Several large, multicenter studies have demonstrated that patient bathing with chlorhexidine gluconate (CHG) is associated with significantly reduced health care–associated infections (HAIs) in intensive care units (ICUs), including bacteremias and infections due to methicillin-resistant Staphylococcus aureus (MRSA).1,2 As S aureus can colonize the anterior nares3 as well as extranasal body sites,4 the addition of intranasal mupirocin to CHG bathing has also been used as an intervention for decolonization and reducing infections.2 Doing so combines a vertical infection control strategy (ie, target anterior nares colonization with MRSA) with a horizontal strategy that is effective across pathogens, including other multidrug-resistant organisms (MDROs).
The study by Lofgren and colleagues5 used a stochastic mathematical model of an ICU to determine the proportion of patients with MRSA who would be decolonized with each mupirocin and CHG application. The model included some of major assumptions, such as optimal hand hygiene for all health care workers (HCWs), no major flaws in the hospital infection control programs (eg, no variation in environmental cleaning), no cumulative or additive benefit of repeated CHG applications, and that transmission or contamination could occur during patient-HCW contact in either direction (ie, either when a HCW is contaminated and patient is not colonized or the HCW is not contaminated but the patient is colonized). They observed a modest impact, with each agent having a 15% chance of decolonizing a patient with MRSA. They conclude that their findings highlight areas of improvement in MRSA decolonization interventions.5
One strength of the study is that Lofgren et al5 altered the frequency of CHG bathing in the model. Bathing with CHG has been performed daily in several of the pivotal studies demonstrating CHG benefit,6,7 but an important logistical and economical question remains: what is the optimal bathing frequency to a outcome but allow for practicality. Lofgren et al5 varied the frequency of CHG and mupirocin applications from 24 hours to 48, 72, 96, and even 120 hours. While the reduction in MRSA acquisitions declined as the time between bathing increased, there was still a reduction noted after more than 24 hours. It remains unclear if, with proper application of CHG (eg, CHG-impregnated clothes or CHG dilution baths with strict quality controls) and adherence to other infection control measures, CHG bathing could be performed less frequently yet still be associated with a meaningful decline in HAIs. An additional noteworthy aspect of the model by Lofgren et al5 is their assumption that each application of CHG was independent. It is unclear if there are potential additive benefits to repeated applications of CHG on the skin over time.
The approach by Lofgren and colleagues5 is unique in trying to isolate the outcome associated with solely the intervention of CHG or mupirocin decolonization on an individual level. The several assumptions needed in the model to answer their study question highlight the key point that infection control prevention in ICU settings, particularly in the context of endemic MDRO spread, is highly complex, ie, numerous factors need attention. There are several major pillars of infection control that function together to limit spread of potential pathogens, including hand hygiene; environmental cleaning; source control strategies, such as CHG (ie, removing potential pathogens from patient skin, thereby reducing opportunities for HCW hand and environmental contamination6); addition of vertical decolonization strategies, as needed, for control of a specific pathogen (eg, mupirocin for MRSA); bundles, such as those used to reduce central line–associated bloodstream infections; checklists; engagement of frontline staff; buy-in from hospital leaders; and adherence to these strategies, which are all important. In addition, while the model by Lofgren et al5 focused on patient-level results, the potential cumulative benefit of ICU-wide strategies for reducing opportunities for transmission of potential pathogens should also be considered.
The findings of Lofgren and colleagues5 suggest that there may be “room for deviation from intensive daily protocols” but still achieve some reduction in MRSA acquisition. While this may be true—particularly when multiple interventions are in place and they are done repeatedly over time to possibly compensate for gaps with 1 intervention—the overall message needs to be consistent, along the lines of daily checklists used in many ICUs. A rigorous daily infection control routine with optimal adherence and buy-in from the ICU team and support staff should be the ultimate goal. Educating everyone on the importance of interventions and ensuring success for implementation is critical. With the rise of MDROs that are even more challenging to treat, this overall framework and combination of strategies is even more essential.
The study by Lofgren and colleagues5 adapted a model to estimate the per-application outcome associated with a widely used infection control strategy and demonstrated that even without ancillary interventions, CHG and mupirocin still made a difference, potentially even at longer intervals between applications. This study serves as an important reminder of the multitude of infection control interventions used in ICU settings to significantly reduce transmission of potential pathogens and ultimately reduce HAIs. Horizontal strategies (eg, hand hygiene, environmental cleaning, and source control, such as with CHG bathing) can be the cornerstone of these infection control interventions, with vertical strategies incorporated in response to certain pathogens (eg, MRSA). One important conclusion of the study by Lofgren et al5 was that there can be significant room for improvement in MRSA decolonization interventions. We can extend this conclusion and say that beyond MRSA infection control strategies, each hospital and ICU can continually assess adherence, areas for improvement, and engage staff and hospital leaders in infection control and work toward improvement.
Published: March 4, 2021. doi:10.1001/jamanetworkopen.2021.1573
Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2021 Popovich KJ. JAMA Network Open.
Corresponding Author: Kyle J. Popovich, MD, MS, Rush University Medical Center/Cook County Health, 600 S Paulina St, Ste 143, Chicago, IL 60612 (firstname.lastname@example.org).
Conflict of Interest Disclosures: None reported.
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Popovich KJ. Delineating the Impact of Mupirocin and Chlorhexidine Gluconate in Intensive Care Units—Models and Real-Life Considerations. JAMA Netw Open. 2021;4(3):e211573. doi:10.1001/jamanetworkopen.2021.1573
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