896. Does Rifaximin Chemoprophylaxis Prevent Campylobacteriosis in the Human Challenge Model?
Session: Poster Abstract Session: Clinical Trials
Friday, October 9, 2015
Room: Poster Hall
Posters
  • IDSA poster_final draft.pdf (993.5 kB)
  • Background:  Travelers’ diarrhea is common; the growing concern regarding post-infectious chronic health sequelae raises the need to consider strategies for primary prevention.  Studies have demonstrated field efficacy of rifaximin prophylaxis in prevention of travelers’ diarrhea where diarrheagenic Escherichia coli predominate, as well as in a Shigella human challenge model.  The efficacy of rifaximin as prophylaxis against other invasive pathogens, such as Campylobacter, remains in question. 

    Methods:  A double-blind, placebo-controlled trial assessing the efficacy of rifaximin in preventing campylobacteriosis in subjects challenged with Campylobacter jejuni, strain CG8421, was performed at the Center for Immunization Research, Johns Hopkins Bayview Medical Center.  Thirty subjects were randomized in a 1:1 ratio to receive either 550 mg of rifaximin BID or placebo BID for 4 days.  After the third dose, 28 subjects received a 1.8 x 105 CFU challenge dose of C. jejuni strain CG8421, administered in bicarbonate buffer. 

    Results:  Following challenge, C. jejuni strain CG8421 was isolated from fecal samples of 100% of subjects; 19 (68%) subjects met criteria for early treatment (Azithromycin 500 mg Daily and Ciprofloxacin 500 mg BID for 5 days); the remainder were treated empirically at day 6 post-challenge.  Incidence of symptoms included: severe diarrhea, 22 (79%); moderate diarrhea, 4 (14%); dysentery, 7 (25%); severe fever (102.1-104°F), 2 (7%); moderate fever (101.2-102°F), 7 (25%); mild fever (100.4 – 101.1°F), 3 (11%).  Following discharge, subjects were assessed on post-challenge days 14, 21, 28, 35, 56 and 84, and by telephone at day 180.  Four subjects experienced a single microbial recrudescence 56 days post-challenge and received a 10 day course of Azithromycin 500 mg daily and Ciprofloxacin 500 mg BID, with subsequent clearance of C. jejuni.  One subject experienced two recrudescent events despite receiving a second course of dual antibiotic therapy. 

    Conclusion:  Campylobacteriosis was induced in the majority of participants under our challenge model.  Based on the high diarrhea attack rates noted in this human challenge model, the efficacy of rifaximin prophylaxis against campylobacteriosis in a field setting requires further evaluation.

    Clayton D. Harro, MD, ScM1, Joanna E. Rimmer, MBChB, DTM&H2,3,4, David Sack, MD1, Kawsar R. Talaat, MD1, Ramiro L. Gutierrez, MD, MPH2, Barbara Denearing, RN, BSN, CCRC1, Chad K. Porter, Ph.D., MPH2, Jessica Brubaker, M.S.1, Alexander C. Maue, Ph.D.2, Renee M. Laird, Ph.D.2, Frederic Poly, Ph.D.2, Patricia Guerry, Ph.D.2, Kayla Jaep, B.S.2, Ashley Alcala, B.S.2, David R. Tribble, MD, DrPH, FIDSA5 and Mark S. Riddle, MD, DrPH2, (1)Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, (2)Enteric Diseases Department, Naval Medical Research Center, Silver Spring, MD, (3)School of Immunity and Infection, University of Birmingham, Birmingham, United Kingdom, (4)Royal Air Force, High Wycombe, United Kingdom, (5)Infectious Disease Clinical Research Program (IDCRP), Uniformed Services University of the Health Sciences, Bethesda, MD

    Disclosures:

    C. D. Harro, None

    J. E. Rimmer, None

    D. Sack, None

    K. R. Talaat, None

    R. L. Gutierrez, None

    B. Denearing, None

    C. K. Porter, None

    J. Brubaker, None

    A. C. Maue, None

    R. M. Laird, None

    F. Poly, None

    P. Guerry, None

    K. Jaep, None

    A. Alcala, None

    D. R. Tribble, None

    M. S. Riddle, Salix Pharmaceuticals: Scientific Advisor , Research support

    See more of: Clinical Trials
    See more of: Poster Abstract Session

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 7th with the exception of research findings presented at the IDWeek press conferences.