Poster Presentation The 3rd Prato Conference on the Pathogenesis of Bacterial Diseases of Animals 2014

Epidemiology And Antimicrobial Resistance Of Salmonella Enterica From European Starlings In Concentrated Animal Feeding Operations  (#22)

Doreene R Hyatt 1 , James C Carlson 2 , George M Linz 3 , Anna Mangan 2 , Kevin T Bentler 2 , Michael M Russell 1 , Richard M Engeman 2
  1. Veterinary Diagnostic Laboratories, Colorado State University, Fort Collins, CO, United States
  2. Wildlife Services, National Wildlife Research Center, U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Fort Collins, CO, USA
  3. Wildlife Services, National Wildlife Research Center, U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Bismarck, ND, USA

Bird-livestock interactions have been implicated as potential sources for bacteria within concentrated animal feeding operations (CAFOs).   European starlings (Sturnus vulgaris) are known to contaminate cattle feed and water with Salmonella enterica through their fecal waste. The goal of this study was to assess if starlings can mechanically move S. enteric within a CAFO on their exterior. In 2012, external wash and gastrointestinal tract (GI) samples were collected from 100 starlings.  Samples (100) were also collected from animal pens (one cattle fecal, one feed, and one water trough sample). Isolates from all S. enterica positive samples were subjected to antimicrobial susceptibility testing and pulsed-field gel electrophoresis (PFGE) with XbaI-digestion. 

All sample types, including 17% of external starling wash samples, contained S. enterica.  All sample types had at least one antimicrobial resistant (AMR) isolate. The serotypes isolated from the starling external wash samples were all found in the farm environment and 11.8% (2/17) of isolates from positive starling external wash samples were resistant to at least one class of antibiotics.  The PFGE analysis was conducted on 182 S. enterica isolates collected from the CAFO between 2009 and 2012. Based upon PFGE analysis, genetically indistinguishable S. enterica isolates were found in cattle feces, feed, water trough, external starling wash and starling gastrointestinal tract samples.

This study describes a novel mechanism of wildlife-introduced microbial contamination in CAFOs and suggests that S. enterica is transmitted between species and shared feed sources which likely contributes to infections within both starlings and cattle. Moreover genetically indistinguishable isolates, across all years, were found suggesting that long term environmental persistence may be mediated by starling visits to CAFOs. Mechanical movement of microbiological hazards, by starlings in CAFOs, should be considered a potential source of AMR bacteria that is of concern to veterinary, environmental and public health.