Abstract
Purpose: :
Methicillin susceptible and resistant Staphylococcus aureus (MSSA and MRSA) are important, increasingly common pathogens in ophthalmology patients. With increasing prevalence of community-acquired MRSA, studies of potential sources of infection in the community are being performed, including of human and veterinary hospitals, public transportation, and ambulances. The purpose of this study was to utilize a standardized method of sampling ophthalmic clinic equipment for screening of MSSA and MRSA.
Methods: :
A standardized method was used to sample twelve randomly selected examination rooms, pooled in sets of 3 and divided according to subspecialty division, from 2 ophthalmology clinic buildings (one hospital-adjoining, one freestanding outpatient clinic). Items sampled in each room included patient-contact items (Goldmann tonometer tips, slit lamp headrests); doctor and staff contact items (computer keyboard, hand-sanitizer dispenser); and general contact items (doorknobs). Common areas as well as imaging equipment and imaging room contact surfaces in both clinic buildings were also sampled. Samples were collected with either cotton-tipped swabs or electrostatic cloths. Samples were pre-enriched in Trypticase Soy Broth with 2.% NaCl for 24 hours at 35o C, then grown on Mannitol Salt Agar plates containing Oxacillin (2µg/ml). Finally, samples were plated on 5% Sheep Blood plates to be further identified and characterized.
Results: :
MSSA was detected on 5/28 pooled samples, and MRSA was detected on 1/28. Samples positive for MSSA included computer keyboards and doorknobs from both hospital-adjoining and freestanding clinic common areas, as well as the doorknobs of one subspecialty area. The single sample positive for MRSA came from the slit lamp headrests of a second subspecialty area.
Conclusions: :
This study demonstrates that both MSSA and MRSA are detectable in common ophthalmology patient, doctor, and staff contact surfaces by the method here described. Because of the flexibility of sample collection and processing, multiple samples can be pooled to cover a large number of contact surfaces and equipment with a minimal cost. Further, more detailed investigation is currently been pursued based upon these initial results. This method has broad implications for the evaluation and surveillance of MSSA and MRSA presence in the ophthalmology clinic, including the assessment of instrument cleaning and disinfection practices.
Keywords: clinical (human) or epidemiologic studies: systems/equipment/techniques • Staphylococcus