Department of Environment and Health, Istituto Superiore di Sanità, Rome, Italy.
Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy.
J Appl Microbiol. 2019 Jan;126(1):324-331. doi: 10.1111/jam.14129. Epub 2018 Nov 19.
Human Sapoviruses (HSaVs) are etiological agents of sporadic cases and outbreaks of acute gastroenteritis in humans of all ages. Evidence of worldwide distribution of HSaV has been documented; however, little is known about HSaV circulation in Italy. To study their occurrence and genetic diversity a nation-wide environmental surveillance was undertaken.
One hundred and sixty-six raw sewage samples, collected from 16 wastewater treatment plants throughout Italy, were processed and analysed by a RT-nested PCR targeting the capsid region, followed by amplicon sequencing. HSaV was detected in 56 of 166 (33·7%) samples, characterized as genotypes GI.1 (n = 30 samples), GI.2 (n = 3), GI.3 (n = 2) and GII.1 (n = 1). Mixed electropherograms were detected in 20 samples. Next-generation sequencing (NGS)-based amplicon sequencing was performed on pools of PCR amplicons to detect viruses in mixed samples and less prevalent genotypes undetectable by conventional Sanger sequencing. NGS revealed three additional genotypes (GI.6, GII.6 and GV.1) beyond the four detected by Sanger sequencing.
Our results show a significant circulation of HSaV in Italy with three genogroups (GI, GII and GV) and seven genotypes detected. The high detection rate in sewage samples suggests that HSaV infection in Italy could be underestimated or associated with asymptomatic or mild cases.
The study detected HSaV in a relevant proportion of raw sewage samples, reflecting a considerable circulation of these viruses in the Italian population, pointing to the usefulness of including HSaV in testing patients with gastroenteritis. Furthermore, our results confirm that wastewater surveillance coupled with NGS is a powerful tool to study the molecular epidemiology of enteric viruses.
人类肠杯状病毒（HSaV）是引起各年龄段人群散发性和暴发急性胃肠炎的病原体。已有证据表明 HSaV 分布于世界各地，但人们对 HSaV 在意大利的流行情况知之甚少。为了研究其发生情况和遗传多样性，我们进行了全国范围的环境监测。
我们采集了来自意大利 16 个污水处理厂的 166 份污水样本，通过针对衣壳区的 RT-巢式 PCR 进行处理和分析，随后对扩增子进行测序。在 166 份样本中的 56 份（33.7%）中检测到了 HSaV，这些样本被鉴定为 GI.1 基因型（n=30 份）、GI.2 基因型（n=3 份）、GI.3 基因型（n=2 份）和 GII.1 基因型（n=1 份）。在 20 份样本中检测到了混合电泳图谱。我们对 PCR 扩增子进行了基于下一代测序（NGS）的扩增子测序，以检测混合样本中的病毒和常规 Sanger 测序无法检测到的较少流行的基因型。NGS 检测到了 4 种通过 Sanger 测序检测到的基因型之外的另外 3 种基因型（GI.6、GII.6 和 GV.1）。
我们的研究结果表明，HSaV 在意大利有显著的传播，检测到了 3 个基因群（GI、GII 和 GV）和 7 种基因型。污水样本中的高检出率表明，意大利的 HSaV 感染可能被低估或与无症状或轻症病例有关。
本研究在相当比例的污水样本中检测到了 HSaV，反映了这些病毒在意大利人群中相当大的传播，这表明将 HSaV 纳入肠胃炎患者的检测是有用的。此外，我们的研究结果证实，污水监测与 NGS 相结合是研究肠道病毒分子流行病学的有力工具。
