[The occurrence and characterization of Campylobacter spp. in silver gulls (Larus argentatus), three-toed gulls (Rissa tridactyla) and house sparrows (Passer domesticus)]

Major structural differences and novel potential virulence mechanisms from the genomes of multiple campylobacter species

Sequencing and comparative genome analysis of four strains of Campylobacter including C. lari RM2100, C. upsaliensis RM3195, and C. coli RM2228 has revealed major structural differences that are associated with the insertion of phage- and plasmid-like genomic islands, as well as major variations in the lipooligosaccharide complex. Poly G tracts are longer, are greater in number, and show greater variability in C. upsaliensis than in the other species. Many genes involved in host colonization, including racR/S, cadF, cdt, ciaB, and flagellin genes, are conserved across the species, but variations that appear to be species specific are evident for a lipooligosaccharide locus, a capsular (extracellular) polysaccharide locus, and a novel Campylobacter putative licABCD virulence locus. The strains also vary in their metabolic profiles, as well as their resistance profiles to a range of antibiotics. It is evident that the newly identified hypothetical and conserved hypothetical proteins, as well as uncharacterized two-component regulatory systems and membrane proteins, may hold additional significant information on the major differences in virulence among the species, as well as the specificity of the strains for particular hosts.

Epidemiology of ovine Campylobacter infection determined by numerical analysis of electrophoretic protein profiles

The relationship of 50 Campylobacter strains isolated from aborted ovine foetuses, and the faeces of sheep, cattle and chickens were determined by numerical analysis of electrophoretic (SDS-PAGE) protein profiles. Comparison of protein patterns by numerical methods revealed differences between C. fetus ssp. fetus, C. jejuni, and C. coli strains as well as heterogeneity among isolates from different outbreaks. Isolates from each farm produced a distinct cluster and flocks from different locations were found to be infected with relatively different strains. In most cases, protein patterns of ovine foetal isolates were very similar to those of ovine faecal isolates. Ovine isolates of C. fetus ssp. fetus, C. jejuni and C. coli gave similar protein patterns to the corresponding Campylobacter species isolated from cattle or chicken, on the same farm. Thus, it was concluded that certain protein types of ovine Campylobacter strains were more likely associated with local areas, and Campylobacter strains causing ovine abortions are distributed in the environment more widely than assumed to date.

NaCl-tolerance of Campylobacter isolates from birds and Campylobacter type strains and variation of their serological behaviour

Growth on media containing 1.5% NaCl is one of the criteria for phenotypical differentiation of Campylobacter laridis from other thermophilic Campylobacter spp. Campylobacter isolates from birds and Campylobacter type strains could be adapted to growth at 3% NaCl within 19 to 72 subsequent passages on nutrient agar with increasing salt contents. The acquisition of salt-tolerance was stable after ten passages on media without salt and did not induce changes in other phenotypical characteristics. The results of slide agglutination demonstrate changes in the antigenic pattern of the Campylobacter strains after growth in salt. Heat-labile and heat-stable antigens of the salt-tolerant variants of Campylobacter type strains differed from those of the parent strains.

Occurrence of Campylobacter spp. in young gulls, duration of Campylobacter infection and reinfection by contact

Two groups of three week old Herring Gulls (Larus argentatus) were held to observe the carrier state with Campylobacter. All 27 birds of group I excreted Campylobacter jejuni biotype III when they were caught from their colony. Four weeks later all but one were negative, indicating that the carrier state lasts until about the seventh week of life, with self-elimination if infection with another Campylobacter species is prevented by housing in a closed environment as in this study. Only one bird became reinfected one year later when gulls from group I were brought into contact with gulls from group II, consisting of ten freshly caught gulls, four of which were infected with the same biotype of Campylobacter, indicating that there might be some kind of immunity protection against infection with the same biotype of Campylobacter spp.