictive value were 91.7%, 100%, 92.8% and 100% for INH, respectively. All of these values were 100% for RIF. Susceptibility testing results were obtained on the 8th day of incubation for 42 isolates and on the 9th day for the other eight strains. Our results indicate that this method is suitable for the early determination of INH and RIF resistance in developing countries because it is inexpensive, rapid and easy to perform.

Topics: Antitubercular Agents; Drug Resistance, Microbial; False Positive Reactions; Humans; Indicators and Reagents; Isoniazid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Oxazines; Predictive Value of Tests; Rifampin; Sensitivity and Specificity; Tuberculosis, Multidrug-Resistant; Tuberculosis, Pulmonary; Xanthenes

This study assessed the performance of a rapid, low-cost, colorimetric method, the resazurin microtitre assay (REMA) plate method, for the detection of resistance to isoniazid and rifampicin in 136 clinical isolates of Mycobacterium tuberculosis from two hospitals in Algiers. MICs were determined and the results were compared with those obtained with the conventional proportion method on Löwenstein-Jensen medium. Excellent results were obtained for the REMA plate method, with a sensitivity of 100 % for both isoniazid and rifampicin and a specificity of 98.3 and 99.2 %, respectively. The REMA plate method appears to be a reliable method for the rapid determination of multidrug-resistant tuberculosis and is a good alternative for use in resource-limited countries such as Algeria.

Topics: Algeria; Antibiotics, Antitubercular; Antitubercular Agents; Colorimetry; Humans; Indicators and Reagents; Isoniazid; Mycobacterium tuberculosis; Oxazines; Rifampin; Tuberculosis, Multidrug-Resistant; Xanthenes

To evaluate the performance of three rapid low-cost methods for the detection of resistance to first-line drugs in Mycobacterium tuberculosis.. One hundred M. tuberculosis clinical isolates were tested by the nitrate reductase assay (NRA), the MTT test and the resazurin microtitre assay (REMA), and the results compared with those obtained with the gold standard proportion method (PM) on Lowenstein Jensen medium.. The results using the three methods showed a good sensitivity and specificity between 94% and 100% for the detection of rifampicin and isoniazid resistance. Specificity for ethambutol and streptomycin using MTT and resazurin was low (58-89%). In contrast, NRA showed a good agreement for all first-line drugs tested.. This study shows a high level of agreement of these three low-cost methods compared with the PM for rapid detection of rifampicin and isoniazid resistance. However, more standardization is needed for ethambutol and streptomycin using the MTT test and resazurin microtitre assay. The nitrate reductase assay might represent an inexpensive procedure for rapid detection of resistance to first-line drugs in low-resource countries.

Topics: Antitubercular Agents; Drug Resistance, Multiple, Bacterial; Ethambutol; Formazans; Isoniazid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Nitrate Reductase; Nitrate Reductases; Oxazines; Rifampin; Sensitivity and Specificity; Streptomycin; Tetrazolium Salts; Xanthenes

The performance of flow cytometry and the microplate Alamar Blue assay in determining susceptibility of Mycobacterium tuberculosis was assessed by testing 150 Brazilian isolates. The overall agreement was 97.3 and 98% for isoniazid and 94.7 and 100% for rifampin by flow cytometry and MABA, respectively. This study was entirely done in a developing country.

Topics: Antitubercular Agents; Brazil; Coloring Agents; Flow Cytometry; Humans; Isoniazid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Oxazines; Rifampin; Xanthenes

To study the performance of three rapid low cost methods for the detection of rifampicin resistance.. A panel of 20 coded Mycobacterium tuberculosis strains was tested blindly by the low cost methods: nitrate reductase, MTT and resazurin assays, and compared with the results obtained with the gold standard methods: the proportion method on Löwenstein-Jensen medium and the BACTEC TB 460 system. We have also tested two commercial tests: MGIT and INNO LiPA Rif.TB kit.. Complete agreement was observed among all methods.. These three simple methods might become inexpensive alternative procedures for rapid detection of rifampicin resistance in low-resource countries.

Topics: Antibiotics, Antitubercular; Colorimetry; Culture Media; DNA-Directed RNA Polymerases; Drug Resistance, Bacterial; Humans; Indicators and Reagents; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Nitrate Reductase; Nitrate Reductases; Oxazines; Oxidation-Reduction; Peru; Reagent Kits, Diagnostic; Rifampin; Tetrazolium Salts; Thiazoles; Tuberculosis; Xanthenes

A method for detecting multidrug-resistant Mycobacterium tuberculosis by using a reduction of resazurin is described. Eighty clinical isolates were evaluated against isoniazid and rifampin; results at 7 days were compared with those of the proportion method. Specificity and sensitivity were excellent. The method is simple, inexpensive, and rapid and might be used with other antituberculosis drugs.

Topics: Antitubercular Agents; Colorimetry; Drug Resistance, Microbial; Humans; Indicators and Reagents; Isoniazid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Oxazines; Peru; Rifampin; Tuberculosis; Xanthenes

A colorimetric, microplate-based Alamar Blue assay (MABA) method was used to determine the MICs of isoniazid (INH), rifampin, streptomycin (SM), and ethambutol (EMB) for 34 Peruvian Mycobacterium tuberculosis isolates (including both pansensitive and multidrug-resistant strains) and the H37Rv strain by using bacterial suspensions prepared directly from solid media. Results for all isolates were available within 8 days. Discordant results were observed on initial tests for 3 of 16 INH-susceptible isolates, 5 of 31 EMB-susceptible isolates, and 2 of 4 SM-resistant isolates (by the BACTEC 460 system). The overall agreements between the MICs obtained by MABA and the results obtained with the BACTEC 460 system were 87.9% for initial results and 93.6% after retesting 12 of 17 samples with discrepant results. Interpretation of MABA endpoints improved with technical experience. The MABA is a simple, rapid, low-cost, appropriate technology which does not require expensive instrumentation and which makes use of a nontoxic, temperature-stable reagent.

Topics: Antibiotics, Antitubercular; Antitubercular Agents; Bacteriological Techniques; Coloring Agents; Culture Media; Drug Resistance, Microbial; Drug Resistance, Multiple; Ethambutol; Humans; Isoniazid; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Oxazines; Peru; Rifampin; Sensitivity and Specificity; Streptomycin; Tuberculosis; Xanthenes