Staphylolysin is an effective therapeutic agent for Staphylococcus aureus experimental keratitis

Area of Science:

• Ophthalmology
• Microbiology
• Infectious Diseases

Background:

• * Staphylococcus aureus (S. aureus) keratitis presents therapeutic challenges due to increasing antibiotic resistance.
• * Staphylolysin, a protease from Pseudomonas aeruginosa, exhibits staphylolytic activity.
• * Investigating staphylolysin as a treatment for S. aureus keratitis is crucial.

Purpose of the Study:

• * To evaluate the therapeutic efficacy of staphylolysin against experimental S. aureus keratitis.
• * To assess the impact of staphylolysin on bacterial load and ocular inflammation.
• * To determine the effectiveness against both methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) S. aureus strains.

Main Methods:

• * A rabbit keratitis model was established using three MRSA strains and one MSSA strain.
• * Topical staphylolysin or control (bovine serum albumin) was administered over 5 hours, starting 4 hours post-infection.
• * Bacterial quantification and histopathological analysis of corneas were performed.

Main Results:

• * Staphylolysin significantly reduced S. aureus bacterial load in all treated corneas compared to controls.
• * MRSA-infected eyes showed a 3-4 log decrease or complete sterilization; MSSA-infected eyes were sterilized.
• * Histopathology revealed reduced inflammation and abscess formation in staphylolysin-treated MSSA-infected eyes.

Conclusions:

• * Staphylolysin demonstrates potent antibacterial activity against various S. aureus strains, including MRSA.
• * The treatment provides long-lasting protection with beneficial histopathological outcomes.
• * Staphylolysin is a promising therapeutic agent for S. aureus keratitis.