title: Salmonella Prevalence and Antimicrobial Susceptibility Among Dairy Farm Environmental Samples Collected in Texas.
abstract: Dairy cattle are a reservoir of several Salmonella serovars that are leading causes of human salmonellosis. The objectives of this study were to estimate the environmental prevalence of Salmonella on dairy farms in Texas and to characterize the antimicrobial susceptibility of the isolates. Eleven dairy farms throughout Texas were sampled from August through October 2013, using a cross-sectional approach. Samples were collected from four locations within each farm (hospital pen, maternity pen, cow housing area, and calf housing area), and feces were collected from cull cows as available. Environmental and fecal samples were processed for Salmonella, and isolates were tested for susceptibility to 15 antimicrobial agents. Serovar characterization was performed on a subset of these isolates. Salmonella was isolated from 67.0% (236/352) of the environmental samples and 64.2% (43/67) of the cull cow fecal samples. Environmental samples from the maternity pen were significantly more likely to be Salmonella positive than samples from the cow and calf housing areas. Multidrug resistance was evident in 11.9% (27/226) of environmental isolates and 19.5% (8/41) of fecal isolates. Salmonella isolates from the calf housing area and maternity pen were significantly more likely to be multidrug resistant (MDR) than isolates from the cow housing area. The most common serovars found among the MDR isolates were Newport, Muenchen, and Typhimurium. These results help provide a focus for efforts to mitigate the burden of antimicrobial-resistant Salmonella at the preharvest level.
authors.affiliation: 1 Department of Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University , College Station, Texas.
authors.forename: Lorraine D
authors.initials: LD
authors.lastname: Rodriguez-Rivera
authors.affiliation: 1 Department of Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University , College Station, Texas.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Cummings
authors.affiliation: 2 International Center for Food Industry Excellence, Texas Tech University , Lubbock, Texas.
authors.forename: Guy H
authors.initials: GH
authors.lastname: Loneragan
authors.affiliation: 3 Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania , Philadelphia, Pennsylvania.
authors.forename: Shelley C
authors.initials: SC
authors.lastname: Rankin
authors.affiliation: 2 International Center for Food Industry Excellence, Texas Tech University , Lubbock, Texas.
authors.forename: Devin L
authors.initials: DL
authors.lastname: Hanson
authors.affiliation: 4 Plainview, Texas.
authors.forename: William M
authors.initials: WM
authors.lastname: Leone
authors.affiliation: 5 Food and Feed Safety Research Unit, Agricultural Research Service, U.S. Department of Agriculture , College Station, Texas.
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Edrington
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000382:microbiology*; D003430:Cross-Sectional Studies; D003612:Dairying; D024901:Drug Resistance, Multiple, Bacterial; D004783:Environmental Microbiology; D005243:Feces / Q000382:microbiology; D005260:Female; D007413:Intestinal Mucosa / Q000382:microbiology; D008297:Male; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D050296:Microbial Viability / Q000187:drug effects; D015995:Prevalence; D012007:Rectum / Q000382:microbiology; D012475:Salmonella / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification*; D012481:Salmonella Infections, Animal / Q000453:epidemiology / Q000382:microbiology*; D013045:Species Specificity; D013781:Texas / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents