广东省结核分枝杆菌MIRU和RD105缺失基因分型研究

摘要

目的 了解广东省结核分枝杆菌(MTB)随时间、地区的动态流行分布特点.方法 应用24位点MTB散在分布重复单位(MIRU)分析广东省2013年455例MTB,筛选适合广东省分型的最佳MIRU组合,然后应用该最佳MIRU组合分析广东省2009年的173例、 2013年的455例及2015年的225例MTB,此外,结合RD105缺失基因法鉴定这些菌株中的北京家族菌株,比例法进行药物敏感性试验(DST),聚类分析采用BioNumerics(7.6).结果 2015年北京家族菌株比率(70.2%)高于2009年(59.5%)和2013年(59.3%),其中,中部地区比率最高(71.3%),东部地区最低(55.0%).MIRU-24位点的多态性存在差异, MIRU-12(HGI=0.999 1)能达到MIRU-15(HGI=0.999 2)相近的分辨率,MIRU-8分辨率较好(HGI=0.998 5).853例MTB的系统发生树(MST)主要包括1个北京家族和2个非北京家族复合群,可分为Ⅰ、Ⅱ两群,广东省MTB的主要流行群是Ⅱ群,Ⅰ群中2009、2013年菌株比率高于2015年,东部地区菌株比率高(43.069%),中部地区低(27.206%),Ⅱ群则与之相反,北京家族菌株的MST主要包括1个复合群,包含407个独特型和46个簇.非北京家族菌株的MST主要包括2个复合群,包含309个独特型和6个簇.另外,广东省不同年份多药耐药(MDR)(X2=2.176,P=0.337)和广泛耐药(XDR)(X2=1.468,P=0.480)耐药率差异无统计学意义(P>0.05).结论 北京家族菌株是广东省的主要流行株,且随时间存在上升趋势,中部地区比率最高,该省MDR和XDR耐药趋势相对稳定,MIRU分型用于广东省MTB的分子流行病学研究可取得满意结果.%Objective To understand the dynamic features of mycobacterium tuberculosis (MTB) in population and distribution in Guangdong province.Methods Mycobacterial interspersed repetitive units-24 (MIRU-24) were analyzed on 455 MTB patients with MTB in Guangdong in 2013, so as to develop an optimal MIRU for M.tuberculosis typing.The 173 patients with MTB in 2009, 455 patients in 2013, and 225 patients in 2015 were analyzed by that optimal MIRU set.RD105 deletion test was applied to distinguish Beijing and Non-Beijing strains.Drug susceptibility test was done by proportion method.Gene clustering was analyzed using BioNumerics (7.6).The statistical analysis used chi-square test.Results The rate of Beijing strains in 2015 (70.2%) was higher than those in 2009 (59.5%) and 2013 (59.3%).At the same time, this rate was the highest in midland (71.3%) and the lowest in east (55.0%).There was no significant difference in multidrug-resistant (X2=2.176, P=0.337) or extensively drug-resistant tuberculosis (X2=1.468, P=0.480) among different years in Guangdong province.There were differences in the polymorphisms of MIRU-24.The resolution capability of MIRU-12 (HGI=0.999 1) was similar with MIRU-15 (HGI=0.999 2) and MIRU-8 (HGI=0.998 5).The minimum spanning tree (MST) of 853 M.tuberculosis cases was mainly comprised of 1 Beijing strain and 2 Non-Beijing strains, which could be divided into Group I and II.The predominant strain in Guangdong was Group II.The rates of Group I strain in 2009 and 2013 were higher than that in 2015, and was higher in east (43.069%) than in midland (27.206%).The results of Group II strain were per contra.The MST of Beijing strains was mainly comprised of one complex consisted of 407 unique genotypes and 46 clusters, while the MST of Non-Beijing strains was mainly comprised of 2 complexes consisted of 309 unique genotypes and 6 clusters.Conclusion Beijing strains are the most predominant strains in Guangdong province and there are a rising trend over time.The rate of Beijing strains in midland is the highest.The trend of MDR and XDR in Guangdong is stable.The study of molecular epidemiology of MTB from Guangdong could achieve satisfactory results by MIRU.