Abstract
Purpose::
To evaluate the incidence of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible Staphylococcus aureus (MSSA) ocular isolates at an academic institution and regional referral center in the Northeastern US.
Methods::
Single institutional retrospective analysis of ocular microbiology data was reviewed from January 1, 2005 to November 30, 2006. All ocular cultures, including eyelid, conjunctival, corneal, vitreal, lacrimal, and orbital cultures, were reviewed for Staphylococcus aureus (S aureus). All MRSA and MSSA were identified. Sensitivity and resistance patterns, especially to fluoroquinolones, were analyzed.
Results::
S aureus was found in 65 cases of community acquired ocular infections. 24.6% (n = 16) of these cases was MRSA and 75.4% (n = 49) of them was MSSA. Among the MRSA positive isolates, 56.3% (n = 9) of them was resistant to the second, third, or fourth generation fluoroquinolones, whereas only 8.2% (n = 4) of MSSA isolates was resistant to the fluoroquinolones. S aureus was cultured positive in eyelid, conjunctival, cornea, lacrimal, and orbital cultures. 57.1% of eyelid S aureus isolates was MRSA, which was followed by orbit (38.5%), cornea (23.5%), conjunctiva (13.3%), and lacrimal specimen (10%). In all the individual type of ocular cultures, the percentage of fluoroquinolone resistant MRSA isolates was higher than that of fluoroquinolone resistant MSSA isolates. No S aureus was isolated in vitreal cultures performed in the past two years.
Conclusions::
S aureus is a major ocular pathogen. Current literature suggests that MRSA infections are on the rise in both hospital and community environments. Our regional data is consistent with this trend, with resistance to fluoroquinolones steadily increasing over time.
Keywords: Staphylococcus • antibiotics/antifungals/antiparasitics • bacterial disease