The importance of the level of metronidazole resistance for the success of Helicobacter pylori eradication

Abstract

SUMMARYAims: To evaluate the role of antibiotic susceptibility for the treatment outcome of proton pump inhibitordependent and independent Helicobacter pylori eradication regimens. Methods: In a placebo-controlled clinical study of peptic ulcer patients with H. pylori infection, patients were randomized to receive lansoprazole, clarithromycin and tinidazole twice-daily, clarithromycin and tinidazole once-daily with lansoprazole or with placebo. Helicobacter pylori status was assessed by culture and antibiotic susceptibility by E-test minimal inhibitory concentration (MIC) in 205 clinical isolates. Results: Primary resistance to clarithromycin and metronidazole was 1 and 76%, respectively. In metronidazole susceptible strains eradication rates were similar at > 90% for all treatment groups (P ¼ 0.49).With low-level metronidazole resistance (4 lg/ mL < MIC < 256 lg/mL), eradication rates were similar at >75% (P ¼ 0.80). The major difference was found at high-level metronidazole resistance (MIC ‡ 256 lg/mL) with 95%, 58% and 21% eradication in the lansoprazole, clarithromycin and tinidazole twice-daily, lansoprazole, clarithromycin and tinidazole once-daily and placebo, clarithromycin and tinidazole once-daily groups, respectively (P < 0.001). Conclusion: In the absence of antibiotic resistance, a once-daily therapy of only clarithromycin and tinidazole can achieve a high rate of H. pylori eradication. Such a combination could offer a simpler and cheaper treatment option for developing countries. The standard, twice-daily proton pump inhibitor-based triple therapy was shown to be efficient in H. pylori eradication even in the presence of high-level metronidazole resistance.

Primary resistance to clarithromycin, metronidazole and amoxicillin of Helicobacter pylori isolated from Tunisian patients with peptic ulcers and gastritis: a prospective multicentre study

“…Our prevalence was much higher than that documented in an European multicentre study and in Bulgaria where the rates were evaluated respectively to 33.1% and 26.5% [11,28], but was lower to that computed in Columbia (82%) [29], in Mexico (76.3%) [30] and in Sweden (76%) [31]. In one Indian study, the resistance to metronidazole was evaluated to 41.9% [32].…”

Helicobacter pyloriDetection and Antimicrobial Susceptibility Testing

“…It was 33.1% in the European multicenter study previously cited, with no significant difference between the North and the South (178). In developing countries, the prevalence is much higher (50 to 80%) (400,525,573), and it is relatively rare in Japan (9 to 12%) (441).…”

Bismuth, lansoprazole, amoxicillin and metronidazole or clarithromycin as first-lineHelicobacter pyloritherapy

“…Estimation of eradication rates in these small subpopulations of resistant subjects is therefore susceptible to the effect of random error and may achieve a less reliable conclusion regarding the actual outcome in the presence of resistance. Effectiveness of therapy should also be determined in relation to the level of metronidazole resistance although, to date, the level of resistance has not proven to relate to differences in effectiveness 7 28…”