Beta-lactam Plus Levofloxacin to Enhance Therapy in Streptococcal Septicemia (BLESS)

August 19, 2026 updated by: Pinyo Rattanaumpawan, Mahidol University

Beta-lactam Monotherapy Versus Beta-lactam Plus Levofloxacin for the Treatment of Streptococcal Bacteremia: A Multicenter, Randomized, Double-Blind, Pragmatic Trial

A double-blind randomized controlled trial comparing beta-lactam plus levofloxacin versus beta-lactam monotherapy for the treatment of Streptococcal bacteremia

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This randomized, double-blind clinical trial enrolls hospitalized or outpatient adults (≥18 years) with blood cultures positive for Streptococcus spp. who are receiving intravenous beta-lactam monotherapy. Eligible participants continue beta-lactam therapy and are randomized (block size of 4, stratified by site) to receive either intravenous levofloxacin 750 mg once daily or a normal saline placebo for 3-7 days, with dosing adjusted for renal function. The primary outcome is a composite endpoint of unfavorable events, and the secondary outcome is the duration of bacteremia

Study Type

Interventional

Enrollment (Estimated)

165

Phase

  • 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 Backup

Study Locations

  • Thailand
      • Bangkok, Thailand
        • Recruiting
        • Faculty of Medicine Siriraj Hospital
        • Contact:
          • Phone Number: +6624192707
      • Chiang Mai, Thailand
        • Not yet recruiting
        • Maharaj Nakorn Chiang Mai Hospital
      • Nakhon Ratchasima, Thailand
        • Recruiting
        • Maharaj Nakhon Ratchasima
      • Ratchaburi, Thailand
        • Not yet recruiting
        • Ratchburi Hospital

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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Adults age>18 years

  2. Blood culture positive for Streptococcus (<72 hours before enrollment)

    • at least 1 bottle of S. pyogenes, S. agalactiae, S. pneumoniae, S. suis
    • at least 2 bottle of other Streptococci
  3. Receiving or having plan of receiving beta-lactam therapy

Exclusion Criteria:

  1. Known allergy to beta-lactam or fluroquinolone antibiotics
  2. Pregnancy or lactating mother
  3. EKG with QT prolongation
  4. Diagnosis of infective endocarditis

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: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Beta-lactam monotherapy
Normal saline 150 cc IV drip in 90 minutes once daily for 3-7 days (in a blinding package)
Drug: Beta-lactam monotherapy
Normal saline placebo
Experimental: Levofloxacin combination therapy
Levofloxacin 750 mg IV drip in 90 minutes once daily for 3-7 days (in a blinding package)
Drug: Beta-lactam plus levofloxacin combination therapy
IV Levofloxacin

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Composite endpointof unfavorable outcome
Time Frame: 28 days after the onset of infection
a composite endpoint comprising persistent bacteremia lasting more than 5 days, 28-day all-cause mortality, and the development of new metastatic foci within 28 days from infection onset
28 days after the onset of infection

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Duration of bacteremia
Time Frame: 28 days after the onset of infection
Duration of bacteremia
28 days after the onset of infection

Collaborators and Investigators

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

Sponsor

Mahidol University

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)

January 8, 2026

Primary Completion (Estimated)

December 31, 2027

Study Completion (Estimated)

December 31, 2028

Study Registration Dates

First Submitted

November 14, 2025

First Submitted That Met QC Criteria

November 19, 2025

First Posted (Actual)

November 20, 2025

Study Record Updates

Last Update Posted (Actual)

August 21, 2026

Last Update Submitted That Met QC Criteria

August 19, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 886/2568(IRB3)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

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.

Subscribe