Mycobacterial interspersed repetitive unit typing in Mycobacterium tuberculosis isolates from Sichuan province in China
Jian-hua Guo1, Wen-liang Xiang2, Geng Zhang3, Tao Luo4, Ning Xie5, Zhi-rong Yang5, Qun Sun5
1 Department of Veterinary Medicine, Southwest University, Chongqing;College of Life Sciences, Sichuan University, Sichuan, China
2 College of Bioengineer, Xihua University, Sichuan, China
3 Department of Veterinary Medicine, Southwest University, Chongqing, China
4 Chengdu Antituberculosis Hospital, Sichuan, P.R, China
5 College of Life Sciences, Sichuan University, Sichuan, China
College of Life Sciences, Sichuan University, 29# Wangjiang Rd, Chengdu, Sichuan 610064, P.R
Source of Support: None, Conflict of Interest: None
Background & objectives : Emergence and spread of drug resistant Mycobacterium tuberculosis is a serious threat to tuberculosis (TB) control programme. Therefore, the objective of this study was to genotype drug-resistant M. tuberculosis strains isolated from patients in Sichuan, China, using Mycobacterial Interspersed Repetitive Units (MIRU) for epidemiological analysis.
Methods: Drug-resistance testing of M. tuberculosis isolates from pulmonary TB patients was confirmed by proportion method. Twelve MIRU loci were analyzed on 80 drug-resistant and 9 susceptible isolates by polymerase chain reaction and agarose gel electrophoresis. Hunter-Gaston discriminatory index (HGI) values were determined for each 12 MIRU loci for the evaluation of their discrimination power.
Results: Among 12 MIRU loci examined, polymorphic bands could be generated on 11 loci. Sixty five isolates had distinct MIRU patterns, while other 24 belonged to 8 clusters and resistant to at least one anti-TB drug tested. The association between the MIRU patterns and the mutation patterns of drug-resistance relevant target genes was not significant among the drug-resistant isolates.
Interpretation & conclusions : The results showed that with a satisfactory discrimination power exhibited, the 12 loci based MIRU typing could be a valuable tool for epidemiological studies in M. tuberculosis isolates from Sichuan.