Rifaximin fails to prevent campylobacteriosis in the human challenge model: a randomized, double-blind, placebo-controlled trial

Abstract

Background

Campylobacter species are a leading cause of diarrheal disease globally with significant morbidity. Primary prevention efforts have yielded limited results. Rifaximin chemoprophylaxis decreases travelers' diarrhea rates and may be suitable for high risk persons. We assessed the efficacy of rifaximin in the controlled human infection model (CHIM) for Campylobacter jejuni.

Methods

Twenty-eight subjects were admitted to an inpatient facility and randomized to a twice daily dose of 550 mg rifaximin or placebo. The following day subjects ingested 1.7x10 ⁵ colony forming units of C. jejuni strain CG8421. Subjects continued prophylaxis for 3 additional days, were followed for campylobacteriosis for 144 hours and subsequently treated with azithromycin and ciprofloxacin. Samples were collected to assess immunologic responses to CG8421.

Results

There was no difference (p=1.0) in the frequency of campylobacteriosis in those receiving rifaximin (86.7%) or placebo (84.6%). Additionally, there were no differences in the clinical signs and symptoms of C. jejuni infection to include abdominal pain/cramps (p=1.0), nausea (p=1.0), vomiting (p=0.2) or fever (p=1.0) across study groups. Immune responses to the CG8421 strain were comparable across treatment groups.

Conclusions

Rifaximin did not prevent campylobacteriosis in this CHIM. Given the morbidity associated with Campylobacter infection, primary prevention efforts remain a significant need.