Phylogenetic Analysis of Serogroup O5 Vibrio cholerae that Caused Successive Cholera Outbreaks - Guangdong Province, China, 2020-2021

Introduction: Gastroenteritis caused by nonO1/non-O139 Vibrio cholerae exhibited an increasing trend in recent years in China. Whole genome sequence (WGS) data could play an important role both in the identification of the outbreaks and in the determination of the serogroup. Here, we present the employment of WGS data in the investigation of two outbreaks caused by non-O1/non-O139 V. cholerae in Guangdong, China, 2020-2021. Methods: We obtained the whole genome sequence of 66 V. cholerae strains isolated in two outbreaks with next generation sequencing technology. We retrieved the publicly available WGS data of nonO1/non-O139 V. cholerae from public database. We used a pipeline integrated in China Pathogen Identification Net (PIN) to complete the phylogenetic analysis. Results: Two outbreaks caused by non-O1/nonO139 V. cholerae were identified using WGS data. These V. cholerae strains were determined as serogroup O5. Type 3 and 6 secretion systems were detected in these serogroup O5 strains. These serogroup O5 strains belonged to sequence type (ST) 88. Conclusions: Our analysis indicated the risk of non-O1/non-O139 V. cholerae of leading to outbreaks of diarrheal diseases. The application of genomic data played important role in the identification of the serogroup of non-O1/non-O139 V. cholerae in the lack of antiserum, which gave an example of the application of genome data in disease surveillance and public health emergency response.