Three Gram-negative, microaerophillic bacteria with a corkscrew-like morphology isolated from the gastric mucosa of cats and designated ASB1, ABS2 and ASB3, were subjected to a polyphasic taxonomic study. The isolates grew on biphasic culture plates in microaerobic conditions at 37°C and exhibited urease, oxidase and catalase activity. They were also able to grow in colonies on dry agar plates. Based on 16S rRNA gene sequence analysis, ASB1, ABS2 and ASB3 were identified as a member of the genus Helicobacter and showed 98 to 99% sequence similarity to H. felis, H. bizzozeronii, Candidatus H. heilmannii, H. cynogastricus and H. salomonis, five related Helicobacter species belonging to the “Helicobacter heilmannii” type 2 group and previously detected in the feline or canine gastric mucosa. Sequencing of the partial hsp60 gene demostrated that ASB1, ASB2 and ASB3 constitute a separate taxon in the “Helicobacter heilmannii” type 2 group. The urease gene sequences of ASB1, ASB2 and ASB3 showed approximately 92% homology to the urease gene sequences of “Candidatus Helicobacter heilmannii” described by O’Rourke et al. (2004). Protein profiling of the strains ASB1, ASB2 and ASB3 using SDS-PAGE also allowed to differentiate them from other Helicobacter species of feline or canine gastric origin. The results of this polyphasic taxonomic study indicate that the cultured isolates constitute a new taxon corresponding to “Candidatus Helicobacter heilmannii” from cats but further investigations are still needed
