title: Variability in acquired resistance of Pasteurella and Mannheimia isolates from the nasopharynx of calves, with particular reference to different herd types.
abstract: To measure the level of antimicrobial resistance in potential bovine respiratory pathogens at different production types, nasal swabs were collected from 57 calves of 13 dairy herds, 150 calves of 9 beef cattle herds, and 289 calves of 5 high-density veal calf herds and investigated for the presence of Pasteurellaceae. All calves were less than 6 months old. Susceptibilities of the Pasteurella and Mannheimia isolates to eight antimicrobials were determined using an agar dilution method. P. multocida (37.3%) and hemolytic Mannheimia organisms (M. haemolytica sensu lato) (6.3%) were the most frequently detected organisms. The overall prevalence of isolates resistant to at least one antimicrobial from the dairy, beef, and veal calves were 17.6% (6/34), 21.9% (14/64), and 71.9% (64/89), respectively. In isolates obtained on the veal calf herds, acquired resistance to ampicillin, oxytetracycline, potentiated sulfonamides, gentamicin, tilmicosin, and enrofloxacin was frequently present, and 32.6% of these isolates were resistant to more than two of the tested antimicrobials. Resistance to ceftiofur and florfenicol was not detected. A substantial within-herd variability of species diversity and resistance profiles among isolates belonging to the genera Pasteurella and Mannheimia was found among the isolates of the veal calf farms.
authors.affiliation: Department of Reproduction, Obstetrics and Herd Health, Ghent University, Belgium. Boudewijn.Catry@UGent.be
authors.forename: Boudewijn
authors.initials: B
authors.lastname: Catry
authors.forename: Freddy
authors.initials: F
authors.lastname: Haesebrouck
authors.forename: Sarne De
authors.initials: SD
authors.lastname: Vliegher
authors.forename: Bianca
authors.initials: B
authors.lastname: Feyen
authors.forename: Mia
authors.initials: M
authors.lastname: Vanrobaeys
authors.forename: Geert
authors.initials: G
authors.lastname: Opsomer
authors.forename: Stefan
authors.initials: S
authors.lastname: Schwarz
authors.forename: Aart De
authors.initials: AD
authors.lastname: Kruif
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002417:Cattle / Q000382:microbiology*; D024901:Drug Resistance, Multiple, Bacterial; D031121:Mannheimia / Q000187:drug effects* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D009305:Nasopharynx / Q000382:microbiology*; D010325:Pasteurella / Q000187:drug effects* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents