Direct identification of mycobacteria from culture media using a multiplex real-time PCR assay: report on its application in a clinical laboratory in a region of high tuberculosis endemicity

Abstract

There are few commercial assays that easily and correctly identify the mycobacteria from culture in a clinical laboratory with a high workload. Thus, we developed and evaluated a scheme for the identification of mycobacteria using a multiplex real-time PCR assay and report on its application in our laboratory. The scheme consisted of 3 stepwise PCRs. Mycobacterium tuberculosis complex (MTC) and nontuberculous mycobacteria (NTM) were differentially detected in the step 1 PCR, and the NTM species were identified in the step 2 and 3 PCRs. Over the 1.5-year study period, 1136 isolates of MTC and 618 isolates of NTM were detected, and the species of 608 (98.4%) of the 618 NTM isolates were identified. We conclude that the established scheme is a very useful diagnostic approach for the rapid and accurate identification of MTC and clinically relevant NTM in a clinical laboratory in a region where tuberculosis is endemic.