Antimicrobial susceptibility testing and antimicrobial resistance parameters of <i>E. coli</i>.

AMP: ampicillin; A/C: amoxicillin/clavulanic acid; SH: spectinomycin; CN: gentamicin; STR: streptomycin; CIP: ciprofloxacin; NAL: nalidixic acid; SXT: sulfamethoxazole/trimethoprim; TET: tetracycline; FFC: florfenicol; CEF: ceftiofur. *No breakpoints were available for E. coli in the CLSI documents. In this study, ≥32 µg ml−1 was the tentative breakpoint for florfenicol, and ≥2 µg ml−1 was used for ceftiofur, according to EUCAST (http://www.eucast.org/mic_distributions/).