Genetic Diversity and Drug Resistance of 133 Mycobacterium tuberculosis Isolates from Jiangxi Province, China

Abstract

The genotypes of Mycobacterium tuberculosis (M. tuberculosis) have been found to differ in their resistance to different drugs. Although there is a high incidence of tuberculosis (TB) in Jiangxi, knowledge of the genotypes of M. tuberculosis in this province is limited in recent years. In this study, we investigated the relationship between genetic diversity and drug resistance in M. tuberculosis isolates collected from Jiangxi during January to October, 2014. A total of 133 M. tuberculosis isolates collected from the Jiangxi Chest Hospital were genotyped using both spacer oligonucleotide typing (spoligotyping) and 24-locus mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR). The resistance of these isolates to four first-line, and four second-line, anti-TB drugs, namely, isoniazid, rifampicin, ethambutol, streptomycin, capreomycin, amikacin, levofloxacin and protionamide, was then tested. The results indicate that the Beijing family was the most prevalent genotype (75.94%), followed by the T1 family (13.53%), the MANU2 family (1.50%), the T2 family (0.75%) and the Beijing-like genotype (0.75%). We also found nine new genotypes that did not match those in the Spoldb4.0 database. The 24-locus MIRU-VNTR method had a low clustering rate (10.53%) and a high HGDI (0.9723), and proved a high resolution method for genotyping M. tuberculosis isolates. More than half of the M. tuberculosis isolates collected in the present study were resistant to anti-TB drugs (56.39%, 75/133), and the majority of these were resistant to more than one drug (81.33%, 61/75). The Beijing family is the most prevalent TB strain in Jiangxi province, China. More than half the M. tuberculosis isolates collected were resistant to anti-TB drugs, and the majority was resistant to more than one drug. There was, however, no relationship between genetic diversity and drug resistance. Moreover, our results suggest that treatment history can lead to the development of drug resistance (P < 0.05), which supports the more moderate use of medication in the treatment of TB.