Description of the two novel species of the genus Helicobacter: Helicobacter anatolicus sp. nov., and Helicobacter kayseriensis sp. nov., isolated from feces of urban wild birds

Abstract

A total of 26 Gram-negative, motile, gently curved, and rod-shaped isolates were recovered, during a study to determine the faeco-prevalence of Helicobacter spp. in urban wild birds. Pairwise comparisons of the 16S rRNA gene sequences indicated that these isolates belonged to the genus Helicobacter and phylogenetic analysis based on the 16S rRNA gene sequences showed that the isolates were separated into two divergent groups. The first group consisted of 20 urease-positive isolates sharing the highest 16S rRNA gene sequence identity levels of 98.5-98.6% to H. mustelae ATCC 43772(T), while the second group contained six urease-negative isolates with the sequence identity level of 98.5% to the type strain of H. pametensis ATCC 51478(T). Five isolates were chosen and subjected to comparative whole-genome analysis. The phylogenetic analysis of the 16S rRNA, gyrA and atpA gene sequences showed that Helicobacter isolates formed two separate phylogenetic clades, differentiating the isolates from the other Helicobacter species. Digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) analyses between strains faydin-H8(T), faydin-H23(T) and their close neighbors H. anseris MIT 04-9362(T) and H. pametensis ATCC 51478(T), respectively, confirmed that both strains represent novel species in the genus Helicobacter. The DNA G+C contents of the strains faydin-H8(T) and faydin-H23(T) are 32.0% and 37.6%, respectively. The results obtained for the characterization of the wild bird isolates indicate that they represent two novel species, for which the names Helicobacter anatolicus sp. nov., and Helicobacter kayseriensis sp. nov., are proposed, with faydin-H8(T)(=LMG 32237(T) = DSMZ 112312(T)) and faydin-H23(T)(=LMG 32236(T) = CECT 30508(T)) as respective type strains.