Epidemiological and etiological characteristics of cholera in Beijing, 2022

Objective  To understand the epidemiological and etiological characteristics of cholera in Beijing in 2022.

Methods The epidemiological and clinical data of cholera cases in Beijing in 2022 were collected for a descriptive analysis. Serotyping, quantitative real-time polymerase chain reaction for the detection of virulence genes, pulsed field gel electrophoresis（PFGE）, and drug susceptibility tests were carried out for the Vibrio cholerae isolates from cholera cases and from the external environment.

Results In 2022, a total of 12 cholera outbreaks occurred in Beijing, in which 18 cases of cholera were reported. The incidence peak was during June - August. A total of 24 strains of V. cholerae were isolated, mainly V. cholerae O1 (20 strains), followed by Inaba V. cholerae O1 (3 strains) and V. cholerae O139 (1 strain). All the V. cholerae isolates were non-virulent-producing strains. The resistance rate of the strains to ceftazidime was highest ( 25.00%), and the strains were all sensitive to meropenem, cefotaxime, azithromycin, ertapenem, chloramphenicol, amikacin. The 24 V. cholerae strains were divided into 12 types by PFGE, and 15 strains clustered in 3 PFGE types.

Conclusion Seasonal epidemic of cholera in Beijing. V. cholerae isolates were mainly non-virulent. The strains isolated from the cases with epidemiological links had same PFGE type, indicating the necessity of strengthened surveillance.