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Abstract

There has been a significant increase in the prevalence of H. pylori resistance to metronidazole in recent years, while clarithromycin resistance is still relatively rare. In this study we assessed: (1) the effect of primary H. pylori resistance to metronidazole and clarithromycin on the clinical efficacy of a one-week regimen consisting of omeprazole, metronidazole, and clarithromycin; and (2) the rate of acquisition of secondary antimicrobial resistance after treatment failure. Eighty-seven patients with duodenal ulceration or nonulcer dyspepsia were included in the study. The primary metronidazole and clarithromycin resistance rates were 35.6% and 3.4%, respectively (all three pretreatment clarithromycin resistant strains had concurrent metronidazole resistance). H. pylori was eradicated in 81.6% of patients. The eradication rate for fully sensitive isolates was 98.2% (55/56) but was significantly reduced to 57.1% (16/28) for isolates that were resistant to metronidazole alone and 0% (0/3) in cases of dual resistance (P < 0.001). Secondary resistance to clarithromycin was acquired in 58.3% of cases of treatment failure. In areas of high prevalence of primary metronidazole resistance, this is a significant cause of treatment failure with this triple therapy regimen. This leads to the selection of strains with dual resistance that are difficult to eradicate and may contribute to an increase in the prevalence of clarithromycin resistance. In such areas an alternative first-line treatment should be prescribed.

Rapid Non-invasive Techniques for Detecting Antibiotic Resistance in Helicobacter pylori: An Update and Clinical Applications

“…The clinical efficacy of currently recommended eradication treatment regimens heavily relies on the susceptibility of H. pylori strains to antibiotics. Early studies have demonstrated that primary or secondary (acquired) resistance leads to treatment failure [21,22] and the persistence or recrudescence of H. pylori infection is associated with chronic or recurrent diseases associated with H. pylori infection [23]. The impact of antibiotic resistance on the success rate of eradication therapies has been confirmed by recent studies.…”

Helicobacter pylori Current Chemotherapy and New Targets for Drug Design

“…For example, for the relatively new antibiotic clarithromycin, resistance in H. pylori is already found in somewhere between 5 and 8% of the U.S. population, while the metronidazole resistance can be found in a whopping 40 to 60% of the population [31,155,186,187]. H. pylori resistance to amoxicillin and bismuth has not been reported.…”