Risk factors of rescue bismuth quadruple therapy failure for Helicobacter pylori eradication

Abstract

Background and Aim Failure of bismuth quadruple therapy for Helicobacter pylori eradication is frequently observed. To increase the eradication rate, comprehensive analyses need to be performed regarding risk factors of bismuth quadruple therapy failure based on complete standard culture and antimicrobial susceptibility testing results. Methods Patients with history of failed first therapy who had H. pylori colonies isolated from culture and successful minimum inhibitory concentration (MIC) test were enrolled. Esomeprazole, bismuth, metronidazole, and tetracycline (quadruple) therapies for 7 or 14 days were given. Eradication rate, treatment compliance, adverse events, and risk factors for the failure of bismuth quadruple therapy were analyzed. Results A total 54 patients were enrolled. Overall eradication rate in the present study was 88.8%. The eradication rate for cases with metronidazole resistance such as MIC 8–16 μg/mL or 16–32 μg/mL was 92.8% (13/14). For cases with high level metronidazole resistance (MIC > 32 μg/mL), the eradication rate was only 60% (6/10). Multivariate analysis regarding compliance, treatment duration, age > 60, three kinds of metronidazole MICs, tetracycline MIC > 4 μg/mL, adverse events and any other parameters, “metronidazole resistance, high level (MIC > 32 μg/mL)” was the only independent risk factor for eradication failure (P = 0.007). Conclusion For cases with metronidazole resistance at MIC > 32 μg/mL, rescue therapy other than bismuth‐containing quadruple therapy is needed.

Primary and secondary antibiotic resistance of Helicobacter pylori in Korea from 2003 to 2018

“…Since H pylori resistance to amoxicillin and tetracycline is uncommon, the explanation for the heterogeneous results could be that both amoxicillin and tetracycline are weak against H pylori or there is a possible antagonistic effect . Recent studies have suggested that a high level of resistance to metronidazole, at an MIC >32 μg/mL, could be a reliable predictor of eradication failure of bismuth‐containing quadruple therapy . In addition, other salvage regimens are needed in patients with high‐level metronidazole resistance for customized tailored therapy through antibiotic susceptibility tests.…”

“…The range of concentrations for tetracycline and metronidazole was from <1 to >16 μg/mL and <2 to >32 μg/mL, respectively. Resistance breakpoints for amoxicillin, metronidazole, and tetracycline were defined as ≥0.5, ≥8, and ≥1 μg/mL, respectively . The breakpoint for tetracycline resistance was used according to EUCAST guidelines.…”

Efficacy and safety of twice a day, bismuth‐containing quadruple therapy using high‐dose tetracycline and metronidazole for second‐line Helicobacter pylori eradication

“…Bismuth‐containing quadruple therapy exhibits a high eradication rate, even in the presence of antibiotic resistance . Although resistance rate to metronidazole is over 30% in Korea, bismuth‐containing quadruple therapy is effective unless the minimum inhibitory concentration (MIC) of metronidazole exceeds 32 μg/mL . Furthermore, H. pylori resistance against tetracycline has been low and stable in Korea for the past 16 years .…”

When repeated Helicobacter pylori therapies fail, what should we do?

“…The current study by Lee et al . has taken this further to assess the level of metronidazole resistance with pretreatment MIC level . Results of this study suggest that low level (MIC 8–32 μg/mL) of metronidazole resistance can still be successfully treated by bismuth quadruple therapy.…”

“…In this issue of the Journal of Gastroenterology and Hepatology , Lee et al . have presented their works on investigating risk factors for failure using rescue bismuth quadruple therapy . The authors have enrolled 54 patients who failed first‐line therapy and had H .…”