Evaluation of Thin Layer Agar 7H11 for Direct Susceptibility Testing of Mycobacterium Tuberculosis Complex against Second Line Anti Tuberculosis Drugs on Smear Positive Specimens

Hussain, Ashfaq; Zaman, Gohar; Satti, Luqman; Ikram, Aamer; Gardezi, Adeel; Khadim, Muhammad Tahir

doi:10.29271/jcpsp.2019.06.520

Cited by 4 publications

(4 citation statements)

References 4 publications

(4 reference statements)

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“…The overall median time until a CT DST result was 13 days, which is consistent with previous results by others [23,35]. Still, we found that a few of the CT plates were read very late, even 45 days after culturing (Fig 2 and 3) because our study protocol for indirect DST using the CT plates insisted of having 50 colonies in the control quadrant before reporting the results.…”

Section: Resultssupporting

confidence: 90%

Successful introduction of the Colour Test into inexperienced settings

Klaos

Kummik

et al. 2020

Preprint

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Implementation of non-commercial in-house methods into routine clinical diagnostics becomes more challenging, because these methods are not internationally standardized, most of the research in that field is underfunded and recommendations for their use is lacking. We conducted a study, where all the technicians were previously unfamiliar to the Colour Test (CT), a colorimetric redox indicator and thin-layer agar based Mycobacterium tuberculosis complex diagnosis and direct drug susceptibility testing (DST) method, and tested whether the performance of this in-house method is dependent on experience of the laboratory personnel.After a two-day hands-on training, six panels of 150 M. tuberculosis isolates were cultured onto CT plates prepared in-house by six technicians in two laboratories. Finally, triplicate readings of 900 CT plates resulted 18 DST patterns for each of the initial isolates. The results were compared to each other and the gold standard of BACTEC MGIT 960 DST results.The median time to produce M. tuberculosis CT DST results for three antituberculosis drugs was 13 days. The overall ability to correctly define phenotypic resistance ranged from 94.7% for levofloxacin to 95.8% and 97.3% for isoniazid and rifampicin, respectively. The test specificities were even higher exceeding 97% for all three drugs tested. Interobserver agreement reached 100% in one of the laboratories and exceeded 97% for levofloxacin and 99% for isoniazid and rifampicin in the second laboratory.The implementation of the CT into a new laboratory was straightforward with only minimal guidance. This study proves that the CT is highly reproducible and easily interpreted by previously inexperienced personnel.

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Section: Resultssupporting

confidence: 90%

Successful introduction of the Colour Test into inexperienced settings

Klaos

Kummik

et al. 2020

Preprint

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“…One could predict that this time could be slightly different and perhaps even shorter in routine settings, where the majority of cultured plates remain negative for 6 weeks and can quickly be examined 3 times weekly. The overall median time until a CT DST result was 13 days, which is consistent with previous results by others using the method either as an indirect or direct DST (Hussain et al, 2019;Toit et al, 2012). We found that a few of the CT plates were read very late, even 45 days after culturing (Figures 2 and 3).…”

Section: Discussionsupporting

confidence: 90%

A successful introduction to a non-expert setting of the thin-layer agar Colour Test as an indirect phenotypic drug susceptibility test for Mycobacterium tuberculosis

Klaos

Kummik

et al. 2021

International Journal of Infectious Diseases

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We evaluated the performance of the MDR/XDR-TB Colour Test (CT) as an in-house thin-layer agar-based indirect drug susceptibility test (DST) for Mycobacterium tuberculosis (MTB) in a non-expert setting in Estonia. Methods: After 2 days of hands-on training for laboratory technicians, 6 panels of 150 MTB isolates were cultured onto CT plates prepared in-house in 2 laboratories. Triplicate readings of 900 CT plates resulted in 18 DST patterns for each initial isolate. Time intervals to the results and for media preparation were estimated, and intra-and interobserver agreement, test sensitivities and specificities were calculated. BACTEC MGIT 960 DST was used as a reference. Results: The median time to produce DST results for isoniazid, rifampicin and levofloxacin was 13 days. CT sensitivity was 94.7% for levofloxacin, 95.8% for isoniazid and 97.3% for rifampicin. Test specificities were >97% for all 3 drugs. Interobserver agreement was 100% in Lab A and in Lab B >97% for levofloxacin and 99% for isoniazid and rifampicin. Conclusions: The implementation of the CT into a new laboratory was straightforward with only minimal guidance required. This study proves that the CT is highly reproducible and easily interpreted by previously inexperienced personnel.

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“…The mean report time of TLA was very close to that of MGIT 960 from pulmonary specimens, within the range of from 9.6 to 12.5 days (Martin et al, 2009b;Satti et al, 2010), but we have not compared with MGIT 960 in pleural TB, simultaneously. Besides, TLA showed comparable results to MGIT 960 for the rapid detection of M.tb drug susceptibility (DST) of second line anti-TB agents (Minion et al, 2010;Ardizzoni et al, 2015;Hussain et al, 2019). However, whether TLA supplemented with Rpfs could be suitable and promote clinical drug resistance detection still needs further study.…”

Section: Discussionmentioning

confidence: 99%

Rapid Detection of Mycobacterium tuberculosis in Pleural Fluid Using Resuscitation-Promoting Factor-Based Thin Layer Agar Culture Method

Xing

et al. 2022

Front. Microbiol.

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BackgroundPleural tuberculous is difficult to diagnose. Culture is still considered the gold standard, especially in resource-limited settings where quick, cheap, and easy techniques are needed. The aim of the study was to evaluate resuscitation-promoting factors (Rpfs)-based thin layer agar (TLA) culture method for quick detection of Mycobacterium tuberculosis in pleural fluid.MethodsPatients with suspected pleural TB were enrolled prospectively in our hospital, pleural fluid of all patients were collected, stained with Ziehl–Neelsen for acid-fast bacilli (AFB), cultured on Rpfs-TLA, TLA, and Löwenstein–Jensen (LJ) medium, and identified according to recommended procedures.ResultsA total of 137 suspected pleural TB were enrolled and categorized, including 103 pleural TB (49 confirmed and 54 probable pleural TB) and 34 non-TBP patients. The sensitivity of Rpfs-TLA for total pleural TB was 43.7% (34.5∼53.3%), higher than that of TLA 29.1% (21.2∼38.5%) and LJ 26.2% (18.7∼35.5%) (p < 0.01), and all specificity was 100% in the diagnosis of pleural TB. Median time to detection of a positive culture was 11.8 days (95% CI 10.4∼13.4) for Rpfs-TLA, 21.0 days (95% CI 19.1∼22.9) for TLA, and 30.5 days (95% CI 28.5∼32.5) for LJ (p < 0.001).ConclusionRpfs-TLA is an accurate, rapid, cheap, and easy culture method, which makes it promising for use in clinical laboratories.

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Evaluation of Thin Layer Agar 7H11 for Direct Susceptibility Testing of Mycobacterium Tuberculosis Complex against Second Line Anti Tuberculosis Drugs on Smear Positive Specimens

Abstract: Objective: To evaluate performance of thin layer agar (TLA) 7H11 method for detection of ofloxacin (OFX) and kanamycin (KM) resistance in smear positive clinical specimens of patients with tuberculosis comparing the results with gold standard MGIT 960 system.

Cited by 4 publications

References 4 publications

Successful introduction of the Colour Test into inexperienced settings

Successful introduction of the Colour Test into inexperienced settings

A successful introduction to a non-expert setting of the thin-layer agar Colour Test as an indirect phenotypic drug susceptibility test for Mycobacterium tuberculosis

Rapid Detection of Mycobacterium tuberculosis in Pleural Fluid Using Resuscitation-Promoting Factor-Based Thin Layer Agar Culture Method

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