Antimicrobial susceptibility of Trueperella pyogenes isolated from cattle and pigs with septicemia in southern Kyushu, Japan.

We investigated the antimicrobial susceptibility of Trueperella pyogenes isolates from cattle and pigs diagnosed with septicemia at slaughter. The strains investigated in this study were found to be susceptible to ampicillin, cefazolin, gentamicin, and levofloxacin. However, 53.3% of the strains were resistant to tetracycline, 49.7% to streptomycin, 13.8% to erythromycin, 13.2% to clindamycin, and 1.2% to oxacillin and kanamycin. We also found that the resistance of pig-derived strains of T. pyogenes to tetracycline, streptomycin, erythromycin, and clindamycin was higher than that of cattle-derived strains, and these strains were resistant to up to four antimicrobial agents used simultaneously. The present results provide new data on the range of the minimum inhibitory concentration (MIC) values of various antimicrobial agents for T. pyogenes isolated from livestock with septicemia. The breakpoint values used in this study are generally considered applicable.