Persistence and Prevalence of MRSA on Ocular Surface

following Primary MSSA/MRSA Infections

Darlene Miller, DHSc, MPH, CICDavid Almeida, MD, PhDEduardo C. Alfonso, MD

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

IntroductionStaphylococcus aureus remains the most common ocular

pathogen recovered from ocular infections at our Institute.

Colonization and persistent S. aureus infections can lead to chronic inflammation and severe ocular surface disease.

43.5

21.8

10.64.2

19.8

0

10

20

30

40

50

conjunctivitis keratitis blepharitis endopthalimitis All ocular

%

S. aureus

Ocular Sources-BPEI 1990-June 2009,

PurposeTo document the prevalence and

persistence of (MRSA) colonization following primary S. aureus infections.

To identify presister populations.To document changes in in vitro

susceptibility to vancomycin among patients with chronic MRSA infections.

MethodsReview of all MRSA Culture Positive Cases -

1990-June 2009 Colonizer= Patient with repeat MRSA positive

culture after a treatment course of at least 10 days.Patient Demographics

AgeSexPresenting Clinical Diagnosis

Review and comparison of Vancomycin MICs

RESULTSMRSA Trends-All Ocular-1990-June 2009

8

14

28

38

05

10152025303540

1990-1994 1995-1999 2000-2004 2005-Jun2009

%

MRSA (N=651/2698, 24.1%)

Prevalence of MRSA Colonization/Persistence

7

98

12

02468

101214

1990-1994 1995-1999 2000-2004 2005-Jun2009

%

Colonizers (N=50, 7.7%)

Persistent MRSA Colonization Profile

70

1812

01020304050607080

MRSA-MRSA MSSA-MRSA MRSA-MSSA

%

Colonization Profile

22%, 11/50 had 3 or more positive cultures

Demographics-Age/Sex (N=50)Female = 54%Males = 46%

32

12

64

1612

108

05

101520253035

<= 20 yrs 21-40 yrs 31-60 yr >60 yrs

%

females males

Clinical Diagnosis-Persistent MRSA Colonizers (N=50)

4

8

12

24

52

0 10 20 30 40 50 60

endophthalmitis

keratoconjunctivitis

dacryocystitis

keratitis

conjunctivitis

%

Presenting diagnosis

Change in Vancomycin MIC Among Repeat MRSA Isolates

010203040506070

Increased 2X Increased 4X Decreased1/2X

No Change

% c

hang

e

Vancomycin MIC

24% increase in vancomycin MIC, (100% susceptible)

SummaryMRSA rates increased from 8% at baseline

(1990-1994) to 38% in the last 4.5 years (2005-June 2009).

Persistent MRSA colonization remain stable over the 19 year period (7.7%).

Persistent MRSA was more frequently recovered from conjunctivitis and women >60 yrs.

24% of repeat MRSA isolates demonstrated increased Vancomycin MICs

Clinical RelevanceColonization or Persistent MRSA on the

ocular surface can serve as:Reservoir/foci for post surgical infections.Antigenic trigger for increased/chronic

inflammation. Repeat or persistent MRSA isolation may

impact in vivo efficacy of vancomycin.