Download Methicillin Resistant Staphylococcus aureus prevalence in a tertiary

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 Ophthalmology
Federal University of São Paulo
São Paulo, Brazil
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 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
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:
S. aureus
MRSA
Blepharitis
151
9 (5.96%)
Conjunctivitis
370
24 (6.49%)
Keratitis
191
14 (7.33%)
21
6 (28.57%)
732
53 (6.78%)
Endophthalmitis
TOTAL (ocular infections)
Normal subjects
50
0
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
Endophthalmitis
S. aureus
Blepharitis
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
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
Percent of infections caused by MRSA
Prevalence of MRSA among S. aureus ocular infections (percent)
Time (year)
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
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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