Salmonella enterica serovar Enteritidis tatB and tatC mutants are impaired in Caco-2 cell invasion in vitro and show reduced systemic spread in chickens.
Salmonella enterica subsp. enterica serovar Enteritidis is a leading causative agent of gastroenteritis in humans. This pathogen also colonizes the intestinal tracts of poultry and can spread systemically in chickens. Transfer to humans usually occurs through undercooked or improperly handled poultry meat or eggs. The bacterial twin-arginine transport (Tat) pathway is responsible for the translocation of folded proteins across the cytoplasmic membrane. In order to study the role of the Tat system in the infection and colonization of chickens by Salmonella Enteritidis, we constructed chromosomal deletion mutants of the tatB and tatC genes, which are essential components of the Tat translocon. We observed that the tat mutations affected bacterial cell morphology, motility, and sensitivity to albomycin, sodium dodecyl sulfate (SDS), and EDTA. In addition, the mutant strains showed reduced invasion of polarized Caco-2 cells. The wild-type phenotype was restored in all our Salmonella Enteritidis tat mutants by introducing episomal copies of the tatABC genes. When tested in chickens by use of a Salmonella Enteritidis Delta tatB strain, the Tat system inactivation did not substantially affect cecal colonization, but it delayed systemic infection. Taken together, our data demonstrated that the Tat system plays a role in Salmonella Enteritidis pathogenesis.
Mickael
Claudia Silva
CS
Vaccine and Infectious Disease Organization, University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK, Canada.
Lam
Po-King S
PK
Berberov
Emil M
EM
Allan
Brenda
B
Potter
Andrew A
AA
Köster
Wolfgang
W
D000818:Animals; D000900:Anti-Bacterial Agents / Q000633:toxicity; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D018938:Caco-2 Cells; D002645:Chickens; D004492:Edetic Acid / Q000633:toxicity; D004847:Epithelial Cells / Q000382:microbiology*; D005291:Ferrichrome / Q000031:analogs & derivatives / Q000633:toxicity; D017353:Gene Deletion; D005816:Genetic Complementation Test; D006801:Humans; D008124:Locomotion; D011201:Poultry Diseases / Q000382:microbiology*; D012481:Salmonella Infections, Animal / Q000382:microbiology*; D012477:Salmonella enteritidis / Q000166:cytology / Q000187:drug effects / Q000472:pathogenicity* / Q000502:physiology; D012967:Sodium Dodecyl Sulfate / Q000633:toxicity; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics / Q000502:physiology*
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D037521:Virulence Factors; D005291:Ferrichrome; C015657:albomycin; D012967:Sodium Dodecyl Sulfate; D004492:Edetic Acid