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P2-162 Drug-resistant and Virulent Salmonella Serovars Can Colonize Pre-harvest Poultry Facilities in the Absence of Selective Antimicrobial Pressure

Tuesday, July 30, 2013
Exhibit Hall (Charlotte Convention Center)
Kelly Johnson, U.S. Food and Drug Administration, Jefferson, AR
Si Hong Park, University of Arkansas, Fayetteville, AR
Bashar Shaheen, US Food and Drug Administration, Jefferson, AR
Jing Han, U.S. Food and Drug Administration, Jefferson, AR
Steven Foley, U.S. Food and Drug Administration, Jefferson, AR
Joanna Deck, U.S. Food and Drug Administration, Jefferson, AR
Brett Kenney, West Virginia University, Morgantown, WV
Steven Ricke, University of Arkansas, Fayetteville, AR
Rajesh Nayak, U.S. Food and Drug Administration, Jefferson, AR
Introduction: Reduction in human illnesses associated with raw and processed poultry meat necessitates comprehensive control at the production facilities.

Purpose: There is limited data on the genetic characteristics of Salmonella isolated from turkeys, particularly in flocks that have not been exposed to antimicrobials.

Methods: Salmonella (n = 95) were isolated from ceca, feed, drinkers, leftover feed, litter and insects from a turkey production facility. Isolates were serotyped and fingerprinted by XbaI-PFGE. Antimicrobial susceptibility profiles (15 antimicrobials), 34 virulence genes, plasmid profiles and replicon incompatibility grouping (18 replicons) were evaluated.

Results: Six serotypes (Agona, Anatum, Kentucky, Montevideo, Senftenberg and Worthington) and roughs were identified, mostly from ceca and feed. PFGE dendrogram clustered the strains into 6 distinct groups based on their serotype. Isolates (36%) were resistant to 2 to 4 antimicrobials. Anatum and Worthington were mostly resistant to gentamicin (GEN), streptomycin (STR) and sulfaxisole (SUL), while Kentucky and roughs were resistant to tetracycline (TET), sulfaxisole and trimethoprim/sulfamethoxazole (SXT). Fifty-three percent of virulence genes were detected in all isolates. Isolates harbored genes encoding for Salmonella Pathogenicity Islands (SPI 1 to 4), including adhesion (fimH), cytoplasmic/effector proteins (rhuM, rmbA, sopE and avrA), entry/survival into macrophages (sipB, spaN, msgA, pagC and spiA), host recognition/invasion (cdtB, hilA, invA, lpfC, orgA, pefB, prgH, tolC and sopB) and iron acquisition (iroN and sitA). Plasmids ranging from ~1 to 95 kb were detected. Isolates with resistance to GEN, STR and SUL were associated with incompatibility group IncI1 plasmids while those resistant to TET and SXT were associated with groups IncT and HI2.

Significance: Nearly one third of the isolates were resistant to multiple antimicrobials even though the flock was untreated with any antimicrobials. With the exception of the IpfC gene, there was no association between serotypes and virulence genes. There is a need to evaluate how on-farm practices affect Salmonella colonization dynamics and to develop guidelines that will interrupt the “cycles” of Salmonella transmission between humans, animals and the production environment.

Back to: Poster Session 2 - Pathogens, Antimicrobials
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