Biological Characteristics Of Avian Pathogenic Escherichia Coli Isolates In China And Identification Of Their Virulence-related Genes

Colibacillosis refers to any localized or systemic infection caused entirely or partly by avian pathogenic Escherichia coli (APEC), including septicaemia, granuloma (Hjarre's disease), air sac disease, chronic respiratory disease (CRD), avian cellulitis, swollen head syndrome, peritonitis, salpingitis, osteomyelitis/synovitis, panophthalmitis, and omphalitis/yolk sac infection. Colibacillosis in mammals is most often a primary enteric disease, whereas colibacillosis in poultry is typically a secondary localized or systemic disease occurring when host defence has been impaired or overwhelmed. Collectively, infections caused by Escherichia coli (E.coli) are responsible for significant economic losses to the poultry industry in many parts of the world. The pioneer serological surveys indicate that the majority of avian septicaemic E.coli strains belong to a limited number of O serogroups (O1, O2, and O78). Analysis of the involvement of these potential virulence factors using experimental models of infection just began during the past few years. Nevertheless, all the actual roles of the known virulence factors are not fully elucidated and certain steps of the infection process have not been related to previously identified factors. Furthermore, the mechanisms by which avian pathogenic E.coli cause infection are largely unknown.1. Isolation and identification of avian pathogenic Escherichia coli isolates in ChinaWe investigated 1351 E.coli isolates collected from visceral organs of poultry having died from colibacillosis from 20 provinces in China. Among these E.coli isolates,...