Genetic profiling of Campylobacter jejuni strains from humans infected in Sweden or in Thailand, and from healthy Swedish chickens, studied by pulsed-field gel electrophoresis (PFGE)

Abstract

The major objective of the study was to explore the genomic diversity between Campylobacter jejuni (C.jejuni) from different sources as a tool for epidemiological considerations. Subtyping was performed using pulsed-field gel electrophoresis (PFGE) and the enzyme used for cleavage was SmaI. Isolates originated from humans infected in Sweden (n=49) and Thailand (n=32) and from healthy Swedish chickens (n=51). Eight PFGE groups were formed in a dendrogram and 48% of the isolates belonged to 1 of these groups. In 2 PFGE groups, strains from humans infected in both Sweden and Thailand were represented. Four of the PFGE groups comprised high frequencies of strains from domestic human infection, as well as from healthy chickens. The PFGE pattern was also compared with the antibiotic resistance pattern in all the above-mentioned isolates. In conclusion, C.jejuni was a diverse group based on PFGE genotyping; about 24% of the clones from Swedish patients and healthy Swedish chickens were similar; and there was no correlation between the antibiotic resistance pattern and the PFGE profiling among the studied strains. Our findings are also in accordance with our hypothesis that there may be similarities between Swedish and Thai strains, which might support a theory of globally occurring C.jejuni.