Ciprofloxacin resistant Campylobacter spp. in humans: an epidemiological and laboratory study.

From the end of April 1991 until the end of 1991, 2209 isolates of Campylobacter spp. have been collected in Plymouth PHL of which 91 (4.1%) were resistant to ciprofloxacin. None of the 91 patients involved had taken a quinolone, but 30/91 (33%) had travelled abroad (16 to the Iberian peninsula) in the three months preceding isolation of the ciprofloxacin-resistant Campylobacter spp. In the case-control study 12/15 (80%) of the cases had recently consumed poultry as had 20/24 (83%) of controls with enteritis due to ciprofloxacin-susceptible Campylobacter spp. A small study of poultry purchased from the supermarket revealed that only 1/37 campylobacters isolated from 64 UK bred chickens was resistant to ciprofloxacin, whereas 7/26 campylobacters isolated from 50 imported chickens were ciprofloxacin-resistant. Of the 75 clinical isolates of ciprofloxacin-resistant Campylobacter spp. subjected to detailed analysis, 68 were Campylobacter jejuni, six were Campylobacter lari, and one was Campylobacter coli. All isolates from man and poultry were resistant to ciprofloxacin, norfloxacin, sparfloxacin and tosufloxacin, and there was an association between fluoroquinolone-resistance and increased MICs of tetracycline. The range of susceptibility to erythromycin and kanamycin were typical of the species. gyrA from C. jejuni P6 (a case with history of travel to Spain) and C. jejuni P16 (isolate from imported chicken) contained point mutations corresponding to an amino acid substitution of isoleucine for threonine at codon 86. It has been suggested that veterinary use of quinolones, notably enrofloxacin, is providing a selective pressure for emergence of resistance to ciprofloxacin amongst human isolates. Now that enrofloxacin has been licensed for use in broiler flocks in the UK, it will be interesting to monitor the prevalence of resistance of campylobacters to quinolones in UK-produced poultry and in UK-acquired human infection.