[Establishment of the standard operation program on multiple loci variable numbers tandem repeats analysis typing on Mycobacterium tuberculosis].

Objective: To establish and evaluate the standardized protocol of multiple loci variable numbers tandem repeats (VNTR) analysis (MLVA) for genotyping Mycobacterium tuberculosis (M. tuberculosis).
Methods: 15 VNTR loci were chosen for genotyping 54 Chinese M. tuberculosis strains by PCR-electrophoresis-based VNTR analysis and the results were analyzed by software BioNumerics (Version 5.0).
Results: MLVA method was successfully established and standardized, including the standard protocol for bacterial culture, DNA isolation,PCR and agarose gel electrophoresis and the software analysis. 15 VNTR loci were confirmed, including ETRA, ETRB, ETRC, ETRD, ETRE, MIRU10, MIRU16, MIRU23, MIRU26, MIRU27, MIRU39, MIRU40, Mtub21, Mtub30 and Mtub39, to be suitable for MLVA analysis of M. tuberculosis.
Conclusion: The standardized MLVA method has been established successfully. This method is simple and has powerful capacity for genotyping and strain differentiation, can be used for the network surveillance on pathogens of M. tuberculosis, and the data are comparable between laboratories. It is valuable for tracing the source and studying the trend of prevalence during investigation of M. tuberculosis infections.