Microbial Keratitis and Ocular Surface Disease: A 5-Year Study of the Microbiology, Risk Factors and Clinical Outcomes in Sydney, Australia

Abstract

<b>Purpose</b>: To report the microbiological and clinical profiles, and outcomes of patients with microbial keratitis who had ocular surface disease (OSD) at the Sydney Eye Hospital, Australia over a 5-year period.<b>Methods</b>: A retrospective case-series study was conducted. Patients diagnosed with microbial keratitis who had a history of OSD (dry eye, blepharitis, Steven Johnson syndrome (SJS) and ocular cicatricial pemphigoid (OCP)) from 1^st January 2012 to 31^st December 2016 were identified from hospital coding and pathology data. Data were extracted from the medical records.<b>Results</b>: 189 eyes from 171 patients with a mean age of 60 ± 19 years (range 20-96 years) were included. OSD included blepharitis (79%), dry eye (25%), SJS (4%) and OCP (2%). Coagulase-negative Staphylococcus (CoNS) (48%) were the most common isolated microorganism, made up of mostly <i>Staphylococcus epidermidis</i> (n = 37, 48%), <i>Staphylococcus capitis</i> (n = 16, 21%), and <i>Staphylococcus warneri</i> (n = 10, 13%). Median visual acuity at initial presentation was 0.52 logMAR and 0.30 logMAR at final visit. Median healing time was 12 days (IQR 6-27). The most common initial antimicrobial treatment prescribed was a combination of topical fortified cephalothin and gentamicin (n = 65, 34%); or topical ofloxacin (n = 56, 30%). Complications occurred in 69 eyes (37%), mainly non or slow-healing epithelial defects (n = 53, 43%) or corneal perforations (n = 24, 20%); and were more common in the elderly (n = 48/69, 70%).<b>Conclusion</b>: Microbial keratitis can affect those with OSD. In our setting, CoNS were the main organisms identified. Furthermore, patients prescribed a combination therapy of fortified antibiotics had poorer outcomes compared to monotherapy fluoroquinolones.