Campylobacter coli and C. jejuni isolated from farmed pigs in Grenada, West Indies and their antimicrobial resistance patterns

Rectal swabs from 138 grower pigs consisting of animals from all six parishes in the island of Grenada, West Indies, were cultured for thermophilic Campylobacter spp. on a selective supplemented blood-free agar medium under microaerophilic conditions at 42°C, and identified by phenotypic methods, including hippurate test and sensitivity to nalidixic acid and resistance to cephalothin. Ninty nine of the 138 samples (71.7%) were positive for Campylobacter spp., of which 56 (57%) were C. coli and 43 (43%) were C. jejuni. There were significant differences among parishes in percent of samples positive for Campylobacter spp. The proportion of C. coli and C. jejuni were also found to vary among the Parishes. There were no significant differences in isolation rates between sexes and age groups of pigs.

Of 7 antimicrobial drugs tested against the 99 isolates, resistance was highest to tetracycline, with 80.4% of C. coli, and 58.1% of C. jejuni being resistant. All isolates were susceptible to gentamicin. None of the C. jejuni isolates were resistant to erythromycin or ciprofloxacin, two drugs used in humans for campylobacter diarrhea and bacterial gastroenteritis in general, respectively. However, up to 10.7% of C. coli isolates showed resistance to these drugs. Resistance to chloramphenicol was 0% for C. jejuni, and 3.6% for C. coli. Resistance among the two Campylobacter spp. to other drugs, ampicillin and metronidazole ranged from 4% to 9%. This study indicates the high prevalence of resistance to tetracycline among both C. jejuni and C. coli, and occurrence of porcine Campylobacter coli strains resistant to erythromycin and ciprofloxacin in Grenada. This is the first study on campylobacters and their antimicrobial susceptibility from pigs in Grenada, West Indies.