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

Autor: Kadri Klaos, Anna Agejeva, Tiina Kummik, Sirje Laks, Olesja Remets, Sirje Sasi, Anneli Tann, Piret Viiklepp, Alan Altraja
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: International Journal of Infectious Diseases, Vol 104, Iss , Pp 19-26 (2021)
Druh dokumentu: article
ISSN: 1201-9712
DOI: 10.1016/j.ijid.2020.12.071
Popis: Objectives: 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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