MKSAP Quiz: H. pylori eradication
A 45-year-old man is evaluated after a positive result on fecal antigen testing for Helicobacter pylori, obtained 2 months after he completed eradication therapy for H. pylori gastritis, and duodenal ulcer documented by upper endoscopy. What is the most appropriate next step in management?
A 45-year-old man is evaluated after a positive result on fecal antigen testing for Helicobacter pylori, obtained 2 months after he completed eradication therapy for H. pylori gastritis, and duodenal ulcer documented by upper endoscopy. The patient was adherent to the initial eradication therapy, consisting of clarithromycin, amoxicillin, and omeprazole for 10 days. He is asymptomatic.
Which of the following is the most appropriate next step in management?
A. Bismuth, tetracycline, metronidazole, and omeprazole for 14 days
B. Clarithromycin, amoxicillin, and omeprazole for 14 days
C. Clarithromycin, metronidazole, amoxicillin, and omeprazole for 14 days
D. Repeat fecal antigen test in 4 weeks
E. Repeat upper endoscopy and biopsy
MKSAP Answer and Critique
The correct answer is A. Bismuth, tetracycline, metronidazole, and omeprazole for 14 days. This content is available to MKSAP subscribers as Question 87 in the Gastroenterology and Hepatology section. More information about MKSAP is available online.
The most appropriate next step in management is a 14-day course of bismuth, tetracycline, metronidazole, and omeprazole (Option A). This patient's fecal antigen test confirms persistent Helicobacter pylori infection despite a previous course of eradication therapy. The most common factors responsible for failure of eradication therapy are lack of adherence to the treatment regimen or resistance of the H. pylori strain to the antibiotics. Other factors that decrease efficacy of eradication therapy include smoking, diabetes, and genetic factors affecting metabolism of proton pump inhibitors. As a result, eradication rates are less than 80% for a treatment regimen consisting of clarithromycin, amoxicillin, and a proton pump inhibitor (Option B), largely due to clarithromycin resistance of some H. pylori strains. Antibiotic resistance also exists for metronidazole (Option C) and levofloxacin, although metronidazole resistance can be overcome with higher doses of metronidazole. Resistance to amoxicillin is rare. Given the importance of antibiotic resistance for treatment efficacy, salvage therapy should not include antibiotics that have been previously taken. Therefore, the combination of bismuth subcitrate or bismuth subsalicylate along with metronidazole, tetracycline, and a proton pump inhibitor is the preferred salvage regimen for H. pylori infection that has not responded to a previous eradication regimen containing clarithromycin. A 14-day course of therapy (rather than a 10-day course) should be used for persistent H. pylori infection. This four-drug regimen can be challenging given the pill count, length of therapy, and potential for adverse effects. It is therefore important to counsel patients about adhering to the regimen and the potential for adverse effects.
The fecal antigen test results are sufficiently accurate to confirm persistent infection, obviating the need for further testing (Option D). The test was done more than 4 weeks after completion of eradication therapy (to reduce false-negative results) and the result was positive; repeating the test 1 month later is unnecessary.
In this asymptomatic patient, repeat upper endoscopy (Option E) is unnecessary to obtain additional gastric biopsy specimens or to document interval healing of the duodenal ulcers.
Key Points
- Salvage therapy for Helicobacter pylori infection should not include antibiotics that have been previously taken.
- The combination of bismuth subcitrate or bismuth subsalicylate along with metronidazole, tetracycline, and a proton pump inhibitor is the preferred salvage regimen for Helicobacter pylori infection.