福建省结核分枝杆菌多位点可变数目串联重复序列基因分型研究

Preliminary study on the MLVA genotyping of Mycobacterium tuberculosis isolates in Fujian province

目的了解福建省结核分枝杆菌的多位点可变数目串联重复序列基因分型（MLVA）的特征。方法选择15个可变数目串联重复位点（VNTR），检测福建省30个耐药监测点临床分离的结核菌株，结果使用BioNumerics（Version4．5）软件进行聚类分析。结果313株结核菌被分为9个基因群（Ⅰ～Ⅸ），分别包含220、9、48、2、1、3、10、10、10株菌，以Ⅰ群为主（70．3％，220／313）；Ⅰ群菌株异烟肼、链霉素、乙胺丁醇和耐多药的耐药率与其他基因群的差异无统计学意义（P〉0．05），但利福平（RFP）耐药率为33．2％（73／220），明显高于其他群菌株RFP的耐药率20．4％（19／93），差异有统计学意义（P〈0．05）。结论福建省结核分枝杆菌菌株存在明显的基因多态性，以Ⅰ群菌株为主，并与RFP耐药性具有相关性，应加强此类菌株流行的监测。

Objective To preliminarily understand the genotyping characteristics regarding the variable number tandem repeats （VNTR） of Mycobacterium tuberculosis clinical isolates so as to provide evidence for the development of tuberculosis control and prevention programs in Fujian province. Methods Fifteen VNTR locus sets were used to detect the clinical isolates from the fifth surveillance project on tuberculosis resistance, in Fujian province. BioNumerics version 4.5 were used to analyze the cluster from the results generated by genotyping. Results 313 Mycobacterium tuberculosis isolates were divided into 9 clusters, including I , II, III, IV, V, VI, VII, VIII and IX, with the number of 220,9,48,2, 1,3, 10, 10, 10 isolates, respectively. Cluster I was the major lineage, accounting for 70.3% （220/313） of the total. Resistance rates of cluster I isolates to isoniazid, streptomycin, ethambutol and multi-drug-resistant were not statistically different from other clusters （P〉0.05）. However, resistance rate to rifampicin （RFP） was significantly higher than that of other isolates of the clusters, 33.2% （73/220） vs. 20.4% （19/93） （P〈0.05）. Conclusion The strains isolated from Fujian province showed significant polymorphism on genotyping. Cluster I seemed to be the dominant, calling for the close monitoring program on cluster I strains. Results from our initial studies demonstrated the existence of significant correlation between cluster I strains and drug resistance to RFP.