Combination versus single-drug antibiotic treatment for Enterococcus faecalis bloodstream infection

Efficacy of Optimized Antimicrobial Combination Therapy for Treatment of Enterococcus Faecalis Bacteremia and Identification of Intestinal Microbiota Signature

Observational IRCCS Azienda Ospedaliero-Universitaria di Bologna · NCT06833593

This project will test whether combining antibiotics helps adults with uncomplicated Enterococcus faecalis bloodstream infections recover better than a single antibiotic.

Quick facts

Study typeObservational
Enrollment510 (estimated)
Ages18 Years and up
SexAll
SponsorIRCCS Azienda Ospedaliero-Universitaria di Bologna Academic / other
Locations4 sites (Bologna, Bologna and 3 other locations)
Trial IDNCT06833593 on ClinicalTrials.gov

What this trial studies

This is a prospective, multicenter observational pharmacological study conducted across Italian hospitals comparing outcomes for adults with uncomplicated Enterococcus faecalis bloodstream infection treated with appropriate monotherapy versus combination therapy. Enrolled patients have monomicrobial EF-BSI and receive at least five days of an in vitro–active antibiotic with or without a synergistic agent; clinical outcomes and short-term mortality are recorded. The study pairs clinical outcome data with in vitro synergy testing of isolates and sequencing of patients' gut microbiota to identify microbial fingerprints associated with treatment response. Investigators will correlate antimicrobial regimens, in vitro synergy results, microbiome profiles, and clinical outcomes to look for patterns that predict benefit from combination therapy.

Who should consider this trial

Good fit: Adults (≥18 years) with monomicrobial Enterococcus faecalis bloodstream infection who receive at least five days of an in vitro–active antibiotic (with or without a synergistic drug) and can provide informed consent.

Not a fit: Patients who die within three days of bacteremia, those with concomitant or polymicrobial infections, or those with complicated EF infections such as endocarditis are unlikely to benefit from this study's findings.

Why it matters

Potential benefit: If successful, the study could clarify whether combination antibiotic therapy lowers mortality or complications and uncover microbiome markers to help guide personalized treatment.

How similar studies have performed: Previous in vitro studies and older uncontrolled clinical reports have suggested synergy with combination regimens, but contemporary, well-controlled clinical evidence is limited.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Adult (≥18 years)
* Monomicrobial EF-BSI
* Receipt of ≥ 5 days of at least one in vitro active drug (ampicillin, amoxicillin/clavulanate, ampicillin/sulbactam, piperacillin, vancomycin, teicoplanin, daptomycin and linezolid) with or without a synergistic drug (ceftriaxone, gentamycin, streptomycin), at common suggested dosages for EF-BSI in empirical or definitive therapy
* Written informed consent

Exclusion Criteria:

* Short term (within 3 days from BSI) mortality
* Other concomitant infection

Where this trial is running

Bologna, Bologna and 3 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Enterococcus Faecalis InfectionBlood Stream InfectionGut MicrobiomesEnterococcus faecalis bloodstream infectionHuman tissue analysis in vitroGut microbiota analysisEnterococcus faecalis genomic analysis
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.