Genomic heterogeneity and O-antigenic diversity of Campylobacter upsaliensis and Campylobacter helveticus strains isolated from dogs and cats in Germany

A serotyping scheme based on heat-stable surface antigens was established f or 101 Camplobacter upsalitensis and 10 Campylobacter helveticus strains is olated from 261 dogs and 46 cats of different ages originating from two geo graphically distinct regions in Germany. The prevalence of C. upsaliensis v aried between 27.8% in juvenile dogs (< 12 months of age) and 55.4% in adul t dogs (P < 0.05), Of the cats, 19.6% harbored C. upsaliensis, whereas 21.7 % carried C. helveticus, Of the C. upsaliensis isolates from both host spec ies, 93.1% belonged to five different serogroups, two of them being prevale nt at rates of 47.5 and 27.7%, with different frequencies in both regions. Six (54.6%) of the C. helveticus isolates also belonged to serotypes found among C. upsaliensis strains, whereas five (45.1%) possessed an O antigen u nique for C. helveticus. In contrast, a considerable degree of genomic dive rsity of the isolates was assessed by macrorestriction analyses with the en donucleases SmaI and XhoI, using pulsed-field gel electrophoresis as well a s enterobacterial repetitive intergenic consensus sequence PCR (ERIC PCR), Restriction with SmaI pointed towards the existence of clonal groups associ ated to some extent with serotypes, while restriction with XhoI disintegrat ed these groups to smaller noncoherent subgroups. Analysis of ERIC PCR prof iles did not exhibit any associations with serotypes. In conclusion these d ata demonstrate the genomic heterogeneity among C. upsaliensis strains and indicate that the combination of SmaI restriction with serotyping is a usef ul tool to investigate the expansion of clonal groups of C. upsaliensis.