Identification of avian pathogenic Escherichia coli genes that are induced in vivo during infection in chicken

Avian pathogenic E. coli (APEC) is associated with extra-intestinal infections in poultry causing a variety of diseases collectively known as colibacillosis. Host and bacterial factors influencing and/or responsible for carriage and systemic translocation of APEC inside the host are poorly understood. Identification of such factors could help in the understanding of its pathogenesis and in the subsequent development of control strategies. Recombination based in vivo expression technology (RIVET) was used to identify APEC genes specifically expressed during infection in chickens. A total of 21 clones with in vivo-induced promoters were isolated from chicken's liver and spleen, indicative for systemic infection. DNA sequencing of the cloned fragments revealed that twelve of the genes were E. coli conserved genes (metH, lysA, pntA, purL, serS, ybjE, ycdK (rutC), wcaJ, gspL, sdsR ylbE and yjiY), six of the genes were phage-related/associated, and three genes were pathogen-specific (tkt1, irp2 and eitD). These genes are involved in various cellular functions such as metabolism, cell envelope and integrity, transport systems and virulence. Others were phage-related or have yet unknown functions.status: publishe