External ocular infections due to methicillin-resistant Staphylococcus aureus (MRSA)

Purpose To determine the prevalence and clinical characteristics of external ocular infections caused by methicillin-resistant Staphylococcus aureus (MRSA) in an ophthalmic hospital in the UK. Methods A retrospective analysis of the case notes of patients who had culture proven external ocular Staphylococcal infections during a 44-month period was undertaken. Results There were a total of 548 external eye infections caused by Staphylococcus aureus. Of these, 17 (3%) were MRSA positive. The most common presentation was conjunctivitis seen in six patients. All MRSA isolates were sensitive to chloramphenicol. Ofloxacin resistance was observed in all isolates from patients over the age of 50 years. All patients had an underlying history of either an ocular surface disease, malignancy, or a debilitating medical illness. Conclusions MRSA is as yet an infrequent cause of external ocular infections. Patients typically have underlying ocular risk factors and/or are medically debilitated. Different strains infect young and old age groups with characteristic antimicrobial sensitivity. This study highlights the need for more work to establish the role of MRSA commensals and ocular infections.