Objective To understand the HIV-1 subtype diversity and transmission characteristics in men having sex with men (MSM) in Zhejiang province.Methods A total of 233 newly diagnosed as HIV-1 positive patients in 2011 were screened out by BED capture enzyme immunoassay (BED-CEIA).Among them,107 eligible subjects were enrolled for further molecular epidemiological study.Viral RNA was extracted from plasma samples and followed by reverse transcription PCR and nested PCR for amplification of pol gene fragments,sequencing,and bioinformatics analysis.Results There were no statistically significant differences regarding the social demographic distribution between the subjects under study and those recently infected MSM population.The rate of success for sequence acquisition was 94.4％ (101/107).The highest proportion of subtype was CRF01_AE (62.4％),followed by CRF07_BC (31.7％) and with three cases of subtype B,one case of CRF55_01B and two cases of unique recombinant form (CRF01_AE/B and CRF01_AE/CRF07_BC).The phylogenetic trees were mainly divided into CRF01_AE cluster 1,cluster 2 and CRF07_BC cluster 3.The strains located in Hangzhou were diffused in the branches of phylogenetic tree.10 transmission clusters were found,in which 80％ involved two or more regions and 90％ was associated with patients residing in Hangzhou.Three surveillance drug resistance mutations (M46I,T215S and G190A) were found in three samples (each sample harbored only one resistance mutation).The overall rate of transmitted drug resistance (TDR) was 2.97％.Conclusion The increasing complexity of HIV was noticed in MSM in Zhejiang province.However,the prevalence of TDR was low.Cross-regional HIV transmission in MSM was common,which inferred from the study.Hangzhou might play a central regional role in the intra-provincial spread of HIV,to form an interwoven complex network in the MSM population.%目的 了解浙江省MSM中的HIV-1新近感染者的毒株亚型组成和传播特征.方法 233例2011年新报告的MSM感染者经BED捕获酶免试验(BED-CEIA)检测为新近感染,其中107例纳入分子流行病学研究,收集血浆样本提取RNA核酸,用反转录/巢式PCR扩增HIV病毒的pol基因片段,测序后进行生物信息学分析.结果 107例研究对象与当年MSM新近感染者在社会人口学特征上差异无统计学意义.序列获得率为94.4％(101/107),CRF01 AE占比最高(62.4％),其次是CRF07 BC(31.7％),另有3例B亚型,1例CRF55_01B和2例独特重组型.毒株在系统进化树上主要分为CRF01 AE的簇1、簇2和CRF07_BC的簇3,杭州地区的毒株散播于各个进化分支.共发现10个传播簇,80％涉及≥2个的地市,90％与现住址为杭州的病例有关; 共发现有3个样本各存在一个监测性耐药突变,分别为M46I、T215S和G190A,传播性耐药率为2.97％.结论 浙江省MSM的HIV亚型呈现复杂性趋势,但传播性耐药处于低度流行水平;HIV的跨地区传播较为普遍,杭州在地域上可能发挥着核心传播作用,全省已形成混杂交织的复杂网络.
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