Free chlorine disinfection as a selection pressure on norovirus.

This study aimed to prove the strain-dependent susceptibility of norovirus to free chlorine. A population originated from murine norovirus S7-PP3, a surrogate for human noroviruses in environmental testing, was exposed to free chlorine and then propagated in a host cell. This cycle of free chlorine exposure followed by propagation in cells was repeated ten times, and populations with lower susceptibility to free chlorine were obtained from two independent trials of chlorine exposure cycles. Open reading frames (ORFs) 2 and 3 of murine norovirus genome were analyzed by next-generation sequencing, and a unique nonsynonymous mutation (from phenylalanine to serine) at nt 7280 in ORF3, encoding the minor capsid protein VP2, was found in chlorine-exposed populations from both trials. It was confirmed that all the clones from the chlorine-treated population had lower susceptibility to free chlorine than those from the control population. These results indicate that there is a different driving force to form MNV quasispecies between the exposure to free chlorine and dilution, and that there is a selective force to form MNV quasispecies under the free chlorine exposure.ImportanceThis study showed that free chlorine disinfection was exerted as a selection pressure for murine norovirus (MNV). The viral strain-dependent susceptibility to the disinfectant elucidated in this study highlights the importance of employing less susceptible strains as representative viruses in the disinfection ...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research