79株结核分支杆菌基因分型研究及耐药相关分析

Study on genotyping and drug-resistance analysis of 79 Mycobacterium tuberculosis

目的通过多位点可变数目串联重复序列(MLVA)分型方法,结合流行病学资料,探讨绵阳地区结核分支杆菌的基因型特征,为本地结核病的防治研究提供科学依据。方法收集结核分支杆菌菌株和患者资料,采用国际上推荐的15个可变串联重复序列位点进行基因分型,应用BioNumerics(Version5.0)软件进行聚类分析,药物敏感性试验采用比例法,率的比较采用χ2检验。结果共对79株结核分支杆菌进行了基因检测,结果显示高度的基因多态性。QUB-11b、MIRU26、Mtub 21和MIRU 16分辨能力更高(HGI>0.7),位点MIRU 4、ETR-A和ETR-C显示分辨能力相对较低(HGI<0.4)。79株菌分为7个基因群,以Ⅲ群和Ⅴ群为主,Ⅲ群占46.8%,Ⅴ群占41.8%,其它群所含菌株较少。复治患者在Ⅲ群、Ⅴ群和其他群中所占比例分别为32.43%、21.21%和11.11%,差异无统计学意义(P>0.05)。Ⅴ群中菌株耐药率高达36.36%,明显高于Ⅲ群(10.81%)和其他群(11.11%),差异有统计学意义(P<0.05)。结论初步证实绵阳地区结核分支杆菌具有明显的基因多态性,主要流行型为Ⅲ群和Ⅴ群,主要耐药型为Ⅴ群,应加强Ⅲ群和Ⅴ群菌株的流行监控,加强Ⅴ群菌株的耐药性监测。

Objective To establish the molecular characteristics of Mycobacterium tuberculosis by multiple locus variable num- bers of tandem repeats（MLVA） genotyping technique and epidemiologic data for providing scientific basis to prevent and control tu- berculosis. Methods M. tuberculosis clinical isolates and the patients＇ data were collected. The polymorphism of 15 VNTR loci which were commended was tested, clustering of genotype was analyzed with BioNumerics（Version 5, 0）, and drug susceptibility testing was performed using proportion method. Statistical analysis was performed with Chi Square Test. Results 79 M. tuberculo- sis clinical isolates were analyzed respectively; the results showed that there were obvious polymorphisms of VNTRs. The discrimi- nation power of QUB-11b,MIRU26 ,Mtub 21and MIRU 16 loci was high（HGI〉0. 7） ,otherwise the MIRU 4 ,ETR-A and ETR-C was low（HGI 〈 0.4）. The clustering of genotype showed that these strains could be categorized into 7 gene clusters,in which the proportions of clusterⅢ and cluster V were the biggest,46.8 % were cluster Ⅲ and 41.8% were cluster V ,other clusters were of scattered distribution. The rate of re-treated patients in the Ⅲ , V and other clusters patients was 32.43% ,21.21% and 11. 11% respectively;there was no statistical significance（P〉0.05）. The drug resistance rate of V clusters strain（36.36 %） was obviously higher than Ⅲ （10.81%） and other clusters（11. 11%） ,the differences was statically significant（P〈0.05）. Conclusion There are obvious polymorphisms of VNTRs of M. tuberculosis clinical strains preliminarily in Mianyang area. The main epidemic strains be longe to cluster Ⅲ and cluster V ,the main drug resistance stains belonge cluster V. It is suggested that epidemic surveillance of cluster Ⅲ and cluster V stains,resistance surveillance of cluster V stains both needs to be strengthened.