Prevalence of clarithromycin-resistant Helicobacter pylori strains in Zambia: A sub-Saharan African country.

INTRODUCTION: Helicobacter pylori (H. pylori) is one of the most important infections globally, affecting more than 50% of the human population. Clarithromycin (CLA) containing regimens are recommended for empirical eradication of H. pylori in populations with less than 15% resistance. The aim of this study was to estimate the prevalence of CLA resistance in samples collected from Zambian patients to determine if CLA is suitable for first-line H. pylori empirical treatment.

METHODOLOGY: We used archival biopsy samples collected from dyspeptic patients undergoing endoscopy. The samples had been snap-frozen immediately after collection and stored at -80oC. We performed Multiplex Real-Time PCR using Bosphore Helicobacter pylori Genotyping Kits v1, Istanbul, Turkey, to determine the presence of wild type H. pylori and three mutations, A2142G, A2142C and A2143G of domain V in 23s rRNA gene.

RESULTS: We tested 256 gastric biopsy samples from patients with dyspepsia, of which 136 (53%) were from females. The median age was 48 years (IQR 40-61 years). Endoscopically, most of the patients 164 (63%) had a normal gastric mucosa. CLA resistance was found in 48 (28%) samples; with A2142G mutation in 23 (13%), A2143G mutation in 32 (18%) and double mutations A2142C & A2143G in 6 (3%).

CONCLUSIONS: The presence of significant levels of CLA resistance in Zambia suggests that it should not be used as first-line empirical treatment for H. pylori infection. However, with a limitation of suitable alternatives, there is an urgent need to formulate new treatment approaches.