Microarray-based pncA genotyping of pyrazinamide-resistant strains of Mycobacterium tuberculosis.

Drug-resistant Mycobacterium tuberculosis poses a significant threat to the treatment of tuberculosis (TB). The current susceptibility testing for the first-line TB drug pyrazinamide (PZA) is not only time-consuming but also difficult, due to the requirement for acid pH for drug activity. Predominantly, resistance to PZA in M. tuberculosis is caused by mutations in the pncA gene, and the detection of pncA mutations can be an indicator of PZA resistance. In this study, the use of a previously developed microarray method for the rapid detection of PZA-resistant M. tuberculosis based on identifying mutations in the pncA gene was evaluated. Microarray analysis was performed in a blind manner on 33 clinical isolates of M. tuberculosis for which the sequence of the pncA gene had not previously been determined. The results showed that all mutations in PZA-resistant strains identified by DNA sequencing could be unambiguously detected by the microarray method. It is concluded that the microarray method is a valuable tool for the rapid screening and genetic identification of potential PZA-resistant M. tuberculosis strains.