Detection, Isolation, and Molecular Characterization of Escherichia albertii from Wild Birds in West Japan

Abstract

Escherichia albertii is an emerging zoonotic foodborne pathogen. Several outbreaks of E. albertii have occurred, particularly in Japan. Although birds have been considered as one of the most important reservoirs of this bacterium, information regarding its prevalence in birds is still scarce. We performed a survey of E. albertii in wild birds in Japan and examined the characteristics of these isolates. E. albertii-specific genes were detected in five cloacal swabs from 156 birds by PCR. Four E. albertii strains were isolated from a swallow with two different E. albertii strains and two pigeons in a flock using XRM-MacConkey agar. These isolates were assigned to biogroup 3, showed no resistance to any tested antimicrobials, and were classified into two EAO-genotypes (EAOg2 and EAOg33) and were untypable. Similar to clinical E. albertii strains, these isolates carried virulence genes, including eae (n = 4), paa (n = 4), Eccdt-I (n = 2), and stx2f (n = 1), as well as Eacdt. Furthermore, stx2f genes in a strain were located on an inducible bacteriophage, which can confer the ability to produce Stx2f in E. coli. In conclusion, Japanese wild birds carried E. albertii at levels similar to the reported prevalence in birds. These isolates may have the potential to cause gastroenteritis in humans.