Rachel E. Reem

Screening and characterization of Staphylococcus aureus from ophthalmology clinic surfaces: a proposed surveillance tool.

PURPOSE To screen environmental surfaces of an outpatient ophthalmic clinic for methicillin-susceptible and methicillin-resistant Staphylococcus aureus (MSSA and MRSA); to identify the most commonly contaminated surfaces and to phenotype and genotype all collected isolates. DESIGN A single institution, 1-year prospective environmental study. METHODS Commonly touched surfaces in examination rooms and common areas were targeted and sampled on a quarterly basis for 1 year. Samples were collected using electrostatic cloths and swabs. S. aureus was isolated using nonselective and selective media. Morphologic characteristics and standard biologic testing were used to confirm staphylococcal species. S. aureus isolates were phenotypically (Kirby-Bauer method) and genotypically characterized (mecA confirmation, SCCmec typing and pulsed-field gel electrophoresis). Dendrogram analysis was used to establish genetic relatedness between the isolates. RESULTS Of 112 total samples, 27 (24%) and 5 (4%) were MSSA- and MRSA-positive, respectively. Both community-associated (SCCmec IV, USA300) and hospital-associated (SCCmec II, USA100) MRSA isolates were found. No single surface remained consistently positive with the same isolate over time, and molecular analysis demonstrated high levels of diversity among isolates. Doorknobs, slit-lamp headrests and chinrests, and computer keyboards were commonly found to be contaminated. CONCLUSIONS The proposed surveillance protocol successfully allowed the detection of both MSSA and MRSA contaminating important high-touch surfaces in a representative ophthalmology clinic. Frequently contaminated surfaces must be targeted for routine cleaning and disinfection because there is a constant introduction of clones over time. Hence, other clinics may consider implementing and adapting surveillance tools, like the one described here, to help them control these important nosocomial pathogens.

Preseptal and Orbital Cellulitis

It is important to distinguish between preseptal and orbital cellulitis, as both can present with similar signs and symptoms of red, swollen eyelids, with or without discharge, and with or without upper respiratory symptoms. Decreased visual acuity, afferent pupillary defect, motility deficit, and proptosis suggest an orbital process as opposed to a preseptal cellulitis. Orbital cellulitis can threaten vision and, through optic nerve and meningeal involvement, life. Hence, a high index of suspicion of orbital cellulitis and close monitoring of the response to treatment are crucial in preventing the severe complications of orbital infection. Radiographic imaging such as contrast-enhanced CT or MRI can help determine whether a subperiosteal or orbital abscess is present, or if infection has spread beyond the orbit, resulting in cavernous sinus thrombosis or cerebral abscess. Both preseptal and orbital cellulitis must be treated with systemic antibiotic therapy and monitored with serial ophthalmologic examinations. Surgical intervention may be necessary to drain subperiosteal or orbital abscesses.

Supplement: Special Considerations in the Management of Amblyopia and Strabismus in Craniofacial Disorders

As many as 60–70 % of children with craniosynostosis have strabismus (Coats, J AAPOS. 4:338–42, 2000). The most common ocular motility issue in these patients is V-pattern strabismus, with apparent overaction of the inferior oblique muscles, and/or underaction of the superior oblique muscles (Coats, J AAPOS. 4:338–42, 2000; Nischal, Am Orthopt J. 64:24–31, 2014; Clement and Nischal, Strabismus. 11:239–42, 2003). For many reasons, strabismus surgery in such patients should be considered with care.