Etiologic and epidemiologic characteristics of diarrheogenic Escherichia coli in diarrhea patients in Maanshan, Anhui, 2014–2018

ObjectiveTo investigate infection status, virulence genes, antibiotic resistance and molecular types of diarrheogenic Escherichia coli (DEC) in diarrhea patients in Maanshan of Anhui province and provide scientific basis for the prevention and control of DEC infection.

MethodsThe stool samples were collected from outpatients with acute diarrhea in three sentinel hospitals in Maanshan during 2014–2018 for DEC isolation, identification and virulence genes detection, and drug susceptibility test and pulsed-field gel electrophoresis (PFGE) were conducted for the positive strains.

ResultsAmong 1 711 stool samples of diarrhea cases, 120 were DEC positive, and 123 DEC strains were isolated. The positive rate was 7.01% (120/1 711). The DEC positive cases were mainly infants aged 0-5 years and young adults aged 20–39 years. The cases mainly occurred in summer (June-August). Enterotoxigenic E. coli (ETEC) and enteropathogenic E. coli (EPEC) were the main types of DEC, accounting for 58.54% and 31.71%, respectively. Drug susceptibility test of 123 DEC strains showed that extended-spectrum beta-lactamase strains were resistant to more than 6 antibiotics. PFGE results of 123 DEC strains showed 119 banding patterns, which were relatively dispersed, and the similarity of banding patterns was 49.7%–97.7%.

ConclusionFrom 2014 to 2018, DEC infections in diarrhea patients in Maanshan were mainly caused by ETEC and EPEC. The age and seasonal distributions of the infection cases was obvious. The antibiotic resistance of DEC strains was serious. The PFGE molecular bands of the strains were dispersed. The non-rational use of antibiotics should be controlled, and more attention should be paid to epidemic risk of ETEC or EPEC infections.