Abstract
Purpose:
To evaluate the molecular epidemiology and antimicrobial resistance profile of methicillin-resistant Staphylococcus aureus (MRSA) isolated from conjunctivitis, keratitis, dacryocystitis and blepharoconjunctivitis.
Methods:
42 MRSA isolates from patients treated at the Visual Sciences and Ophthalmology Department, Federal University of Sao Paulo from January 2007 to May 2013 were included. PCR to nuc, mecA and luk genes was performed in order to confirm species identification, methicillin resistance and presence of the Panton-Valentine leukocidin (PVL). Staphylococcal Cassette Chromosome (SCCmec) typing was assessed by multiplex PCR. Macrorestriction profile of chromosomal DNA was performed by pulsed field gel electrophoresis (PFGE). Minimum inhibitory concentration (MIC) to oxacillin, ciprofloxacin, moxifloxacin, gatifloxacin, linezolid and vancomycin was determined by E-test.
Results:
SCCmec type IV (40.5%) and type II (35.7%) were the most prevalent. MRSA type IV grouped in 4 different clusters by PFGE, while type II isolates formed only 2 clusters, with 73.3% belonging to the cluster A. Only 1 isolate was SCCmec type I; 2 type V; 3 type III; and 4 were non-typable. MRSA types IV and V were most frequently recovered from conjunctivitis (58.8%) and presented higher susceptibility to the fluoroquinolones compared with types I, II and III. MRSA type II were predominant in keratitis (80%) and were 100% resistant to the fluoroquinolones tested. MRSA type III were recovered from previously hospitalized patients and were all related to the brazilian epidemic clone. All isolates were susceptible to vancomycin and linezolid. All specimens were negative for the presence of luk gene.
Conclusions:
MRSA types IV and V usually correlated to community-acquired infections (CA-MRSA) were the most susceptible to fluoroquinolones. We demonstrated that SCCmec types II and III, which are mainly associated with hospital-acquired infections (HA-MRSA), may be causative agents of ocular infections. The last were susceptible only to vancomycin and linezolid.