Aline S. Moriyama, Heloisa Nascimento, Ana Luisa Höfling-Lima Department of Ophthalmology Federal University of São Paul

1. 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 Aline S. Moriyama, Heloisa Nascimento, Ana Luisa Höfling-Lima Department of OphthalmologyFederal University of São PauloSão Paulo, Brazil

2. 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

3. 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

4. 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

5. Methods • Retrospective review of the microbiological records • Laboratory of Ocular Microbiology of the Federal University of São Paulo (UNIFESP) • January 2003 - 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

6. Results 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:

7. 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

8. 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) Percent of infections caused by MRSA Time (year)

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

10. 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

11. 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

12. References • Asbell PA et all. Increasing prevalence of methicillin resistance in serious ocular infections caused by Staphylococcus aureus in the United States: 2000 to 2005. J Cataract Refract Surg 2008; 34:814–818. • Asbell PA et all. Ocular TRUST: Nationwide Antimicrobial Susceptibility Patterns in Ocular Isolates. Am J Ophthalmol 2008;145:951–958. • Chambers HF. Community-associated MRSA—resistance and virulence converge. N Engl J Med 2005;352:1485–1487. • Chawla B, Agarwal P, Tandon R, Titiyal JS, Sharma N, Agarwal T, Navak N, Satpathy G. In vitro susceptibility of bacterial keratitis isolates to fourth-generation fluooquinolones. Eur J Ophthalmol. 2009 Nov 12. [Epub ahead of print] • Deramo VA, Lai JC, Winokur J, Luchs J, Udell IJ. Visual outcome and bacterial sensitivity after methicillin-resistant Staphylococcus aureus-associated acute endophthalmitis. Am J Ophthalmol 2008;145:413– 417. • Gayoso MFA, Oliveira ADD, d’Azevedo PA, Yu MCZ, Höfling-Lima AL, Francisco W. Suscetibilidade antimicrobiana in vitro dos Staphylococcus coagulase negativa oculares. Arq Bras Oftalmol. 2007;70(6):924-8. • Major JC Jr, Engelbert M, Flynn HW Jr, Miller D, Smiddy WE, Davis JL. Staphylococcus aureus endophthalmitis: antibiotic susceptibilities, methicillin resistance, and clinical outcomes. Am J Ophthalmol 2010;149:278 –283. • Marangon FB, Miller D, Muallem MS, Romano AC, Alfonso EC. Ciprofloxacin and levofloxacin resistance among methicillin-sensitive Staphylococcus aureus isolates from keratitis and conjunctivitis. Am J Ophthalmol 2004;137:453– 458.