Related Experiment Video

Updated: May 20, 2026

Development of a Polymicrobial Colony Biofilm Model to Test Antimicrobials in Cystic Fibrosis
07:16

Development of a Polymicrobial Colony Biofilm Model to Test Antimicrobials in Cystic Fibrosis

Published on: September 20, 2024

Enhanced Efficacy of Cefiderocol With PolyTrim Combination Therapy in a Rabbit Model of Extensively Drug-Resistant

Eric G Romanowski1, Emily K Young1, Jonathan B Mandell1

  • 1The Charles T. Campbell Ophthalmic Microbiology Laboratory, UPMC Vision Institute, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States.

Investigative Ophthalmology & Visual Science
|May 19, 2026
PubMed
Abstract

Insights

The combination of cefiderocol (FDC) with PolyTrim (PT) effectively treated Pseudomonas aeruginosa keratitis in rabbits, sterilizing corneas and preventing spread. This FDC + PT therapy shows promise for extensively drug-resistant bacterial eye infections.

Area of Science:

  • Ophthalmology
  • Microbiology
  • Pharmacology

Background:

  • The 2023 Pseudomonas aeruginosa keratitis outbreak highlighted the urgent need for novel therapies against drug-resistant ocular pathogens.
  • In vitro studies suggested cefiderocol (FDC) combined with moxifloxacin (MOX) or polymyxin B sulfate (PB) may be effective.

Purpose of the Study:

  • To evaluate the in vivo efficacy of combining cefiderocol (FDC) with commercial formulations of moxifloxacin (MOX) or PolyTrim (PT) for treating Pseudomonas aeruginosa keratitis.

Main Methods:

  • New Zealand White rabbits with intrastromal Pseudomonas aeruginosa infections were treated with FDC combined with MOX or PT.
  • Treatments were administered every 30 minutes for 8 hours, followed by bacterial burden assessment (CFU/cornea) and anterior chamber cultures.

Main Results:

  • The FDC + PT combination achieved a 6.9 log10 reduction in bacterial burden and sterilized 10 of 12 corneas, significantly outperforming monotherapies and FDC + MOX.
  • FDC-containing treatments prevented anterior chamber invasion, and FDC or PT treatments prevented corneal perforations.

Conclusions:

  • The combination of cefiderocol and PolyTrim (FDC + PT) demonstrated superior efficacy in treating Pseudomonas aeruginosa keratitis.
  • FDC + PT is a promising therapeutic strategy for extensively drug-resistant Pseudomonas aeruginosa keratitis, offering sterilization and protection against intraocular spread and perforation.

More Related Videos

Establishing a Porcine Ex Vivo Cornea Model for Studying Drug Treatments against Bacterial Keratitis09:22

Establishing a Porcine Ex Vivo Cornea Model for Studying Drug Treatments against Bacterial Keratitis

Published on: May 12, 2020

Cefoperazone-treated Mouse Model of Clinically-relevant Clostridium difficile Strain R2029106:51

Cefoperazone-treated Mouse Model of Clinically-relevant Clostridium difficile Strain R20291

Published on: December 10, 2016

Related Concept Videos

Combined Effects of Drugs: Synergism01:27

Combined Effects of Drugs: Synergism

Synergism is a useful mechanism where combining two or more drugs is more effective than each constituent used alone. Such combinations are also called supra-additive interactions. The drugs collectively enhance the final therapeutic effect by acting on different targets. Another advantage is that the low dose of each constituent drug is sufficient to achieve the desired effect. This helps reduce the duration of therapy and lower the adverse effects of these drugs.
Such synergistic combinations...
Acute Pyelonephritis II: Diagnostic Studies and Management01:28

Acute Pyelonephritis II: Diagnostic Studies and Management

Introduction:For diagnosing acute pyelonephritis, a comprehensive patient history is collected to identify symptoms such as dysuria, frequent or urgent urination, flank pain, or costovertebral angle (CVA) tenderness that may suggest a kidney infection.Physical ExaminationDuring the physical examination, CVA tenderness is assessed. This involves gentle percussion over the costovertebral angle, where tenderness often indicates a kidney infection.Diagnostic TestsUrinalysis: Used to identify white...
Clinical Significance of Antibiotic Resistance01:25

Clinical Significance of Antibiotic Resistance

Methicillin-resistant Staphylococcus aureus (MRSA) presents a critical public health threat, arising from its capacity to resist β-lactam antibiotics due to acquisition of the mecA gene within the staphylococcal cassette chromosome mec (SCCmec). This gene encodes penicillin-binding protein 2a (PBP2a), which impairs binding efficacy of methicillin and other β-lactams. MRSA has evolved into distinct clonal lineages impacting humans and animals alike, reinforcing its significance within the One...