Aline S. Moriyama, Heloisa Nascimento, Ana Luisa Höfling-Lima

Department of OphthalmologyFederal University of São Paulo

São Paulo, Brazil

Aline S. Moriyama, Heloisa Nascimento, Ana Luisa Höfling-Lima

Department of OphthalmologyFederal University of São Paulo

São Paulo, Brazil

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 posterThe 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 posterThe authors have no financial interest in the subject matter of this poster

BackgroundBackground

Staphylococcus aureus Staphylococcus aureus • Gram positive bacteria• Normal skin flora• Present in mucous membranes:– Nasopharynx– Conjunctiva

• Eventual causative agent of infections in virtually all human tissues

BackgroundBackground

Methicillin Resistant Methicillin Resistant Staphylococcus aureus Staphylococcus aureus (MRSA)(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

PurposePurpose

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

MethodsMethods

• 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

ResultsResults

S. aureus MRSA

Blepharitis 151 9 (5.96%)

Conjunctivitis 370 24 (6.49%)

Keratitis 191 14 (7.33%)

Endophthalmitis 21 6 (28.57%)

TOTAL (ocular infections) 732 53 (6.78%)

Normal subjects 50 0

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:

ResultsResults

• 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

Endophthalmitis Blepharitis

S. aureus MRSA S. aures MRSA

2003 3 1 (33.33%)

2004 2 1 (50%)

2005 2 0

2006 6 0

2007 3 1 (33.33%)

2008 0 0 145 9 (6.21%)

2009 5 3 (60%) 6 1 (16.67%)

Total 21 6 (28.57%) 151 10 (6.62%)

Results 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)

Perc

ent o

f inf

ectio

ns c

ause

d by

MRS

A

ResultsResults

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

ConclusionConclusion

• 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

DiscussionDiscussion

• 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

ReferencesReferences

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