MRSA Screening & Isolation—Finding the Right Mix

Finding the right mix of Methicillin-resistance Staphylococcus aureus (MRSA) screening and isolation practices in intensive care units (ICU’s) can be challenging. Some hospitals automatically isolate all patients admitted into the ICU until a MRSA-screen confirms they are negative. Other hospitals make the choice to isolate patients only after a positive confirmation is received. Which approach is correct? Should we wait for a positive MRSA result, or should we preemptively isolate patients to avoid exposure on the chance he or she has MRSA? I explore both options in this article.

Because MRSA is one of the more common organisms in hospitals, and the frequent cause of healthcare-associated infections (HAIs), it is especially concerning that it is drug-resistant. The concern is particularly high in the ICU because those patients are more vulnerable for HAIs. Therefore, it is not unusual that screening protocols are common in these areas of the hospital. Indeed, in my experience as an infection preventionist in both adult and pediatric acute care hospitals, there have been several times where MRSA-screening aided in rapid isolation and prevention of HAIs. Sadly, it is frequently a challenge to make the justification to hospital administrators about the cost-effectiveness of MRSA screening and isolation. Patient satisfaction, the risk for HAIs, and costs associated with isolation are all things that come into play when infection prevention and infectious disease programs attempt to initiate such a screening protocol. Overall, MRSA-screening is a common practice among many hospitals within the United States in an attempt to not only avoid the spread of resistant bacteria, but also as a means of avoiding a future HAI. The question then becomes, should ICU’s isolate every patient until a MRSA-screen comes back negative?

Universal preemptive isolation is effective in reducing transmission of MRSA (among other organisms), but it can also be taxing on healthcare staff, patients and their visitors, and it can be an additional financial stressor. Targeted isolation, on the other hand, requires that patients are only isolated after a positive screening result. Although targeted isolation may save the patient and healthcare workers from unnecessary isolation practices, and even a financial burden to the hospital, it also means that there is a delay in isolation for those patients. However, this practice can increase the risk of transmission of MRSA to healthcare workers and other ICU if the patient who is not isolated does, in fact, have MRSA.

In many ways, the choice simply comes down to dollars; however, a recent study from George Mason University in which researchers looked at this problem through the lens of cost-minimization analysis, can be especially helpful in deciding which approach to take.

In the study, the researchers found that, if universal preemptive precautions are used, it is important to use a MRSA-screening test that had a short turn-around time. The same need is applicable for targeted isolation; however, the study authors note that it is important to consider the additional costs of universal preemptive precautions (ie, personal protective equipment costs for ongoing isolation).

The study authors looked at the cost of several different kinds of MRSA-screening tests (as well as their sensitivity and turn-around time), costs associated with the personnel needed to administer and read the test, and additional costs associated with isolation, among other variables. One of the most interesting components to this investigation was the inclusion of appropriate versus inappropriate isolation costs, which were considered for patients who were isolated and truly MRSA-positive versus those who were isolated and had negative MRSA tests.

By utilizing a decision tree model, the researchers found that polymerase chain reaction (PCR) and other rapid MRSA-screening was best for ICUs that employ a universal preemptive isolation approach. Although these testing methods may be more expensive, the cost is offset by reducing the costs of time in isolation. The researchers found that the total cost of preemptive isolation “was minimized when a PCR screen was used ($82.51 per patient). Costs were $207.60 more per patient when a conventional culture was used due to the longer turnaround time.” For ICUs that used targeted isolation, the researchers found that costs would be lowest when chromogenic agar 24-testing was used and not PCR.

Overall, there is a significant place for MRSA-screening in ICUs given the vulnerability of the patients for such infections. Regardless of which isolation methods a hospital prefers (universal preemptive precautions or targeted isolation), a cost-effective screening method can be utilized. This study highlights the importance of having a screening program in place while addressing the financial burden that is often a struggle from a budgetary aspect.