Clostridium difficile infection associated with metronidazole-based treatment for Helicobacter pylori eradication

Dear Editor,

We have read the work of Castro-Fernández et al.,¹ on a case of Clostridium difficile infection (CDI) that manifested seven days after completing treatment to eradicate Helicobacter pylori (HP) with metronidazole, bismuth, omeprazole and tetracycline. We agree with the majority of the comments they make, including that regarding the low frequency of CDI after treatments for HP including metronidazole. This is what is described, even though the application of this therapy entails the combined use of various antibiotics together with antisecretory agents, which is a risk factor for CDI. In view of the above, we believe it is of interest to present the case of a patient we assessed recently in our unit for CDI seven days after having started treatment with omeprazole, metronidazole, clarithromycin and amoxicillin.

A 55-year-old female patient with a personal history of Löfgren’s syndrome for which she was not receiving treatment. Due to a diagnosis of HP infection, made by means of an antigenic study in faeces motivated by dyspepsia, she started treatment with amoxicillin 1 g/12 h, clarithromycin 500 mg/12 h, omeprazole 20 mg/12 h and metronidazole 500 mg/12 h. Seven days after starting treatment, this had to be suspended due to food intolerance and a diarrhoeal syndrome with 4–6 liquid stools per day with mucus and, on some occasions, blood. The physical examination was normal. Blood tests revealed a normal blood count and biochemistry, with a CRP of 37 mg/dl. The stool culture and three determinations for parasites were negative. Both Clostridium difficile toxins A and B and its antigen were positive. Treatment was started with vancomycin for 14 days, with an immediate disappearance of the symptoms and Clostridium difficile negativisation at three weeks after the end of treatment.

Both our patient and that described by Castro-Fernández et al. are an example of the broad spectrum of Clostridium difficile infection, a complication of treatment to eradicate HP that is likely underdiagnosed and that can arise, as has been described, through the use of drugs that, moreover, can be effective in the treatment of the disease.