Genomic and pathogenicity analyses to identify the causative agent from multiple serogroups of non-O1, non-O139 Vibrio cholerae in foodborne outbreaks

In 2013, foodborne outbreaks in Japan were linked to non-O1, non-O139 <i>Vibrio cholerae</i>. However, laboratory tests have detected several serogroups, making it difficult to determine the causative agent. Therefore, whole-genome analyses revealed that only serogroup O144 <i>V. cholerae</i> possesses a genomic island with a type III secretion system (T3SS). A T3SS-deficient mutant was subsequently generated, and its pathogenicity was assessed using a rabbit ileal loop test. This led to the conclusion that serogroup O144 <i>V. cholerae</i> with T3SS was the causative agent of foodborne outbreaks. This study provides an illustrative example of the utilization of whole-genome data for pathogenicity and molecular epidemiological analyses in outbreak investigations.