scholarly journals Rapid drug susceptibility testing for Mycobacterium tuberculosis in Thin layer agar media

2013 ◽  
Vol 7 (1) ◽  
pp. 02-06 ◽  
Author(s):  
Habiba Binte Alam ◽  
Md. Ruhul Amin Miah ◽  
S. M. Mostafa Kamal ◽  
Chandan Kumar Roy ◽  
Ahmed Abu Saleh
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Thin Layer ◽  
Rapid Detection ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Drug Susceptibility Testing ◽  
Clinical Isolates ◽  
Resistant Tuberculosis ◽  
Proportion Method ◽  
Petri Plate

There is a great need to determine the susceptibility of individual Mycobacterium tuberculosis strains as rapidly as possible because emergence of multidrug-resistant and extensively drug-resistant tuberculosis in developing countries. The study was conducted to evaluate the thin layer agar (TLA) media for rapid detection of resistance of M.tuberculosis to rifampicin (RMP) and isoniazid (INH) in clinical isolates and to determine the sensitivity and time to positivity compared to the proportion method. One hundred clinical isolates of M.tuberculosis were studied. For the TLA method, three compartment Petri plate containing 7H11 agar and 7H11 agar with RMP and INH. Results were compared to the proportion method for RMP and INH. The sensitivity for INH and RMP+INH was 85.7 % and 100%. The use of a TLA plate enables the rapid detection of resistance to the two prime anti-tuberculosis drugs RMP and INH in a median time of 9.60 days. TLA was a rapid method for the detection of resistance of M.tuberculosis in the two drugs studied. This faster method is simple to perform, providing an alternative method when more sophisticated techniques are not available in low-resource settings.DOI: http://dx.doi.org/10.3329/bjmm.v7i1.19313 Bangladesh J Med Microbiol 2013; 07(01): 2-6

scholarly journals Disparities in Capreomycin Resistance Levels Associated with therrsA1401G Mutation in Clinical Isolates of Mycobacterium tuberculosis

2014 ◽  
Vol 59 (1) ◽  
pp. 444-449 ◽  
Author(s):  
Analise Z. Reeves ◽  
Patricia J. Campbell ◽  
Melisa J. Willby ◽  
James E. Posey
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Strong Predictor ◽  
Critical Concentration ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Drug Susceptibility Testing ◽  
Clinical Isolates ◽  
Cross Resistance ◽  
Second Line ◽  
Content Type

ABSTRACTAs the prevalence of multidrug-resistant and extensively drug-resistant tuberculosis strains continues to rise, so does the need to develop accurate and rapid molecular tests to complement time-consuming growth-based drug susceptibility testing. Performance of molecular methods relies on the association of specific mutations with phenotypic drug resistance and while considerable progress has been made for resistance detection of first-line antituberculosis drugs, rapid detection of resistance for second-line drugs lags behind. TherrsA1401G allele is considered a strong predictor of cross-resistance between the three second-line injectable drugs, capreomycin (CAP), kanamycin, and amikacin. However, discordance is often observed between therrsA1401G mutation and CAP resistance, with up to 40% ofrrsA1401G mutants being classified as CAP susceptible. We measured the MICs to CAP in 53 clinical isolates harboring therrsA1401G mutation and found that the CAP MICs ranged from 8 μg/ml to 40 μg/ml. These results were drastically different from engineered A1401G mutants generated in isogenicMycobacterium tuberculosis, which exclusively exhibited high-level CAP MICs of 40 μg/ml. These data support the results of prior studies, which suggest that the critical concentration of CAP (10 μg/ml) used to determine resistance by indirect agar proportion may be too high to detect all CAP-resistant strains and suggest that a larger percentage of resistant isolates could be identified by lowering the critical concentration. These data also suggest that differences in resistance levels among clinical isolates are possibly due to second site or compensatory mutations located elsewhere in the genome.

scholarly journals Drug susceptibility patterns of Mycobacterium tuberculosis from adults with multidrug-resistant tuberculosis and implications for a household contact preventive therapy trial

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Anne-Marie Demers ◽  
◽  
Soyeon Kim ◽  
Sara McCallum ◽  
Kathleen Eisenach ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Sputum Sample ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Preventive Therapy ◽  
Drug Susceptibility Testing ◽  
Study Entry ◽  
Resistant Tuberculosis ◽  
Mdr Tb ◽  
Therapy Trial

Abstract Background Drug susceptibility testing (DST) patterns of Mycobacterium tuberculosis (MTB) from patients with rifampicin-resistant tuberculosis (RR-TB) or multidrug-resistant TB (MDR-TB; or resistant to rifampicin and isoniazid (INH)), are important to guide preventive therapy for their household contacts (HHCs). Methods As part of a feasibility study done in preparation for an MDR-TB preventive therapy trial in HHCs, smear, Xpert MTB/RIF, Hain MTBDRplus, culture and DST results of index MDR-TB patients were obtained from routine TB programs. A sputum sample was collected at study entry and evaluated by the same tests. Not all tests were performed on all specimens due to variations in test availability. Results Three hundred eight adults with reported RR/MDR-TB were enrolled from 16 participating sites in 8 countries. Their median age was 36 years, and 36% were HIV-infected. Routine testing on all 308 were confirmed as having RR-TB, but only 75% were documented as having MDR-TB. The majority of those not classified as having MDR-TB were because only rifampicin resistance was tested. At study entry (median 59 days after MDR-TB treatment initiation), 280 participants (91%) were able to produce sputum for the study, of whom 147 (53%) still had detectable MTB. All but 2 of these 147 had rifampicin DST done, with resistance detected in 89%. Almost half (47%) of the 147 specimens had INH DST done, with 83% resistance. Therefore, 20% of the 280 study specimens had MDR-TB confirmed. Overall, DST for second-line drugs were available in only 35% of the 308 routine specimens and 15% of 280 study specimens. Conclusions RR-TB was detected in all routine specimens but only 75% had documented MDR-TB, illustrating the need for expanded DST beyond Xpert MTB/RIF to target preventive therapy for HHC.

scholarly journals Use of Genotype MTBDRplus Assay for Diagnosis of Multidrug-Resistant Tuberculosis in Nepal

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Elina Maharjan ◽  
Narayan Dutt Pant ◽  
Sanjeev Neupane ◽  
Jyoti Amatya ◽  
Bhawana Shrestha
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Susceptibility Testing ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Drug Susceptibility Testing ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Conventional Drug ◽  
Mdr Tb ◽  
Genotype Mtbdrplus

The main aims of this study were to study the patterns of mutations in rpoB, katG, and inhA genes in Mycobacterium tuberculosis strains isolated from patients from Nepal and to evaluate the performance of genotype MTBDRplus assay, taking conventional drug susceptibility testing as gold standard for diagnosis of MDR-TB. A total of 69 Mycobacterium tuberculosis strains isolated from 73 smear positive sputum samples from patients suspected of suffering from multidrug-resistant tuberculosis were used in our study. The drug susceptibility pattern of Mycobacterium tuberculosis isolated from these sputum specimens was determined by using genotype MTBDRplus assay taking conventional drug susceptibility testing as reference. The sensitivity and specificity of the genotype MTBDRplus assay for the detection of MDR-TB were found to be 88.7% and 100%, respectively. 88.7% of the rifampicin resistant isolates had mutations in rpoB gene. Similarly, 79.7% and 9.4% of isoniazid resistant isolates had mutations in katG and inhA genes, respectively. Genotype MTBDRplus assay was found to be very rapid and highly sensitive and specific method for diagnosis of MDR-TB and will be very helpful for early diagnosis of MDR-TB in high tuberculosis burden countries.

Evaluation of MTBDRsl for detecting resistance in Mycobacterium tuberculosis to second-line drugs

2019 ◽  
Vol 23 (12) ◽  
pp. 1257-1262 ◽  
Author(s):  
R. J. Chandak ◽  
B. Malhotra ◽  
S. Bhargava ◽  
S. K. Goel ◽  
D. Verma ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Rapid Test ◽  
Drug Susceptibility ◽  
Turnaround Time ◽  
Multidrug Resistant ◽  
Drug Susceptibility Testing ◽  
Tb Treatment ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Mdr Tb

SETTING: Patients with presumed multidrug-resistant tuberculosis (MDR-TB) and undergoing MDR-TB treatment from Rajasthan, India.OBJECTIVE: To compare the GenoType® MTBDRsl v.1.0 (MTBDRsl) assay capacity to detect resistance to ofloxacin, amikacin, capreomycin, kanamycin and ethambutol in Mycobacterium tuberculosis with phenotypic drug susceptibility testing (DST) using MGIT™960™ in sputum samples and isolates.DESIGN: Fifty-three smear-positive sputum samples were tested directly by MTBDRsl and 205 MDR-TB isolates were processed using MTBDRsl and DST for five drugs on MGIT960. DNA sequencing was performed in isolates with discordance in the results between the two methods for the gyrA, gyrB and rrs genes.RESULT: Sensitivity and specificity of MTBDRsl was found to be respectively 93.1% and 100% for fluoroquinoline, respectively 75–78% and 100% for aminoglycosides/cyclopeptides, respectively 70% and 92% for ethambutol and respectively 92.3% and 100% for extensively drug-resistant (XDR) TB detection. On sequencing eight discordant isolates for quinolones, mutations were seen in 12.5% of the gyrB gene and among 20 discordant isolates for aminoglycosides/cyclopeptides in the rrs gene in 15% isolates. The turnaround time was 2 days for MTBDRsl vs. 10 days for MGIT960.CONCLUSIONS: MTBDRsl can be used as an initial rapid test for detecting XDR-TB, resistance to quinolones and aminogycosides/cyclopeptides in smear-positive sputum samples.

scholarly journals Resazurin Microtiter Assay Plate Testing of Mycobacterium tuberculosis Susceptibilities to Second-Line Drugs: Rapid, Simple, and Inexpensive Method

2003 ◽  
Vol 47 (11) ◽  
pp. 3616-3619 ◽  
Author(s):  
Anandi Martin ◽  
Mirtha Camacho ◽  
Françoise Portaels ◽  
Juan Carlos Palomino
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Second Line ◽  
Aminosalicylic Acid ◽  
Resistant Tuberculosis ◽  
Proportion Method ◽  
Susceptibility Tests ◽  
Visual Reading ◽  
Microtiter Assay

ABSTRACT The emergence of multidrug-resistant tuberculosis calls for new, rapid drug susceptibility tests. We have tested 150 Mycobacterium tuberculosis isolates against the second-line drugs ethionamide, kanamycin, capreomycin, ofloxacin, and para-aminosalicylic acid by the colorimetric resazurin microtiter assay and the proportion method. By visual reading, MICs were obtained after 8 days. A very good correlation between results by the colorimetric resazurin microtiter assay and the proportion method was obtained. The colorimetric resazurin microtiter assay is inexpensive, rapid, and simple to perform, and implementation of the assay is feasible for low-resource countries.

scholarly journals Performance of the New Version (v2.0) of the GenoType MTBDRslTest for Detection of Resistance to Second-Line Drugs in Multidrug-Resistant Mycobacterium tuberculosis Complex Strains

2016 ◽  
Vol 54 (6) ◽  
pp. 1573-1580 ◽  
Author(s):  
Florence Brossier ◽  
David Guindo ◽  
Anne Pham ◽  
Florence Reibel ◽  
Wladimir Sougakoff ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Dna Sequencing ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Drug Susceptibility Testing ◽  
Second Line ◽  
Content Type ◽  
Injectable Drugs ◽  
Resistant Tuberculosis

Detecting resistance to fluoroquinolones (FQ) and second-line injectable drugs (amikacin [AMK], kanamycin [KAN], and capreomycin [CAP]) is crucial given the worldwide increase in the incidence of extensively drug-resistant tuberculosis (XDR-TB). A new version of the GenoType MTBDRsltest (v2.0) has been developed to improve the detection of resistance to FQ (involvinggyrAandgyrBmutations) and to second-line injectable drugs (involvingrrsandeispromoter mutations) inMycobacterium tuberculosis. A collection of 127 multidrug-resistant (MDR)M. tuberculosiscomplex strains was tested using the first (v1) and second (v2.0) versions of the MTBDRsltest, as well as DNA sequencing. The specificities in resistance detection of v1 and v2.0 were similar throughout, whereas the levels of sensitivity of v2.0 were superior for FQ (94.8% versus 89.6%) and KAN (90.5% versus 59.5%) but similar for AMK (91.3%) and CAP (83.0%). The sensitivity and specificity of v2.0 were superior to those of v1 for the detection of pre-XDR strains (83.3% versus 75.0% and 88.6% versus 67.1%, respectively), whereas the sensitivity of v2.0 was superior to that of v1 only for the detection of XDR strains (83.0% versus 49.1%). In conclusion, MTBDRslv2.0 is superior to MTBDRslv1 and efficiently detects the most common mutations involved in resistance to FQ and aminoglycosides/CAP. However, due to mutations not recognized by v2.0 or to the presence of resistance mechanisms not yet characterized (particularly mechanisms related to monoresistance to aminoglycosides or CAP), the results for wild-type strains obtained with MTBDRslv2.0 should be confirmed by further DNA sequencing and phenotypic drug susceptibility testing.

scholarly journals Multicenter Study of the Accuracy of the BD MAX Multidrug-resistant Tuberculosis Assay for Detection of Mycobacterium tuberculosis Complex and Mutations Associated With Resistance to Rifampin and Isoniazid

2019 ◽  
Vol 71 (5) ◽  
pp. 1161-1167 ◽  
Author(s):  
Maunank Shah ◽  
Sonia Paradis ◽  
Joshua Betz ◽  
Natalie Beylis ◽  
Renu Bharadwaj ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Sensitivity And Specificity ◽  
High Sensitivity ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Drug Susceptibility Testing ◽  
Sputum Smear ◽  
Smear Microscopy ◽  
Resistant Tuberculosis ◽  
Mdr Tb

Abstract Background Tuberculosis (TB) control is hindered by absence of rapid tests to identify Mycobacterium tuberculosis (MTB) and detect isoniazid (INH) and rifampin (RIF) resistance. We evaluated the accuracy of the BD MAX multidrug-resistant (MDR)-TB assay (BD MAX) in South Africa, Uganda, India, and Peru. Methods Outpatient adults with signs/symptoms of pulmonary TB were prospectively enrolled. Sputum smear microscopy and BD MAX were performed on a single raw sputum, which was then processed for culture and phenotypic drug susceptibility testing (DST), BD MAX, and Xpert MTB/RIF (Xpert). Results 1053 participants with presumptive TB were enrolled (47% female; 32% with human immunodeficiency virus). In patients with confirmed TB, BD MAX sensitivity was 93% (262/282 [95% CI, 89–95%]); specificity was 97% (593/610 [96–98%]) among participants with negative cultures on raw sputa. BD MAX sensitivity was 100% (175/175 [98–100%]) for smear-positive samples (fluorescence microscopy), and 81% (87/107 [73–88%]) in smear-negative samples. Among participants with both BD MAX and Xpert, sensitivity was 91% (249/274 [87–94%]) for BD MAX and 90% (246/274 [86–93%]) for Xpert on processed sputa. Sensitivity and specificity for RIF resistance compared with phenotypic DST were 90% (9/10 [60–98%]) and 95% (211/222 [91–97%]), respectively. Sensitivity and specificity for detection of INH resistance were 82% (22/27 [63–92%]) and 100% (205/205 [98–100%]), respectively. Conclusions The BD MAX MDR-TB assay had high sensitivity and specificity for detection of MTB and RIF and INH drug resistance and may be an important tool for rapid detection of TB and MDR-TB globally.

scholarly journals Molecular Investigation of Resistance to Second-Line Injectable Drugs in Multidrug-Resistant Clinical Isolates of Mycobacterium tuberculosis in France

2016 ◽  
Vol 61 (2) ◽  
Author(s):  
Florence Brossier ◽  
Anne Pham ◽  
Christine Bernard ◽  
Alexandra Aubry ◽  
Vincent Jarlier ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Primary Culture ◽  
Susceptibility Testing ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Drug Susceptibility Testing ◽  
Clinical Isolates ◽  
Second Line ◽  
Injectable Drugs ◽  
Resistant Strains

ABSTRACT The second-line injectable drugs (SLID, i.e., amikacin, kanamycin, capreomycin) are key drugs for the treatment of multidrug-resistant tuberculosis. Mutations in rrs region 1400, tlyA, and eis promoter are associated with resistance to SLID, to capreomycin, and to kanamycin, respectively. In this study, the sequencing data of SLID resistance-associated genes were compared to the results of phenotypic drug susceptibility testing by the proportion method for the SLID in 206 multidrug-resistant clinical isolates of Mycobacterium tuberculosis collected in France. Among the 153 isolates susceptible to the 3 SLID, 145 showed no mutation, 1 harbored T1404C and G1473A mutations in rrs, and 7 had an eis promoter mutation. Among the 53 strains resistant to at least 1 of the SLID, mutations in rrs accounted for resistance to amikacin, capreomycin, and kanamycin for 81%, 75%, and 44% of the isolates, respectively, while mutations in eis promoter were detected in 44% of the isolates resistant to kanamycin. In contrast, no mutations in tlyA were observed in the isolates resistant to capreomycin. The discrepancies observed between the genotypic (on the primary culture) and phenotypic drug susceptibility testing were explained by (i) resistance to SLID with MICs close to the critical concentration used for routine DST and not detected by phenotypic testing (n = 8, 15% of SLID-resistant strains), (ii) low-frequency heteroresistance not detected by sequencing of drug resistance-associated genes on the primary culture (n = 8, 15% of SLID-resistant strains), and (iii) other resistance mechanisms not yet characterized (n = 7, 13% of SLID-resistant strains).

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