Antimicrobial susceptibility of clinical isolates of Campylobacter jejuni from New South Wales, Australia

Objectives: The aim of this study was to investigate the prevalence of resistance to commonly used antimicrobials in Campylobacter jejuni isolates from clinical faecal samples in New South Wales (NSW), Australia.

Methods: A total of 117 C. jejuni isolates from human faecal samples from regional and metropolitan NSW were examined for antimicrobial resistance.

Results: Of the 117 isolates tested, 15.4% were resistant to ampicillin, 5.1% to tetracycline and 13.7% to ciprofloxacin. Most of the isolates were susceptible to erythromycin, except for three that showed intermediate resistance. Furthermore, 9.4% of isolates were resistant (or intermediate-resistant) to more than one antimicrobial agent. Isolates that were resistant to ampicillin and tetracycline harboured the bla_OXA-61 and tet(O) genes, respectively. A mutation in the gyrA gene, resulting in the T86I substitution, was identified in the majority of ciprofloxacin-resistant isolates.

Conclusion: The data obtained in the current study demonstrate that the majority of C. jejuni isolates evaluated were susceptible to one or more antimicrobials tested. Apart from three isolates that demonstrated intermediate resistance, all of the isolates were susceptible to erythromycin, which is the drug of choice for treating Campylobacter infections.