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

ABSTRACT

Purpose: 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.

Methods: 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.

Results: 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 Staphylococcus epidermidis (n = 37, 48%), Staphylococcus capitis (n = 16, 21%), and Staphylococcus warneri (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%).

Conclusion: 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.

KEYWORDS:

• Microbial keratitis
• dry eye
• ocular surface disease
• keratitis
• cornea

Acknowledgments

The authors acknowledge the corneal unit at the Sydney Eye Hospital who managed the patients with microbial keratitis in this case series.

Additional information

Funding

Pauline Khoo is supported by an Australian Government Training Program Scholarship from the University of Sydney, Australia and the Ophthalmology and Vision Science PhD Scholarship from the Sydney Eye Hospital Foundation. Stephanie Watson is supported by the Sydney Medical School Foundation. Dana Robaei is supported by an NHMRC Early Careers fellowship (APP1073846). The Sydney Eye Hospital Foundation supported the study. The authors have no competing/conflicts of interest to declare.