scholarly journals Can Thin Layer Agar Test Play a Key Role in the Diagnosis of Tuberculosis in Low-Resource Settings?

2021 ◽  
Vol 14 (7) ◽  
Author(s):  
Sulaiman A Al Yousef ◽  
Khalid AbdelRahim ◽  
Ahmed Mohamed Ali
Keyword(s):  
Thin Layer ◽  
Susceptibility Testing ◽  
Characteristic Curve ◽  
Cost Effective ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
Resource Limited Settings ◽  
Resource Limited ◽  
Tuberculosis Diagnosis ◽  
Agar Method

Background: Fast, reliable, and cost-effective tests are recommended for tuberculosis diagnosis and drug susceptibility testing, especially in resource-limited settings. Objectives: This study aimed to evaluate the performance of thin-layer agar for tuberculosis diagnosis and drug susceptibility testing. Methods: Samples were collected from patients with presumptive tuberculosis and tested using thin-layer agar for tuberculosis and drug susceptibility testing in parallel with Lowenstein Jensen culture method for tuberculosis diagnosis and proportion method for drug susceptibility testing as the gold standard. Receiver operating characteristic curve analysis was performed to calculate the performance parameters. Results: Thin-layer agar method showed sensitivity and specificity values of 96.63% and 62.50%, respectively, for the isolation of Mycobacterium tuberculosis directly from specimens. Drug susceptibility results using thin-layer agar showed sensitivity values for isoniazid, rifampicin), ethambutol and streptomycin were 94.74%, 86.84%, 94.74% and 81.58%, respectively, while the specificity values were 100%, 100%, 86.27% and 100% for isoniazid, rifampicin, ethambutol and streptomycin, respectively. Results were available in a median time of 16 days for thin-layer agar and 25 days for the conventional method. Conclusions: The thin-layer agar method is a relatively rapid, simple, and cost-effective method for the diagnosis and drug susceptibility testing of M. tuberculosis. It may be a useful tool for establishing tuberculosis laboratories in resource-limited settings because it does not require expensive equipment and a high level of training. Our study may help in choosing the appropriate treatment and control of tuberculosis.

scholarly journals Thin layer agar-based direct phenotypic drug-susceptibility testing on sputum in Eswatini rapidly detects Mycobacterium tuberculosis growth and rifampicin resistance, otherwise missed by WHO endorsed diagnostic tests.

2021 ◽  
Author(s):  
E. Ardizzoni ◽  
E. Ariza ◽  
D. Mulengwa ◽  
Q. Mpala ◽  
R. de La Tour ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Thin Layer ◽  
Susceptibility Testing ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
Field Conditions ◽  
Reference Laboratory ◽  
Solid Media ◽  
Specific Setting ◽  
Lowenstein Jensen

BACKGROUND: Xpert®MTB/RIF rapidly detects resistance to rifampicin (RR), however this test misses the I491F-RR conferring rpoB mutation, common in Southern Africa. In addition, Xpert®MTB/RIF does not distinguish between viable and dead Mycobacterium tuberculosis (MTB). OBJECTIVE: To investigate the ability of thin layer agar (TLA) direct drug-susceptibility testing (DST) to detect MTB and its drug-resistance profiles in field conditions in Eswatini. DESIGN: Consecutive samples were tested in parallel with Xpert®MTB/RIF and TLA for rifampicin (1.0 μg/ml) and ofloxacin (2.0 μg/ml). TLA results were compared at the Reference Laboratory in Antwerp with indirect DST on Löwenstein-Jensen or 7H11 solid media and additional phenotypic and genotypic testing to resolve discordance. RESULTS: TLA showed a positivity rate for MTB detection of 7.1% versus 10.0% for Xpert®MTB/RIF. Of a total of 4547 samples included in the study, 200 isolates were available for comparison to the composite reference. Within a median of 18.4 days, TLA detected RR with 93.0% sensitivity (CI-77.4-98.0) and 99.4% specificity (CI 96.7-99.9), versus 62.5% (CI 42.7-78.8) and 99.3% (CI 96.2-99.9) for Xpert®MTB/RIF. Eight isolates, 28.6% of all RR confirmed isolates, carried the I491F mutation, all detected by TLA. TLA also correctly identified 183 of the 184 ofloxacin-S isolates (99.5% specificity, CI 97.0-99.9). CONCLUSIONS: In field conditions, TLA rapidly detects RR, and in this specific setting contributed to detection of additional RR patients over Xpert®MTB/RIF, mainly but not exclusively due to I491F. TLA also accurately excluded fluoroquinolones resistance.

scholarly journals Direct drug susceptibility testing of Mycobacterium tuberculosis against primary anti-TB drugs in northern India

2010 ◽  
Vol 4 (11) ◽  
pp. 695-703 ◽  
Author(s):  
Anamika Gupta ◽  
Shampa Anupurba
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Susceptibility Testing ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
Inexpensive Method ◽  
Sensitivity Testing ◽  
Northern India ◽  
Resource Limited ◽  
Nitrate Reductase Assay ◽  
Proportion Method

Introduction: The present study aimed to evaluate a rapid and inexpensive colorimetric nitrate reductase assay (NRA) performed directly on sputum specimens for detection of drug resistance in Mycobacterium tuberculosis (MTB). Methodology: A total of 55 sputum samples were decontaminated and processed by modified Petroff's method.  A part of the resulting suspension was used to perform direct NRA (DNRA) and direct proportion method (DPM) analysis. Of the 55 samples, 45 could be used to compare the two methods. Indirect drug sensitivity testing (DST) was also done for 14 MTB strains. Results: Excellent agreement was found between DNRA and DPM testing with κ values of 1, 0.91, 0.91, and 1 for RIF, INH, STR and EMB respectively. The sensitivities and specificities of DNRA compared to that of DPM were observed to be 100 and 100%, 100 and 93%, 95 and 96%, 100 and 100 % for RIF, INH, STR, and EMB respectively. Comparing the results of DNRA, DPM and indirect NRA with those of the gold standard indirect PM for 14 MTB strains showed that sensitivities, specificities and percent agreements were 100, 100 and 100% for all four tested drugs. Results for most of the specimens (55.6%) were available in 21 days with DNRA. Conclusions: We have saved valuable time by omitting the pre-isolation step and conclude that DNRA is a rapid, accurate and inexpensive method for direct DST of MTB and may become an appropriate alternative method for the resource limited settings.

scholarly journals Drug susceptibility testing using molecular techniques can enhance tuberculosis diagnosis

2008 ◽  
Vol 2 (01) ◽  
Author(s):  
Thomas C. Victor ◽  
Rabia Johnson ◽  
Annemie M. Jordaan ◽  
Rob Warren ◽  
Marleine Bosman ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
Molecular Techniques ◽  
Tuberculosis Diagnosis

Intelligent whole-blood imaging flow cytometry for simple, rapid, and cost-effective drug-susceptibility testing of leukemia

Lab on a Chip ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 2688-2698 ◽  
Author(s):  
Hirofumi Kobayashi ◽  
Cheng Lei ◽  
Yi Wu ◽  
Chun-Jung Huang ◽  
Atsushi Yasumoto ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Deep Learning ◽  
Whole Blood ◽  
Susceptibility Testing ◽  
Cost Effective ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
Leukemia Cells ◽  
Imaging Flow Cytometry ◽  
Blood Imaging

The drug susceptibility of leukemia cells in whole blood is evaluated by using extreme-throughput imaging flow cytometry with deep learning.

Accuracy of molecular drug susceptibility testing amongst tuberculosis patients in Karakalpakstan, Uzbekistan

2021 ◽  
Author(s):  
Horacio Gil ◽  
Hasmik Margaryan ◽  
Ismailov Azamat ◽  
Bekturdieva Ziba ◽  
Halmuratov Bayram ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
Tuberculosis Patients
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