Phylogenetic analysis of Helicobacter species based on partial gyrB gene sequences

• Published in: International journal of systematic and evolutionary microbiology Vol. 57; no. 3; pp. 444 - 449
• Main Authors: Hannula, Minna, Hanninen, Marja-Liisa
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.03.2007; Society for General Microbiology
• Subjects: Animals; Bacteriology; Biological and medical sciences; DNA Gyrase - genetics; DNA, Bacterial - genetics; Dogs; Feces - microbiology; Felis; Fundamental and applied biological sciences. Psychology; Helicobacter - classification; Helicobacter - genetics; Helicobacter - isolation & purification; Helicobacter bizzozeronii; Helicobacter felis; Helicobacter Infections - microbiology; Helicobacter mustelae; Helicobacter pullorum; Helicobacter pylori; Helicobacter salomonis; Humans; Liver - microbiology; Microbiology; Phylogeny; Polymerase Chain Reaction; Stomach - microbiology; Systematics; Spirillales; Investigation method; Nucleotide sequence; Helicobacter; Taxonomy; Spirillaceae; Bacteria; Phylogeny
• ISSN: 1466-5026; 1466-5034
• DOI: 10.1099/ijs.0.64462-0

Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland Correspondence Minna Hannula minna.hannula{at}helsinki.fi Analysis of 16S rRNA gene sequences is one of the most common methods for investigating the phylogeny and taxonomy of bacteria. However, several studies have indicated that the 16S rRNA gene does not distinguish between certain Helicobacter species. We therefore selected for phylogenetic analysis an alternative marker, gyrB , encoding gyrase subunit B. The aim of this investigation was to examine the applicability of gyrB gene fragments ( 1100 bp) for the phylogenetic study of 16 Helicobacter species and a total of 33 Helicobacter strains included in this study. Based on the sequenced fragments, a phylogenetic tree was obtained that contained two distinct clusters, with gastric species forming one cluster and enterohepatic species the other. The only exception was the gastric species Helicobacter mustelae , which clustered with the enterohepatic species. The calculated similarity matrix revealed the highest interspecies similarity between Helicobacter salomonis and Helicobacter felis (89 %) and the lowest similarity between Helicobacter pullorum and H. felis (60 %). The DNA G+C content of the sequenced fragments was 40 mol% in enterohepatic species and >46 mol% in gastric species, excluding Helicobacter pylori and H. mustelae , with G+C contents of 34 and 42 mol%, respectively. In summary, the gyrB gene fragments provided superior resolution and reliability to the 16S rRNA gene for differentiating between closely related Helicobacter species. A further outcome of this study was achieved by designing gyrB gene-based species-specific PCR primers for the identification of Helicobacter bizzozeronii .