title: Prevalence and antimicrobial resistance of Campylobacter in US dairy cattle.
abstract: OBJECTIVE
  To obtain an overview of the prevalence and antimicrobial resistance of Campylobacter in faeces of US dairy cows in 2002.
  
  
  RESULTS
  Faeces from 1435 cows, representing 96 dairy operations in 21 US states, were collected for the culture of Campylobacter. A total of 735 Campylobacter strains were isolated (51.2% positive samples) with 94 operations positive (97.9%) for Campylobacter. From this collection, 532 isolates (473 Campylobacter jejuni and 59 Campylobacter coli) were randomly selected for susceptibility testing to eight antimicrobials: azithromycin, chloramphenicol, ciprofloxacin, clindamycin, erythromycin, gentamicin, nalidixic acid and tetracycline. The C. jejuni isolates exhibited resistance to tetracycline (47.4%), nalidixic acid (4.0%) and ciprofloxacin (2.5%), while the C. coli strains exhibited some resistance to all antimicrobials except chloramphenicol and ciprofloxacin. Only 3.6% of the C. jejuni isolates were resistant to two or more antimicrobials but 20.3% of the C. coli strains were multiresistant.
  
  
  CONCLUSIONS
  On most operations, at least one cow was positive for Campylobacter and more than half of the cows sampled were shedding Campylobacter. The C. coli isolates had significantly higher levels of resistance to macrolides and to tetracycline compared with the C. jejuni strains, but were susceptible to ciprofloxacin.
  
  
  CONCLUSIONS
  This study demonstrated a high prevalence of Campylobacter on US dairy operations; however, US dairy cattle have not been recognized as a major source of human infection compared with poultry. Campylobacter coli appears to develop antimicrobial resistance more readily than C. jejuni from the same environment.
authors.affiliation: USDA-ARS, Bacterial Epidemiology and Antimicrobial Resistance Research Unit, Richard B. Russell Agricultural Research Center, Athens, GA 30605-2720, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Englen
authors.forename: A E
authors.initials: AE
authors.lastname: Hill
authors.forename: D A
authors.initials: DA
authors.lastname: Dargatz
authors.forename: S R
authors.initials: SR
authors.lastname: Ladely
authors.forename: P J
authors.initials: PJ
authors.lastname: Fedorka-Cray
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002169:Campylobacter Infections / Q000453:epidemiology / Q000662:veterinary*; D017000:Campylobacter coli / Q000187:drug effects; D016123:Campylobacter jejuni / Q000187:drug effects; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology* / Q000382:microbiology; D002701:Chloramphenicol / Q000494:pharmacology; D002939:Ciprofloxacin / Q000494:pharmacology; D002981:Clindamycin / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D024901:Drug Resistance, Multiple, Bacterial; D004917:Erythromycin / Q000494:pharmacology; D005839:Gentamicins / Q000494:pharmacology; D009268:Nalidixic Acid / Q000494:pharmacology; D015995:Prevalence; D013752:Tetracycline / Q000494:pharmacology; D014481:United States / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents; D005839:Gentamicins; D009268:Nalidixic Acid; D002981:Clindamycin; D002939:Ciprofloxacin; D004917:Erythromycin; D002701:Chloramphenicol; D013752:Tetracycline