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!
A number of options are available for preventing the introduction of microbes into central venous access devices (CVAD) via needleless connectors, including disinfection using alcohol or chlorhexidine, or disinfectant impregnated caps. A recent ICHE study compared three different needleless connectors, and three different decontamination approaches (alcohol scrubbing, chlorhexidine-alcohol scrubbing, and an alcohol-impregnated cap). Chlorhexidine scrubbing was by far the most effective method: so it’s caps off to chlorhexidine for needleless connector disinfection!
The laboratory study tested a range of bacteria and fungi (Staphylococcus aureus, S. epidermidis, Pseudomonas aeruginosa, and Candida albicans) in three of the most common needleless connectors with or without the presence of human serum. Connectors were inoculated with a clinically-relevant amount of micro-organism, which was allowed to dry. Then, connectors were disinfected using three different methods:
– Scrubbed with 70% isopropyl alcohol (IPA) swabs for 5, 15, or 30s;
– Scrubbed with 2% chlorhexidine gluconate + 70% isopropanol swabs for 5, 15, or 30s; or
– Covered with 70% isopropyl alcohol-impregnated caps for 5 minutes.
The results show clearly that chlorhexidine + 70% alcohol was superior to the other two methods, both with and without the presence of human serum (see chart below). A 5s scrub with chlorhexidine was superior to a 30s scrub with IPA or the caps. Although the effectiveness of all methods was reduced in the presence of human serum, chlorhexidine continued to outperform the other methods.
Chart: Proportion of organisms remaining following disinfection of the needleless connector.
IPA, 70% isopropyl alcohol with 5-, 15-, or 30-second decontamination; CHG, chlorhexidine gluconate in 70% isopropyl alcohol with 5-, 15-, or 30-second decontamination; IC, 70% isopropyl alcohol impregnated cap. * P=<0.05. (Click the image to enlarge)
The study also reports some data on the cost implications of these findings. The chlorhexidine swabs cost around 5p compared with 1p for the IPA swabs, and 15p for the antimicrobial-impregnated cap. Whilst volume would be high given how much needleless connection disinfection goes on in hospitals, the total cost of switching to chlorhexidine swabs from IPA swabs would be pennies compared with the cost of a single CLABSi, which can cost tens of thousands.
This important study establishes firmly that a 5s scrub with IPA is not the way to go for disinfecting needleless connectors, despite this being standard practice in some hospitals. It also shows that active scrubbing is better than passive disinfection: we need to “scrub the hub“! A 15 or 30s scrub with chlorhexidine was markedly more effective than 5s. Although chlorhexidine swabs are more expensive than IPA swabs, the switch will be cost effective even if a single CLABSI is prevented.
Although this is a laboratory study, and may not be representative of the contamination challenge faced in the real world, the authors did their best to make the study representative of the clinical setting; they did this by using a range of organisms at a clinically relevant inoculum, and testing with or without the presence of human serum (to simulate contamination of the needleless connector with blood products). Chlorhexidine disinfection of needleless connectors seems to be the way forward, and it’s good to see the recommendation in the EPIC3 guidelines for at least 15s scrub with chlorhexidine plus alcohol for disinfecting needleless connectors!
A US study has found C. difficile spores in the hospital laundry. Whilst most of the spores were identified on the dirty side of the laundry, a small number of spores were also identified on the clean side of the laundry. The identification of C. difficile spores in both the clean and dirty hospital laundry could present a potential transmission risk.
The study team sampled 120 surfaces in the dirty side of the laundry, and 120 surfaces on the clean side of the laundry. C. difficile was identified from around 1 in 5 surfaces on the dirty side, and 1 in 50 surfaces on the clean side. Whilst is not surprising to find contamination with C. difficile spores on the dirty side of the laundry, it is a concern to find these spores on the clean side, where hospital linen is folded before being taken to clinical areas. Furthermore, there is a risk of laundry workers becoming contaminated with the spores and sharing them with other parts of the hospital.
The findings of this study prompted a review of the workflows of staff between the dirty and clean areas of the laundry, resulting in increased disinfection of surfaces, and changes in how staff moved between the dirty and clean sides of the laundry. Perhaps this study should also prompt a review of cleaning and disinfection protocols, and staff workflows in your hospital laundry?
The long-awaited BETR-D study has finally been published, in the Lancet. The huge cluster randomised controlled trial proves that UV-C is effective in reducing the rate of acquisition of VRE and MRSA, and argues strongly for the adoption of UV-C to improve patient safety.
This is a very impressive study. It’s a huge two year cluster-randomised controlled trial (RCT) spanning nine US hospitals, which is the absolute gold standard for a study of an infection control intervention. The hospitals implemented a randomised sequence for four different terminal disinfection approaches: QAC, QAC+UV, bleach, bleach+UV. There was a statistically significant 31% reduction in the acquisition of target organisms (MRSA, VRE and C. difficile) for patients admitted into rooms disinfected using QAC+UV compared with QAC alone. The effect on VRE was bigger than on MRSA. When C. difficile patients were removed from the analysis, there was a statistically significant 28% reduction in the acquisition of target organisms (MRSA and VRE) for patients admitted into rooms disinfected using bleach + UV compared with bleach alone. It is worth noting that the QAC + UV arm was not inferior to the bleach + UV arm, suggesting that bleach cleaning prior to UV isn’t necessary. Environmental sampling showed trends that matched the clinical reductions (UV pretty much eliminated MRSA and VRE, but didn’t reduce the level of C. difficile contamination. The study was exceptionally well controlled, with rates of hand hygiene, compliance with standard cleaning, and colonisation pressure all meticulously measured and shown not to change. UV disinfection added only 10 minutes to room turnaround time.
There was no clinical impact on C. difficile in this study, in contrast to a number of other studies, which have showed that UV-C reduces the acquisition of C. difficile. Could it be that the levels of reduction in spores that UV-C systems are able to achieve are not high enough to reduce significantly the acquisition rate of C. difficile? Or perhaps there was something about the way that UV-C was applied in this study that explains this apparent discrepancy? In this study, the UV-C system was staged at a single point in the patient room, and a separate cycle was not performed in the bathroom (which isn’t our recommended use of the Clinell UV-360!). It would be interesting to see whether altered device staging and multiple cycles improve the clinical impact of UV-C against C. difficile.
Overall though, this is a powerful study, which argues strongly for the adoption of UV-C into a hospital’s disinfection strategy for the terminal disinfection of rooms vacated by patients with MRSA / VRE, and perhaps C. difficile as well.
There is increasing evidence that UV-based automated room decontamination systems reduce the transmission of key hospital pathogens. There seems to be an exponential multiplication of suppliers of UV room decontamination systems! So how to choose between the many options available? An article in AJIC provides a framework for making this decision. The evidence shows that UV-C systems are more effective than pulsed-xenon systems. Beyond that, the decision between UV-C systems will depend on a number of factors. Here, we review the various parameters that are discussed in the article, explaining why we chose the Clinell UV-360 room sanitiser.
The evidence base is clear that conventional methods of cleaning are not always adequate to reduce the risk of transmission to an acceptable level, arguing strongly for the use of automated room decontamination systems, such as UV-C, to augment conventional cleaning and disinfection. GAMA have carefully reviewed the UV market and chosen the UV-360 room sanitiser as their UV-C system of choice! If you would like further information, please get in touch!