Jiesong Hua

Predominance of a Single Strain of Helicobacter pylori in Gastric Antrum

Diversity of DNA among H. pylori strains isolated from different patients can serve as a useful marker for differentiating strains. DNA profiles of H. pylori obtained from sequential gastric biopsies were identical in most patients indicating that a given strain can persist from months to years. Patients colonized with more than two strains isolated mainly from different anatomical sites have been reported. This work examined whether the gastric antrum of patients with dyspepsia is colonized by single or multiple strains of H. pylori as well as the in vitro competition of different strains of H. pylori.

Isolation of a single strain of Helicobacter pylori from the antrum and body of individual patients.

Objectives This study aimed to determine intra‐patient colonization patterns of Helicobacter pylori strains based on DNA fingerprinting and antibiotic susceptibility. Methods Two biopsies, one from the antrum and one from the body of the stomach, were taken from 97 patients. Prior informed consent was obtained. The status of cagA gene of H. pylori strains was analysed by using the polymerase chain reaction (PCR) technique, while DNA fingerprints were generated by PCR‐based, random amplified polymorphic DNA (RAPD) fingerprinting. The antibiotic susceptibility of the H. pylori isolates was examined by the disk diffusion method. Results A total of 51 pairs of H. pylori strains were isolated from both antrum and body specimens of 51 patients. This included two patients who were endoscoped twice because of treatment failure. All strains were positive for cagA gene by PCR. These 51 patients were found to harbour a single strain of H. pylori with identical or highly similar DNA profiles by PCR‐based RAPD fingerprinting. In four of the 51 pairs, the DNA patterns of H. pylori from antrum and body showed minor differences, while three pairs of strains with different metronidazole sensitivities showed identical DNA fingerprints. Interestingly, the two treatment failure patients remained colonized with the strains that had the same RAPD fingerprinting patterns before and after treatment. Conclusion The present study demonstrates that a single H. pylori strain colonizes a single stomach. However, this single genotypic strain may exhibit different metronidazole susceptibility in different parts of stomach.