A novel agar base medium for drug susceptibility testing of Mycobacterium tuberculosis isolates

Aim: In this study, it was aimed to evaluate AYC.2.2 agar for susceptibility testing of Mycobacterium tuberculosis clinical isolates against first-line drugs. Materials & methods: In the present study, 208 M. tuberculosis clinical isolates were tested on AYC.2.2 agar, which was previously validated for the first-line drugs isoniazid, rifampicin, streptomycin and ethambutol. Results: Specificity, sensitivity, positive predictive value, negative predictive value and agreement for isoniazid–rifampicin–ethambutol–streptomycin were 100–100–97.2–99.3%, 94.8–94.8–79.3–94.3%, 100–100–82.1–98.03%, 97.03–98.03–96.7–98.08%, 98.07–98.5–94.7-98.07%, respectively. Conclusion: Results had shown that the newly developed AYC.2.2 agar promises as an alternative medium that can be used to perform susceptibility testing of M. tuberculosis isolates. However, further multicenter studies are needed to be used in routine mycobacteriology laboratories.