Minnesota makes the call on MRSA isolation
State takes on issue left 'unresolved' by CDC
The Minnesota Department of Health has issued guidelines for methicillin-resistant Staphylococcus aureus (MRSA) that address an issue the Centers for Disease Control and Prevention has left unresolved: when to discontinue contact isolation precautions.
The Minnesota guidelines recommend that patients with risk factors for MRSA colonization and infection (i.e., hemodialysis patients and long term care residents) should not be considered for discontinuation of contact precautions for MRSA infection.1 Other patients may have isolation discontinued after three negative cultures. In a sense, the state recommendations codify some of the considerations recommended by the CDC, though the federal agency officially left isolation discontinuation as an unresolved issue in its 2006 recommendations on multidrug-resistant organisms (MDROs) and its 2007 isolation guidelines.2,3
"The Minnesota department of health has written MRSA guidance so that our state would be consistent on discontinuing precautions," Michelle Farber, RN, CIC, said recently in Denver at the annual APIC conference.
As evidenced by the APIC session, the issue of discontinuing contact isolation measures (e.g., staff don gloves and gowns before entering room) was the subject of much confusion and question among infection preventionists (IPs). At the heart of the matter is the question of whether or not the isolated patient is a risk for transmission to other patients and health care workers. It is not an easy question, but simply leaving patients in isolation raises issues of quality of care and places a premium on private rooms that sets off a series of related problems from ambulance diversions to cohorting and decolonization. "There is no evidence [supporting only] one methodology, so we are going to be studying and re-looking at our guidance," said Farber, an infection control specialist at Mercy Hospital in Coon Rapids, MN.
The 2006 CDC MDRO guidelines cited a lack of data in leaving the issue unresolved, though they suggested that IPs consider discontinuing contact precautions "when three or more surveillance cultures are repeatedly negative over the course of a week or two in a patient who has not received antimicrobial therapy for several weeks, especially in the absence of a draining wound, profuse respiratory secretions, or evidence implicating the specific patient in ongoing transmission of the MDRO within the facility." The 2007 CDC isolation guidelines also left the issue unresolved but went a bit further in saying, "It may be prudent to assume that MDRO carriers are colonized permanently and manage them accordingly. Alternatively, an interval free of hospitalizations, antimicrobial therapy, and invasive devices (e.g., six or 12 months) before re-culturing patients to document clearance of carriage may be used."
The Minnesota guidelines, which were written in consultation with IPs, note that the uncertainly about the issue has been exacerbated by the increasing use of active surveillance cultures to detect MRSA in certain units or patient populations. That means more patients are being placed in isolation, so discontinuing the measures as quickly as possible could free up much-needed private rooms.
"As a result, the question of when to discontinue precautions is quickly becoming more pressing," the Minnesota guidelines emphasized. One factor that must be considered when in the decision is the duration of MRSA colonization, which can vary in any given patient from three months to more than two years, according to published studies.3,4 Risk factors associated with persistent carriage included breaks in the skin, indwelling devices, receipt of immunosuppressive therapy, and receipt of hemodialysis, the state guidelines note. "Although not explicitly done for the purpose of developing a protocol to discontinue contact precautions, the studies of MRSA carriage provide background for developing a protocol for discontinuation of contact precautions," the Minnesota guidelines state.
Indeed, the lack of distinct risk stratifications for individual patients makes it harder to take patients out of contact precautions, creating a default position where more hospitals may err on the side of isolation, APIC discussions revealed.
"We don't want to have all of our patients in isolation," said Vickie Brown, RN, MPH, CIC, associate director of hospital epidemiology at UNC Hospitals, Chapel Hill, NC. "There is good evidence that the risk of carriage is associated with breaks in the skin and skin conditions. Keep in mind that the patient that has a draining wound who has a history of MRSA is much more likely to still have MRSA than someone who has just been picked up on a nasal swab and they don't have any [other risk factors for transmission]."
Discontinuing isolation is a judgment call based upon published guidelines, research, and assessment of the patient population, she noted. IPs must weigh the negative consequences of isolation with the potential risk of disease transmission to susceptible patients. "Our first priority is always to protect other patients and employees," she concluded.
Questions continue
Still, the issue raises some tricky questions. For example, one APIC audience member asked whether to use MRSA cultures or rapid PCR tests in deciding whether to discontinue isolation.
"For our rapid screening of admissions for MRSA, we use PCR and we isolate based upon that," Brown noted. "But we would recommend to a physician that if you want to get a patient off isolation, use the MRSA culture. That is because we are not certain if the PCR is detecting MRSA genetics that are not actually viable — maybe it is [picking up] such a small amount that it wouldn't play a role in transmission. We simply don't know the answer to that."
References
- Minnesota Department of Health. Recommendations for Prevention and Control of Methicillin-Resistant Staphylococcus aureus (MRSA) in Acute Care Facilities, 2008. Available on the web at: http://www.health.state.mn.us.
- Siegel J, Rhinehart E, Jackson M, et al. Centers for Disease Control and Prevention. Healthcare Infection Control Practices Advisory Committee. Management of multidrug-resistant organisms in health care settings, 2006. Available at: http://www.cdc.gov/ncidod/dhqp/.
- Siegel JD, Rhinehart E, Jackson M, et al. Centers for Disease Control and Prevention Healthcare Infection Control Practices Advisory Committee. Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings, 2007. Available at: www.cdc.gov/ncidod/dhqp/.
- Marschall J, Muhlemann K. Duration of methicillin-resistant Staphylococcus aureus carriage, according to risk factors for acquisition. Infect Control Hosp Epidemiol 2006; 27:1,206-1,212.
- Scanvic A, Denic L, Gaillon S, et al. Duration of colonization by methicillin-resistant Staphylococcus aureus after hospital discharge and risk factors for prolonged carriage. Clin Infect Dis 2001; 32:1393-1,398.
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