| ObjectiveTo study the molecular epidemiological characteristics of multidrug-resistant(MDR)Mycobacterium tuberculosis in Jiangsu province.(1)To establish the genotyping system of Mycobacterium tuberculosis based on MIRU-VNTR method,and with MIRU-VNTR,to analyze the genetic strains and dominant strains of MDR-TB in different areas of Jiangsu province and to establish MDR-TB genome polymorphism database.(2)To evaluate the application of MIRU-VNTR typing in MDR-TB epidemiology,to describe the genotype distribution and clustering characteristics of multidrug-resistant Mycobacterium tuberculosis in Jiangsu province,and to compare with that of non-MDR-TB;To analyze the relevance between MDR-TB genotype and drug-resistant gene mutations and to know about the possible influence of drug-resistant Mycobacterium tuberculosis gene mutations on the strain genetic evolution.MethodsA total of 235 MDR-TB strains isolated from drug-resistance monitoring project in Jiangsu province in 2008 were selected as study objects,and 272 non-MDR isolates were randomly selected as control.The ratio of the two groups was 1:1.2.The internationally standardized MIRU-VNTR24 locus was used to detect the genotypes of Mycobacterium tuberculosis and the resistance mutation locus of MDR were detected by HAIN linear probe technique.ResultsComparing the MIRU-VNTR gene polymorphisms of MDR-TB with non-MDR-TB,the 235 MDR strains were divided into 206 genotypes,of which 185 genotypes unique,17 genotypes 2 strains,3 genotypes 3 strains and 1 genotype 7 strains.The clustering rate was 21.3%(50/235).272 non-MDRs were divided into 229 genotypes,of which 210 were unique,11 genotypes 2 strains,4 genotypes 3 strains,2 genotypes 4 strains,1 genotype 7 strains,and 1 genotype 13 strains.The rate of clustering was 22.8%(62/272).Comparing with the clustering rate of the two groups,there was no statistical difference(X2 = 0.169,p = 0.681),which showed that there was no significant difference in clustering between MDR and non-MDR.MIRU-VNTR24 locus was used to detect 235 MDR-TB strains and 272 non-MDR-TB strains.The non-parametric test showed that there was no statistically significant difference between the two groups at 24 locus.The resolution index of each locus was calculated and 13 sites with a resolution index greater than 0.3 were selected.The other two groups had a P value of less than 0.1 and a total of 14 locus(ETRA?ETRE?MIRU10?MIRU23?MIRU26?MIRU39?MIRU40?Mtub04?Mtub21?Mtub30?Mtub39?Oubllb?Qub26?Qub4156c).The resolution of the 24 locus and 14 locus was 0.9982,the MDR-24 was 0.9964,the MDR-14 was 0.9958,and the non-MDR-14 was 0.9967.There was no significant difference between the 14 loci and the 24 locus.The mutations of rifampin resistance gene(rpoB)and isoniazid resistance gene(katG,inhA)were detected in 235 MDR strains by HAIN linear probe technique.The mutation type of MDR-TB gene was obtained.The further analysis of Mycobacterium tuberculosis drug resistant mutation sites of 5 strains cluster or above showed that Mycobacterium tuberculosis drug resistant mutation sites of clusters were not similar,indicating that there was no direct relevance between strain clustering and its drug resistance mutations.Conclusion:There was no statistical difference in gene polymorphism between MDR-TB and non-MDR-TB and there was no relevance between Mycobacterium tuberculosis clustering and drug-resistance genes.The current general tuberculosis control strategy can be applied to the prevention and treatment of MDR-TB. |
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