HELICOBACTER-SALOMONIS SP. NOV., A CANINE GASTRIC HELICOBACTER SP. RELATED TO HELICOBACTER-FELIS AND HELICOBACTER-BIZZOZERONII

During a study of the prevalence and distribution of gastric helicobac ters in domestic pets, a novel group of Helicobacter-like organisms we re identified, These ''Helicobacter group 2'' strains were initially d istinguished from the species Helicobacter felis and Helicobacter bizz ozeronii by their cellular morphology and the type of motility exhibit ed. Bacterial cells were only slightly spiral, 5 to 7 mu m long, and 0 .8 to 1.2 mu m wide and showed an unusual slow wavelike motion, Each c ell had tufts of sheathed flagella at one or both ends, Phylogenetic a nalysis by 16S ribosomal DNA sequence comparison revealed that H. feli s, H. bizzozeronii, ''Gastrospirillum hominis'' 2, and the new group o f helicobacters formed a distinct cluster with intraspecies similarity values of more than 98%. These taxa were clearly separated from all o ther known Helicobacter species, Dot blot DNA-DNA hybridization studie s indicated that the Helicobacter group 2 strains are genetically homo geneous and distinct from other canine and feline gastric helicobacter s, Quantitative DNA-DNA hybridization experiments showed that Helicoba cter group 2 strains exhibit >90% DNA homology to each other, but <39% homology to the phylogenetically related taxa H, felis and H. bizzoze ronii, We propose the name Helicobacter salomonis for the novel Helico bacter group 2 strains, The type strain is H. salomonis Inkinen (= CCU G 37845).