Cefiderocol Is Effective In Vitro Against Numerous Gram-Negative Species Isolated from Keratitis Patients.

Area of Science:

• Ophthalmology
• Infectious Diseases
• Pharmacology

Background:

• Keratitis is an eye infection often caused by Gram-negative bacteria.
• There is a need for effective topical ophthalmic antibiotics to treat keratitis.
• Cefiderocol is a novel siderophore-cephalosporin antibiotic.

Purpose of the Study:

• To evaluate cefiderocol's potential as a topical ophthalmic antibiotic.
• To determine the susceptibility of Gram-negative bacterial keratitis isolates to cefiderocol.

Main Methods:

• Minimum Inhibitory Concentrations (MICs) of cefiderocol were determined using broth dilution.
• Iron-depleted, cation-adjusted Mueller-Hinton broth was used.
• A panel of Gram-negative bacteria, including *Acinetobacter baumannii*, *Pseudomonas aeruginosa*, and *Escherichia coli*, were tested.

Main Results:

• Cefiderocol demonstrated in vitro activity against most tested Gram-negative keratitis isolates.
• MIC90 values varied by species, with low concentrations (0.25-1.0 µg/mL) for most.
• 100% susceptibility was observed except for *Achromobacter xylosoxidans* and *Moraxella* spp. due to lack of established breakpoints.

Conclusions:

• Cefiderocol exhibits significant in vitro activity against a broad range of Gram-negative keratitis pathogens.
• These findings support the potential utility of cefiderocol for topical treatment of Gram-negative bacterial keratitis.
• Further research and development for topical ophthalmic application of cefiderocol are warranted.