Effect of disposable barriers, disinfection, and cleaning on controlling methicillin-resistant Staphylococcus aureus environmental contamination

Abstract

Environmental contamination and transmission of methicillin-resistant Staphylococcus aureus (MRSA) have been reported in dental health care settings. National professional dental associations recommend controlling surface contamination using disposable barriers or disinfection. Because these procedures may be costly, impractical, and/or toxic, we compared their effect against traditional detergent-based cleaning for decontaminating a dental chair sprayed with MRSA. Five MRSA strain suspensions were aerosolized to give a density of approximately 10 colony-forming units/cm(2) MRSA on the dental chair 5 minutes after dispersal. Three different decontamination protocols were applied: protocol 1: disposable barriers positioned before aerosol production and removed after 5 minutes; protocol 2: disinfection (wipe-rinse method) with 1:10 dilution of 5.25% to 6.15% sodium hypochlorite solution; protocol 3: cleaning (wipe-rinse method) with a sodium-lauryl-sulphate-based detergent. Contact plates containing Mannitol Salt Agar were used to assess the level of MRSA contamination. All 3 protocols decreased MRSA surface load by >99%. Residual densities on the dental chair were 0.030 ± 0.010 (protocol 1), 0.029 ± 0.09 (protocol 2), and 0.030 ± 0.011 (protocol 3) colony-forming units/cm(2). Cleaning (wipe-rinse method) using a sodium-lauryl-sulphate-based detergent demonstrated equivalence with disposable barrier placement or disinfection-based protocol for reducing MRSA contamination on dental chairs. This has practical and cost implications for controlling MRSA transmission in dental health care settings.