title: Determination of Mycoplasma bovis susceptibilities against six antimicrobial agents using the E test method.
abstract: The objective of this study was to determine the susceptibility of Mycoplasma bovis against six antibiotics using the E test methodology. Fifty-eight isolates of M. bovis originating from 55 affected cattle were evaluated. Specimen originated from: lung tissue, synovial fluid, tracheo-bronchial wash, milk, and external or inner ear discharge. Antimicrobial agents tested were azythromycin, clindamycin, erythromycin, enrofloxacin, spectinomycin and tetracycline. The E test strips were placed on the surface of Hayflick plates on which organism suspension was spread. Plates were incubated at 35 degrees C in a candle jar for 72 h. MICs were then read by determining where the growth inhibition zone intersected with the MIC scale on the strip. M. bovis Donetta isolate was used as a control. All MICs were >256 microg/ml for erythromycin. MIC50 and MIC90 obtained for azythromycin were 3 and >256 microg/ml, respectively. MIC50 and MIC90 obtained for tetracycline were 4 and 8 microg/ml, respectively. MIC50 and MIC90 obtained for spectinomycin were 2 and >1021 microg/ml, respectively. MIC50 and MIC90 obtained for clindamycin were 0.19 and >256 microg/ml, respectively. MIC50 and MIC90 obtained for enrofloxacin were 0.19 and 0.25 microg/ml, respectively. Resistance was not associated with the specimen source except for azythromycin. M. bovis susceptibilities were easily determined by the E test which demonstrated the efficacy of enrofloxacin and the acquired resistance to tetracycline, spectinomycin, azythromycin and clindamycin.
authors.affiliation: Département des Sciences Cliniques, Faculté de Médecine Vétérinaire, Université de Montréal, CP 5000, Saint Hyacinthe, Qué., Canada. david.francoz@umontreal.ca
authors.forename: David
authors.initials: D
authors.lastname: Francoz
authors.forename: Mado
authors.initials: M
authors.lastname: Fortin
authors.forename: Gilles
authors.initials: G
authors.lastname: Fecteau
authors.forename: Serge
authors.initials: S
authors.lastname: Messier
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D005260:Female; D008826:Microbial Sensitivity Tests; D009175:Mycoplasma Infections / Q000382:microbiology / Q000662:veterinary*; D045682:Mycoplasma bovis / Q000187:drug effects* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents