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Defects in organ colonization and intestinal persistence of non-subspecies I Salmonella enterica in mice

Erin Katribe, Lydia Bogomolnaya, Megan Reynolds, Andrew Bugbee, Helene Andrews-Polymenis
College of Veterinary Medicine, Texas A&M University and College of Medicine, Texas A&M University System Health Science Center.  College Station, Texas.Erin Picture


Objective: Our objective was to compare intestinal persistence and organ colonization of ssp. I and non-ssp. I Salmonella in murine models of infection.

Animals: Competitive infection experiments were performed in groups of six either genetically Salmonella-susceptible (BALB/c) or Salmonella-resistant (CBA) mice.

Procedure: Fecal samples were collected over 40 days post infection from the CBA mice to assess intestinal persistence.  Organs were harvested at 5 days post infection for the BALB/c mice and at 40 days for the CBA mice to assess organ colonization.

Results: In intestinal persistence experiments, Salmonella enterica subspecies I (ssp. I) outgrew both S. enterica subspecies IIIa (ssp. IIIa) and S. enterica subspecies IIIb (ssp. IIIb) over 40 days of infection.  In Salmonella-susceptible mice, ssp. I outnumbered ssp. IIIa in all organs harvested.  However, in organ colonization ssp. IIIb colonized the Peyer’s patches and cecum equally, at levels similar to ssp. I in Salmonella-susceptible mice, but was defective for colonization of the mesenteric lymph nodes, liver, and spleen.

Conclusions and Clinical Relevance: These data show that ssp. IIIa and ssp. IIIb are unable to persist well in murine intestine, in contrast to ssp. I.  Ssp. IIIa is defective for colonization of all organs tested, while ssp. IIIb is able to colonize the intestine but is defective for systemic spread in short term experiments with Salmonella-susceptible mice.