Jason R. Daley, Xingdi Wang, Matin Ly, Maria Cabrera-Aguas, Stephanie Watson, Chameen Samarawickrama

Purpose: Microbial keratitis (MK) is a serious sight threatening eye condition, requiring urgent empirical antimicrobials. Periodical surveillance of microbes and their antibiotic resistance profiles is critical to optimise patient outcomes. We present pilot data, along with treatment burden, prevalence, morbidity and current therapies for MK across South Western Sydney.

Method: Retrospective review between 2017-2020 of MK cases at Liverpool Hospital was conducted. Data was sou- rced from the ophthalmology department, the pharmacy’s dispensing history for antimicrobial eye drops and pathology records of corneal scrapes.

Results: One hundred and two presentations of unilateral MK were included; 64.3% were male and the average age was 59.5 years (range: 5–101). Sixty-four cases involved admission with an average length of stay of 7.31 days. Contact lens use was the most frequent risk factor (10.8%). The culture positivity rate was 62%, of which 75% were bacteria, 19% were viral and 6% were fungal. Gram stain results indicated 44% of the bacteria were gram positive and 37% were gram negative. The most common bacteria were Staphylo- coccus aureus (18%) and Pseudomonas aeruginosa (16%). Staphylococcus aureus had a 31% resistance rate to flucloxacillin, but these were all cases of methicillin-resistant Staphylococcus aureus (MRSA). Methicillin-resistant Staph- ylococcus aureus had 0% resistance (n = 4) to vancomycin. Pseudomonas aeruginosa was most sensitive to gentamicin 100% and ceftazidime 88%. In 75% of presentations, the visual acuity improved by at least 1 Snellen line.

Conclusion: Staphylococcus aureus was the most com- mon isolate. Monotherapy with a fluoroquinolone was the most common treatment and is highly effective for empirical antibiotic therapy of bacterial keratitis