Outbreaks of Carbapenem-Resistant Enterobacteriaceae

Arjun Srinivasan, MD


May 02, 2012

Editorial Collaboration

Medscape &

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Hi. I am Dr. Arjun Srinivasan from the Centers for Disease Control and Prevention (CDC). I am here at the Society for Healthcare Epidemiology of America (SHEA) spring meeting in Florida. I wanted to talk to you for a few minutes today about some important issues in healthcare outbreaks that we are seeing. Many issues related to unsafe injection practices are leading to outbreaks in healthcare. Outbreaks in non-acute care settings, such as ambulatory surgical centers and long-term care facilities, are also posing challenges for us.

The issue I would like to focus on today is a highly drug-resistant pathogen that we see as a growing cause of outbreaks in healthcare facilities, namely carbapenem-resistant Enterobacteriaceae, sometimes referred to as CRE.

Enterobacteriaceae, as you may remember from medical school, is a large group of gram-negative organisms that are common residents of the gastrointestinal tract. Classically, these organisms have been readily treatable with antibiotics, but over the last several years we have encountered a growing number of Enterobacteriaceae that are resistant to all of our antibiotics, including carbapenems. Historically, carbapenems had been our last line of defense in treating Enterobacteriaceae, and so the development of resistance to these last-line agents has been a significant issue in healthcare. Indeed, CRE now pose a major therapeutic dilemma in some facilities.

Some good studies have shown that the mortality from CRE infections can be as high as 40%.[1]These pathogens obviously pose a major therapeutic dilemma because there are simply no antibiotics left to treat them. Additionally, we have seen that these organisms can spread very quickly in our healthcare facilities. A number of very well-described outbreaks have occurred in this country and in others where, in short order, 1 case of CRE infection in a healthcare facility has led to many others. Several important issues have come to light that have very relevant implications for steps that we can take to control the spread of CRE in our healthcare facilities. I would like to share a few of those with you today.

The first is the issue of the interdependence of acute care facilities and long-term care facilities when we are talking about CRE. Outbreaks following the transfer of patients between different healthcare facilities have been well described when the transferred patient subsequently became the source of an outbreak. For example, patients who are in long-term care or long-term acute care facilities can be transferred to acute care hospitals, and then other cases can arise from that initial transfer. This can happen the other way around, too, when patients go from acute care facilities to long-term care facilities and then become the source of outbreaks in those facilities. That suggests to us as clinicians that we need to know where our patients are coming from and where our patients are going. We have to communicate with transferring and accepting facilities so that we can better understand problems that they may be having with CRE, so that we can treat their patients most appropriately.

The other issue that has come to light as an important factor in controlling CRE is the awareness that CRE are not normal pathogens in healthcare. The presence of a CRE(most commonly E coli or a Klebsiella species that is resistant to carbapenems) should trigger immediate action on behalf of clinicians, microbiologists, and infection-control staff. We need to rapidly isolate those patients using contact precautions. Early implementation of isolation is very effective in preventing transmission of CRE, and the only way we can isolate these patients effectively is to be aware that they are infected and take action promptly.

Another important control measure for CRE is using active surveillance testing to identify cases. Active surveillance testing involves performing cultures of patients who are asymptomatic. Most commonly this is performed with a rectal swab, and it can be very helpful in identifying patients who may be unrecognized carriers of CRE. This can be accomplished following exposure to a case that might have been in your facility that you didn't know about. This active surveillance strategy, conducted in a very targeted and limited way, has been very effective in controlling the spread of CRE in some settings and should be given serious consideration to try and control the spread of CRE.

Finally, one thing that we can all work on to reduce the spread of CRE in our healthcare facilities is to improve antibiotic use. Carbapenem exposure has been shown in studies to be the single most important risk factor for the development of CRE.[2] So, it stands to reason that reducing the use of carbapenems in our healthcare facilities will go a long way toward helping us prevent the spread and development of these carbapenem-resistant organisms.

We know that there are steps we can take to control the spread of CRE. This organism is a growing problem in US healthcare facilities, but at the same time we have an important opportunity to act now to prevent this from becoming a more serious problem. By taking the steps that we know are effective, we can help reduce the spread of CRE. I encourage all of us to be aware of what we can do and to take the steps necessary to prevent more patients from suffering from these infections.

This is Arjun Srinivasan on behalf of the CDC, SHEA, and Medscape.

Thank you.


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