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CRE infection: Sorting out patient-care complexities


doi: 10.1097/01.NURSE.0000530312.86810.23

Sorting out patient-care complexities for CRE infection

Sue Chen was formerly an infection preventionist for the California Department of Public Health.

The author has disclosed no financial relationships related to this article.

AT THE BEGINNING of the night shift, the charge nurse is informed that an older adult (Mrs. B) is awaiting admission from the ED. She has a catheter-associated urinary tract infection caused by a carbapenem-resistant Enterobacteriaceae (CRE). The nurse is also informed that Mrs. B's strain of CRE produces the enzyme carbapenemase. He runs through a mental checklist of actions needed to provide safe nursing care.

First, the nurse alerts the infection preventionist to ensure a consultation and prepares for Mrs. B's arrival on the unit. Because no single-occupancy rooms are available, can she be safely cohorted with another patient on the unit? Ms. R may be the best fit because she isn't colonized or infected with a multidrug-resistant organism (MDRO), has no draining wounds or indwelling devices, and isn't immunocompromised.

The infection preventionist agrees with this assessment and notes that the same precautions are appropriate regardless of whether the CRE is asymptomatic or colonizing, because CRE that progresses to infection has high morbidity and mortality.1,2 This approach is intended to prevent inadvertent spread of CRE within the hospital because treatment options are limited.

After explaining the situation to Ms. R, the staff moves her to the bed by the door to minimize staff crossing a potentially contaminated area. Mrs. B's privacy will be maintained because the sign on her door will list actions staff must take in her room, but the sign won't list her diagnosis. Touchable areas in and near the vacated area are cleaned and disinfected by housekeeping before Mrs. B arrives from the ED. Before admitting Mrs. B, the nursing staff ensures that the housekeeper has had time to clean that side of the room thoroughly.

If Mrs. B is mobile, a commode will be brought to the bedside because she shouldn't share a common bathroom. A sign for contact precautions and a cart with sufficient gowns, gloves, and a dedicated disposable stethoscope and BP cuff is placed outside the door. Staff are informed of this admission and reminded to practice scrupulous hand hygiene and contact precautions. They are to offer Mrs. B and Ms. R frequent opportunities to perform hand hygiene, as appropriate. If possible, nursing staff should be cohorted so the staff member caring for Mrs. B doesn't care for fresh postoperative or severely immunocompromised patients. The infection preventionist notifies the local health department, as CRE is a reportable disease in this county.

Housekeeping will clean the patients' room daily and as needed to minimize bacterial levels, using a different clean cloth to remove soil from each side of the room and the bathroom. Mrs. B's side of the room will be mopped after Ms. R's side to avoid spreading contamination.

Any equipment taken from either patient in the room must be cleaned and disinfected before use on another patient. A policy is in place to ensure that all equipment in the room is disinfected as assigned, whether by nursing or housekeeping. If this task isn't clearly assigned, each discipline may assume that the other is doing the cleaning, creating a potential for the cleaning to be skipped.

Guidelines for hospitals require that all disinfectants used for cleaning be preapproved by the Infection Control Committee, so the solution used here follows policy. Resistant CRE is just as susceptible to disinfectants as nonresistant CRE.3

Visitors to either patient must be taught necessary precautions. Finally, the nurse makes a mental note to assess whether Mrs. B's urinary catheter is still needed. If not, it should be removed.

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How CRE infection develops

Enterobacteriaceae are a class of Gram-negative bacteria that normally reside in the intestines.4 Strains include Escherichia coli, salmonella, shigella, and Klebsiella. Resistance to carbapenems (antibiotics used to treat infections caused by MDROs) can develop in response to antimicrobial pressure or when organisms living in biofilm share plasmids carrying genes for other types of resistance. Mechanisms that can render an organism resistant to a specific antibiotic or class of antibiotics can include efflux (antibiotics are pumped out of cells), alteration or inactivation of antimicrobial targets, and/or collapse of the cell wall.5,6 The most concerning from an epidemiologic perspective is when the bacteria produce an enzyme (carbapenemase) that destroys carbapenems (fourth-generation penicillins).

Different definitions of CRE based on antibiogram cut points (degrees of organism sensitivity to a particular antibiotic) have been developed and updated in attempt to more fully capture carbapenem-resistant organisms, whether or not they produce carbapenemase. CRE is an emerging threat to public health because it has the potential to spread from its current niche in healthcare-exposed patients into the community and because of the limited antimicrobial treatment options remaining.7

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CRE is epidemiologically important in both healthcare settings and the community. It began appearing in the United States in the early 1990s and has spread rapidly throughout the world.8

Klebsiella pneumoniae carbapenemase (KPC) has emerged as the most common strain in the United States. First discovered in North Carolina in 2001, KPC is resistant to the beta-lactam class of antimicrobials and to other agents commonly used to treat Gram-negative bacteria such as aminoglycosides and quinolones.9 Examples of other phenotypes of CRE include New Delhi metallo-beta-lactamase 1 (NDM-1), VIM (Verona integron-encoded NDM), and OXA-48 (oxacillinase producers).10

Mortality associated with CRE bacteremia can be as high as 50%.1 Exposure to healthcare and to antimicrobial drugs are the most prominent risk factors for CRE. Other risk factors include poor functional status (wounds, comorbidities, and/or immunosuppression) and an ICU stay, especially if prolonged.1,11,12 One recent study found mortality of up to 27% if CRE is the underlying organism for a pneumonia or bacteremia.2 This study impressively controlled for all risk factors except whether the patient was colonized or infected with CRE.

While transmission of CRE can occur in any setting, another study found that more than half of patients with CRE were admitted from long-term acute care or postacute care facilities. As the use of such facilities grows, the role of these facilities as a potential reservoir for MDROs becomes increasingly important.13

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No universal screening mechanism can detect all strains of CRE with adequate sensitivity and specificity, and the capacity of individual labs to perform testing for carbapenemase production varies widely.10 A lab must be able to accurately identify CRE or have access to a reference lab that can. Ideally, the lab should be able to test for KPC, NDM, and other common phenotypes.

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Multiple strategies have been used to control transmission of CRE and/or control outbreaks, including:7,14,15

  • early recognition of CRE
  • transmission-based precautions, including cohorting, as possible
  • meticulous hand hygiene
  • chlorhexidine gluconate bathing
  • prevention of environmental transmission
  • antimicrobial stewardship
  • multidisciplinary approach with good communication between stakeholders.

Consider the answers to the following questions to make sure your facility is prepared to minimize the spread of CRE when a patient presents with CRE infection.

Does your facility have a policy to routinely screen for colonization or infection with an MDRO, such as CRE? One study noted that 60% of 250 hospitals queried may screen for patient infection or colonization with methicillin-resistant Staphylococcus aureus but only 11% to 12% screen for other resistant organisms such as CRE, vancomycin-resistant enterococci, and/or Clostridium difficile.16 This study found that screening practices varied widely, with larger teaching hospitals more likely to comply with such policies. In a different study, patients found to be colonized had a 28% chance of progressing to CRE infection within 30 days.17

Active case detection has been used to control CRE in acute and long-term acute care settings.7 If a decision is made to culture patients presumptively for CRE on admission, perianal or rectal cultures are recommended.18,19

Does your facility have a system where patients with a history of colonization or infection with specified resistant organisms are identified on admission? Presumptive transmission-based contact precautions based on whether the patient has diarrhea or a draining wound not contained by dressings were initiated by 31% of facilities in one study.6 Patients (and the staff who care for them) should be cohorted when possible if the patient isn't already receiving 1:1 care. It's not recommended that Mrs. B be cohorted with another patient who's also colonized or infected with CRE if that CRE is noncarbapenemase-producing to help prevent transmission of carbapenemase-producing genes.

The Society for Healthcare Epidemiology of America recently issued guidelines on the duration of contact precautions for hospitalized patients with drug-resistant infections (see Clinical Rounds, “Experts address duration of contact precautions,” on page 23 of this issue). A conservative approach to preventing uncontrolled spread is to maintain contact precautions throughout hospitalization.

Does your unit staff participate in hand hygiene initiatives? Initiatives to improve compliance with hand hygiene in many cases can lead to statistically significant decrease in infection rates.20 (See My 5 Moments for Hand Hygiene.) Is hand hygiene compliance monitored and are results provided to unit staff?

Does your facility have a policy for using chlorhexidine to bathe these patients? Chlorhexidine bathing for patients in isolation precautions is part of a bundled approach that's been used to control outbreaks. It's been found to decrease colonization of CRE and other MDROs.15,18,22

Does your facility policy mandate increased frequency of environmental cleaning and disinfection in isolation rooms? Progressive evidence over the past 10 years shows that numerous outbreaks have occurred where exposure to the environment was implicated as a reservoir for healthcare-associated pathogens.3,15,23 In a study of terminal cleaning published in 2008, 20,000 items in patient rooms were secretly marked with an invisible fluorescent marker, then the rooms were terminally cleaned twice. Reinspection with a black light showed that fewer than half (48%) of the marks had been removed by cleaning.24 Some facilities have explored the use of technology to monitor the efficacy of cleaning and touchless technology, such as the use of fogging or UV light after terminal cleaning of a room. These strategies have been documented to both improve manual cleaning and decrease environmental contamination.25,26

Does your facility have an active antimicrobial stewardship program? In a recent study, use of an antimicrobial stewardship program for management of patients with suspected or confirmed urinary tract infections was associated with a higher rate of discontinuation of inappropriate antibiotics for asymptomatic bacteriuria and a more optimal duration of therapy.27 While responsibility for antimicrobial stewardship is in the purview of the prescriber and pharmacist, nurses can review their patients' culture and sensitivity reports and evaluate whether the organism is resistant to prescribed antibiotics. This may be critical if the culture and sensitivity results become available after the patient has already started an antibiotic.28 Lab results may signal that the patient should be placed on another antibiotic more specific to the organism. Nurses can also discuss with the prescriber if the patient can receive an oral rather than I.V. antibiotic so the venous access device can be removed as soon as possible.

When a lab culture report is positive for an MDRO, is there a well-defined pathway to communicate this information to those who need to know, including the infection preventionist? Does your unit/facility communicate with receiving destinations the need for precautions to safely care for a patient with CRE before the patient arrives at that destination, such as radiology, off-site dialysis, or a different facility? This preplanning can help receiving staff maintain appropriate precautions by making sure personal protective equipment is readily available, ensuring minimal contact with other patients in the area, and planning for disinfection of the area before other patients use the area.

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Take a proactive approach

Guidance for management of CRE across all types of healthcare settings is continuing to evolve. It's recognized that prevention of CRE transmission is more successful as a proactive rather than reactive strategy and that prevention of horizontal (patient-to-patient) transmission requires a multidisciplinary effort.28

Failure to adequately address prevention of the CRE transmission is driving healthcare back to the preantibiotic era. As a nurse, you're on the front line of the multidisciplinary team effort to slow or prevent the spread of dangerous infections. For more information, see CDC resources.

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My 5 Moments for Hand Hygiene21

This approach promoted by the World Health Organization defines the key moments when healthcare workers should perform hand hygiene. It's designed to be easy to learn, logical, and applicable to many settings. Healthcare workers should clean their hands:

  1. before touching a patient.
  2. before clean/sterile procedures.
  3. after body fluid exposure/risk.
  4. after touching a patient.
  5. after touching patient surroundings.
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CDC resources

Definitive resources for the care of patients with CRE can be found on the CDC website. These include a guidance in the form of frequently asked questions, infection control toolkits, a booklet from the federal Agency for Healthcare Research and Quality, and guidelines for antimicrobial stewardship programs. Access your local and state health department for current information on incidence and prevalence of CRE in your geographical area. This is important because it helps inform local CRE prevention efforts.

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