Carbapenem-Resistent Enterobacteriaceae (CRE): An Overview of the “Superbug”

Carbapenem-Resistent Enterobacteriaceae (CRE) is a worldwide epidemic that is both life threatening and difficult to treat. It is recognized by the Center for Disease Control (CDC) and USAToday as a “superbug”. Immune to antibiotics and other forms of treatment, CRE can be fatal. For this reason medical professionals and community members remain concerned about the risk CRE has on patients and the greater community.  A infectious bacteria that continues to plague individuals and baffle medical professionals around the world, it is important to be are aware of CRE. This includes its history, those at heightened risk, treatment, and necessary precautions to reduce its spread and negative effects on individuals and families.


Carbapenem-Resistent Enterobacteriacea is classified as bacteria belonging to a family that is drug resistant and immune to antibiotic treatments or gram-negative. This can be observed by its name and title. Carbapenem refers to an antibiotic that is strong and highly effective in treating infections, “the last line of defense in the medical tool box of antibiotics”, (Eisler, 2013, n.p). Enterobacteriaceae, on the other hand, refers to a family of infectious bacteria. Enterobacteriaceae is bacteria typically found in urine, feces, and the bowels. Consequently, it is possible for CRE to live in the human intestines and colonize there with no harmful effects. When CRE is colonized, the host will experience no signs or symptoms of infection. Unrecognized and untreated, this can often be fatal in patients due to the proper laboratory analysis required for detection and to determine a relevant form of treatment, (Eisler, 2013, n.p).

Entrobacteriaceae refers to a list of bacteria resistant to treatment and carrier of a resistance gene that is able to jump to different bacteria creating new superbugs in its wake. “Klebsiella species and Escherichia Coli or E-Coli are examples of entrobacteriaceae, a normal part of the human gut bacteria that can become carbapenem-resistant”, (CDC, 2014, 2).  Additional types of CRE include Klebsiella Pneumonia Carbapenem (KPC) and New Delhi Metallo-Beta-Lactamase (NDM). These subtypes have the ability to interrupt carbapenems making antibiotic treatment ineffective. Incidentally, E-Coli and KPC has caused a significant increase in CRE infections across U.S. Research indicates that in the past decade KPC infections have increased by more than 10% and E-Coli cases are up 4%, (Gupta, Limbago, Patel, and Kallen 60). This demonstrates the rise of infections present and the detrimental effects this has on individuals and the community at large.


CRE is a new medical phenomenon unheard of 25 years ago. During this time, there were no identified resistant strains of bacteria as outbreaks were effectively treated with antibiotics. In this way CRE derived from the creation and continuous use of antibiotics. Carbapenems, a form of antibiotic, was first created in the 1980’s from the family of thyanamycin. Thyanamycin was formerly used to treat bacterial infections however taken off the market due to its high toxicity. Once developed, they became highly popular among medical professionals as a best form of treatment. Yet, it didn’t take long for bacteria to quickly resist and become immune to this treatment. By the 1990’s Entrobacteriaceae began to develop resistance with its first report occurring in 1992. To improve treatment outcomes Carbapenems were prescribed in higher doses increasing its use by almost 60% after the turn of the century, (Van Duin and Perez 226). Since then CRE and its subtypes have continued to infiltrate the medical community putting individuals at risk. However, drug resistant strains continued to be rare. It wasn’t until 2010 that medical professionals including the CDC began to identify these superbugs and recognize this as a problem within the medical community. The increased use and popularity of carbapenems developed the first reported case of KPC in 2001, from a North Carolina facility, (Gupta, Limbago, Patel, and Kallen 61). Since then, cases of CRE continue to be reported by the thousands, in Isreal, Europe, India and 42 states across the U.S. Effecting individuals at an alarming rate, it “demonstrate resistance to many agents commonly used to treat gram-negative bacteria including quinolones and aminoglycosides”, (Gupta, Limbago, Patel, and Kallen 60). As scientists continue to modify and develop medications to treat CRE, the superbug as continued to increase remaining a critical factor in its emergence and development over time.

CRE Populations and Transmission

Not everyone is susceptible to CRE. Healthy people do not attract CRE, however is most often seen in specific populations including the elderly, the ill, and those receiving residential medical treatment and care. Vulnerable individuals are likely to be “debilitated and have multiple comorbidities, including diabetes, mellitus, and immunosuppression”, (Van Duin and Perez 228). It also includes individuals in intensive care, those living in long-term care facilities, burn victims, cancer patients, children with chronic illnesses, those with pneumonia, transplant patients, and individuals who receive frequent doses of antibiotics.  It becomes clear that hospitals and care facilities are likely to house these infections and linked to transmission. Research determined that “75% of patients with CRE were admitted in long term care”, (Van Duin and Perez 229). Thus, these individuals are not only more likely to have CRE they are also more likely to die as a result of infection.

Hospitals and medical facilities continue to be a leading cause for enterobacteriaceae transmission due to the care, treatment, and open wounds observed in this environment. Those who are ill or elderly are more likely to receive catheters, require breathing machines, and other factors that increase CRE exposure, (CDC 2). These are patients who require medical devises in sensitive areas. For this reason, transplant patients and those with open wounds are also susceptible to CRE including people with infections to the blood stream, skin, soft tissue, and the central nervous system. While it is often transmitted from these medical devises it can also be transmitted from patient to patient. “CRE is shed in feces, urine or draining wounds of patients who are infected or colonized”, (Division of Infection Disease, 2011, 1). Items and devises can be contaminated with CRE unbeknownst to the patient and medical staff. It can live on the patient’s skin, sheets, door knobs, and hand rails. As such, it is easy to see how medical devises and equipment can transfer CRE from one patient to another. These individuals are already ill with reduced immunity to bacteria and diseases. This causes a high rate of death as they are likely to have poor outcomes and “contribute to death in up to 50% of patients who become infected”, (CDC 1).

Treatment and Prevention

Due to its high rate among ill and hospitalized patients, it is critical that medical professionals take the necessary precautions to prevent the emergence and spread of Carbapenem-resistant enterobacteriaceae. A significant way to reduce CRE is early detection. However, this too can prove to be difficult. CRE has the unique ability to lurk on patients and contaminated items seeking an opportunity to enter a host. Once inside, it can lay dormant inside the body until the immune system is compromised and infection can begin. It can often resemble other bacterial infections and require special lab cultures to better determine if CRE is prevalent.  Misidentified as urinary tract infections or other asymptomatic bacteria, CRE can go undetected.  Research indicates it is best detected using “reduced disk diffusion zones tested for production of carbapenemase using Modified Hodge Test (MHT)”, (Gupta, Limbago, Patel and Kallen 64). If medical institutions are unable to apply early detection, the end result can be fatal. Identified too late, CRE spreads quickly and widely increasing transmission to other patients and mortality. As a result, “treating patients infected with CRE includes timely and accurate diagnoses, source control, distinguishing between infection and colonization”, (Van Duin and Perez 230).

CRE is highly difficult to treat due to its resilience against antibiotics. Some scholars suggest that combination of treatment may improve outcomes but research indicates this is unlikely. With carbapenems now ineffective against CRE, so are other antibiotics.  Many antibiotics are ineffective due to resistance and medical professionals are less likely to use different medications due to lack of clinical evidence or high toxicity. This leaves limited treatment options. There are only four antibiotics which may help however there is no guarantee of success. This includes the class of polymyxins: Colistin, Tigercycline, Aminoglycosides, and Fosfomycin, (Van Duin and Perez 231). However, most sub-strains of CRE are currently resistant to Colistin, Tigecycline, and Fosfomycinoptions. This may not be a treatment option for all patients affected by CRE. Additionally, tigecycline has been present in incidents of CRE mortality suggesting that this drug may increase infection. Only “Aminoglycosides may be very useful in the treatment of CRE”- especially if CRE is contracted as a result of urinary catheters and urinary tract infection, (Van Duin and Perez 231).


Carbapenem-Resistant Enterobacteriaceae is a bacterial infection that can end in mortality and difficult to treat. Most disturbing, it only affects individuals who are sick and under hospital care. This increases the need for awareness and preventive measures to be established throughout the medical field. Weather this is an elder care facility, rehabilitation center, or hospital, medical professionals must be up to date with CRE and take the appropriate preventive measures to reduce its spread among patients. So far the best treatment available for CRE is early detection and reduced transmission. This can be done by hand washing, keeping wounds clean, and maintaining a clean environment. The Center for Disease Control calls this “detect and protect strategies”, (2). Medical staff should be educated on CRE precaution and detection. Patients being transferred from one facility to another should be screened for CRE. Additionally, once detected these patients should be separated from others and items sterilized. Research suggested that, “with the implantation of a bundle consistency of chlorhixidine baths, cohorting of colonized patients, and health care personnel, increased environmental cleaning and staff education may be effective in controlling outbreaks”, (Van Duin and Perez 239). In conclusion, although treatment is unreliable and limited, nursing and medical professionals can do what they should do reduce incidents of CRE in their facility.



Works Cited

Centers for Disease Control and Prevention. Carbapenem-Resistant Enterobacteriaceae in Healthcare Settings. Atlanta, Ga: , 2014. Print. <;.

Eisler, Peter. “Deadly .” USA Today 06 March 2013, Nation. Web. 12 Jun. 2014. <;.

Gupta, N, B Limbago, J Patel, and A Kallen. “Carbapenem-Resistant Enterobacteriaceae: Epidemiology and Prevention.” Clinical Infectious Disease. 53.1 (2011): 60-67. Print. < html>.

West Virginia Bureau for Public Health. Department of Health and Human Resources. Patient Information Sheet for Carbapenem Resistant Enterobacteriaceae. Charleston, WV: Division of Infectious Disease Epidemiology, 2911. Web. < Patient Information Sheet.pdf>.

Van Duin, D, and F Perez. “Carbapenem-Resistant Enterobacteriaceae: A menace to out most vulnerable patients.” Cleveland Clinic Journal of Medicine. 80.4 (2013): 225-233. Web. 12 Jun. 2014. < html>.


About Russia Robinson

I use my writing talents, and skills I’ve learned through academics and experience, to benefit the greater good of society. Conducting research, writing articles, essays, and blogging, I give informative information on a variety of topics and issues that affect society. I also write creative works like children’s books, short stories, poems, and a novel in progress. I earned a BA in English creative writing and American literature from San Francisco State and graduate studies in Technical Writing at Kennesaw State University. Through my career in education and mental health I have spent more than 10 years’ helping young people succeed. I am a certifiable Language Arts teacher, working in education, social services, and mental health. Interested in my writing services? Feel free to contact me via email.
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