Approaches for Characterizing Surfaces Damaged by Disinfection in Healthcare

Healthcare-Associated Infections (HAIs) are a significant cause of morbidity and mortality and occur in many healthcare facilities including hospitals, surgery centers and long-term care facilities. It is well known that some pathogens can persist on healthcare surfaces for weeks to months and spread readily to new surfaces. It is current practice to disinfect or clean surfaces routinely in order to reduce the risk of HAIs. However, routine cleaning can damage the surface chemically or mechanically, which may actually increase the surface contamination. Fundamental knowledge is therefore needed to understand the influence of cleaning and disinfection on healthcare surfaces in order to mitigate pathogen persistence. In this study, materials and objects found in healthcare facilities were selected and exposed to disinfection procedures including wiping and soaking with readily available chemical disinfectants. A variety of chemical disinfectants were selected which contain hydrogen peroxide, quaternary ammonia, and chlorine, respectively. Optical microscopy, contact angle measurement, atomic force microscopy (AFM), Fourier Transform Infrared (FTIR) spectroscopy and nanoindentation are used to analyze surface characteristics before and after disinfection in order to study the effect of disinfection on material properties. Disinfection procedures are found to cause changes to surface properties of materials and objects which can be detected and observed or quantified by the approaches used in this study. The methods should become regular practice in the studies of healthcare surfaces and their role in HAIs. Each method in this study may not be reliably applied to every object or disinfection scenario. Sample geometry and features may influence response during measurement and affect results. The combination of the approaches is able to sufficiently characterize chemical, mechanical, and topological changes to the surface.