Purpose: To analyse the demographics and clinical features of patients with microbial keratitis presenting to Cairns Hospital in Far North Queensland, Australia, over the past 15 years. Far North Queensland is a tropical climate with a unique demographic.
Method: Retrospective review of 192 consecutive presentations of microbial keratitis to Cairns Hospital between 1998 and 2013. Patients were identified by searching hospital databases for terms related to bacterial, fungal, or protozoal keratitis. Viral and non-infectious keratitis was excluded. Culture-negative (presumed) cases were included based on clinical information. Demographic, clinical and microbiological data was entered into a standardised worksheet.
Results: Microbial keratitis was more prevalent in males (59%; P=<0.001). Twenty-four percent of patients were Australian interstate or international tourists, with 63% (P=0.004) of these being between 18-3o years old. The majority of patients had no known risk factor (28%), followed by contact-lens wear (26%).
Pseudomonas aeruginosa (36%) was the most common pathogen cultured. It was most prevalent in autumn (48%; P=<0.001), and in females (61%; P=<0.001). Corynebacterium (4%) was the second most prevalent bacterial isolate. It was found solely in males (P=0.002), was more common in summer (50%; P=0.008), and observed to be most common post-trauma.
There were 25 cases of fungal keratitis (13%), which was most prevalent in summer (48%; P=0.006). Fusarium sp. (52%) then Curvularia sp. keratitis (20%) were the most commonly cultured fungal species.
Conclusion: This study highlights the influence of population and environment on the presentations of microbial keratitis in Tropical North Queensland.