Spoligotyping of clinical isolates of Mycobacterium tuberculosis in Xinjiang

Objective To investigate the spoligotyping of the clinical isolates of Mycobacterium tuberculosis in Xinjiang, the gene polymorphism and main prevalent strain of M. tuberculosis in this region. Methods M. tuberculosis isolates were collected consecutively in The Chest Hospital of Xinjiang Uyghur Autonomous Region. The drug susceptibility test was conducted with proportion method. Genotyping on these strains was conducted with the spacer oligonucleotide typing (Spoligotyping), and clustering of gene was analyzed with BioNumerics 5.0 software. Results A total of 175 M. tuberculosis isolates have been collected, of which 115 were sensitive to four first line drugs: rifampin (RFP), isoniazid (INH), streptomycin (SM) and ethambutol (EMB), 60 were drug resistant, including 31 single drug resistant and 29 multi drug resistant strains. The spoligotyping Results showed that there were 4 clusters including 49 genotypes, in which the biggest cluster was Beijing strains (Beijing genotype), accounting for 68.57%(120/175). Of 119 Beijing strains, 76 were drug sensitive and 43 were drug resistant, accounting for 63.87% and 36.13% respectively, while of 54 non-Beijing strains, 37 were drug sensitive and 17 were drug resistant, accounting for 68.52% and 31.48% respectively. No significant difference on drug resistance was found between Beijing strains and non-Beijing strains. Conclusion It is confirmed that there is obvious gene polymorphism of clinical strains of M. tuberculosis isolated in Xinjiang, the main prevalent strain belongs Beijing genotype. The result showed that there is no relationship between Beijing genotype and drug resistance.