Comparison of in vitro activity of various macrolides against Helicobacter pylori

Abstract

Objective. Compare the in vitro activity of clarithromycin, erythromycin, azithromycin and josamycin against the collection of H. pylori strains isolated in 2010–2017 in Smolensk. Materials and Methods. H. pylori strains were collected prospectively from biopsy specimens of the gastric mucosa. Antimicrobial susceptibility testing of H. pylori was performed by the agar dilution method. Interpretation of the results of the susceptibility determination for clarithromycin was carried out in accordance with the recommendations of EUCAST (v 8.0) 2018. The resistance breakpoints for erythromycin, azithromycin, and josamycin were all set at ≥1.0 mg/L. For comparison of the results, the value of the minimal inhibitory concentrations of the tested antibiotic inhibiting the growth of 50% (MIC50) and 90% (MIC90) of H. pylori strains was used. Results. A total of 276 H. pylori strains were tested. 90% of the MIC values of clarithromycin were in the range from 0.015 to 0.125 mg/l. The percentages of resistance were as follows: clarithromycin 5.1%, azithromycin 7.5%, erythromycin 8%, josamycin 23.2%. Clarithromycin demonstrated significantly higher activity in suppressing the growth of H. pylori strains than azithromycin, erythromycin, and josamycin. Conclusions. Among the tested macrolide antibiotics maximal anti-H. pylori activity in vitro was observed in clarithromycin.