CDC Commentary: Preventing Carbapenem-Resistant Enterobacteriaceae

Arjun Srinivasan, MD


February 16, 2010

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Hello. I’m Dr. Arjun Srinivasan from the Centers for Disease Control and Prevention and I’m pleased to have the chance to talk with you today about an important type of antibiotic resistant gram-negative bacteria. The most commonly encountered type of these resistant bacteria is a drug -resistant form of Klebsiella pneumonia known as carbapenem-resistant Klebsiella pneumoniae, sometimes referred to as “KPC producers” or “KPCs,” in reference to the enzyme which inactivates carbapenems, the Klebsiella pneumoniae carbapenemase (or KPC). This KPC enzyme is also present in some strains of E. coli. Because both Klebsiella pneumonia and E. coli are in the family of bacteria known as Enterobacteriaceae, the carbapenem resistant strains of these organisms are referred to as carbapenem-resistant Enterobacteriaceae (or CRE).

These organisms pose a particular challenge because they are very hard to treat and have the potential to spread within healthcare facilities. Given the lack of new drugs to treat these infections, we must focus our efforts on preventing transmission of these pathogens. Today’s talk will discuss ways in which to prevent the transmission of carbapenem-resistant Enterobacteriaceae (or CRE).

Those of you who have cared for a patient with a CRE infection know that these organisms are resistant to almost all available antimicrobial agents, and infections with these organisms are associated with high rates of morbidity and mortality. Patients who are critically ill or have been exposed to invasive devices (such as ventilators or central venous catheters) and antibiotics are most likely to be infected with CRE. Fortunately, experience from outbreak investigations and in endemic settings in other countries has suggested that early detection and implementation of strict infection control measures can help control the spread of carbapenem-resistant organisms in healthcare facilities.

This past year, CDC and the Healthcare Infection Control Practices Advisory Committee (or HICPAC) released new guidance in an effort to limit the further emergence of carbapenemase-producing Enterobacteriaceae in acute care settings. The guidelines recommend that microbiology laboratories in all acute care facilities should implement established protocols to detect carbapenemase production in Enterobacteriaceae, particularly in Klebsiella species or E coli. If clinical laboratory staff identify an organism of concern, they should immediately alert hospital infection prevention or epidemiology staff.

When a hospitalized patient with CRE is identified, the most important immediate control measure is to implement contact precautions for the patient. Contact precautions require the use of gloves and gowns for patient care. If the CRE is thought to have been acquired within the facility, that is, it was not known to be present when the patient was admitted, the guidelines recommend a “search and contain” strategy through the use of active surveillance among patients who are epidemiologically linked to the case-patient. Active surveillance cultures for CRE can be done through the use of rectal swabs with published protocols that are available in the medical literature and in the related links on this page. These may be patients in the same unit or patients who have been cared for by the same healthcare personnel as case-patients. By conducting active surveillance in this manner, you can identify additional patients colonized with these organisms; which can determine whether you have ongoing patient-to-patient transmission of these bacteria in your facility.

If you detect transmission – meaning that you identify cases among patients with epidemiologic links to your case-patient, then infection prevention measures should be vigorously reinforced, and surveillance cultures repeated periodically until no new cases are identified. If no other colonized patients are identified after several instances where surveillance cultures are done on epidemiologically linked patients, it likely means that your facility is effectively controlling transmission. In this circumstance, you may wish to forgo active surveillance in response to new cases of CRE and replace it with periodic point prevalence surveys in units with patients at high-risk for CRE infection to ensure that carbapenem-resistant or carbapenemase-producing Klebsiella species and E. coli do not reemerge.

What about recommendations for facilities where CRE have not been reported? Experience also indicates that in some instances, cases of CRE are reported by the microbiology laboratory, but are not detected and acted upon by infection control staff. Hence, to ensure infection control staff have the most accurate information on CRE within their facilities, the guidelines recommend that staff in acute care facilities review microbiology records for the past 6-12 months to ensure that previously unrecognized CRE cases have not occurred. If you find a previously unrecognized case, it is recommended that you perform some form of active surveillance to determine if there is unrecognized transmission of CRE in your facility. This can be done by conducting a point prevalence survey, which involves performing a single round of active surveillance cultures in units with patients at high risk -- such as ICUs, units where previous cases have been identified, and units where many patients are exposed to broad-spectrum antimicrobial agents. The goal of this survey is to identify any additional patients infected or colonized with carbapenem-resistant or carbapenemase-producing Klebsiella species or E. coli.

Since first being described in North Carolina in 1999, CRE has been found in at least 24 states and are now widespread in some locations. However, we do have an opportunity to act aggressively now to halt the spread of CRE. I would encourage all of you to review and implement the CDC/HICPAC Guidelines for the Control of CRE in acute care facilities. Experience with CRE in this country and others do suggest that an aggressive and comprehensive infection approach can be effective in limiting the transmission of these pathogens. By taking action, we can prevent CRE from becoming a more significant threat to our patients. Thank you.

Web Resource

Guidance for Control of Infections with Carbapenem-Resistant or Carbapenemase-Producing Enterobacteriaceae in Acute Care Facilities

Arjun Srinivasan, MD, is an epidemiologist in the Division of Healthcare Quality Promotion at CDC. This division seeks to protect patients and healthcare personnel and promotes safety and quality in healthcare delivery systems.

He is the Response Team leader for the division, supervising the investigation and prevention of adverse events related to healthcare delivery and antimicrobial resistance. He has supervised more than 20 successful field investigations, five of which led to national recalls of medical products or medications. Dr. Srinivasan′s expertise was specifically sought by the U.S. Army to help investigate and control an outbreak of Acinetobacter infections among service members injured in Iraq/Afghanistan.

Before coming to CDC he was as Assistant Professor of Medicine in the Infectious Diseases Division at the Johns Hopkins School of Medicine where he was the founding director of the Johns Hopkins Antibiotic Management Program and the associate hospital epidemiologist. His primary responsibilities include investigation of outbreaks that occur in healthcare facilities and policy and research work related to these outbreaks. His areas of concentration include outbreak investigations, infection control, multi-drug resistant gram negative pathogens, device related infections and infections related to organ and tissue transplantation. Dr. Srinivasan has published several articles in peer-reviewed journals on his research in healthcare epidemiology, infection control and antimicrobial use and resistance. He is a member of the Association for Professionals in Infection Control and Epidemiology, the Infectious Diseases Society of America and the Society for Healthcare Epidemiology of America. He is board certified in both internal medicine and infectious diseases.

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