Genetic diversity of the Helicobacter pylori sialic acid-binding adhesin (sabA) gene.

A putative virulence factor, SabA, a sialic acid-binding adhesin, has recently been characterized in Helicobacter pylori from European isolates. However, little genetic information is available for sabA genes in strains isolated from Japanese patients. Here, we investigated the presence of the sabA gene in 23 H. pylori clinical isolates using polymerase chain reaction detection. It was found that 91.3% of H. pylori isolates examined contain the sabA gene. Sequence comparison and phylogenetic analysis based on the deduced amino acid sequence of sabA in nine H. pylori isolates from Japanese patients and three H. pylori strains from Western individuals suggested that sabA is genetically diverse and the clustering of the strains based on SabA is related to their geographical origin. It needs to be further assessed whether the genetic diversity of sabA is associated with the clinical outcomes of H. pylori infection.