Objective  To evaluate the impact of Helicobacter pylori (Hp) infection on the subpopulation of normal flora in human stomach

and to further understand the contribution of gastric normal flora to Hp-related diseases.    Methods  Totally 220 specimens of gastric mucous were collected from the health individuals

Hp carriers and patients with Hp associated diseases. Colonized bacteria were cultivated on selective media in different conditions as needed

and the amount of bacteria was calculated according to the visible colony on plates.    Results  Hp detection results showed that 62.73% of the 220 investigated people were colonized with Hp. The total number of bacteria investigated in the stomach of the health individuals was significantly higher than that of the patients and the normal carriers (P0.05). Significant difference of the lactobacillus positive rates was only observed between the health individuals and the patients (P0.05). The percentage of Lactobacillus

Enterobacteriaceae and Streptococcus from the health individuals was 41.39%

16.90% and 18.28%

respectively

and any of them was higher that from the patient group (P0.05). The percentage of anaerobic bacteria in the patient group was 43.77%

which accounting for the highest proportion when compared with the other groups (P0.05).    Conclusion  The subpopulation of normal flora in the stomach is closely associated with Hp colonization and the clinical outcome.