Study on the genotypes of 260 Mycobacterium tuberculosis isolates by Spoligotyping method in Jiangsu province, China

Abstract

To study the genotypes of Mycobacterium tuberculosis (M. tuberculosis) strains isolated from Jiangsu province and to explore the relationship between the 'Beijing family' and the drug resistance of M. tuberculosis. Two hundred and sixty M. tuberculosis strains were isolated from 30 drug surveillance sites in Jiangsu province. Susceptibility of the isolates to the first-line antituberculosis drugs (isoniazid, streptomycin, rifampicin and ethambutol) was tested by using the proportion method. Molecular typing of M. tuberculosis strains was determined by Spoligotyping and analyzed with BioNumerics software. Based on Spoligotyping fingerprint, 260 strains showed 34 different genotypes, including 27 exclusive genotypes and 7 shared genotypes. These strains could be clustered into two groups: the Beijing family (80.4%, 209/260) and the Non-Beijing family (19.6%, 51/260). Data from logistic regression analysis revealed that infection by the Beijing family was related to an increased risk of multi-drug resistant M. tuberculosis, with the OR (95%CI) of 11.07 (1.45 - 84.50). Non-Beijing families including T1, T2, H3, H4, CAS, LAM, U and MANU2 families were also found. Among them, the CAS, LAM and MANU2 families were first reported in Jiangsu province. It was revealed that the marked gene polymorphisms did exist in M. tuberculosis strains. The Beijing family had been the predominant strain circulating in Jiangsu province, which might be related to multi-drug resistant M. tuberculosis strains.