Comparison of repetitive-sequence-based polymerase chain reaction with random amplified polymorphic DNA analysis for rapid genotyping of nontuberculosis mycobacteria.

Nontuberculosis mycobacteria (NTM) are an important cause of human disease and infections. Though less notorious than tuberculosis, these infections are clinically significant and have been associated with outbreaks in various settings. To accommodate outbreak investigations for the numerous species of NTM, we evaluated a DiversiLab repetitive-sequence-based PCR (rep-PCR) kit for genotyping of mycobacteria. This kit was used to genotype both rapidly and slowly growing mycobacteria and was compared with other PCR-based genotyping methods, including random amplified polymorphic DNA (RAPD) analysis, hsp65 gene sequencing, and mycobacterial interspersed repetitive unit - variable number of tandem repeat (MIRU-VNTR) analysis. Compared with RAPD analysis, rep-PCR achieved better reproducibility in testing. When compared with hsp65 gene sequencing and MIRU-VNTR for Mycobacterium avium , rep-PCR provided results that agreed with these less discriminatory genotyping methods but provided a higher level of discrimination for situations such as outbreak investigations. We also evaluated the kit for its ability to identify closely related rapidly growing NTM. While rep-PCR was informative in some cases, a much larger library of isolates would be necessary to truly evaluate it as an identification tool. Overall, rep-PCR was able to provide improved reproducibility over RAPD and a discriminatory genotyping method for the isolates evaluated in this study.