Methicillin-resistant Staphylococcus aureus (MRSA) is a common hospital-acquired infection with significant morbidity and mortality. The CDC currently recommends contact precautions as a mainstay to prevent transmission of MRSA in health care settings. Most hospitals routinely screen patients for MRSA and use contact precautions for those who screen positive. The duration of these precautions vary across hospitals and no standard recommendation exists.
A recent study of members of the Society for Healthcare Epidemiology of America (SHEA) research network indicated that the majority of physicians (94%) and nurses (76%) dislike contact precautions (CP) and most (63%) were in favor of implementing CP in a different way than current practice.1 Patients also report less satisfaction and increased isolation.1
My colleagues and I recently published a study2 in the American Journal of Infection Control to explore the necessary duration of contact precautions for hospitalized patients with MRSA. Our goal was to maintain contact precautions as long as necessary to prevent undesired MRSA infections and colonization but minimize unnecessary days in contact isolation. We also sought to figure out whether patients with positive MRSA surveillance cultures should always remain in isolation and, if not, at what point they could be considered for rescreening and removal of precautions if culture negative.
Our hospital has been performing active surveillance cultures weekly to screen for MRSA among our hospitalized patients for many years; however from 2010 to 2014, we began screening patients who were previously known to be positive for MRSA colonization or infection for at least 1 year. We then assessed medical and demographic factors associated with persistent carriage of MRSA.
In our study, more than 400 patients with known MRSA were rescreened with an active surveillance culture at a subsequent hospital admission. Ultimately 20% of the patients remained MRSA positive on the active surveillance culture. Most patients who were culture positive for MRSA were found on the first active surveillance culture (16.4%) but the remaining positive cultures were found on a second active surveillance culture or a clinical culture.
The amount of time that passed since the patient was culture positive was significantly associated with a lower risk of a positive culture at screening. This continued to drop over time with only 12.5% of patients remaining active surveillance culture positive for MRSA at 5 years after the original positive culture.
Two factors were found to significantly impact the MRSA culture on the multivariate analysis: (1) Female sex reduced the risk of positivity, and (2) Presence of a foreign body increased the risk of positivity.
Most patients who remained positive for an MRSA culture were found with the first active surveillance culture, less than 4% were detected subsequently with a repeat surveillance or clinical culture and this percentage also decreased over time. This indicates that in the absence of a positive active surveillance culture it may be reasonable to discontinue contact precautions, which could result in a substantial cost savings for the hospital and improved patient and provider satisfaction without increasing the risk of MRSA transmission.
We concluded that in the absence of a foreign body and with at least a year from the last known positive culture, patients with known MRSA should be rescreened and, if negative on an active surveillance culture, should be removed from contact precautions.
Lauren Richey, MD, MPH, is assistant professor in the infectious diseases division at the Medical University of South Carolina.
References
1. Morgan DJ, Diekema DJ, Sepkowitz K, Perencevich EN. Adverse outcomes associated with contact precautions: A review of the literature. Am J Infect Control. 2009 Mar;37(2):85-93. doi: 10.1016/j.ajic.2008.04.257 .
2. Richey LE, Oh Y, Tchamba DM, Engle M, Formby L, Salgado CD. When should contact precautions be discontinued for patients with Methicillin-resistant Staphylococcus aureus? Am J Infect Control. 2016 Aug 30. doi: 10.1016/j.ajic.2016.05.030 .
