[Resistance of bovine and porcine Pasteurella to florfenicol and other antibiotics].

The resistance pattern of 221 (89 bovine, 132 porcine) pasteurella strains isolated in 1996 against 16 antibiotics or chemotherapeutics was determined by agar diffusion. Pasteurella haemolytica showed a higher level of resistance compared to Pasteurella multocida; porcine strains were more resistant than bovine strains. Over 90% of porcine Pasteurella multocida were sensible to penicillin G, ampicillin, cephalothin, polymyxin B, enrofloxacin, chloramphenicol and florfenicol. In addition, bovine strains were at least 90% sensible to oxacillin, erythromycin, gentamycin and sulfmethoxazole-trimethoprim. More than 90% of porcine Pasteurella haemolytica were classified as sensible to polymyxin B, enrofloxacin und florfenicol; bovine strains to cephalothin, neomycin und chloramphenicol as well. In 1996, 2 years after the chloramphenicol ban for food rendering animals, only 6.3% of bovine pasteurella strains proved to be resistant against chloramphenicol compared to a 16.27% fraction in 1994. The mean MIC-values of florfenicol against pasteurella spp. were nearly the same in bovine and porcine isolates with 0.53 microgram/ml and 0.52 microgram/ml respectively. Pasteurella haemolytica, however, showed higher MIC-values (0.68 microgram/ml in bovine, 0.70 microgram/ml in porcine isolates) than Pasteurella multocida with 0.47 microgram/ml in bovine and 0.51 microgram/ml in porcine strains. No isolate had a MIC of florfenicol greater than 1.0 microgram/ml, all pasteurella strains were classified sensible to florfenicol.