天津地区KI和WU多瘤病毒在儿童急性呼吸道感染中的分子流行病学研究

A molecular epidemiological study of KI polyomavirus and WU polyomavirus in children with acute respiratory infection in Tianjin, China

摘要:

目的 了解KI和WU多瘤病毒（KIPyV和WUPyV）与天津地区儿童急性呼吸道感染的关系。方法 采用PCR扩增方法对2011年1月至2013年12月收集的3 730份来自天津地区的急性呼吸道感染患儿鼻咽分泌物标本进行KIPyV和WUPyV基因检测，同时所有标本均用直接免疫荧光法检测7种常见呼吸道病毒。选取部分KIPyV和WUPyV PCR阳性产物进行测序，利用测序序列与已知序列比对并绘制进化树。再从中选取两株KIPyV VP1基因克隆到T载体上，进行序列测定和分析，并将核苷酸序列提交GenBank。结果 3 730份标本中，KIPyV阳性检出453份（12.14%），WUPyV阳性检出63份（1.69%）。KIPyV平均感染率在6~7月明显偏高，WUPyV平均感染率在2~3月达到一个小高峰。两种多瘤病毒感染的阳性患儿年龄主要集中在3岁以内。KIPyV和WUPyV与其他7种呼吸道病毒存在混合感染，混合感染率为2.31%（86/3 730）；WUPyV和KIPyV混合感染9份。选取的35份KIPyV阳性PCR产物序列与GenBank已公布的KIPyV序列的同源性在94%~100%之间；选取的12份WUPyV阳性PCR产物序列与GenBank已公布的WUPyV序列的同源性在95%~100%之间。两株KIPyV VP1基因序列已被GenBank收录，登录号为KY465925和KY465926。结论 天津地区部分儿童的急性呼吸道感染可能与WUPyV和KIPyV感染相关。KIPyV感染多发于夏季，WUPyV感染多发于春季。KIPyV和WUPyV与国内外流行株间差异较小，基因组相对稳定。

Abstract:

Objective To investigate the relationship of KI polyomavirus (KIPyV) and WU polyomavirus (WUPyV) with acute respiratory infection in children in Tianjin, China. Methods A total of 3 730 nasopharyngeal secretions were collected from hospitalized children with acute respiratory infection in Tianjin Children's Hospital from January 2011 to December 2013. Viral nucleic acid was extracted, and virus infection (KIPyV and WUPyV) was determined by PCR. Some KIPyV-positive and WUPyV-positive PCR products were subjected to sequencing. Sequencing results were aligned with the known gene sequences of KIPyV and WUPyV to construct a phylogenetic tree. Amplifed VP1 fragments of KIPyV were inserted into the cloning vector (PUCm-T) transformed into E. coli competent cells. Positive clones were identifed by PCR and sequencing. The nucleotide sequences were submitted to GenBank. In addition, another seven common respiratory viruses in all samples were detected by direct immunofluorescence assay. Results In the 3 730 specimens, the KIPyV-positive rate was 12.14% (453/3 730) and the WUPyV-positive rate was 1.69% (63/3730). The mean infection rate of KIPyV was signifcantly higher in June and July, while the mean infection rate of WUPyV peaked in February and March. Most of the KIPyV-positive or WUPyV-positive children were < 3 years. The co-infections with KIPyV, WUPyV, and other respiratory viruses were observed in the children. The coinfection rate was 2.31% (86/3 730) and there were nine cases of co-infections with WUPyV and KIPyV. Thirty-fve KIPyV-positive and twelve WUPyV-positive PCR products were sequenced and the alignment analysis showed that they had high homology with the known sequences (94%-100% vs 95%-100%). The VP1 gene sequences obtained from two KIPyV strains in this study were recorded in GenBank with the accession numbers of KY465925 and KY465926. Conclusions For some children with acute respiratory infection in Tianjin, China, the acute respiratory infection may be associated with KIPyV and WUPyV infections. KIPyV infection is common in summer, and WUPyV infection in spring. The epidemic strains in Tianjin have a high homology with those in other regions.