| Obejective The aim of this study was to identify the genotype and molecular epidemiological characteristics of Mycobacterium tuberculosis(M.tuberculosis)isolates and to investigate the drug resistance situation including the related factors in four proivnces(municipality,autonomous region)of south China for providing the basic reference data to prevent and control of tuberculosis(TB).Method The clinical M.tuberculosis isolates were collected from Guizhou,Sichuan,Guangxi and Chongqing provinces.The genetic typing was conducted by Spoligotyping and MLVA,respectively.The cluster analysis of the genetic typing was completed with BioNumerics software 5.1.The susceptibility of the strains was tested by the proportion method.The results were analysed with Chi-square and Logistic regression analysis by using SPSS software 22.0.The level of significance was set at P<0.05.Result A total of 500 clinical M.tuberculosis isolates were collected in this study.The genotyping results of the 500 clinical M.tuberculosis isolates presented obvious genetic polymorphism.With Spoligotyping all strains were divided into 2 major gene clusters: Beijing family(58.60%)and Non-Beijing family(41.40%).Among the Non-Beijing family,the proportion of T family,MANU family,LAM family,H family,Orphan genotypes were 20.80%,2.40%,1.60%,2.00% and 14.60%,respectively.The largest of the genotypes in the strains from Guizhou,Guangxi,Sichuan and Chongqing were Beijing family.There was no significant correlation between Beijing family and gender,age,case history,region and the drug-resistance(P>0.05).The genotyping results genotyped by means of MLVA with 15 MIRU-VNTR loci showed that the 500 clinical M.tuberculosis isolates were identified to 323 genotypes and the genetic polymorphism of M.tuberculosis was 64.40%.The total cluster rate was 35.40%.There was no significant correlation between the cluster rate of M.tuberculosis strains and gender,age,case history and genotype(P>0.05).The cluster rate of the sensitive strain was more than that of the drug-resistant strain,the difference between them has statistically significance(P<0.05).The total HGDI for all strains was 0.966 by the MLVA with 15 MIRU-VNTR loci.The results of drug sensitivity test(DST)showed that: the total drug resistant rate was 40.60%.The retreatment drug resistant rate(63.59%)was significantly higher than the initial drug resistant rate(27.22%).The percentages of drug resistance to INH,RFP,EMB and SM were 30.40%,26.00%,9.80% and 24.40%,respectively;of the retreatment cases the percentages of drug resistance to INH,RFP,EMB and SM were 52.17%,50.54%,16.85% and 39.13%,respectively;the monoresistance rate and MDR rate were 13.40% and 20.80%;respectively.The total drug resistant rates in Guizhou,Guangxi,Sichuan and Chongqing were 64.10%,28.88%,59.54% and 20.19% and the MDR rates were 34.62%,11.23%,39.69% and 3.85%,respectively.There were significant differences(P<0.05)in drug-resistant rate to INH,RFP,EMB,SM,the total drug resistance and MDR in these areas.The influence factors were case types and area(P<0.05).The possibilities of drug resistance and MDR in retreatment cases were 3.430 times(95%CI=2.238~5.256)and 4.858 times(95%CI= 2.935~8.041)more than that in the initial treatment cases,respectively.Conclusion The clinical M.tuberculosis strains presented obviously genetic polymorphism in south China and Beijing family was major epidemic strains.We discovered 73 new Spoligotyping genotypes,which could enrich the information of SpolDB4.0 database.There was no obvious correlation between the Beijing genotype and the patients’ gender,age,case history and drug-resistance.The status of TB drug resistance was very severe in south China,especially drug resistance TB and MDR-TB in Guizhou and Sichuan province,and the drug resistant rate of retreatment patients was much more highly than that of the initial treatment patients. |
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