Campylobacter jejuni strains coresistant to tetracycline and ciprofloxacin in patients with gastroenteritis in Croatia.

Background: Antibiotic-resistant Campylobacter jejuni strains are rapidly emerging worldwide. Here, we aimed to determine the antibiotic-resistance patterns and genetic structure of C. jejuni from stool samples of symptomatic patients in Dalmatia, the largest Croatian county.

Methods: In a population-based laboratory surveillance programme for campylobacteriosis in Dalmatia from May 2012 to May 2013, C. jejuni (n = 76) were collected from stool samples of all the patients hospitalized with gastroenteritis and matched positive outpatients (n = 77). Antibiotic susceptibility testing and pulsed-field gel electrophoresis (PFGE) genotyping of isolates were performed.

Results: Approximately 60% of the isolates were resistant to ciprofloxacin, whereas 24% of isolates were resistant to tetracycline; of the latter, 89% were also coresistant to ciprofloxacin. Resistance to erythromycin and gentamicin was infrequent (≤ 0.7%). Antibiotic-resistant strains were generally not associated with the need for hospitalization. However, the prevalence of coresistant strains increased sharply after 2010, and these coresistant strains were more prevalent in infections caused by clonal PFGE types, with distinct patterns of temporal occurrence and age distribution in infected patients.

Conclusion: A high prevalence of coresistant Tc/Cip C. jejuni strains were detected in patients in Croatia. Strains were significantly associated with several clonal-type PFGE genotypes, shared common patterns of temporal occurrence, and showed distinct age distribution in infected patients, suggestive of newly identified strains. Since a high prevalence of coresistant Tc/Cip strains was also observed in other countries, further in-depth studies are essential to evaluate whether this phenomenon is linked to C. jejuni epidemiology in food animals and agricultural ecosystems.