After an infected wound heals or a patient tests negative subsequent to a positive culture result, the person may still be colonized with the multidrug-resistant organism (MDRO) that caused the infection. Like infected patients, colonized patients serve as “reservoirs” of resistant organisms that can be transmitted to other patients. Most hospitals place infected and colonized patients on contact isolation precautions at some time during their hospitalization. However, there are no standard national guidelines for the duration of contact precautions for MDROs. Protocols for contact precautions are based on the hospital's resistant organism profile, its priorities and available resources, and published guidance.
Many factors in addition to the use of contact precautions affect transmission of organisms within a facility, and there is not yet an abundance of evidence on which to base recommendations for how long people infected or colonized by MDROs should remain on precautions. Therefore, rules about discontinuing contact precautions for MDROs vary widely from one facility to another. Should patients first be screened for colonization? If so, what body sites should be sampled? How much time should elapse between screening cultures? How many negative urine, blood, or other culture results are needed before a patient is thought to have cleared the resistant organism?
To begin to answer these questions, the Society for Healthcare Epidemiology of America (SHEA) released an expert guidance report, Duration of Contact Precautions for Acute-Care Settings, earlier this year.1 SHEA publishes these reports “to address areas of relatively narrow scope that lack the level of evidence required for a formal guideline but are important for the provision of safe and effective healthcare.”1Table 1 details SHEA's recommendations for discontinuing contact precautions in patients who have been infected by an MDRO.1 This information provides a place to start. Each hospital should then devise its protocols based on risk factors within the facility and additional considerations, which are summarized below.
METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS (MRSA)
The endemic level of any MDRO within a facility affects the likelihood of patient-to-patient transmission. In a hospital that has a low endemic rate of MRSA infection and is not in the midst of a MRSA outbreak, staff might safely place a patient on contact precautions only for the duration of the admission in which the patient has a positive culture for MRSA, but does not need to do so for future admissions.1 SHEA's report notes that when this approach is used, staff should “maximize and consider monitoring” adherence to standard precautions and avoid placing the patient in a shared room. This protocol should be revised if the facility's MRSA rate rises.1
Certain patients are at higher risk for persistent colonization of MRSA (“prolonged carriage”), including people who have wounds,2 people who are admitted from a long-term care facility,2 those who have experienced a prolonged stay in a health care facility,3 older adults,4 people whose household members are colonized with MRSA,4 and those who need help with personal care.5 MRSA colonization can continue for more than three years.3
The MRSA contact precaution protocols of some hospitals include active attempts to eradicate MRSA colonization by using topical mupirocin (Bactroban) or other agents before screening samples are taken.
VANCOMYCIN-RESISTANT ENTEROCOCCI (VRE)
As with MRSA, VRE colonization can be persistent and require an extended duration of contact precautions. Antibiotic use, prolonged hospitalization, and ICU stays can extend colonization of the organism.6, 7 SHEA's report recommends that hospitals proactively consider extended contact precautions when the patient has a positive VRE culture and is highly immunosuppressed, is taking broad spectrum antibiotics that are not active against VRE, or is being cared for in a protected environment (in a burn or bone marrow transplant unit or any unit with neutropenic patients, for example).1 When a hospital's VRE infection rates are low and there is no current outbreak, staff might consider employing contact precautions only during the admission when a patient is first infected with VRE (but not for any subsequent admissions).
Rectal and perirectal swabs appear to be equally sensitive in detecting VRE colonization.8
MULTIDRUG-RESISTANT ENTEROBACTERIACEAE (MDR-E)
Enterobacteriaceae include such organisms as Escherichia coli, Klebsiella, Proteus, Serratia, Enterobacter, and Citrobacter. This MDRO category includes organisms that produce extended-spectrum β-lactamases (ESBLs), such as ESBL E. coli or ESBL Klebsiella pneumoniae, carbapenem-resistant Enterobacteriaceae (CRE), and any Enterobacteriaceae susceptible to two or fewer antibiotics.
Most studies suggest that MDR-E organisms are persistent colonizers.1 SHEA's report points out that when there are limited or no treatment options for an MDR-E organism—that is, the organism is susceptible to few, if any, antibiotics—transmission to just one other patient is a significant problem. SHEA therefore recommends that contact precautions be continued indefinitely.1
People who have been infected with C. difficile can continue shedding the organism for weeks after diarrhea has ended.1 Carriers who are asymptomatic are usually not placed on contact precautions. However, SHEA's report suggests that in hospitals with high rates of C. difficile, staff should consider maintaining contact precautions throughout the hospitalization of any patient diagnosed with the infection.1 One hospital reduced the incidence of C. difficile by placing all asymptomatic carriers (along with patients who had diarrhea and tested positive for C. difficile) on contact precautions.9
Every hospital should have in writing its policy for discontinuing contact precautions after infection or colonization with MDROs. Still, nurses often need to make decisions about whether contact precautions should be discontinued, especially when patients are admitted from another facility or when there are limited beds available for patients on contact precautions. In these situations, consider the organism of concern and any factors that might increase its transmission. Does the patient have diarrhea or significant respiratory or other secretions? Are wounds or tubes present? When unsure about the continued need for contact precautions, maintain precautions until the clinical team can meet to review the situation.
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2. Scanvic A, et al. Duration of colonization by methicillin-resistant Staphylococcus aureus
after hospital discharge and risk factors for prolonged carriage Clin Infect Dis 2001 32 10 1393 8
3. Rogers C, et al. Duration of colonization with methicillin-resistant Staphylococcus aureus
in an acute care facility: a study to assess epidemiologic features Am J Infect Control 2014 42 3 249 53
4. Cluzet VC, et al. Duration of colonization and determinants of earlier clearance of colonization with methicillin-resistant Staphylococcus aureus
Clin Infect Dis 2015 60 10 1489 96
5. Lucet JC, et al. Carriage of methicillin-resistant Staphylococcus aureus
in home care settings: prevalence, duration, and transmission to household members Arch Intern Med 2009 169 15 1372 8
6. Byers KE, et al. Duration of colonization with vancomycin-resistant Enterococcus
Infect Control Hosp Epidemiol 2002 23 4 207 11
7. Sohn KM, et al. Duration of colonization and risk factors for prolonged carriage of vancomycin-resistant enterococci after discharge from the hospital Int J Infect Dis 2013 17 4 e240 e246
8. Weinstein JW, et al. Comparison of rectal and perirectal swabs for detection of colonization with vancomycin-resistant enterococci J Clin Microbiol 1996 34 1 210 2
9. Longtin Y, et al. Effect of detecting and isolating Clostridium difficile
carriers at hospital admission on the incidence of C difficile
infections: a quasi-experimental controlled study JAMA Intern Med 2016 176 6 796 804