Genetic diversity and clonal characteristics of ciprofloxacin-resistant Campylobacter jejuni isolated from Chilean patients with gastroenteritis

Only one of the isolates was resistant to erythromycin. However, 48% of them were resistant to ciprofloxacin. The minimal inhibitory concentration of these ciprofloxacin-resistant isolates was in the range between 4 and 32 μg/ml. Moreover, MLST analyses showed that most ciprofloxacin-resistant strains were grouped into three dominant clonal complexes (ST-21, ST-48 and ST-353), while the unique strain resistant to both antibiotics belonged to the ST-45 complex. Our results evidence a high ciprofloxacin resistance and suggest that there is a dissemination of resistant clonal lineages responsible for cases of campylobacteriosis in Chile. Further studies should elucidate the origin of these resistant genotypes.