Antibiotics have saved many lives. However, their widespread use has promoted the survival and spread of a growing variety of antibiotic resistant bacteria, resulting in nosocomial infection nightmares like MRSA, VRE, and ESBL. Of growing concern is a multidrug resistant bacteria known as Acinetobacter baumannii (MDRAB), which causes infections like pneumonia and bacteremia in persons who are ill, wounded, or immunocompromised. Although MDRAB existed in Europe before the onset of the Iraq War, its numbers have been on the rise since a military outbreak in 2003.
Acetinobacter Baumannii
Bacteria of the genus Acinetobacter are hardy, rod-shaped gram-negative bacteria that are normally found in soil and can survive for days, even weeks, in the environment and on objects. Their name, Acinetobacter, comes from the Latin word for "motionless," because they lack cilia or flagella with which to move. Most species are not significant sources of infection. However, one opportunistic species, Acinetobacter baumannii, is found primarily in hospitals and poses a risk to people whose defenses are down. This includes the chronically ill, the critically ill, the wounded, and the immunocompromised. According to the CDC, A. baumannii causes 80% of all Acinetobacter infections.
Although it has a low virulence (i.e., it has a low ability to cause infection in healthy people), Acinetobacter baumannii can cause complications and serious illness in people who are critically hospitalized. It is introduced into the body via wounds or invasive devices (including PICC lines, IV lines, Foley catheters, chest tubes, and tracheal tubes), and can cause many kinds of symptoms depending on what body site is infected. A. baumannii can cause pneumonia (the lungs), bacteremia and septicemia (the blood), wound infections, urinary tract infections, and osteomyelitis (the bones). A. baumannii infections can be indistinguishable from infections caused by other bacteria.
Acinetobacter causes colonization more often than infection; this means that it lives in or on the body without causing illness (e.g., the skin of a healthcare worker). People who are colonized can become carriers who spread the bacteria to other people, usually without realizing it.
Multidrug Resistant Acinetobacter Baumannii
Typical A. baumannii, which can be treated with several different antibiotics, is not the real problem. It is multidrug resistant Acinetobacter baumannii (MDRAB), which is very challenging and dangerous to treat, that raises concerns. MDRAB causes the same sort of infections as normal A. baumannii, but it is resistant to almost every known antibiotic; this makes it much more serious. Researchers studying its genetics found that MDRAB contains many genes that code for different kinds of antibiotic resistance. These genes were taken by MDRAB from other superbugs, including E. coli and Pseudomonas. (Bacteria are known for taking genes from other bacteria--even other species.)
"Iraqibacter," Multidrug Resistant Acinetobacter in Iraq
In April 2003, physicians aboard the hospital ship USNS Comfort came across a number mysterious infections in military patients that had been wounded in Iraq. They pinpointed the cause of the infections to Acinetobacter baumannii. However, this was not the typical A. baumannii, but MDRAB. Suddenly, the healthcare workers found themselves on the front line of a metaphorical battle with the bacteria as they struggled to bring it under control. Since then, the MDRAB (dubbed "Iraqibacter") has spread to other military facilities and subsequently to civilian facilities as well.
Where the Iraqibacter came from remains something of a mystery. Soil samples taken by researchers in Iraq and Kuwait came back negative. However, it was found thriving in the hospitals. When Iraqibacter was compared to MDRAB samples taken in Europe before the war, they were found to be identical (Silberman, 2007). Thus, scientists believe that the current outbreak originated from European sources. (Yes, MDRAB did exist before the Iraq War.)
Acinetobacter Treatment
Multidrug resistant Acinetobacter treatment options are very few. The struggle to discover antibiotics to treat it sounds something like an arm's race. MDRAB appears to be susceptible to only one contemporary antibiotic, imipenem--but a growing number of strains are resistant even to this.
Only one old, toxic antibiotic known as colistin remains effective. Because it fell out of favor in the 1970s, it never underwent the rigorous testing that newer drugs are subject to. Thus, the parameters that physicians use to determine dosing were never established for colistin. This lack of parameters, paired with the drug's toxic effect on the kidneys (the severity of which is dependent on dose amount), make this drug a nightmare for physicians and patients.
Acinetobacter Infection Control
As it is extremely difficult to treat once contracted, Acinetobacter infection control consists primarily of prevention. MDRAB is is spread through direct contact with infected people, colonized people (carriers), and contaminated objects, including hospital equipment and cell phones.
Hand washing remains the number one most effective, most important method to prevent the spread of pathogens. It is very important that health care workers and visitors wash their hands before and after contact with patients, especially those who are known to carry A. baumannii. (This includes after removing gloves.)
Because this multidrug resistant bacteria, Acinetobacter baumannii, enters the body through invasive devices and wounds, it is also important to keep these clean. (And to discontinue and remove these as soon as safely possible.)
References and Resources:
Borer, A., Gilad, J., Smolyakov, R., Eskira, S., Peled, N., Porat, N.,...Schlaeffer, F. (2005). Cell phones and acinetobacter transmission. Emerging Infectious Diseases, 11(7), 1160-1161.
Chong, J.R. (2007, October 1). The path of war sets doctors on the warpath of disease. Napa Valley Register, on-line edition.
Levin, A.S., Barone, A.A., Penço, J., Santos, M.V., Marinho, I.S., Arruda, E.A., Manrique, E.I., & Costa, S.F. (1999). Intravenous colistin as therapy for nosocomial infections caused by multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii. Clinical Infectious Diseases, 28(5), 1008-1011.
Li, J., Nation, R.L., Turnridge, J.D., Milne, R.W., Coulthard, K., Rayner, C.R., & Paterson, D.L. (2006). Colistin: The re-emerging antibiotic for multidrug-resistant gram-negative bacterial infections. The Lancet Infectious Diseases, 6, 589-601.
Silberman, S. (2007). The invisible enemy. WIRED, 15(2), on-line edition.
Sunenshine, R.H., Wright, M.O., Maragakis, L.L., Harris, A.D., Song, X., Hebden, J.,...Srinivasan, A. (2007). Multidrug-resistant acinetobacter infection mortality rate and length of hospitalization. Emerging Infectious Diseases, 13(1), 97-103.
Christie Bailey - Christie is an RN, BSN with a passion for holistic health. Currently, she is pursuing her masters degree to become a holistic nurse ...
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