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为了解重庆地区流行的7型腺病毒(Human adenovirus 7,HAdV-7)基因型型别,从全基因组水平探讨HAdV-7b和HAdV-7d可能的致病性差异,收集儿童急性下呼吸道感染患儿的呼吸道分泌物标本分离培养,提取DNA后进行HAdV-7基因型别鉴定、限制性酶切分析和全基因组测序,再利用MEGA6比较分析。本研究在2009年6月~2013年1月间共收集4334份急性下呼吸道感染患儿的鼻咽抽吸物标本,随机选取2411份进行病毒分离培养,共有164份(164/2411,6.8%)鼻咽抽吸物HAdV阳性,其中HAdV-7 87例。限制性酶切分析显示,随机挑选的3株HAdV-7分离株均为HAdV-7d。CQ1198株行全基因组测序并与其他HAdV-7全基因组构建进化树,结果发现16株中国地区的HAdV-7为HAdV-7d基因型,且上述16株HAdV-7与7d2的同源性为99.9%,与7b的同源性为98.2%。相较于ak40株(HAdV-7b),CQ1198共有49处核苷酸替换,其中20处可导致非同义替换;4处核苷酸插入,其中24bp和18bp 2个片段插入分别位于病毒相关RNAⅡ(Virus-associated RNAⅡ,VA RNAⅡ)和L3的pⅥ区域。HAdV-7可有多个基因型致病,且一直处于进化过程中,其主要流行基因型由HAdV-7b变为HAdV-7d。应加强对HAdV分子流行病学监测,明确其进化规律,为HAdV疫苗研发提供分子流行病学依据。
In order to understand the genotype of HAdV-7 that is endemic in Chongqing, the possible pathogenic differences between HAdV-7b and HAdV-7d were investigated at the genome-wide level. Acute lower respiratory tract infection The samples of respiratory secretions of children were isolated and cultured. The genotypes of HAdV-7, restriction analysis and whole genome sequencing were extracted after DNA extraction, and then compared with MEGA6. A total of 4334 samples of nasopharyngeal aspirates from children with acute lower respiratory tract infection were collected from June 2009 to January 2013. A total of 2411 samples of 164 nasopharyngeal aspirates were collected from 164 children (164 / 2411,6.8% ) Nasopharyngeal aspirate HAdV positive, of which 87 cases of HAdV-7. Restriction analysis showed that all three HAdV-7 isolates randomly selected were HAdV-7d. The complete genome of CQ1198 was sequenced and phylogenetic tree was constructed with other HAdV-7 whole genomes. The results showed that HAdV-7 genotype was found in 16 Chinese HAdV-7 genotypes and the homologies of these 16 HAdV-7 and 7d2 genes were 99.9 %, The homology with 7b is 98.2%. Compared with ak40 strain (HAdV-7b), there were 49 nucleotide substitutions in CQ1198, of which 20 resulted in non-synonymous substitutions. Four nucleotide insertions, of which 24 bp and 18 bp were inserted in viral RNA II (Virus-associated RNA II, VA RNA II) and the p VI region of L3. HAdV-7 has multiple genotypes and has been in the process of evolution. Its major epidemic genotype is changed from HAdV-7b to HAdV-7d. Epidemiological surveillance of HAdV molecules should be strengthened to clarify the evolutionary rules and provide a molecular epidemiological basis for the development of HAdV vaccine.