title: In vitro antimicrobial inhibition of Mycoplasma bovis isolates submitted to the Pennsylvania Animal Diagnostic Laboratory using flow cytometry and a broth microdilution method.
abstract: Mycoplasma bovis is an important pathogen of cattle, causing mastitis, pneumonia, conjunctivitis, otitis, and arthritis. Currently there are only a few reports of sensitivity levels for M. bovis isolates from the United States. Mycoplasma bovis isolates submitted to the Pennsylvania Animal Diagnostic Laboratory between December 2007 and December 2008 (n = 192) were tested for antimicrobial susceptibility to enrofloxacin, erythromycin, florfenicol, spectinomycin, ceftiofur, tetracycline, and oxytetracycline using a broth microdilution method. The most effective antimicrobials against M. bovis determined by using the broth microdilution method were florfenicol, enrofloxacin, and tetracycline with minimum inhibitory concentration (MIC) ranges of 2-32 µg/ml, 0.1-3.2 µg/ml, and 0.05 to >12.8 µg/ml, respectively. Spectinomycin, oxytetracycline, and tetracycline showed a wide-ranging level of efficacy in isolate inhibition with broth microdilution with MIC ranges of 4 to >256 µg/ml, 0.05 to >12.8 µg/ml, and 0.05 to >12.8 µg/ml, respectively. A significant difference in the susceptibility levels between quarter milk and lung isolates was found for spectinomycin. When MIC values of a subset of the M. bovis isolates (n=12) were tested using a flow cytometric technique, the MIC ranges of enrofloxacin, spectinomycin, ceftiofur, erythromycin, tetracycline, oxytetracycline, and florfenicol ranges were 0.1-0.4 µg/ml, 4 to >256 µg/ml, >125 µg/ml, >3.2 µg/ml, <0.025 to >6.4 µg/ml, 0.8 to >12.8 µg/ml, and <2-4 µg/ml, respectively. Flow cytometry offers potential in clinical applications due to high-throughput capability, quick turnaround time, and the objective nature of interpreting results.
authors: Department of Veterinary and Biomedical Sciences, Pennsylvania State University, University Park, PA 16802, USA.
authors: Marty K
authors: MK
authors: Soehnlen
authors: M Elaine
authors: ME
authors: Kunze
authors: K Eranda
authors: KE
authors: Karunathilake
authors: Brittnee M
authors: BM
authors: Henwood
authors: Subhashinie
authors: S
authors: Kariyawasam
authors: David R
authors: DR
authors: Wolfgang
authors: Bhushan M
authors: BM
authors: Jayarao
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy / Q000382:microbiology; D002511:Cephalosporins / Q000494:pharmacology; D000077422:Enrofloxacin; D004917:Erythromycin / Q000494:pharmacology; D005434:Flow Cytometry / Q000662:veterinary*; D024841:Fluoroquinolones / Q000494:pharmacology; D008826:Microbial Sensitivity Tests / Q000379:methods / Q000662:veterinary*; D009175:Mycoplasma Infections / Q000188:drug therapy / Q000662:veterinary; D045682:Mycoplasma bovis / Q000187:drug effects*; D010118:Oxytetracycline / Q000494:pharmacology; D000198:Spectinomycin / Q000494:pharmacology; D013752:Tetracycline / Q000494:pharmacology; D013839:Thiamphenicol / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D000890:Anti-Infective Agents; D002511:Cephalosporins; D024841:Fluoroquinolones; D000077422:Enrofloxacin; D004917:Erythromycin; C053503:ceftiofur; D000198:Spectinomycin; C035534:florfenicol; D013752:Tetracycline; D013839:Thiamphenicol; D010118:Oxytetracycline