MIC (mg/L) and beta-lactamase production in isolates from untreated cows (Cow1 and Cow2), penicillin-treated cows (Cow3Pc and Cow4Pc), and aborted fetuses of penicillin-treated cows (Fetus1Pc and Fetus 2Pc).

Na: not available; Pc: penicillin; Am: ampicillin; Cip: ciprofloxacin; Tc: tetracycline; Gm: gentamicin; Km: kanamycin; Sm: streptomycin; Em: erythromycin; Cl: clindamycin; Tm: trimethoprim; Cm: chloramphenicol. Breakpoints for susceptibility according to CLSI (2010) [33] are given inside brackets when available.