Tetracycline resistance determinants, Tet B and Tet M, detected in Pasteurella haemolytica and Pasteurella multocida from bovine herds.

Resistance to antibiotics has recently emerged in Pasteurella haemolytica and Pasteurella multocida isolated from bovine herds. Forty-two clinical strains resistant to antibiotics and isolated through a French national network from different origins were analysed for their resistance to tetracycline. The MICs of tetracycline ranged from 32-256 mg/L. The resistance determinants Tet B and Tet M were detected in two strains, in which they are probably chromosomal.