Abstract
Minimal inhibitory concentrations of ampicillin (ABPC), cefazolin (CEZ), oxytetracycline (OTC), kanamycin (KM), chloramphenicol (CP), florfenicol, bicozamycin, danofloxacin, and orbifloxacin were tested for 75 strains ofPasteurella multocidaserotype A isolated from the pneumonic lungs of 41 slaughtered calves at 16 farms in Hyogo prefecture and for 51 strains ofHaemophilus somnusisolated from the pneumonic lungs of 27 slaughtered calves at 9 farms in Hyogo prefecture during 1994 and 1995. Of the P. multocida serotype A strains, 6 (8.0%) were resistant to ABPC, 10 (13.3%) to CEZ, 32 (42.7%) to OTC, 17 (22.7%) to KM, and 17 (22.7%) to CP. Of theH. somnusstrains, 24 (47.1%) were resistant to OTC, 20 (39.2%) to KM, and 20 (39.2%) to CP. Twentyseven (36.0%) of theP. multocidaserotype A strains and 20 (39.2%) of theH. somnusstrains were resistant to plural antimicrobial agents.
