Study On The Genotype And Epidemic Characteristics Of Mycobacterium Tuberculosis Isolates From Southern Xinjiang

Objective: To study the genotype polymorphism and epidemic characteristics of Mycobacterium tuberculosis isolated from southern Xinjiang,explore the main epidemic strains and associated risk factors,and then provide molecular epidemiology clues for tuberculosis prevention and control in the region.Methods: Three hundred and fifty-three M.tuberculosis clinicals isolates collected in Southern Xinjiang were genotyped using15-locus MIRU-VNTR typing and spoligotyping.The results were analyzed with the software Bio Numerics(Version7.6).Multi-factor logistic regression analysis was used to understand the factors affecting the clustering of strains and the prevalence of Beijing family strains.Results: The 353 isolates were divided into 56 SIT(Shared International Types)by spligotyping.Beijing family strains accounted for the largest proportion,up to58.92%.Among them,190 isolates were with typical Beijing family genotype(SIT1)and18 isolates with atypical Beijing family genotype.Among the 145 non-Beijing family isolates,26 are undefined isolates,and the other 119 non-Beijing family isolates are divided into 7 known families,including 47 of CAS family,21 of T family,30 of Ural-2,11 of EAI family,3 of H family,2 of LAM9,5 of Manu2.The prevalence of Beijing genotype in patients of youger age group(≤30 years old)were higher than that in patients with ≥50 years old(odds ratio=2.867,95%CI:1.578～5.209).The 353 strains were divided into 288 genotypes with 15-locus MIRU-VNTR,including 29 genehclusters and 259 unique genotypes.The clustering rate was 18.41%.The clustering rate of Beijing strains was significantly higher than that of non-Beijing strains(P<0.05).The 353 isolates were classified into I,II,III,IV and V gene clusters according to 15-locus MIRU-VNTR results,among which the II group accounted for the highest,up to 80.7%.MIRU10,MIRU16,MIRU26 and MTUB21 were highly discriminative in the 15-locus MIRU-VNTR typing.The resolution of 15-locus MIRU-VNTR against M.tuberculosis was significantly higher than that of Spoligotyping,especially for the strains of Beijing family.Conclusion: Obvious genetic polymorphism of M.tuberculosis were found with Beijing family genotype as the most prevalent and youger patients incline to infect with Beijing genotype in southern Xinjiang.