Prevalence and characteristics of Escherichia albertii in Zigong, China

Abstract

Objective To study the prevalence and characteristics of a new pathogen Escherichia albertii in human, animal-derived food, poultry and birds in Zigong city, Sichuan province. Methods Samples of beef, mutton, pork, chicken, duck, chicken intestine, duck intestine and birds′ droppings were collected from markets and stool samples of diarrheal patients and their close contacts were collected from hospitals. The samples were enriched with EC broth and tested for the presence of eae gene by PCR. Each eae-positive enrichment culture was streaked on MacConkey agar. The eae-positive non-lactose fermenting strains were identified as Escherichia albertii by 16S rDNA sequencing and housekeeping genes analysis. Those strains were further analyzed by intimin and cdtB subtyping and pulsed-field gel electrophoresis (PFGE). Results Fifty-one strains were identified as Escherichia albertii, including 19 from duck intestines, 18 from chicken intestines, 3 from diarrheal patients, 3 from close contacts, 1 from egret excrement, 3 from chicken meat, 2 from duck meat, 1 from pork and 1 from mutton. Six intimin subtypes (sigma, rho, iota2, epsilon3, nu and N5) were harbored by those strains. All 51 strains carried the Ⅱ/Ⅲ/Ⅴ subtype group of cdtB and among them, 3 strains possessed another copy of Ⅰ/Ⅳ subtype group. Results of PFGE showed high genetic diversity with 40 different band patterns. Conclusion It is the first time that Escherichia albertii was identified in diarrheal patients, close contacts, egret, poultry and animal-derived food in China. It is practically important for understanding the etiology and epidemiology of Escherichia albertii in China. Key words: Escherichia albertii; Animal-derived food; eae; cdtB; MLST; PFGE; 16S rDNA