Evaluation of crystal violet decolorization assay for minimal inhibitory concentration detection of primary antituberculosis drugs against Mycobacterium tuberculosis isolates

Abstract

In this study we evaluated the crystal violet decolorization assay (CVDA) for detection of minimum inhibitory concentration (MIC) of antituberculosis drugs. 53 isolates were tested in this study and 13 of them were multidrug resistant (MDR) isolates. The antibiotics concentrations were 2-0.06 mg/L for isoniazid (INH) and rifampicin (RIF) and were 16-0.25 mg/L for streptomycin (STM) and ethambutol (EMB). Crystal violet (CV-25 mg/L) was added into the microwells on the seventh day of incubation and incubation was continued until decolorization. Decolorization of CV was the predictor of bacterial growth. Overall agreements for four drugs were detected as 98.1%, and the average time was detected as 9.5 ± 0.89 day after inoculation. One isolate for INH and two isolates for STM were determined resistant in the reference method, but susceptible by the CVDA. One isolate was susceptible to EMB by the reference method, but resistant by the CVDA. All results were concordant for RIF. This study shows that CVDA is a rapid, reliable and suitable for determination of MIC values of Mycobacterium tuberculosis. And it can be used easily especially in countries with limited-sources.

Multicenter evaluation of crystal violet decolorization assay (CVDA) for rapid detection of isoniazid and rifampicin resistance in Mycobacterium tuberculosis

“…In his study, sensitivity and specificity were 92.5% and 96.4%for INH and were 88.8% and 100% for RIF. Coban et al 20. evaluated CVDA for MIC detection of primary anti-tuberculosis drugs.…”

Evaluation of crystal violet decolorization assay and resazurin microplate assay for antimycobacterial screening

“…If the MIC value exceeds the susceptibility breakpoint value, the isolate was considered to be resistant to that tested antibiotics. Susceptibility breakpoints values were 0.125 and 0.5 mg/L for isoniazid and rifampicin, respectively (Coban et al., 2016b).…”