Cleaning and Antimicrobial Efficacy of Surface Disinfectants
P.D. Nelson and J.A. Molinari, Dental Consultants, Inc. Ann Arbor, MI
Objectives: To evaluate the ability of water- and alcohol-based surface disinfectant wipes to clean environmental surfaces coated with dried organic debris and to demonstrate the ability of water- and alcohol-based surface disinfectant wipes to kill vegetative bacteria in 5, 25, 50, and 100% blood solutions using a single-step application procedure. Methods: 24-hour culture of Methicillin-Resistant Staphylococcus aureus (MRSA) ATCC#33591 was added to 5%, 25%, 50%, and 100% whole human blood. 0.2 mL of the bacteria/blood suspensions were applied to 2x2” laminated countertop tiles and allowed 2-3 hours to dry. Tiles were treated with test surface disinfectants according to manufacturers' instructions. Following treatment, the remaining bioburden was pictorially recorded, then replica plated on 5% sheep blood agar, and incubated at 37°C for 24 hours (n=5). Results: Water-based disinfectants, Optim TB33 (OTB, SciCan, Inc.) and CaviWipes 1 (CW, Metrix), were able to clean organic debris and kill 100% of challenge bacteria (Table). High-alcohol disinfectants, Discide Ultra (DU, 63% alcohol) (Palmero-Healthcare) and Super Sani-Cloth (SSC, 55% alcohol) (PDI), were able to clean only the 5% blood suspension and effectively kill challenge bacteria on tiles coated with 5 and 25% blood suspensions (Table).
Table. Percent of MRSA Remaining after Treatment
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Blood Suspension | OTB | CW | DU | SSC |
100% | 0(0) | 0(0) | 21(6.4) | 20(4.0) |
50% | 0(0) | 0(0) | 5(2.7) | 2(1.0) |
25% | 0(0) | 0(0) | 0(0) | 0(0) |
5% | 0(0) | 0(0) | 0(0) | 0(0) |
Means with standard deviations in parentheses.
Conclusions: High-alcohol wipes were able to kill the majority of test bacteria, but surfaces remained visibly soiled. In contrast, water-based disinfectants were able to penetrate and clean high concentrations of organic debris better than alcohol-based products. In addition, water-based disinfectants were shown to kill all of the challenge bacteria. Supported by Dental Consultants, Inc.