title: Salmonella enterica serovar enteritidis antimicrobial peptide resistance genes aid in defense against chicken innate immunity, fecal shedding, and egg deposition.
abstract: Salmonella enterica serovar Enteritidis (S. Enteritidis) is a major etiologic agent of nontyphoid salmonellosis in the United States. S. Enteritidis persistently and silently colonizes the intestinal and reproductive tract of laying hens, resulting in contaminated poultry products. The consumption of contaminated poultry products has been identified as a significant risk factor for human salmonellosis. To understand the mechanisms S. Enteritidis utilizes to colonize and persist in laying hens, we used selective capture of transcribed sequences to identify genes overexpressed in the HD11 chicken macrophage cell line and in primary chicken oviduct epithelial cells. From the 15 genes found to be overexpressed in both cell types, we characterized the antimicrobial peptide resistance (AMPR) genes, virK and ybjX, in vitro and in vivo. In vitro, AMPR genes were required for natural morphology, motility, secretion, defense against detergents such as EDTA and bile salts, and resistance to antimicrobial peptides polymyxin B and avian β-defensins. From this, we inferred the AMPR genes play a role in outer membrane stability and/or modulation. In the intestinal tract, AMPR genes were involved in early intestinal colonization and fecal shedding. In the reproductive tract, virK was required in early colonization whereas a deletion of ybjX caused prolonged ovary colonization and egg deposition. Data from the present study indicate that AMPR genes are differentially utilized in various host environments, which may ultimately assist S. Enteritidis in persistent and silent colonization of chickens.
authors.affiliation: Department of Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
authors.forename: Jessica A
authors.initials: JA
authors.lastname: McKelvey
authors.affiliation: Department of Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
authors.forename: Ming
authors.initials: M
authors.lastname: Yang
authors.affiliation: College of Veterinary Medicine, Mississippi State University, Starkville, Mississippi, USA Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong, China.
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Department of Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA zhangshup@missouri.edu.
authors.forename: Shuping
authors.initials: S
authors.lastname: Zhang
mesh_terms: D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000276:immunology* / Q000494:pharmacology; D057138:Bacterial Shedding; D002478:Cells, Cultured; D002645:Chickens; D004361:Drug Tolerance; D004531:Eggs / Q000382:microbiology*; D004847:Epithelial Cells / Q000382:microbiology; D005243:Feces / Q000382:microbiology*; D005260:Female; D020869:Gene Expression Profiling; D054884:Host-Pathogen Interactions; D057131:Immune Evasion; D007113:Immunity, Innate; D008264:Macrophages / Q000382:microbiology; D012477:Salmonella enteritidis / Q000276:immunology* / Q000502:physiology; D014481:United States
chemical_list: D023181:Antimicrobial Cationic Peptides