Methicillin-resistant Staphylococcus aureus ocular infection: a 10-year hospital-based study

Abstract

Purpose: To characterize the patient demographics, clinical features, and antibiotic susceptibility of ocular infections caused by methicillin-resistant Staphylococcus aureus (MRSA), including community-associated (CA) and healthcare-associated (HA) isolates.

Design: Retrospective, observational study.

Participants: Patients (n = 519) with culture-proven S. aureus ocular infections seen between January 1, 1999, and December 31, 2008, in Chang Gung Memorial Hospital.

Methods: Data collected included patient demographics and clinical information. Antibiotic susceptibility was verified by disc diffusion method.

Main outcome measures: Proportion of MRSA in S. aureus ocular infections and the clinical characteristics, diagnoses, and antibiotic susceptibility patterns of CA-MRSA versus HA-MRSA ocular infections.

Results: We identified 274 patients with MRSA ocular infections, which comprised 181 CA-MRSA and 93 HA-MRSA isolates. The average rate of MRSA in S. aureus infections was 52.8% with a stable trend, whereas the annual ratio of CA-MRSA in ocular MRSA infections averaged 66.1% and tended to increase over the 10-year interval. Patients with ocular CA-MRSA were younger. Lid and lacrimal system disorders were more common, but keratitis, endophthalmitis, and wound infection were less common among CA-MRSA cases than HA-MRSA cases. Both CA-MRSA and HA-MRSA isolates were resistant to clindamycin and erythromycin, but CA-MRSA was more susceptible to sulfamethoxazole/trimethoprim.

Conclusions: Community-associated MRSA is an important pathogen of ocular infections; CA-MRSA and HA-MRSA ocular infections differ demographically and clinically, but both strains were multi-resistant in Chang Gung Memorial Hospital, one of the biggest referral centers in Taiwan. In a country with a high prevalence of MRSA, ophthalmologists should be aware of such epidemiologic information.