127株结核分枝杆菌基因分型及耐药相关研究

Genotyping and drug resistance of 127 strains of Mycobacterium tuberculosis

目的研究山西省长治及周边地区结核分枝杆菌的基因多态性及基因型与耐药的相关性。方法收集结核分枝杆菌临床分离株,运用MLVA方法进行基因分型,对8种抗结核药物分别采用比例法进行药敏试验,应用BioNumerics 5.0软件进行聚类分析。结果 15个位点中Mtub21、MIRU26和ETRE多态性较高(HGI>0.6),MIRU40、ETRB、MIRU16、ETRD、MIRU23和ETRC位点多态性较低(HGI<0.3)。127株结核分枝杆菌共分为11个基因群102种基因型,90株为独特型,基因群中Ⅰ群所占比例最大(80.31%)。127株菌株对一线和二线抗结核药物的总耐药率分别为47.24%和23.62%。一线药物中链霉素(40.94%)的耐药率最高,乙胺丁醇(6.30%)最低。二线药物中左氧氟沙星(14.17%)的耐药率最高,丙硫异烟胺(3.15%)最低。链霉素的单耐药率最高(11.81%);耐多药率为21.26%(27/127);广泛耐多药率为3.15%。Ⅰ群菌株的耐药率与其它菌株的差别无统计学意义。结论初步证实山西长治及周边地区的结核分枝杆菌具有明显的多态性,Ⅰ群为主要流行群。结核分枝杆菌对二线药物的敏感性高于一线药物。主要流行菌株Ⅰ群菌株与耐药无明显的相关性。

To understand the genetic polymorphism and the correlation of genotype and drug resistance of Mycobacterium tuberculosis(M.tuberculosis)circulating in Changzhi and the surrounding area in Shanxi Province,multi-loci variable number tandem repeats(VNTRs)analysis(MLVA)were utilized for the genotyping of the clinical isolates and drug susceptibility test(DST)of the 8 antituberculosis agents was performed on the Lowenstein-Jensen(L-J)medium by the proportion method.The BioNumerics(Version 5.0)software was used for clustering analysis.The result showed that Mtub21,MIRU26 and ETRE revealed high polymorphism(Hunter-Gaston Index,HGI>0.6).MIRU40,ETRB,MIRU16,ETRD,MIRU23 and ETRC showed low polymorphism(HGI<0.3).The 127 M.tuberculosis strains were divided into 11 groups of which the groupⅠaccounting for the largest percentage of 80.31%and 102 genotypes including 90 idiotopes.The drug resistance of the first-line antituberculosis agents and the second-line antituberculosis drugs were 47.24%and 23.62%.Among the first-line antituberculosis agents,streptomycin(SM)(40.94%)had the highest drug resistance,and ethambutol(EMB)(6.30%)was the best antibacterial agents against experimental strains.Of the second-line antituberculosis drugs,protionamide(PTH)(3.15%)was the good choice with the lowest drug resistance,and levofloxacin(LFX)(14.17%)had the highest drug resistance.The single drug resistance of streptomycin(11.81%)was the highest followed by isoniazid(2.36%),and we found that no strains were drug resistant for single rifampicin or single ethambutol.The 21.26%(27/127)were multi-drug resistant,and the 3.15%were widely multi-drug resistant.It’s no statistical significance that the difference of the drug resistance rate between the groupⅠstrains and other strains.In conclusion,it’s preliminarily confirmed that the M.tuberculosis has obvious genetic polymorphism and the groupⅠstrains were popular in Changzhi and the surrounding area.The sensitivity to the second-line antituberculosis drugs was higher than that to the first-line antituberculosis drugs.It had no obvious correlation between the major epidemic strains groupⅠand drug resistance.