bHisto-blood group antigens (HBGAs) have been suggested to be receptors or coreceptors for human noroviruses (HuNoVs) expressed on the intestinal epithelium. We isolated an enteric bacterium strain (SENG-6), closely related to Enterobacter cloacae, bearing HBGA-like substances from a fecal sample of a healthy individual by using a biopanning technique with anti-HBGA antibodies. The binding capacities of four genotypes of norovirus-like particles (NoVLPs) to Enterobacter sp. SENG-6 cells were confirmed by enzyme-linked immunosorbent assay (ELISA). Transmission electron microscopy demonstrated that NoVLPs bound mainly to extracellular polymeric substances (EPS) of Enterobacter sp. SENG-6, where the HBGA-like substances were localized. EPS that contained HBGA-like substances extracted from Enterobacter sp. SENG-6 was shown by enzyme-linked immunosorbent assay (ELISA) to be capable of binding to NoVLPs of a GI.1 wild-type strain (8fIIa) and a GII.6 strain that can recognize A antigen but not to an NoVLP GI.1 mutant strain (W375A) that loses the ability to bind to A antigen. Enzymatic cleavage of terminal N-acetyl-galactosamine residues in the bacterial EPS weakened bacterial EPS binding to the GI.1 wild-type strain (8fIIa). These results indicate that A-like substances in the bacterial EPS play a key role in binding to NoVLPs. Since the specific binding of HuNoVs to HBGA-positive enteric bacteria is likely to affect the transmission and infection processes of HuNoVs in their hosts and in the environment, further studies of human enteric bacteria and their binding capacity to HuNoVs will provide a new scientific platform for understanding interactions between two types of microbes that were previously regarded as biologically unrelated.
Our investigation attributed this large HEV outbreak to the consumption of an undercooked pig liver-based stuffing. After infection, the cases became a temporary reservoir for HEV, which was detected in the island's untreated wastewater.
cTo secure food and water safety, quantitative information on multiple pathogens is important. In this study, we developed a microfluidic quantitative PCR (MFQPCR) system to simultaneously quantify 11 major human viral pathogens, including adenovirus, Aichi virus, astrovirus, enterovirus, human norovirus, rotavirus, sapovirus, and hepatitis A and E viruses. Murine norovirus and mengovirus were also quantified in our MFQPCR system as a sample processing control and an internal amplification control, respectively. River water contaminated with effluents from a wastewater treatment plant in Sapporo, Japan, was collected and used to validate our MFQPCR system for multiple viruses. High-throughput quantitative information was obtained with a quantification limit of 2 copies/l of cDNA/DNA. Using this MFQPCR system, we could simultaneously quantify multiple viral pathogens in environmental water samples. The viral quantities obtained using MFQPCR were similar to those determined by conventional quantitative PCR. Thus, the MFQPCR system developed in this study can provide direct and quantitative information for viral pathogens, which is essential for risk assessments.
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