Effectiveness of Contact Precautions on Impact of Infection Rates for MRSA and VRE

By Peter Teska and Jim Gauthier

The use of contact precautions (CP) in healthcare to prevent the transmission of pathogens capable of causing healthcare associated infections (HAIs) has been advocated for many years by the Centers for Disease Control and Prevention (CDC) despite a lack of a strong evidence base in the literature to support this recommendation. While it is generally accepted that the use of CP can interrupt the chain of transmission and thus can prevent some portion of HAIs, many facilities are challenging the universal use of CP, especially for MRSA and VRE, and alternatively are advocating for a more nuanced application of CP.

CDC Guidance: The current CDC guidelines for the use of isolation precautions builds upon previous CDC guidelines and recommendations first issued in 1970. When the first guidelines were recommended, there was minimal surveillance for HAIs, a lack of awareness the role of the environment plays as a reservoir for microorganisms, few single bed rooms, poor compliance with hand hygiene, no use of alcohol hand rubs, no CHG bathing to decolonize patients, no use of cleaning compliance programs and no enhanced technology for environmental disinfection. As a result of adding these practices, the CDC guidelines have substantially evolved and today promote the use of standard precautions (SP) and transmission-based precautions (TBP) as the basis for standard infection prevention and control practices implemented by healthcare facilities in the United States and other countries that follow US-CDC recommendations. Within these guidelines are the recommendations for the use of TBP “for patients who are known or suspected to be infected or colonized with infectious pathogens, which require additional control measures to effectively prevent transmission.”

Within TBP, CP are intended to interrupt the chain of transmission for pathogens that can be spread by direct or indirect contact with the patient or the patient’s environment. CP automatically apply in the presence of wound drainage that cannot be controlled by a dressing or cannot be covered, fecal incontinence and where there is the risk of contact with other body fluids that are likely to result in an increased potential for environmental contamination (such as a patient with vomiting or productive cough) and a subsequent risk of pathogen transmission. Since often the pathogen causing infection is not known for several days, TBP are to be used while waiting for test results based on the symptoms with which a patient presents.

It is less clear that CP are needed if the patient is infected but does not present these conditions that favor pathogen transmission, but the current CDC language seems to suggest that CP may not be required if the patient is not at risk of heavily contaminating their environment with body fluids that may contain infectious pathogens. The CDC guidelines do not directly address this consideration, which is an opportunity for the CDC to provide clarity in the future.

SHEA/IDSA 2014 Practice Recommendations for MRSA: SHEA/IDSA provides consensus recommendations for prevention of MRSA infections, but not for VRE. The MRSA guidance recommends the use of CP for patients colonized or infected with MRSA but does not differentiate between a patient with a MRSA-infected wound with uncontrolled drainage and a patient with a MRSA skin infection contained by a dressing, which may be adequately addressed through the use of SP.

Evidence for Use of Contact Precautions: Healthcare facilities have for several years questioned the blanket use of CP for patients infected or colonized with MRSA and VRE and many healthcare facilities in the U.S. have adopted a more nuanced approach using CP in some situations, but not all situations. Researchers have reviewed the scientific literature to evaluate the evidence base for the use of CP.

Morgan Review: Morgan (2015) coordinated a review by a series of experts from the SHEA Guidelines review committee, (but independent of SHEA or SHEA endorsement) to assess the state of the literature on the application and discontinuance of CP for endemic MRSA and VRE. They found there were very few studies looking at the impact of contact precautions alone and thus included studies that incorporated other interventions in addition to the use of CP. Of the studies reviewed, lower quality quasi-experimental studies generally showed a decrease in transmission rates of MRSA when using contact precautions for MRSA, but not for VRE. Studies looking at universal glove and gown use have shown mixed results, with the largest study showing a decrease in MRSA rates. However, this study has a number of limitations. When applying universal glove and gown use, the number of patient interactions by healthcare staff was lower with better hand hygiene rates reported and thus the decrease in MRSA rates may be caused only indirectly by the use of CP.

The authors comment that many studies suffer from small size, interventions introduced simultaneously and a lack of comparison groups. Adherence to CP was typically not tracked and when it was, it was poor. Healthcare worker behavior is reportedly affected by the use of CP including less frequent patient contact and shorter times spent with patients. The use of single patient rooms may also be a significant factor versus seeing more benefit from the use of CP versus when patients are in multi-patient rooms. The impact of single patient rooms has not been well studied and the number of single patient rooms may reduce the impact of implementing CP.

Marra Review: Marra (2018) identified 14 studies for a systematic review, all of which were considered quasi-experimental. The systematic review found that discontinuing CP for endemic MRSA and VRE did not result in an increase in MRSA and VRE infection rates across a range of different healthcare facilities. The rise of horizontal infection control practices used in some studies to prevent infections with multi-drug resistant organisms (MDRO) include an increased focus on hand hygiene, bare below the elbows staff practices, CHG patient bathing and an increased focus on environmental hygiene. The Marra review discusses that facilities that do not routinely use CP, but do use horizontal practices are not seeing increases in infection rates for MRSA and VRE.
Marra further discussed why the elimination of CP did not result in an increase in infection rates and theorized that (1) Contact precautions may not prevent endemic MRSA and VRE infections; (2) There may be low compliance with CP or a low transmission of endemic infections, so it is difficult to measure the impact of using CP properly; (3) Once contact precautions are removed, standard precautions and/or other interventions (CHG bathing, hand hygiene protocol, and bare below the elbow) may be preventing transmission and may be as effective as CP; (4) Studies on CP may not be powered to detect changes in rates if the endemic rates are low or if the benefit from contact precautions is small. The review also notes that typically hospitals that discontinue CP for MRSA and VRE continue to apply CP for Clostridium difficile infections and the presence of drug resistant Gram negative bacteria, suggesting that CP can reduce infection rates for some pathogens, but may have less impact on endemic MRSA and VRE rates.

Cohen Review: Cohen (2015) also reviewed literature on the impact of contact precautions. Of the studies reviewed, six were selected for further analysis. Five of six showed no impact on MDRO infection rates, suggesting at best a minimal improvement by using CP, while one study showed an improvement in Acinetobacter baumannii colonization rates. The quality of the papers was viewed as moderate overall, but each had poor performance on key quality indicators (such as limited information in bias and confounding) and thus study quality was a significant factor. As a result, the authors conclude that the evidence base was not strong enough to support a change in practice to eliminate CP and advise that in practice healthcare facilities should be regularly monitoring compliance with CP and investigating potential lapses when cross-transmission is documented to identify and resolve system based inefficiencies.

Kullar Review: Kullar (2016) performed a literature review on the use of CP specifically for MRSA and concluded through analysis of 15 key studies there was little data to support use. The authors wrote that the use of CP to stop the spread of infection in epidemic outbreaks has been well documented, including MRSA. However, benefits from the use of CP in non-epidemic conditions are much less clear. Additionally, CP are often used as part of a bundle of interventions and it is very difficult to separate out the benefit of using CP versus other interventions such as increased use of alcohol hand rubs or decolonization via CHG patient bathing. However, there is also a risk of CP negatively impacting care. While studies have found differing results, Dashiell-Earp (2014) performed a trial measuring the time medical interns spent with patients on CP with the trial structured to minimize observer bias and found interns spent 6.9 min per day with non-isolated patients and 5.2 min per day with isolated patients.

Kullar discusses that when studies are conducted looking at the impact of CP on infection rates, these studies need to assess and acknowledge that hand hygiene compliance, compliance with CP, percentage of patients on CP and the level of knowledge about when to use standard precautions all are important factors. Typically, studies do not consider all these factors or analyze them as confounders in the studies. Active surveillance, improved housekeeping and antimicrobial stewardship may also play a role and should also be assessed for their impact on MRSA rates.

Several well-performed literature reviews have concluded that in the existing literature there is little evidence to show that routine use of CP lowers infection or colonization rates for endemic MRSA and VRE. However, in all cases, the quality of the studies is low to moderate with all studies failing to account for some important confounding measures, which may be creating bias in the studies. Additionally, when CP do show a benefit, CP are typically studied as part of an intervention bundle that includes other elements that may include hand hygiene programs, enhanced environmental cleaning/disinfection, cohorting etc. As a result, it is difficult to draw definitive conclusions from the literature as supporting or not supporting the use of routine CP for MRSA and VRE.

Peter Teska is a global infection prevention application expert at Diversey and can be reached at peter.teska@diversey.com. Jim Gauthier is a senior clinical advisor at Diversey and can be reached at james.gauthier@diversey.com.