陕西省铜川市HIV-1亚型和分子传播网络分析

Distribution of HIV-1 Subtypes and Molecular Transmission Network among HIV/AIDS in Tongchuan, Shaanxi Province

目的了解陕西省铜川市HIV-1亚型分布特征和传播网络情况,为精准实施当地艾滋病随访干预措施提供科学依据。方法以全国艾滋病综合防治基本信息系统截至2019年8月陕西省铜川市HIV/AIDS感染者为研究对象,2019年常规随访CD4^(+)T淋巴细胞检测的全血样品,提取HIV前病毒DNA,扩增pol区基因片段,构建系统进化树判断HIV-1分子亚型,TN93模型计算序列两两之间基因距离构建分子传播网络,贝叶斯系统进化分析铜川市CRF55_01B毒株进化特征。结果193例HIV/AIDS感染者中,成功扩增获得100例HIV-1 pol区基因片段,HIV-1亚型有CRF01_AE(36.00%)、CRF07_BC(29.00%)、CRF55_01B(16.00%)、B亚型(9.00%)、CRF08_BC(7.00%)、CRF68_01B(1.0%)和独特重组型01_AE/07_BC(2.00%)。以1.5%为基因距离阈值构建分子传播网络,共形成7个分子传播簇,成簇病例构成比为34.00%。多因素Logistic回归分析显示,初中及以下文化程度和毒株亚型为CRF55_01B是分子传播簇形成的促进因素。贝叶斯系统进化分析显示,铜川市CRF55_01B型毒株高度同源(后验概率0.99),最近共同祖先时间约为2009年3月。结论陕西省铜川市HIV-1亚型分布复杂多样,文化程度和HIV-1亚型类别与当地分子传播簇形成相关。分子传播网络有助于了解局部地区HIV/AIDS感染者传播特征,指导干预措施的制定。

Objective To understand the distribution of HIV-1 subtypes and molecular transmission network among people living with HIV in Tongchuan, Shaanxi province, for the purpose of providing evidence for precise intervention and control.Methods A total of 193 whole blood samples were collected from individuals who were diagnosed as HIV-infection and living in Tongchuan at the follow-up of January to August, 2019. Proviral DNA was extracted and then the fragment of HIV-1 pol gene was amplified. The phylogenetic tree was constructed to determine the HIV-1 subtypes. TN93 model was used for calculating the distance between two sequences for drawing molecular transmission network. Bayesian Markov Chain Monte Carlo(MCMC) method was employed to analyze the transmission history of the CRF55_01B strains identified from Tongchuan.Results A total of 100 fragments of pol gene was successfully harvested. A variety of HIV-1 genotypes was identified, including CRF01_AE(36.00%), CRF07_BC(29.00%), CRF55_01B(19.00%), subtype B(9.00%), CRF08_BC(7.00%), CRF68_01B(1.00%), and unique recombinant forms 01_AE/07_BC(2.00%). Under the optimal genetic distance threshold(1.5%), seven transmission clusters were detected in the molecular transmission network with a clustering rate of 34.00%sequences in the study. The multiple logistic regression showed that lower educational level and CRF55_01B were more likely clustered with Tongchuan related sequences in the transmission network. Bayesian phylogenetic inference showed the CRF55_01B strain identified from Tongchuan were highly homologous with a posterior rate 0.99, and had been spreading to the local area since approximately Mar, 2009.Conclusion The distribution of HIV-1 subtypes is complex at Tongchuan. Education and HIV-1 genotype were associated with genetic cluster in the transmission network. The key characteristics of molecular transmission network help to understand the patterns of HIV/AIDS transmission in local area and provide guidance for precise prevention and control.