Resistance of Helicobacter pylori to antibiotics

The acquired resistance of Helicobacter pylori to the macrolide and imidazole antibiotics is a major problem in the eradication of the organism. Cross-resistance to all macrolide antibiotics is a consequence of point mutations at two specific locations in the gene coding for the 23S subunit of the bacterial ribosome. In contrast, the mechanism of resistance to metronidazole is poorly understood but resistance to one imidazole confers resistance to all other antibiotics of this class. It is estimated that 30% of the strains of H. pylori in the US and Europe are resistant to metronidazole although these rates may be significantly higher in countries where there is a large immigrant population. The rate of resistance to macrolide antibiotics is lower than for metronidazole but in contrast to metronidazole resistance, macrolide resistance is closely bound to sales volume. Once macrolide resistance has emerged in a population, it spreads very rapidly. In the event of resistance to metronidazole, increasing the duration of treatment improves the eradication rate of H. pylori, but levels similar to those with antibiotic-sensitive strains are not achieved. The use of proton pump inhibitors has highlighted the difference in the ability to eradicate resistant and susceptible strains of H. pylori. In cases where metronidazole resistance is a particular problem, quadruple therapy may be recommended. Resistance to clarithromycin appears to be the most compromising factor for H. pylori eradication.SCOPUS: cp.j