High occurrence rates of enrofloxacin and ciprofloxacin residues in retail poultry meat revealed by an ultra-sensitive mass-spectrometric method, and antimicrobial resistance to fluoroquinolones in <i>Campylobacter</i> spp

<p>An ultra-sensitive mass spectrometric confirmation and quantification method for the determination of selected fluoroquinolones—enrofloxacin and its main metabolite ciprofloxacin—was developed and validated in poultry meat samples. The achieved limits of quantification were 1 ng kg⁻¹ for enrofloxacin and 10 ng kg⁻¹ for ciprofloxacin. The analysis of 40 retail poultry samples originating from Estonia, Latvia, Lithuania, Poland and France revealed that 93% of samples contained residues of enrofloxacin in the range from 3.3 to 1126 ng kg⁻¹. Previous studies have shown high levels of antimicrobial resistance to fluoroquinolones, particularly in <i>Campylobacter</i> spp. and various faecal indicators isolated from broiler meat. Consequently, the revealed widespread usage of fluoroquinolones in the poultry industry may result in the further emergence of antimicrobial resistance of <i>Campylobacter</i> in the food chain.