Contribution of Salmonella Enteritidis virulence factors to intestinal colonization and systemic dissemination in 1-day-old chickens.
Salmonella enterica serovar Enteritidis is one of the most common serovars associated with poultry and poultry product contamination in the United States. We previously identified 14 mutant strains of Salmonella Enteritidis phage type 4 (PT4) with significantly reduced invasiveness in human intestinal epithelial cells (Caco-2), chicken macrophages (HD-11), and chicken hepatocellular epithelial cells (LMH). These included Salmonella Enteritidis mutants with transposon insertions in 6 newly identified Salmonella Enteritidis-specific genes (pegD and SEN1393), and genes or genomic islands common to most other Salmonella serovars (SEN0803, SEN0034, SEN2278, and SEN3503) along with 8 genes previously known to contribute to enteric infection (hilA, pipA, fliH, fljB, csgB, spvR, and rfbMN). We hypothesized that Salmonella Enteritidis employs both common Salmonella enterica colonization factors and Salmonella Enteritidis-specific traits to establish infection in chickens. Four Salmonella Enteritidis mutants (SEN0034::Tn5, fliH::Tn5, SEN1393::Tn5, and spvR::Tn5) were indistinguishable from the isogenic wild-type strain when orally inoculated in 1-d-old chickens, whereas 2 mutants (CsgB::Tn5 and PegD::Tn5) were defective for intestinal colonization (P < 0.05) and 8 mutants (hilA::Tn5, SEN3503::Tn5, SEN0803::Tn5, SEN2278::Tn5, fljB::Tn5, rfbM::Tn5, rfbN::Tn5, and pipA::Tn5) showed significant in vivo attenuation in more than one organ (P < 0.05). Complementation studies confirmed the role of rfbN and SEN3503 during infection. This study should contribute to a better understanding of the mechanisms involved in Salmonella Enteritidis pathogenesis, and the target genes identified here could potentially serve as targets for the development of live-attenuated or subunit vaccine.
Department of Veterinary Microbiology and Pathology, Washington State University, Pullman 99164-7040.
Tarek M
TM
Addwebi
Douglas R
DR
Call
Devendra H
DH
Shah
D000818:Animals; D002645:Chickens; D005798:Genes, Bacterial; D005816:Genetic Complementation Test / Q000662:veterinary; D007422:Intestines / Q000382:microbiology; D011201:Poultry Diseases / Q000382:microbiology*; D011897:Random Allocation; D012481:Salmonella Infections, Animal / Q000382:microbiology*; D012477:Salmonella enteritidis / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology*; D013047:Specific Pathogen-Free Organisms; D037521:Virulence Factors / Q000235:genetics*
D037521:Virulence Factors
Salmonella Enteritidis; chicken; virulence