天津地区临床分离结核分枝杆菌分型的初步研究

目的探讨天津地区结核分枝杆菌临床分离株分子流行病学特征。方法连续收集天津市海河医院2005年8月16日11月25日就诊患者痰培养阳性的结核分枝杆菌100株，采用间隔区寡核苷酸分型（spoligotyping）和多位点可变串联重复序列（VNTR）两种方法进行基因分型，并运用软件对二者的结果进行分析。依据北京分化支的定义，运用多重和实时定量PCR方法将其区分为W菌／典型北京家族菌株和非典型北京菌株，Χ^2检验分析两种亚群与患者年龄和耐药性之间的联系。结果排除污染菌株，共对96株结核分枝杆菌临床分离株进行两种方法的基因分型，spoligotyping结果91．7％为北京基因型（含3株类北京基因型）结核分枝杆菌（88／96）。VNTR分型可将北京基因型分为60种基因型。在北京分化支结核分枝杆菌中，W菌／典型北京家族菌株占93．2％（82／88）。两种北京分化支亚群与患者年龄及耐药性之间差异无统计学意义（P〉0．05）。结论天津地区结核病患者临床分离的结核分枝杆菌中，北京基因型呈现较为明显的优势。VNTR的分辨率明显高于spoligotyping。北京分化支的两种亚群在天津地区临床结核病患者中均有流行，但以W菌／典型北京家族菌株为主。

Study on the genotype of Mycobacterium tuberculosis isolates from hospitals in Tianjin

OBJECTIVE: To explore the characteristics on molecular epidemiology of Mycobacterium tuberculosis isolates from hospitals in Tianjin area. METHODS: One hundred M. tuberculosis isolated strains were collected in succession from August 16th-December 25th, 2005 in Tianjin Haihe Hospital and genotyped by spoligotyping and multiple locus variable number-tandem repeat(VNTR). Data was analyzed by cluster software. Based on the concept of Beijing lineage, it was determinate two sub-groups: atypical Beijing strains and W strain/typical family strains by multiplex and real-time PCR. The associations of subgroups with drug resistance and age were assessed by the chi2 test. RESULTS: 96 M. tuberculosis strains were genotyped in which 91.7% (88/96) strains belonged to Beijing genotype (including 3 Beijing-like strains) by spoligtyping. VNTR typing could differentiate 60 genotypes among the 88 Beijing genotype strains. 93.2% of the Beijing lineage M. tuberculosis strains of this study belonged to W strain/typical Beijing family strains (82/88). No statistically significant differences were observed in the proportions of the two sub-groups in patients of different age, or drug resistance (P > 0.05). CONCLUSION: The M. tuberculosis Beijing genotype strains were dominated on tuberculosis hospital patients of Tianjin area. The discriminatory power of VNTR typing was higher than that of spoligtyping. The two sub-groups of Beijing lineage had been prevalent in Tianjin, however W strain/typical Beijing family strains were of preponderance.