[Epidemiological characteristics of diarrheagenic Escherichia coli infection in infectious diarrhea outpatients aged 15 years and older in Shanghai, 2014-2021].

Objective: To understand the epidemiological characteristics of diarrheagenic Escherichia ( E. ) coli infection in infectious diarrhea outpatients aged 15 years and older in Shanghai and provide evidence for the development of disease control strategies . Methods: Based on multistage systematic sampling, diarrhea surveillance was conducted in 22 sentinel hospitals in Shanghai, the information about cases' demographic, clinical, and epidemiological characteristics were collected. Stool samples were collected for the detection and typing of diarrheagenic E. coli by local centers for disease control and prevention. The positive rate of diarrheagenic E. coli in different populations and seasons from 2014 to 2021 were analyzed. Statistical analysis was conducted by using χ 2 test. Results: In 15 185 diarrhea cases, 8.05% (1 222/15 185) were positive for diarrheagenic E. coli . The positive rate was higher in men (8.74%, 684/7 824) than in women (7.31%, 538/7 361). The positive rate was highest in age group 15-29 years (9.14%, 335/3 665) and the annual positive rate was highest in 2021 (10.21%, 83/813), the differences were all significant ( P <0.05). In the 1 264 strains of diarrheagenic E. coli analyzed through PCR, enterotoxingenic E. coli was the most frequently identified pathogen (50.24%, 635/1 264), followed by enteroadhesive E. coli (27.93%, 353/1 264), and enteropathogenic E. coli (21.36%, 270/1 264). The positive rate of diarrheagenic E. coli showed obvious seasonality with peak in summer (13.92%, 774/5 562) ( χ 2 =495.73, P <0.001). Conclusions: Diarrheagenic E. coli has become a prominent pathogen in infectious diarrhea cases in Shanghai, the disease can occur all the year round with incidence peak during summer and autumn. Predominant subtypes included enterotoxingenic E. coli , enteroadhesive E. coli and enteropathogenic E. coli . Targeted prevention and control strategies are needed for diarrheagenic E. coli -induced infectious diarrhea in different age groups, seasons and for different types of infections.