Effects of Infections of Helicobacter Pylori With Different Virulent Factors on Severity of Gastrointestinal Diseases

Abstract

Background: Helicobacter Pylori (H. pylori) infection, one of the most common chronic bacterial infections, has been considered as a major cause of diseases such as lymphoma, gastritis, peptic ulcers, and stomach cancer. Here, we aimed to determine whether H. pylori strains with different virulence contribute to the gastrointestinal diseases differentially in clinical settings, which may provide future direction for eradication of H. pylori infection. Methods: We recruited 501 patients with gastrointestinal disorders for analysis of antibody types of H. pylori infection. Correlation analysis was done to determine the association of different virulence of H. pylori with patients’ baseline parameters and personal disease history. Next, subjects with each type of anti- H. pylori infection antibody were subjected to esophagogastro duodenoscopy（EGD) and colonoscopy examinations. The pathological diagnosis was also conducted in endoscopic samples. Chi-squared test was employed to compare the differences in endoscopic assessments and pathological findings among three types of H. pylori infection determined by the presence of antibodies to virulent factors. Results: There were 296 cases with Type I H. pylori infection, 120 cases with Type II H. pylori infection, and 85 cases without H. pylori infection (negative, Type III). No correlation was found between different virulence of H. pylori and participants’ baseline data (P > 0.05). EGD results showed that the incidences of peptic ulcer, bleeding and malignant lesions in Type I group were significantly higher than that in Type II and Type III (P＜0.05). Despite of increased trends of incidences of precancerous alterations and the malignance in Type I group compared with type II and III groups, there was no significant difference (P > 0.05). In addition, coloscopic features were similar among three groups. On the other hand, infections of H. pylori with cytotoxin-associated gene A (CagA) and/or vacuolating cytotoxin A (VacA) virulent factors resulted in more severe histopathological diseases than that with only Ure A/B factor and without infection (P < 0.05). Conclusions: Infections of H. pylori strains with CagA/VacA are likely to cause development of severe gastrointestinal diseases. These results are helpful to treat for H. pylori infection clinically.