Aline S. Moriyama, Heloisa Nascimento, Ana Luisa Höfling-Lima Department of Ophthalmology Federal University of São Paulo São Paulo, Brazil Aline S. Moriyama, Heloisa Nascimento, Ana Luisa Höfling-Lima Department of Ophthalmology Federal University of São Paulo São Paulo, Brazil The authors have no financial interest in the subject matter of this poster Methicillin Resistant Staphylococcus aureus prevalence in a tertiary eye care center in Brazil The authors have no financial interest in the subject matter of this poster

Background Staphylococcus aureus Gram positive bacteria Normal skin flora Present in mucous membranes: – Nasopharynx – Conjunctiva Eventual causative agent of infections in virtually all human tissues

Background Methicillin Resistant Staphylococcus aureus (MRSA) Resistance to β-lactam antimicrobial agents through the production of penicillin binding proteins (PBP1 and PBP2) regulated by the mecA gene Associated to resistance to others antibiotic classes, including increased resistance to fluoroquinolones, commonly used in the treatment and prophylaxis of ocular infections Controversial evidences regarding the possibility of a different pathogenicity with more aggressive behavior Rising incidences in eye diseases, emerging as an important ocular pathogen

Purpose To describe the prevalence of ocular infections caused by methicillin-resistant Staphylococcus aureus (MRSA) and to compare the in vitro susceptibility profiles of methicillin-susceptible Staphylococcus aureus (MSSA) and MRSA in patients with blepharitis, conjunctivitis, keratitis, endophthalmitis and subjects with no ocular complains

Methods Retrospective review of the microbiological records – Laboratory of Ocular Microbiology of the Federal University of São Paulo (UNIFESP) – January December 2009 Data of subjects with – Endophthalmitis – Keratitis – Conjunctivitis – Blepharitis – Normal subjects with no ocular complains Analysis regarding – prevalence of MRSA in the different S. aureus ocular infections – MRSA was established based on resistance to either oxacillin or cefoxitin – in vitro susceptibility to antibiotics commonly used to treat and/or prevent eye infections

Results S. aureusMRSA Blepharitis1519 (5.96%) Conjunctivitis37024 (6.49%) Keratitis19114 (7.33%) Endophthalmitis216 (28.57%) TOTAL (ocular infections)73253 (6.78%) Normal subjects500 During the seven years period, 732 exams confirmed S. aureus infection in different types of eye diseases and 50 exams were made to evaluate normal conjunctiva and eyelid flora in healthy individuals. The number of S. aureus isolates according to the type of ocular infection as well as the respective prevalence of MRSA among those infections are shown in the following table:

Results The total cases of endophthalmitis caused by S. aureus and the proportion of MRSA strains are featured in table above Included also blepharitis data, only available in our records from 2008 to 2009 EndophthalmitisBlepharitis S. aureusMRSAS. auresMRSA (33.33%) (50%) (33.33%) (6.21%) (60%)61 (16.67%) Total216 (28.57%)15110 (6.62%)

Results The featured graph presents the yearly prevalence of MRSA among the conjunctivitis, keratitis and overall (blepharitis, conjunctivitis, keratitis and endophthalmitis) S. aureus cases from 2003 to 2009 Prevalence of MRSA among S. aureus ocular infections (percent) Time (year) Percent of infections caused by MRSA

Results The graph bellow shows the susceptibility profile of MSSA and MRSA to antimicrobial agents commonly used in ophthalmic practice Percent sensitive Antimicrobial Susceptibility profile: MMSA vs. MRSA

Conclusion Our results show a trend of increasing prevalence of MRSA in S. aureus ocular infections MRSA was more prevalent among S. aureus endophthalmitis cases than in the others eye diseases (keratitis, conjunctivitis and blepharitis) Resistance rates to others antimicrobial, including fourth-generation fluoroquinolones, was higher among MRSA compared to MSSA No case of vancomycin resistance was documented

Discussion The emerging rates of MRSA in ocular infections can have therapeutic implications and ophthalmologists should consider the possibility of MRSA when selecting empiric treatment Although recent studies have not found significant pathogenic differences between MSSA and MRSA regarding visual outcomes, the higher prevalence of MRSA among endophthalmitis cases might be related to diverse pathogenic mechanisms

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