An Invisible EnemyHannah MarshallMay 19, 2011


Acinetobacter baumannii is a pathogenic bacterium that has increased in transmission since the latest Iraqi War. Even though it has recently been contracted at an alarming rate in Iraq the bacterium is also known to cause nosocomial infections in hospitals. The harmful bacterium has unique characteristics which allow it to be resistant to several antibiotics. It is also transmitted very easily and undetectably which is why it is considered to be one of the most dangerous kinds of gram negative bacteria. Precautions can be taken and treatment options are available so that you are less susceptible to being infected with A. baumannii.


Acinetobacter baumannii, also known as “Iraqibacter” is causing subsequent harm to soldiers fighting the war in Iraq. It was thought to have declined in the 1980’s however, in the last decade the destructive pathogen has made its appearance again and at an alarming rate. Soldiers are faced with an invisible arch enemy that has it in for them. Since 2003, nearly 700 soldiers have been infected or colonized with the extremely dangerous pathogen (Pollack). A.baumannii is a multi-resistant gram negative bacterium that is very harmful because of its opposition against several antibiotics. It is not only harming soldiers but also infects at least 10,000 hospital patients yearly and is considered to be a nosocomial pathogen (Peleg, Seirfert, and Paterson 538-582). A. baumannii is characterized as an opportunistic pathogen because it commonly infects a host with a compromised immune system. In addition, this pathogen is dangerous because it not only infects humans, but it can be transmitted or carried on the surface of the skin, not infecting the host if it doesn’t enter the body. The pathogen commonly enters the body through open wound infections, respiratory infections, catheters, and breathing tubes (Cunha). Researchers and microbiologists have been experimenting with different antibiotics, however the drugs are very expensive and because of the resistance of A. baumannii it’s very hard to find a drug that will be effective, but won’t cause harmful symptoms. petri2.jpg

· Characteristics:
A. baumannii is an aerobic gram negative coccobacilli bacterium that is generally non-motile (Peleg, Seirfert, and Paterson 538-582). It starts out as rods but becomes cocci during a decrease in cell division. When observed microscopically you can examine that it is encapsulated and the bacterium has features called porins and efflux channels on its outer cell membrane. These features contribute to the antibiotic resistance of the bacterium. A. baumannii has fewer and much smaller porins, (protein channels that allow the transport of molecules across the membrane) which provide sites of attachment for antibiotics (Larsen). These unique characteristics of the bacterium are the reason why the cell is less permeable and increases its resistance against antibiotics (Cunha). In addition, when A. baumannii was placed in dry conditions there was an increase in the thickness of the cell wall, which was caused by a change in the distance of the outer membrane and the plasma membrane.


A. baumannii is known to be found in water and soil and it contributes to the mineralization of aromatic compounds. It is able to survive on dry or wet surfaces, including in hospitals or in soil (Peleg, Seirfert, and Paterson 538-582). A certain strain of A. baumannii is capable of forming biofilms on glass or plastic surfaces which is why this bacterium leads to nosocomial infections. The bacterium can survive static conditions, meaning it can survive on bed sheets or furniture in a hospital or also harsh conditions, such as catheters and respiratory tubes (Larsen). This is how A. baumannii is contracted in hospitals. The bacterium can also be contracted through your mouth, nose, or opening in your skin. However, it usually doesn’t infect a healthy human; it will cause infections in humans with low immune systems that are already sick; especially targeting the young or elderly. The ICU (Intensive Care Unit) of the hospital is most prone to the bacterium because the patients are all very weak and the patients are commonly using the hospital equipment that contributes to A. baumannii infections (Peleg, Seirfert, and Paterson 538-582). The bacterium commonly colonizes patients who have multiple monitoring devices, surgical drains, or urinary catheters (Larsen). This bacterium has recently also targeted soldiers in Iraq and Afghanistan through bloodstream infections. This occurs when the bacterium enters through the open wounds on their body. The bacterium is transferred throughout the hospital in Iraq because of the constant patients wounded and a soldier can also be infected if A. baumannii enters their body from the soil it is living in. In addition, not only can people be infected with the bacteria but it can colonize on the surface of their skin, not infecting them, but could then easily be transferred to a soldier with an open wound (Allina).

If you are infected with A. baumannii it can lead to several severe and deadly infections. The most common include: pneumonia, blood stream infection, meningitis, bone infection, urinary tract infection, and skin and wound infections (Pollack).

Signs and symptoms include:
· Fever (high body temperature).
Red, swollen, warm or painful skin areas or wounds.
· An area of orange, bumpy skin with blisters.
· Cough chest pain or trouble breathing.
· Burning feeling while urinating.
· Sleepiness, headaches or a stiff neck.
How could you be diagnosed?
· A culture of your blood, urine, or tissue could be sent to the lab and they can examine it for the bacterium.
· A chest x-ray could also be used, so that the doctor can take a look at your lungs. If there is infection you may have pneumonia, which is a symptom of the bacterium.
· A lumbar puncture could also be used to extract some of your spinal fluid and check for infection (Allina).

If you are infected with A. baumannii there are multiple ways your doctor could protect you from the infection spreading, however it depends on where in the body you have contracted the infection. For instance, if you have a wound infection you will need surgery to remove the dead, infected tissue. If you contract pneumonia you can use a ventilator or take medications to help you breathe more easily (Allina). If the infection is more serious, your caregiver will take the precautions of:
· Putting you in isolation so that you don’t spread the infection to other patients
· You can be treated with antibiotics; however there are risks with taking antibiotics, which will be discussed further.
· Pain/fever medication

Problems encountered with Antibiotics:
Because A. baumannii is a very resistant bacterium many standard antibiotics such as Penicillin and Macrolides have no effect on the bacterium. Antibiotics such as: Amikacin, Colistin and Imipenem are all supposed to fight off the infection; however there are some risks with taking the antibiotics. Amikacin doesn’t work against some strains of A. baumannii and doesn’t treat bone infections (Herper). Colistin is not healthy to use anymore because of the toxic effect it has on the kidneys, and Imipenem carries the risk of seizures (Pollack).

**Video includes and elaborates on "Iraqibacter"


Along with other nosocomial infections you can prevent them from frequent hand washing and constant disinfection of medical treatment facilities and equipment.

Literature Cited:

  • Peleg, Anton, Harald Seirfert, and David Paterson. "Acinetobacter baumannii: Emergence of a Successful Pathogen." Clinical Microbiology Reviews. 3. 21. Washington D.C.: American Society of Microbiology, 2008. Web. <>.
  • Pollack, Andrew. "..Rising Threat of Infections Unfazed by Antibiotics." New York Times 26 Feb 2010: Web
  • Tortora, Garard. Funke, Berdell. Case, Christine Microbiology. 10th ed. U.S.: Pearson Education, 2010. 317. Print.