An Evaluation of Methicillin-Resistant Staphylococcus aureus Survival on Five Environmental Surfaces

This study evaluated methicillin-resistant Staphylococcus aureus (MRSA) survival on environmental surfaces: glass, wood, vinyl, plastic, and cloth. Effects of relative humidity (RH) and bovine serum albumin (BSA) were examined. Surfaces were inoculated with 10(7)-10(8) colony forming units per milliliter (CFU/ml) of MRSA with and without 1% BSA and incubated at 35 degrees C at 45%-55% and 16% RH. Surfaces were sampled, and each collected sample was re-suspended in phosphate buffer, spread plated, and incubated at 35 degrees C for 24 hrs; resulting colonies were enumerated. Samples were collected immediately on drying, and at 3 hrs, 24 hrs, 2 days, 3 days, 4 days, and 5 days. Results demonstrated that MRSA survived the longest on plastic and vinyl and for the least amount of time on wood (p < 0.001). BSA enabled MRSA to survive for significantly longer duration (p < 0.001). The number of CFU/ml was significantly lesser on surfaces stored in 45%-55% RH versus 16% RH. This study demonstrates that viable MRSA bacteria can remain on surfaces for days, which may impact the public health of occupants in workplace and residential settings.