Studies have shown that Streptococcus exists in the stomach of healthy people (Sharma et al., 1984; Monstein et al., 2000; Mowat et al., 2000; Kato et al., 2006; Zilberstein et al., 2007) and is the dominant bacterium other than Hp (Seo et al., 2014); in addition, it was also found that Streptococcus abundance was significantly increased in gastric cancer, and Streptococcus remained one of the most abundant genera after subtotal gastrectomy (Tseng et al., 2016). This evidence concerns the gene HP and gastric cancer.