What is Acinetobacter baumannii?Acinetobacter baumannii bacteria are aerobic short-rod bacteria. © Robert Kneschke - stock.adobe.com
Acinetobacter baumannii is a Gram-negative short-rod bacterium from the group Acinetobacter. It belongs to the gamma-proteobacteria and comes from the family Moraxellaceae. It also forms a new generation of hospital germs.
The Acinetobacter baumannii bacterium is considered of particular concern because it is resistant to antibiotics. Thus, it proves to be insensitive to four different antibiotic groups, such as cephalosporins, which come from the third and fourth generation, carbapenems, fluoroquinolones and Acylureidopenicilline. As a result, conventional therapies with antibiotic agents such as ciprofloxacin, ceftazidime, metopes, imipenem, tazobactam, cefotaxime or piperacillin have no effect.
Not infrequently, people who previously had to undergo hospital treatment abroad carry the resistant germs to German hospitals. How dangerous Acinetobacter baumannii is was shown at the beginning of 2015 at the University Hospital Kiel. There, a total of 31 patients with the pathogen infected, of which twelve died.
Occurrence, distribution & characteristics
Acinetobacter baumannii is sometimes called Iraki bacter, since the germ attacked US soldiers between 2003 and 2004, who were stationed in Iraq and were injured in combat operations. Likewise, the germ of Bundeswehr soldiers who served in Afghanistan and suffered severe wounds showed up. Over the years Acinetobacter spread in the US and Europe and became a problematic germ. In German hospitals, patients who previously had hospital stays in Southeastern Europe, Eastern Europe, Southern Europe, Africa or Asia are classified as risk factors. So threatens a lugging in of the multidrug-resistant bacterium. The cause of the spread of Acinetobacter baumannii is the too frequent use of broad-spectrum antibiotics.
The bacterium Acinetobacter baumannii is one of the environmental germs. So the pathogen occurs on the one hand in water and soil and on the other hand on the human skin or in the intestine. Acinetobacter baumannii is believed to be part of its natural bacterial flora in around 25 percent of all people. Furthermore, the germ can be found on plants as well as in insects and parasites. In addition, Acinetobacter baumannii is counted among the opportunistic germs. So its spread always takes place under the best conditions. This means that the bacterium prefers to settle on sufferers or injured people who already have a weak immune system. Not infrequently the affected persons are already in the intensive care unit. Furthermore, a contagion from human to human is conceivable.
The name Acinetobacter is due to the fact that the bacterium is not endowed with flagella. Therefore, the germs are considered immobile. However, the bacteria do have the ability to move quickly on moist surfaces. Furthermore, the germs form biofilms and are able to persevere on surfaces for several weeks. These can be phones, computer keyboards or ventilators. Thus, the transmission of Acinetobacter baumannii takes place in hospitals usually by infested surfaces of medical devices or by the hands of employees there. Eventually even a transmission through the air is possible.
In addition to Acinetobacter baumannii, Acinetobacter nosocomialis and Acinetobacter pittii are of clinical importance in Germany. The correct identification of the respective species, however, is considered problematic because the Gram stain of the bacteria is variable and thus no reliable classification of the cocoa rods is possible. Also, biochemical methods do not allow identification of the germs at the species level. Thus, the finding ends mostly with a limitation in an ABC complex, but this is clinically unsatisfactory. However, a reliable identification can now be made, at least for Acinetobacter baumannii, by MALDI-TOF mass spectrometry.
Diseases & complaints
If a person is healthy, Acinetobacter baumannii is usually not dangerous for them. However, if they are already very ill or have low immune deficiency, there is a risk that the bacterium will lead to a hospital infection and severe pneumonia (pneumonia ) or blood poisoning (sepsis). Due to their severity, their course often leads to the death of the patient. Particularly at risk are people who are in the intensive care unit and there are artificially ventilated.
Other diseases that can be caused by Acinetobacter baumannii are wound infections and urinary tract infections. Various risk factors further promote infection with Acinetobacter baumannii. These include surgery without antibiotic treatment, ineffectiveness of the antibiotic, and the use of medical instruments such as respirators or catheters. Treatment of Acinetobacter infection, usually with reserve antibiotics, is very difficult.
Around the world, around 9 percent of all infections with bacteria that occur in intensive care units are said to be related to Acinetobacter. Especially in Asia, the morbidity rate is high at 19 percent. In Western European countries, the incidence of infection is about 6 percent. In Germany, two percent of all pneumonia is attributed to Acinetobacter baumannii.
However, it is possible to prevent the dangerous germ. Especially important are disinfecting, cleaning and insulating measures. The thorough washing of the hands of doctors, nurses, patients and hospital visitors plays a central role. In case of infection, the patient is severely isolated. Only after two different tests, in which Acinetobacter baumannii can no longer be detected, the patient may be released again.