A new study in BMC Infectious Diseases models the impact of various cleaning strategies on the transmission of MRSA. Regular wiping of high touch surfaces was more effective than daily cleaning of the whole room in preventing the transmission of MRSA.
The study team created a simple mathematical model to explore the transmission of MRSA. And herein lies the main limitation: "all models are wrong, but some are useful"! The real challenge with modelling studies is whether we really know enough to accurately 'parameterise' the model. Also, even when there is data for a given variable (e.g. the amount of MRSA that is shed by a patient into the environment), this will vary greatly (e.g. where the patient is infected or colonised, strain of MRSA, how mobile the patient is, and environmental factors such as airflow, and others). Models like this have to come up with mathematical ways to model all of these uncertainties. So, you can see why some people think that mathematical models are not really that useful. However, they allow us to explore transmission pathways in a way that would be extremely challenging to do, and sometimes not possible to do, using experimental studies.
The study evaluated the transmission of MRSA from one patient to another who were in adjacent hospital rooms. The key variables were the type of cleaning (either irregular cleaning of the whole room), or wiping of touch points (variable frequency of cleaning high and low touch points). The main finding was that regular cleaning of touch points in the room was much more effective than once daily cleaning of the entire room. The effectiveness of wiping touch points in preventing transmission increased with the frequency of wiping, perhaps unsurprisingly!
Further work is required to confirm this observation (this is a modelling study after all), but this idea could change the way that we approach hospital cleaning and disinfection. Could we start talking in terms of the "Five Moments for Environmental Hygiene" to mirror the "Five Moments for Hand Hygiene"? Should healthcare workers disinfect each surface that they touch? Or perhaps the same wipe should be used to disinfect both hands and surfaces following each of the Five Moments for Hygiene?! Just thoughts at this stage, but this study certainly does make you think!