Frequency and molecular characteristics of ciprofloxacin- and rifampicin-resistant Helicobacter pylori from gastric infections in the UK

Abstract

Treatment failure with standard Helicobacter pylori eradication regimes may require the use of ‘rescue’ therapies containing fluoroquinolones or rifamycins. The susceptibilities of H. pylori in the UK to such antimicrobials are unknown; therefore, this study aimed to determine the frequencies and molecular markers of resistance. Ciprofloxacin and rifampicin susceptibilities were determined by Etest and/or disc diffusion for 255 isolates of H. pylori, including 171 isolates from adult dyspeptic patients with refractive infections. Mutations in known resistance-determining regions of gyrA and rpoB were determined. The ciprofloxacin resistance rate was 7.5 %, and gyrA mutations, predominantly at codon position 91, were identified in most resistant isolates. One isolate (<1 %) had an unequivocal rifampicin-resistant phenotype by Etest yet had no associated mutations in the rpoB gene. As resistance rates were low in H. pylori isolates, including those from patients with refractive infections, it was concluded that fluoroquinolones or rifamycins might be considered in the UK for inclusion in ‘rescue’ therapies.