Prevalence of Salmonella and multiple antimicrobial-resistant Salmonella in California dairies.
A cross-sectional survey was conducted on 75 randomly selected dairies in one California county. Salmonella was isolated from 12 (16%) dairies; S newport was isolated from 6 (8%). Chloramphenicol-resistant S newport and S dublin were isolated from 8 (10.7%) dairies. Dairies with Salmonella had higher average calf mortality rates (P = 0.064; odds ratio [OR], 3.8). Dairies with S newport had a greater than expected occurrence of illnesses in adult cows compared with dairies with no S newport (P = 0.048; OR, 6.7) or with no Salmonella serotypes isolated (P = 0.047; OR, 6.9). Dairies with chloramphenicol-resistant Salmonella were more likely to have used chloramphenicol during the preceding 18-month period compared with dairies with chloramphenicol-susceptible Salmonella or no Salmonella (P = 0.023; OR, 9.5).
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Division of Viral Diseases, Centers for Disease Control, Atlanta, GA 30333.
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D000818:Animals; D002140:California; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology* / Q000382:microbiology; D002702:Chloramphenicol Resistance; D003430:Cross-Sectional Studies; D003612:Dairying; D004352:Drug Resistance, Microbial; D005243:Feces / Q000382:microbiology; D005260:Female; D011897:Random Allocation; D012475:Salmonella / Q000187:drug effects / Q000302:isolation & purification*; D012481:Salmonella Infections, Animal / Q000453:epidemiology* / Q000382:microbiology; D012703:Serotyping / Q000662:veterinary; D011795:Surveys and Questionnaires