Characterization of high-level fluoroquinolone resistance in Escherichia coli O78:K80 isolated from turkeys

Abstract

Fluoroquinolone resistance was characterized in Escherichia coli O78:K80 isolated from diseased turkeys. The level of resistance to fluoroquinolones of the isolates appeared closely correlated with substitutions in GyrA and ParC, but not with the production of the AcrAB efflux pump. Among isolates highly resistant to ciprofloxacin (MIC 8 mg/L) and harbouring identical substitutions (two in GyrA and one in ParC), two close but distinguishable ribotypes were identified. This indicated that at least two independent selection events may have occurred.