S100A8 and chronic atrophic gastritis: In chronic atrophic gastritis (CAG) patients, the abundance of several oral bacteria including the genus Neisseria, Staphylococcus, and Haemophilus was lower in type I H. pylori infection subjects (serum anti-CagA and/or anti-VacA positive) than in type II H. pylori infection subjects (serum anti-CagA and anti-VacA negative) [71].