Surveillance of Methicillin -Resistant Staphylococcus From the Ocular Surface of Cataract Surgery Patients - PowerPoint PPT Presentation

Surveillance of Methicillin-Resistant Staphylococcus From the Ocular Surface of Cataract Surgery Patients

Eric Donnenfeld, MD1; Randall Olson, MD2; Kerry Solomon, MD3; R. Bruce Wallace, MD4; Taryn Conway, BS5; Rhett Schiffman, MD5; David Hollander, MD5

1Ophthalmic Consultants of Long Island and Connecticut, Rockville Centre, NY; 2The John A. Moran Eye Center, University of Utah, Salt Lake City, UT; 3Ophthalmology, Medical University of South Carolina, Charleston, SC; 4Wallace Eye Surgery, Laser and Surgery Center, Alexandria, LA; 5Allergan, Inc., Irvine, CA

Financial Disclosures

This study was funded by Allergan, Inc., Irvine, CA.

Drs. E. Donnenfeld, R. Olson, K. Solomon, and R.B. Wallace are consultants to Allergan, Inc.

Ms. T. Conway and Drs. R. Schiffman and D. Hollander are employees of Allergan, Inc.

Endophthalmitis is a rare, yet potentially devastating complication following cataract extraction.1-4

The ocular surface (lids and conjunctiva) and nasal flora are the predominant source of bacteria leading to postoperative endophthalmitis.5-7

The EndophthalmitisVitrectomy Study (EVS) demonstrated that the vast majority of cases of postcataractendophthalmitis arise secondary to Gram-positive organisms, including Staphylococcus epidermidis and S aureus.8

Methicillin-resistant staphylococcal infections are on the rise and no longer confined to healthcare workers.4,9-12

This study was designed to determine the bacteria present on the ocular surface (lids and conjunctiva) in patients undergoing cataract surgery. An additional goal of the study was to evaluate the presence of oxacillin (methicillin)–resistant bacterial species on the ocular surface of both healthcare and non-healthcare workers.

A multicenter (10 sites), prospective study.

Swabs were performed on the superior lid lash margin and inferior tarsal conjunctiva of the nonsurgical eye of patients undergoing cataract surgery at the time of operation.

Gram-negative bacteria were speciated by the BBL™Enterotube™ II.

Gram-positive bacteria were tested for the presence of catalase to separate Staphylococcus species from other Gram-positive bacteria.

Staphylococcal species were identified using the API® Staph kit (bioMérieux , Inc.; Durham, NC).

Susceptibility to oxacillin was tested byEtest® (oxacillin [OX], AB Biodisk; Solna, Sweden) in Staphylococcus species.

The oxacillin breakpoints were ≤ 2 µg/mL (sensitive) and ≥ 4 µg/mL (resistant) for S aureus and S lugdunensis and ≤ 0.25 µg/mL (sensitive) and ≥ 0.5 µg/mL (resistant) for all other coagulase-negative staphylococci.

Some patients had cultures positive for 2 or 3 pathogens. The total number of positive lid and conjunctival isolates were 393 and 256, respectively.

Lid

Conjunctiva

S aureus

n = 31

(12%)

S aureus

n = 60 (15%)

Micrococcus species

Micrococcus species

S capitis

n = 13 (5%)

n = 18 (5%)

n = 7 (3%)

S xylosus

S warneri

n = 12 (3%)

n = 6 (2%)

S lugdunensis

n = 9 (2%)

n = 6 (2%)

S warneri

n = 9 (2%)

S epidermidis

n = 243 (62%)

S lugdunensis

n = 12 (5%)

Other Gram-positive

bacteria

n = 7 (2%)

S capitis

n = 21 (5%)

S epidermidis

n = 165 (64%)

n = 9 (4%)

Other Gram-positivebacteria

n = 14 (4%)

Enterobacter agglomerans

n = 7 (3%)

Gram-negative bacteria

Other Gram-negative bacteria

(N = 393)

(N = 256)

• The majority of positive lid (303/393; 77%) and conjunctival (196/256; 76%) isolates were either S epidermidis or S aureus.

48%

Oxacillin Resistant

S epidermidis (n = 224)a

51%

34%

Oxacillin Susceptible

S aureus (n = 59)a

59%

58%

S xylosus (n = 12)

42%

0%

S warneri (n = 8)a

88%

33%

S lugdunensis (n = 9)

66%

17%

S capitis (n = 6)

83%

0%

S hominis (n = 4)

100%

S caprae (n = 2)

50%

50%

S haemolyticus (n = 2)

0%

S saprophyticus (n = 2)a

50%

0%

S lentus (n = 1)

100%

0%

S sciuri (n = 1)

100%

100%

S cohnii spp urealyticus (n = 1)

0%

Percentage of Staphylococcus Species

aFour (7%) S aureus, 2 (1.0%) S epidermidis, 1 (50%) S saprophyticus, and 1 (12%) S warneriwere intermediately resistant to oxacillin.

• Oxacillin (methicillin) susceptibility was tested on 331 (92%) of 358 lid staphylococci.
• The rate of oxacillin (methicillin) resistance was highest among lid S xylosus (58%), followed by S epidermidis (48%) and S aureus (34%).

45%

S epidermidis (n = 154)a

Oxacillin Resistant

52%

Oxacillin Susceptible

21%

S aureus (n = 29)a

76%

0%

S warneri (n = 5)

100%

0%

S lugdunensis (n = 5)

100%

25%

S capitis (n = 4)

75%

S caprae (n = 3)a

33%

0%

S hominis (n = 3)

100%

67%

S haemolyticus (n = 3)

33%

0%

S xylosus (n = 2)

100%

Percentage of Staphylococcus Species

aFour (3%) S epidermidis,1 (3%) S aureus, and 1 (33%) S caprae were intermediately resistant to oxacillin.

• Oxacillin (methicillin) susceptibility was determined for 208 (92%) of 227 conjunctival staphylococci.
• The rate of oxacillin (methicillin) resistance was 45% among conjunctival S epidermidis and 21% among S aureus species.

Non-Healthcare Workers

120

Healthcare Workers

69

Patients (n)

14

7

Resistant Lid Cultures

Resistant Conjunctival Cultures

• Of 134 patients with resistant lid Staphylococcus cultures, 120 (90%) patients were not healthcare workers.
• Of 76 patients with resistant conjunctival Staphylococcus cultures, 69 (91%) were not healthcare workers.

aMRSA = Oxacillin (methicillin)-resistant S aureus; bMRSE = Oxacillin (methicillin)-resistant S epidermidis

• The percentage of resistant Staphylococcus isolates was similar between healthcare and non-healthcare workers.

Over 75% of bacterial isolates on the ocular surface (lids and conjunctiva) of cataract surgery patients were either S epidermidis or S aureus.

Overall, approximately one-half of S epidermidis isolates and one-quarter of S aureus isolates were resistant to oxacillin (methicillin).

The percentage of Staphylococcus isolates resistant to oxacillin (methicillin) was similar between healthcare and non-healthcare workers.

The high rate of oxacillin (methicillin)–resistant Staphylococcus species on the ocular surface of cataract surgery patients underscores the need to use an antibiotic in the perioperative period with a favorable profile against Gram-positive species, including Oxacillin (methicillin)–resistant S aureus (MRSA) and Oxacillin (methicillin)–resistant S epidermidis (MRSE).

S epidermidis and S aureus were the most common bacterial species identified on the ocular surface of cataract surgery patients.

A significant portion of ocular surface staphylococcal species were resistant to oxacillin (methicillin), even among non-healthcare workers.

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