Epidemiological and Genomic Characterization of a Campylobacter jejuni Outbreak in Lishui, China

Campylobacter is one of the leading causes of bacterial foodborne diarrheal diseases throughout the world. Reported outbreaks of Campylobacter are infrequent in China. This article described such an outbreak among students from a junior high school in East China during November 2019. A total of 40 samples were collected as follows: 24 stool samples from patients, 12 stool samples from kitchen staff members, and 4 water samples from cafeteria. The stool samples were tested for the presence of Salmonella, enterotoxigenic Escherichia coli, Shigella, Vibrio parahaemolyticus, Vibrio cholera, Listeria monocytogenes, Staphylococcus aureus, Yersinia enterocolitica, Bacillus cereus, Clostridium perfringens, norovirus, rotavirus, adenovirus, astrovirus, and sapovirus by real-time polymerase chain reaction (PCR). Pulsed-field gel electrophoresis (PFGE), next-generation sequencing, and antimicrobial susceptibility testing were performed to determine the relatedness of the Campylobacter jejuni isolates in this outbreak. Forty-seven cases were reported with diarrhea among 569 seventh grade students and staff. In these 47 cases, we detected that C. jejuni through real-time PCR in 16 fecal samples was positive, whereas the remaining fecal samples were tested negative by real-time PCR. Only three C. jejuni strains were isolated from stool samples of case patients, and all of them showed 100% PFGE similarity to strain ST6913. Whole genome sequencing analysis revealed no single nucleotide variation in the three isolates. This is one of the few reports in China about outbreak caused by C. jejuni. C. jejuni ST6913 was responsible for this outbreak.