Center for Disease Dynamics, Economics & Policy

The latest Morbidity and Mortality Weekly Report (MMWR) by the US Centers for Disease Control (CDC) addresses the emerging threat of carbapenem-resistant Enterobacteriaceae (CRE). The MMWR, featuring a contribution from CDDEP researchers, reports on the rising prevalence of CREs in US health care facilities and stresses the need for increased surveillance and “a broader, multi-institutional or regional approach” to prevent and control infections.

Enterobacteriaceae are a family of Gram-negative bacteria that include Escherichia coli, Klebsiella pneumoniae and other species that usually inhabit the human gut without causing disease. Strains showing resistance to carbapenems – one of the most powerful drugs in our antibiotic arsenal – have spread throughout the US, causing highly lethal infections among critically ill patients. The difficult-to-control nature of CRE infections made national headlines following a 2011 outbreak that killed 11 patients at the National Institutes of Health’s Clinical Center.

Exactly how common are CRE infections? The current CDC release summarizes the most comprehensive information to date, combining data from three national surveillance systems. The agency reports 4% of tracked short-term hospitals and 18% of long-term ones had reported at least one CRE infection. Between 5-10% of tested K. pneumoniae clinical cultures were resistant to carbapenems, compared to 0-1.6% in 2001.

Last week, the agency released an advisory urging medical practitioners and public health officials to take heed, and provided an updated toolkit informing stakeholders of best practices to contain and manage CRE outbreaks. Some highlights from the toolkit include:

• Institutions that detect patients with CREs should place them on contact precautions – have caregivers wear special gloves and gowns, even use dedicated rooms and staff to care for these patients to prevent transmission.
• Regions and facilities with rare or no CRE events should adopt an aggressive approach to preempt CRE outbreaks, including strengthening compliance with hand hygiene measures and prompt removal of invasive devices like catheters and ventilators.
• Whenever known CRE carriers are transferred between facilities, special transfer forms should be used, clearly indicating the patient has history of colonization with the bug.

Although it summarizes the most comprehensive metrics available, the MMWR data do not give a complete picture of the CRE problem. A major reservoir of the strain lies with patients in nursing homes and long-term hospitals, who often carry the bacteria without exhibiting symptoms. In addition, many states lack mandates to report CRE outbreaks.

Nevertheless, it is clear the CDC advisories for preventing the spread of CREs should be taken very seriously. The well-publicized outbreak in the prestigious NIH clinical center demonstrates CRE outbreaks can circumvent even the most stringent infection control efforts - including using robots to disinfect hospital rooms and, quite literally, throwing the kitchen sink at the outbreak. It is critical to act now and ensure the majority of US hospitals never reach the point where they have to resort to such measures.

Related Tools:

1. Read the MMWR report, a plain-language summary and other communication materials released as part of this month’s Vital Signs publication.
2. See our recent study in Infection Control and Hospital Epidemiology for a more detailed analysis of one of the datasets used in the report, including trends in carbapenem resistance by age, patient location and region.
3. The following tools from the study show the key regional and temporal trends in K. pneumoniae isolates exhibiting resistance to third-generation cephalosporins and carbapenems. For more visualizations on antibiotic use and resistance, visit our Tools and Resistance Map sections.

Image via nathanreading/Flickr

This post was written in collaboration with CDDEP researcher Nikolay Braykov.