title: Salmonella enterica in commercial swine feed and subsequent isolation of phenotypically and genotypically related strains from fecal samples.
abstract: The purpose of this study was to determine the occurrence and genotypic relatedness of Salmonella enterica isolates recovered from feed and fecal samples in commercial swine production units. Of 275 feed samples, Salmonella was detected in 10 feed samples that originated from 8 of 36 (22.2%) barns, with a prevalence of 3.6% (10/275 samples). In fecal samples, a prevalence of 17.2% was found at the early finishing stage (1,180/6,880 samples), with a significant reduction in prevalence (7.4%) when pigs reached market age (392/5,321 samples). Of the 280 Salmonella isolates systematically selected for further characterization, 50% of the feed isolates and 55.3% of the isolates of fecal origin showed similar phenotypes based on antimicrobial resistance patterns and serogrouping. About 44% of the isolates were multidrug resistant. Pulsed-field gel electrophoresis (PFGE) genotyping grouped the 46 representative isolates into five genotypic clusters, of which four of the clusters consisted of genotypically related isolates recovered from feed and fecal samples. The occurrence of genotypically related and, in some cases, clonal strains, including multidrug-resistant isolates in commercially processed feed and fecal samples, suggests the high significance of commercial feed as a potential vehicle of Salmonella transmission.
authors.affiliation: The Ohio State University, College of Veterinary Medicine, Department of Veterinary Preventive Medicine, 1920 Coffey Rd., Columbus, OH 43210, USA.
authors.forename: Bayleyegn
authors.initials: B
authors.lastname: Molla
authors.forename: Allyson
authors.initials: A
authors.lastname: Sterman
authors.forename: Jennifer
authors.initials: J
authors.lastname: Mathews
authors.forename: Valeria
authors.initials: V
authors.lastname: Artuso-Ponte
authors.forename: Melanie
authors.initials: M
authors.lastname: Abley
authors.forename: William
authors.initials: W
authors.lastname: Farmer
authors.forename: Päivi
authors.initials: P
authors.lastname: Rajala-Schultz
authors.forename: W E Morgan
authors.initials: WE
authors.lastname: Morrow
authors.forename: Wondwossen A
authors.initials: WA
authors.lastname: Gebreyes
mesh_terms: D000821:Animal Feed / Q000382:microbiology*; D000822:Animal Husbandry; D000818:Animals; D016521:Electrophoresis, Gel, Pulsed-Field; D005243:Feces / Q000382:microbiology*; D005838:Genotype; D006799:Housing, Animal; D010641:Phenotype; D012481:Salmonella Infections, Animal / Q000382:microbiology; D019779:Salmonella enterica / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D013552:Swine / Q000382:microbiology*