Tuesday, March 05, 2013

MMWR Vital Signs: Carbapenem-Resistant Enterobacteriaceae (CRE)

image

Credit CDC Vital Signs

 

# 6982

 

Carbapenems are class of broad spectrum β-lactam antibiotics that includes imipenem, meropenem, doripenem, and ertapenem, that are often the drug of last resort for treating difficult bacterial infections.

 

Enterobacteriaceae comprise a large family of Gram-negative bacteria that range from harmless strains to pathogenic invaders, and includes such familiar names as Salmonella, Escherichia coli, Klebsiella and Shigella.

 

Over the past decade we’ve seen a slow, but worrisome rise in the number of CRE (carbapenem-resistant Enterobacteriaceae) infections around the globe.

 

Thus far in the United States, the actual numbers are low.  But the trend is unmistakable.

 

Last month, in APIC: The Persistence Of CRE, we looked at a study published in the March issue of the American Journal of Infection Control, that showed that it can take a year or longer to clear an infection with CRE. 

 

Also in February we looked at the report: MMWR: Denver Hospital Outbreak Of NDM-Producing CRKP, which examined a Denver hospital’s response to an outbreak of NDM-Producing CRKP in 2012, and  we also reviewed a CDC HAN Advisory: Increase In CRE Reports In The United States.

 

Today, the CDC’s MMWR has published an early release called Vital Signs: Carbapenem-Resistant Enterobacteriaceae that helps to quantify the spread of these difficult (and sometimes impossible) to treat bacterial infections across the United States over the past 10 years.

 

 

Vital Signs: Carbapenem-Resistant Enterobacteriaceae

Early Release

March 5, 2013 / 62(Early Release);1-6
Abstract

Background: Enterobacteriaceae are a family of bacteria that commonly cause infections in health-care settings as well as in the community. Among Enterobacteriaceae, resistance to broad-spectrum carbapenem antimicrobials has been uncommon. Over the past decade, however, carbapenem-resistant Enterobacteriaceae (CRE) have been recognized in health-care settings as a cause of difficult-to-treat infections associated with high mortality.

Methods: The percentage of acute-care hospitals reporting at least one CRE from health-care–associated infections (HAIs) in 2012 was estimated using data submitted to the National Healthcare Safety Network (NHSN) in 2012. The proportion of Enterobacteriaceae infections that were CRE was calculated using two surveillance systems: 1) the National Nosocomial Infection Surveillance system (NNIS) and NHSN (for 2001 and 2011, respectively) and 2) the Surveillance Network–USA (TSN) (for 2001 and 2010). Characteristics of CRE culture-positive episodes were determined using data collected as part of a population-based CRE surveillance project conducted by the Emerging Infections Program (EIP) in three states.

Results: In 2012, 4.6% of acute-care hospitals reported at least one CRE HAI (short-stay hospitals, 3.9%; long-term acute-care hospitals, 17.8%). The proportion of Enterobacteriaceae that were CRE increased from 1.2% in 2001 to 4.2% in 2011 in NNIS/NHSN and from 0% in 2001 to 1.4% in 2010 in TSN; most of the increase was observed in Klebsiella species (from 1.6% to 10.4% in NNIS/NHSN). In the EIP surveillance, 92% of CRE episodes occurred in patients with substantial health-care exposures.

Conclusions: Carbapenem resistance among common Enterobacteriaceae has increased over the past decade; most CRE are associated with health-care exposures.

Implications for Public Health: Interventions exist that could slow the dissemination of CRE. Health departments are well positioned to play a leading role in prevention efforts by assisting with surveillance, situational awareness, and coordinating prevention efforts.

<SNIP>

Key Points

  • Enterobacteriaceae are gram-negative bacteria (e.g., Klebsiella, Proteus, Serratia, Enterobacter, and Escherichia coli) that can cause invasive disease but generally have been susceptible to a variety of antibiotics. Carbapenem-resistant Enterobacteriaceae (CRE) are Enterobacteriaceae that have become highly resistant to most or all antibiotics through several mechanisms. Carbapenem resistance, while relatively uncommon among Enterobacteriaceae (observed in about 4% of Enterobacteriaceae in this study), has increased from about 1% during the past decade. CRE bloodstream infections are associated with mortality rates approaching 50%.
  • CRE has now spread throughout the United States but in most areas they remain relatively uncommon; about 4% of acute-care hospitals and 18% of long-term acute-care hospitals reported at least one CRE to the National Healthcare Safety Network in the first 6 months of 2012. Nearly all patients with CRE were currently or recently treated in a health-care setting. However, CRE could spread into the community among otherwise healthy persons.
  • Preventing spread is important before CRE gains a foothold in more hospitals or in the community. This requires active case detection and contact precautions for colonized or infected patients as well as cohorting of patients and staff; appropriate antibiotic use in all settings; and communication about infections when patients transfer. Regional and state-based approaches have been shown to be effective in reducing incidence.
  • Additional information is available at http://www.cdc.gov/vitalsigns.

 

This afternoon, in conjunction with this early release, CDC Director Tom R. Frieden and Arjun Srinivasan, Associate Director for Healthcare-Associated Infection Prevention Programs, held a telephone press briefing.

 

Dr. Frieden called CRE a `nightmare bacteria’, that poses a triple threat.

 

  1. The are resistant to nearly all antibiotics
  2. They can be quite deadly, with as much as a 50% mortality rate for systemic infections
  3. These bacteria can swap `resistance genes’ with other bacteria.

Today’s report is a `call to action’, to prevent the spread of CRE before it becomes unmanageable. A transcript should be available on the CDC’s Newsroom Webpage later today.

 

More information is available on the CDC’s Vital Signs webpage.

 

Making Health Care Safer

Stop Infections from Lethal CRE Germs Now

 

In 2012 the CDC released updated Guidance For Control Of CRE.

image

 

For more on carbapenamases (carbapenem-resistant bacteria) you should definitely check out Maryn McKenna’s terrific Superbug Blog.

 

And for some of my earlier blogs, you may wish to revisit:

 

NDM-1: A Matter Of Import

Carbapenemases Rising

Chan: World Faces A `Post-Antibiotic Era’

WHO: The Evolving Threat Of Antimicrobial Resistance

 

Perhaps the most disturbing aspect of CRE is its ability to `share’ its highly developed carbapenem-resistant genes via tiny snippets of DNA called plasmids, that may be easily transferred between different types of bacteria.

 

This is a topic we’ve looked at before, including:

 

Study: Adaptation Of Plasmids To New Bacterial Species