Infectious keratitis in South Australia: Emerging resistance to cephazolinq

Area of Science:

• Ophthalmology
• Microbiology
• Infectious Diseases

Background:

• Infectious keratitis is a significant cause of vision loss.
• Understanding the causative pathogens and their antibiotic resistance patterns is crucial for effective treatment.

Purpose of the Study:

• To analyze the spectrum of microorganisms causing infectious keratitis.
• To determine the patterns of antibiotic resistance in these pathogens.
• To evaluate treatment outcomes at a tertiary hospital in South Australia.

Main Methods:

• Retrospective review of microbiology laboratory records from 1998 to 2003.
• Analysis of corneal scraping results, including Gram staining and cultures.
• Assessment of antibiotic sensitivity and resistance profiles.

Main Results:

• Coagulase-negative Staphylococcus (29.8%) was the most frequent pathogen, followed by Staphylococcus aureus (18.7%) and Pseudomonas aeruginosa (12.7%).
• Fungal keratitis accounted for 5.2% of positive cultures.
• Emerging resistance to cephazolin was observed in 35% of coagulase-negative Staphylococcus isolates, while no ciprofloxacin resistance was found in Pseudomonas isolates.

Conclusions:

• Staphylococcus species are the predominant cause of infectious keratitis.
• There is a notable increase in resistance to cephazolin among Gram-positive cocci.
• This finding has implications for first-line antibiotic selection in managing infectious keratitis.