Antibiosensibilité in vitro de diverses souches de Mycoplasma capricolum

The in vitro sensitivity of 20 wild strains of M. capricolum and that of the reference strain (California kid) against 14 antibiotics was investigated by means of a micromethod. The technique is based on the determination of the inhibitory minimum concentration (IMC) in a liquid medium as revealed by the inhibition of glucose metabolism. The following results were obtained: all strains were sensitive to five antibiotics (tylosin, oxytetracyclin, gentamycin, neomycin, nalidixic acid) with an IMC varying from 0.06 to 8 meg/ml. The variation in the IMC values from 8 to 32 meg/ml for spiramycin and erythromycin indicated that some of these strains were sensitive and other resistant to these two drugs. All strains were resistant to seven antibiotics (streptomycin, bacitracin, polymyxin, chloramphenicol, lincomycine, rifampicine and novobiocine), sometimes at a concentration exceeding 128 meg/ml.