Abstract
Purpose:
The Purpose of this study is to perform molecular characterization and epidemiological analysis of MRSA causing ocular infections in South India.
Methods:
Between Jan 2012 and Oct 2012, 33 MRSA isolates were collected at Aravind eye Hospital, Madurai, India, from the patients who presented with various ocular infections like orbital infections, infective keratitis and lacrimal sac abscess. Preliminary screening was performed by antibiotic susceptibility method using oxacillin and cefoxitin discs and further confirmed by mecA screening. Staphylococcal chromosome mec typing, Staphylococcal protein A typing and detection of Panton-Valentine leucocidine toxin were done for 17 isolates by PCR.
Results:
A total of 127 Staphylococcus aureus were isolated, among that 33 were confirmed as MRSA. 17 of 33 were screened, in which 10 were SCCmec type V, 5 were SCCmec type IV and 2 were not typeable. Most of the SCCmec type V isolates belonged to spa type t657 (7/10) and 3 isolates had spa type t037, t3387, t386. SCCmec type IV had the spa type t852 (2/5), t363, t7181 and t1598. 82% (14/17) isolates were found to be positive for the toxin Panton-Valentine leucocidine.
Conclusions:
Community acquired MRSA strains (SCCmec type IV and V) are more prevalent than hospital acquired MRSA in causing ocular infections. Severe and non severe ophthalmic manifestations are characterized with the emergence of an epidemic spa type t657. Most of the community acquired MRSA isolates are harboring the PVL gene which may be responsible for the pathogenicity and ocular morbidity.
Keywords: 594 microbial pathogenesis: experimental studies •
433 bacterial disease •
720 Staphylococcus