Prevalence of metronidazole resistant Helicobacter pylori (Hp) strains among the Chinese peptic ulcer disease patients and normals in Hong Kong

Abstract

We have recently investigated the prevalence of metronidazole resistant (MR) and metronidazole sensitive (MS) Hp strains among our peptic ulcer disease (PUD) patients and volunteers in Hong Kong. Antral biopsies (x2) were obtained for culture of Hp and sensitivity testing against metronidazole from 44 consecutive PUD (38 DU & 6 GU) patients (28 males [m], mean age 44.7 yrs; and 16 females [f], mean age 56.4 yrs), 26 (25 DU & 1 GU) post eradication therapy (16 m, mean age 47.8 yrs; 10 f, mean age 52.7 yrs), and 51 asymptomatic volunteers (N, 23 m, mean age 49.1 yrs; 28 f, mean age 60.6 yrs) who were recruited from medical exhibitions. The sensitivity and specificity of culture results were calculated with reference to CLO test, anti-Hp ELISA or histology results. Chi-square or Fisher exact test was used for statistical analysis. Results The sensitivity and specificity of culture for Hp was 87% and 100% respectively. All the PUD patients were Hp+. 6/26 post eradication treatment patients were still Hp +, having missed by culture but diagnosed by CLO test &/or histology. There was singificantly higher MR Hp in the N than the PUD group (p =0.0007). There was no significant difference in the MR Hp between the m and the f in either the PUD (p=0.052) or the N (p=0.19) group. But, the overall MR Hp was significantly higher in f than in m (p =0.005). Conclusions Iust over 50% of the Hp is MR in I-Iong Kong. The frequency of MR Hp strains in the N population (80%) is approx, double that of the PUD patients (38.6%). Overall, they are more frequent in f than in m. MR does not seem to correlate with ulcerogenic potential.