title: Transcriptome analysis of avian pathogenic Escherichia coli O1 in chicken serum reveals adaptive responses to systemic infection.
abstract: Infections of avian pathogenic Escherichia coli (APEC) result in annual multimillion-dollar losses to the poultry industry. Despite this, little is known about the mechanisms by which APEC survives and grows in the bloodstream. Thus, the aim of this study was to identify molecular mechanisms enabling APEC to survive and grow in this critical host environment. To do so, we compared the transcriptome of APEC O1 during growth in Luria-Bertani broth and chicken serum. Several categories of genes, predicted to contribute to adaptation and growth in the avian host, were identified. These included several known virulence genes and genes involved in adaptive metabolism, protein transport, biosynthesis pathways, stress resistance, and virulence regulation. Several genes with unknown function, which were localized to pathogenicity islands or APEC O1's large virulence plasmid, pAPEC-O1-ColBM, were also identified, suggesting that they too contribute to survival in serum. The significantly upregulated genes dnaK, dnaJ, phoP, and ybtA were subsequently subjected to mutational analysis to confirm their role in conferring a competitive advantage during infection. This genome-wide analysis provides novel insight into processes that are important to the pathogenesis of APEC O1.
authors.affiliation: Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, 1802 University Blvd., Ames, IA 50011, USA.
authors.forename: Ganwu
authors.initials: G
authors.lastname: Li
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Tivendale
authors.forename: Peng
authors.initials: P
authors.lastname: Liu
authors.forename: Yaping
authors.initials: Y
authors.lastname: Feng
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Wannemuehler
authors.forename: Wentong
authors.initials: W
authors.lastname: Cai
authors.forename: Paul
authors.initials: P
authors.lastname: Mangiamele
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Johnson
authors.forename: Chrystala
authors.initials: C
authors.lastname: Constantinidou
authors.forename: Charles W
authors.initials: CW
authors.lastname: Penn
authors.forename: Lisa K
authors.initials: LK
authors.lastname: Nolan
mesh_terms: D000818:Animals; D002645:Chickens; D004926:Escherichia coli / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000097:blood / Q000235:genetics / Q000662:veterinary*; D015870:Gene Expression; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics; D055106:Genome-Wide Association Study; D017403:In Situ Hybridization; D020411:Oligonucleotide Array Sequence Analysis; D011201:Poultry Diseases / Q000097:blood / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018805:Sepsis / Q000235:genetics; D014774:Virulence / Q000235:genetics