Efficacy of fosfomycin on Escherichia coli isolated from bitches with pyometra.

The aim of this study was to determine the antimicrobial resistance of Escherichia coli isolated from the uteri of bitches with pyometra, and 38 E. coli isolates were used. The antimicrobials used were ampicillin (ABPC), amoxicillin/clavulanic acid, gentamicin, minocycline, cefazolin, levofloxacin (LVFX), trimethoprim-sulfamethoxazole (ST) and fosfomycin (FOM). Resistance to ABPC occurred most frequently, followed by LVFX and ST. Multi-drug resistance, defined as resistance against 3 or more classes of antimicrobials, was found in 23.7% of all isolates. Nine out of 13 resistant strains were multi-drug resistant, but no strain was found to be resistant to FOM. This suggests that FOM should be administered for E. coli from pyometra.