Combination Antibiotic Therapy for Staphylococcus Aureus Bacteremia (COMBAT-SAB)

August 22, 2026 updated by: Brandon Webb, Intermountain Health Care, Inc.

COMBAT-SAB: Combination Antibiotic Therapy for Staphylococcus Aureus Bacteremia

The purpose of this study is to see if, in selected patients with a serious bacterial infection of the bloodstream, treating the bacterial infection with a combination of antibiotics is more effective than treating the infection with a single antibiotic. Participants must have blood cultures which are positive for a certain type of bacteria.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Staphyloccocus aureus bacteremia (SAB) is a common infectious disease condition in hospitalized patients which is associated with significant morbidity, excessive costs, and high mortality, despite effective antibiotic therapy. This pragmatic study is designed to test the hypothesis that outcomes in adults hospitalized with SAB will be improved by using combination antibiotic therapy (CAT) as early, targeted therapy in a high-risk subgroup. A group of patients identified early in their course as meeting at least one high-risk criterion who have no contraindications will be treated with one of two antibiotic strategies commonly used within usual care, namely: 1) antibiotic monotherapy or 2) combination antibiotic therapy, depending on the random assignment for each hospital, each month. Low-risk patients will be treated per usual care. Data from all patients admitted to participating hospitals with SAB will be included in the analysis.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
2096

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United States
    • Colorado
      • Brighton, Colorado, United States, 80601
      • Denver, Colorado, United States, 80218
      • Grand Junction, Colorado, United States, 81501
      • Lafayette, Colorado, United States, 80026
      • Wheat Ridge, Colorado, United States, 80401
    • Montana
      • Billings, Montana, United States, 59101
      • Butte, Montana, United States, 59701
      • Miles City, Montana, United States, 59301
    • Utah
      • Murray, Utah, United States, 84107
        • Recruiting
        • Intermountain Medical Center
        • Contact:
        • Contact:
        • Principal Investigator:
          • Brandon J Webb, MD
      • Ogden, Utah, United States, 84403
      • Provo, Utah, United States, 84604
      • Salt Lake City, Utah, United States, 84143
      • St. George, Utah, United States, 84790

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age ≥18 years
  • Alive and admitted to an Intermountain Health (IH) hospital acute care unit at enrollment

  • Initial positive blood culture with either methicillin-resistant Staphylococcus aureus (MRSA) or methicillin-susceptible Staphylococcus aureus (MSSA), collected:

    1. on or during the index admission to an IH hospital, or
    2. in an ambulatory setting (laboratory, clinic or emergency department) within 48 hours of the index admission, or

    3. at a non-IH network hospital within 24 hours of subsequent transfer to an IH hospital

      Exclusion Criteria:

  • Patient requests that patient health data not be included in the analysis

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Patients with methicillin-sensitive S. aureus bacteremia (MSSAB)
Patients with methicillin-sensitive S. aureus bacteremia (MSSAB) will be assigned to one of two different antibiotic treatment strategies appropriate for MSSA: 1) antibiotic monotherapy, or 2) combination antibiotic therapy
Drug: Antibiotic Monotherapy (AM) for patients with methicillin-sensitive S. aureus bacteremia (MSSAB)
Intravenous anti-staphylococcal beta-lactam, either cefazolin or nafcillin, per the discretion of the treating physician.
Drug: Combination Antibiotic Therapy (CAT) for patients with methicillin-sensitive S. aureus bacteremia (MSSAB)
Patients with methicillin-sensitive S. aureus bacteremia (MSSAB) and no contraindications will receive an anti-staphylococcal beta-lactam, either cefazolin or nafcillin, plus ertapenem
Experimental: Patients with methicillin-resistant S. aureus bacteremia (MRSAB)
Patients with methicillin-resistant S. aureus bacteremia (MRSAB) will be assigned to one of two different antibiotic treatment strategies appropriate for MRSA: 1) antibiotic monotherapy, or 2) combination antibiotic therapy
Drug: Antibiotic Monotherapy (AM) for patients with methicillin-resistant S. aureus bacteremia (MRSAB)
Vancomycin or daptomycin, per discretion of the treating physician
Drug: Combination Antibiotic Therapy (CAT) for patients with methicillin-resistant S. aureus bacteremia (MRSAB)
Daptomycin plus ceftaroline

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Desirability of Outcome Ranking (DOOR)
Time Frame: From enrollment to 30 days post enrollment
The DOOR ordinal scale includes four possible outcomes: treatment failure, infectious complications, antibiotic-associated adverse events and death. The ordinal scale comprises five levels: levels 1-4 are defined by survival at 30 days and the presence of either none, one, two or three of three possible outcomes; level 5 indicates death before 30 days. A DOOR analysis estimates the probability that overall outcomes in any given subject in one group are overall superior to those in a random subject from the other treatment group; probabilities >50% reject the null hypothesis.
From enrollment to 30 days post enrollment

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
90-day hospital-free days alive
Time Frame: From enrollment to 90 days after enrollment
Number of days the patient is alive and out of the hospital
From enrollment to 90 days after enrollment
30-day all cause mortality
Time Frame: From enrollment to 30 days after enrollment
Number of deaths from any cause within 30 days after enrollment
From enrollment to 30 days after enrollment
90-day all-cause mortality
Time Frame: From enrollment to 90 days after enrollment
Number of deaths from any cause within 90 days after enrollment
From enrollment to 90 days after enrollment
30-day bacteremia-free days
Time Frame: From enrollment to 30 days after enrollment
Number of days without bacteremia within 30 days after enrollment
From enrollment to 30 days after enrollment
Length of stay
Time Frame: Measured at the time of hospital discharge, up to 30 days after enrollment
Number of days in the hospital following enrollment
Measured at the time of hospital discharge, up to 30 days after enrollment
Total hospital direct costs
Time Frame: Measured at the time of hospital discharge, up to 30 days after enrollment
Total financial charges incurred by a patient during their hospitalization
Measured at the time of hospital discharge, up to 30 days after enrollment
Total inpatient antibiotic cost
Time Frame: Measured at the time of hospital discharge, up to 30 days after enrollment
Total cost of all antibiotics received by a patient while hospitalized
Measured at the time of hospital discharge, up to 30 days after enrollment
Combination antibiotic days
Time Frame: Measured from the time of enrollment until study day 7, death, or hospital discharge
Number of days a patient receives combination antibiotic therapy (CAT) as defined in protocol, instead of antibiotic monotherapy (AM)
Measured from the time of enrollment until study day 7, death, or hospital discharge
Antibiotic-associated adverse events
Time Frame: From enrollment to 30 days after enrollment
Number and type of patient adverse events definitively associated with the receipt of antibiotics while hospitalized
From enrollment to 30 days after enrollment
Clostridioides difficile infection
Time Frame: From enrollment to 30 days after hospital discharge
Presence of infection with Clostridioides difficile while hospitalized
From enrollment to 30 days after hospital discharge

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Intermountain Health Care, Inc.

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Brandon J Webb, MD, Intermountain Health Care, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
February 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
January 1, 2029

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
January 1, 2029

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
January 21, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 26, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 29, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 25, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 22, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 1053331

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

In order to protect patient privacy and comply with relevant regulations, identified data will be unavailable. Requests for deidentified data from qualified researchers with appropriate ethics board approvals and relevant data use agreements will be processed by the Intermountain Office of Research, officeofresearch@imail.org

IPD Sharing Time Frame

Data sharing will be available six months after anticipated enrollment completion, estimated August 2029, for a period to be determined by the Intermountain Office of Research and IRB

IPD Sharing Access Criteria

Will be determined on an individual basis, upon request to the IH Office of Research.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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