Helicobacter cynogastricus sp. nov., isolated from the canine gastric mucosa

Abstract

A Gram-negative, microaerophilic helical rod, isolated from the gastric mucosa of a dog and designated strain JKM4^T, was subjected to a polyphasic taxonomic study. The tightly coiled organism, measuring 10–18 μm long and up to 1 μm wide, was motile by means of multiple sheathed flagella located at both ends of the cell and by a periplasmic fibril running along the external side of the helix. Strain JKM4^Tgrew preferably on biphasic culture plates or on very moist agar. Coccoid forms predominated in cultures older than 4 days as well as in growth obtained on dry agar plates. The strain grew at 30 and 37 °C, but not at 25 or 42 °C and exhibited urease, oxidase and catalase activities. On the basis of 16S rRNA gene sequence analysis, the novel isolate was identified as a member of the genusHelicobacterand showed > 97 % similarity toHelicobacter felis,Helicobacter bizzozeroniiandHelicobacter salomonis, three species previously isolated from the canine gastric mucosa. Protein profiling of strain JKM4^Tusing SDS-PAGE revealed a pattern different from those of otherHelicobacterspecies of mammalian gastric origin and fromHelicobacter canis. Additionally, the urease gene sequence of strain JKM4^Twas different from those of urease genes ofH. felis,H. bizzozeronii,H. salomonisand ‘CandidatusHelicobacter heilmannii’. It is thus proposed that strain JKM4^T(=LMG 23188^T) represents a novel species within this genus,Helicobacter cynogastricussp. nov.