Recurrent microbial keratitis and endogenous site Staphylococcus aureus colonisation

Area of Science:

• Ophthalmology
• Microbiology
• Infectious Diseases

Background:

• Microbial keratitis (MK) is a serious eye infection.
• Recurrent MK poses significant challenges in treatment and management.
• Staphylococcus aureus is a common pathogen implicated in ocular infections.

Purpose of the Study:

• To investigate Staphylococcus aureus (S. aureus) carriage in patients with microbial keratitis (MK).
• To determine if S. aureus colonization in endogenous sites is associated with recurrent MK.
• To compare S. aureus carriage rates between MK patients and control groups.

Main Methods:

• Prospective study involving 215 MK patients, 60 healthy controls, and 35 rheumatoid arthritis patients.
• Collection of corneal scrapes from MK patients and conjunctival, nasal, and throat swabs from all participants.
• Microbiological culture techniques used for S. aureus isolation and identification.

Main Results:

• Recurrent MK patients showed significantly higher S. aureus isolation rates from the cornea compared to single-episode MK patients (p<0.01).
• Conjunctival S. aureus carriage was higher in recurrent MK patients (20.6%) than in controls (3%, p=0.01).
• A higher proportion of recurrent MK patients (17.6%) had S. aureus in both conjunctiva and nose compared to single-episode MK (4.8%, p=0.002) and controls (5.0%, p=0.03).

Conclusions:

• Patients with recurrent MK exhibit elevated rates of S. aureus carriage.
• Endogenous colonization, particularly in the conjunctiva and nose, is a likely source for recurrent S. aureus MK infections.
• Findings suggest screening for S. aureus carriage in endogenous sites for managing recurrent MK.