2017-2018重庆市手足口病病原谱及主要病原体基因特征分析

Pathogen spectrum of hand, foot, and mouth disease and the genetic characteristics of major pathogens in Chongqing from 2017 to 2018

目的分析2017—2018年重庆地区手足口病病原谱及其主要病原体的基因特征。方法选择重庆市儿童医院作为研究对象,收集并整理该院区2017—2018年1071例诊断为手足口病患者的核酸检测信息,其中810份已明确了肠道病毒血清型,剩余175份血清型待鉴定,另有86份肠道病毒为阴性。通过病毒分离、核酸浓缩及基因测序等方法对上述261份样本进行鉴定,获得该地区手足口病完整的病原谱。使用MEGA 7.0软件构建四种主要病原体的系统进化树,进行基因特征的研究。结果通过改良的鉴定方法,261份标本中,除3份被鉴定为人副肠孤病毒(Human parechovirus,HPeV)外,其余258份样本均为肠道病毒阳性。其中CVA6(coxsackievirus A6)血清型占比最多,其次为EV-A71(enterovirus A71)另有CVA16(coxsackievirus A16)和CVA10(coxsackievirus A10)以及其他肠道病毒共计13种血清型。系统进化结果显示,重庆市CVA6血清型均为D3a基因亚型,EV-A71、CVA10和CVA16的优势基因亚型分别为C4a,C2b和B1b,这四种优势基因型与全国其他地区的基因型共同循环进化。结论本研究通过优化鉴定方法,提高了肠道病毒的检出率,进一步明确了重庆地区手足口病病原谱构成,CVA6是该地区2017—2018年手足口病的主要病原体,其次是EV-A71,同时这两种血清型也是导致重庆地区重症手足口病主要的病原体。

Objective To analyze the pathogen spectrum and genetic characteristics of the main pathogens of hand,foot,and mouth disease(HFMD)in Chongqing from 2017 to 2018.Methods Chongqing Children's Hospital was selected as the study object.Nucleic acid detection information of 1071 patients diagnosed with HFMD from 2017 to 2018 was collected.The enterovirus serotypes of 810 samples were identified.There were 175 samples remaining unidentified for serotypes.Eighty-six samples were enterovirus-negative.Through virus isolation,nucleic acid concentration and gene sequencing,the above 261 samples were tested to obtain a complete pathogen spectrum of HFMD in this area.MEGA 7.0 software was used to construct phylogenetic trees of the four major pathogens for the study of genetic characteristics.Results Except for 3 samples that were identified as Human parechovirus(HPeV),258 samples were positive for enterovirus by the improved identification method.Among them,coxsackievirus A6(CVA6)was the dominant serotype,followed by enterovirus A71(EV-A71).There were also 13 serotypes of CVA16,CVA10 and other enteroviruses.The phylogenetic analysis results showed that the serotypes of CVA6 in Chongqing were all D3a sub-genotype,while the dominant gene subtypes of EV-A71,CVA10 and CVA16 were C4a,C2b and B1b,respectively.These four dominant genotypes co-evolved with the genotypes in other areas of China.Conclusions This study improved the detection rate of enterovirus by optimizing the identification method,and further defined the pathogen spectrum of HFMD in Chongqing.The dominant pathogen of HFMD was CVA6 in Chongqing from 2017 to 2018,followed by EV-A71,and both serotypes were also the main pathogen causing severe HFMD in Chongqing area.