Incidence and Mechanism of Ciprofloxacin Resistance in Campylobacter spp. Isolated from Commercial Poultry Flocks in the United Kingdom before, during, and after Fluoroquinolone Treatment

Abstract

Five commercial broiler flocks were treated with a fluoroquinolone for a clinically relevant infection. Fresh feces from individual chickens and environmental samples were cultured for campylobacters before, during, and weekly posttreatment until slaughter. Both Campylobacter jejuni and C. coli were isolated during all treatment phases. An increased proportion of quinolone-resistant strains was seen during treatment, and these strains persisted posttreatment. One quinolone-resistant isolate of each species, each serotype, and each phage type from each sample at all treatment phases was examined for its phenotype and mechanism of resistance. Two resistant phenotypes were isolated: Nal r Cip r and Nal r Cip s . The majority (269 of 290) of fluoroquinoloneresistant isolates, whether they were C. jejuni or C. coli, had a mutation in gyrA that resulted in the substitution Thr-863Ile. The other gyrA mutations detected were Thr-863Ala (n ‫؍‬ 17) and Asp-903Asn (n ‫؍‬ 10). The genotypic variation, based on the silent mutations in gyrA identified by the denaturing high-performance liquid chromatography pattern and DNA sequencing, was used to supplement typing data and provided evidence for both the spread of preexisting resistant strains and the selection of spontaneous resistant mutants in treated flocks. Multidrug resistance was significantly (P < 0.01) associated with resistance to ciprofloxacin. Twentyfive percent (73 of 290) of ciprofloxacin-resistant isolates but only 13% (24 of 179) of susceptible isolates were resistant to three or more unrelated antimicrobial agents. In conclusion, quinolone-resistant campylobacters were isolated from commercial chicken flocks in high numbers following therapy with a veterinary fluoroquinolone. Most ciprofloxacin-resistant isolates had the GyrA substitution Thr-863Ile. Resistant isolates were isolated from the feces of some flocks up to the point of slaughter, which may have consequences for public health.

Campylobacter coliin Swine Production: Antimicrobial Resistance Mechanisms and Molecular Epidemiology

“…Mutation at amino acid position 86 has been shown to confer high resistance to this antimicrobial at concentrations ranging from 32 g/liter up to 128 g/liter (17,36). A single isolate carried another mutation at position 147 in addition to the mutation at position 86.…”

Effect of Macrolide Usage on Emergence of Erythromycin-Resistant Campylobacter Isolates in Chickens

“…Previous studies by us and other researchers (22,31,35) showed that C. jejuni is highly mutable in response to FQ treatment and that FQ-resistant mutants occurred in FQtreated chickens rapidly after the initiation of treatment. The feature of FQ resistance development in response to antibiotic treatment is in clear contrast to the emergence of Ery r Campylobacter in poultry, and this difference may be due to the dissimilarity in the mode of action and resistance mechanisms.…”

“…Since chickens are frequently colonized by Campylobacter in the intestinal tract and since contaminated poultry meat is considered a significant source of food-borne campylobacteriosis in humans, it has been a concern whether exposure of chickens to therapeutic or subtherapeutic doses of macrolides promotes the emergence of macrolide-resistant Campylobacter, as is reported for the emergence of FQ resistance (22,32,35). To address this concern, we conducted in vitro and in vivo studies to examine the frequencies of emergence of Ery r C. jejuni and C. coli under the selection pressure of macrolide usage.…”

β-Lactamase-Mediated β-Lactam Resistance in Campylobacter Species: Prevalence of Cj0299 ( bla OXA-61 ) and Evidence for a Novel β-Lactamase in C . jejuni

“…Bacterial strains were isolated between 2000 and 2006 from chicken flocks in the United Kingdom, during studies OZO501 and VMO2200 funded by the Department for Environment, Food and Rural Affairs (9,10,19; N. C. Elviss, L. K. Williams, F. Jorgensen, S. A. Chisholm, A. J. Lawson, C. Swift, R. J. Owen, D. J. Griggs, M. M. Johnson, T. J. Humphrey, and L. J. V. Piddock, submitted for publication). In total, 1,288 Campylobacter isolates were studied; 967 of the isolates were C. jejuni, 319 were C. coli, and 2 were C. lari.…”

“…The agar doubling dilution procedure recommended by the NCCLS (now CLSI) Campylobacter Working Group (15) was used throughout the study as described previously (9) to determine the MICs of a range of ␤-lactam agents, including penams, cephalosporins, and carbapenems for ampicillin-and amoxicillin-resistant isolates. C. jejuni NCTC 11168 and C. coli NCTC 11366 were used as control strains.…”