Epidemiological characteristics and PFGE molecular typing of Enterotoxigenic E.coli in Longgang district, Shenzhen, 2010-2015

Objective To study the epidemiological and molecular characteristic of Enterotoxigenic E.coli in diarrhea patients. Methods A total of 1204 stool samples were collected from patients with infectious diarrhea at Longgang district from 2010 to 2015. Enterotoxigenic E.coli strains were isolated and identified by biochemical identification and serotyping. Then detection of virulence genes was conducted with polymerase chain reaction(PCR). The molecular typing of the positive isolates was determined by using Pulsed-field gel electrophoresis. Results The positive rate of Enterotoxigenic E.coli in diarrhea patients was 5.8%. There were significant differences in the detection rate among different age groups, and the patients were mainly adults aged 19-25 years.There were no significant season specific differences in the detection rate. The fourteen serotypes were detected in all the isolates, and the serotype of O159 and O148 were predominant, accounting for 25.7% and 18.6% respectively. The estIb was the predominant virulence genes, accounting for 65.7%. Sixty XbaⅠ-pulsed field gel electrophoresis patterns (PTs)were identified.Ten main clone groups were identified at a 90% similarity. Among them, C and G were predominant. Conclusion The detection rate of Enterotoxigenic E.coli in diarrhea patients was stable from 2010 to 2015. The age distributionof Enterotoxigenic E.coli infection was obvious and the infection mainly occurred sporadically, but some predominant clone strains existed.