Divergence between the highly virulent zoonotic pathogen Helicobacter heilmannii and its closest relative, the low virulent Helicobacter ailurogastricus sp. nov.

• Helicobacter heilmannii naturally colonizes the stomach of dogs and cats, and has been associated with gastric disorders in humans. Nine feline Helicobacter strains, classified as H. heilmannii based on ureAB and 16S rRNA gene sequences, were divided into a highly virulent and a low virulent group. The genomes of these strains were sequenced to investigate their phylogenetic relationships, to define their gene content and diversity and to determine if the differences in pathogenicity were associated with the presence/absence of potential virulence genes. The binding capacity of these helicobacters to the gastric mucosa was investigated as well.Our analyses revealed that the low virulent strains do not belong to the H. heilmannii species, but to a novel, closely related species for which we propose the name H. ailurogastricus. Several homologs of H. pylori virulence factors, such as IceA1, HrgA and jhp0562-like glycosyltransferase, are present in H. heilmannii but absent in H. ailurogastricus. Both species contain a VacA-like autotransporter, from which the passenger domain is remarkably larger for H. ailurogastricus compared to H. heilmannii. In addition, H. ailurogastricus shows clear differences in binding to the gastric mucosa compared to H. heilmannii. These findings highlight the low virulent character of this novel Helicobacter species.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine (hsv//eng)

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