Acinetobacter baumannii

***Acinetobacter baumannii*** (***A. baumannii***) is a pathogenic bacterial species that causes disease in humans. It is commonly found in soil and water. _A. baumannii_ is the most important member of the Acinetobacter genus associated with infections gained in hospitals. A._Baumannii is resistant_ to a specific class of antibiotic called carbapenems. Carbapenems-resistant _Acinetobacter_ infection is common in hospitals and is very dangerous. In 2017, it resulted in an estimated 8,500 infections in hospital patients and 700 deaths in the United States of America. The World Health Organisation (WHO) released a list of top bacteria pathogens of concern, called ESKAPE pathogens, due to their high levels of antibiotic resistance. _A. baumannii_ was named as one of the most dangerous ESKAPE pathogens. In order to treat _A. baumannii_ effectively, it is important to understand how it acts as pathogen and its mechanism of antibiotic resistance.

## Biology

_A. baumannii_ are short and rod-shaped. They average between 1.0 and 1.5 micrometers in length. They do not all look the same and can vary in size and shape. _Acinetobacter_ do not have a flagella, a tail-like structure used by many bacteria to move around. They are immobile but sometimes twitch and swarm to move around.

## Habitat

The first _Acinetobacter_ was found in the soil by M.W. Beijerink in 1911. Since then, it has also been found in water, animals, and humans. _A. baumannii_ are often found in hospitals and makeup almost 15% of infections that are transmitted in hospitals. _A. baumannii_ target moist environments. The respiratory tract, blood, open wounds, skin, and eyes are all possible sites of infection.

## Hospital infections

_A. baumannii_ can cause many different diseases with different symptoms. Types of infection include pneumonia, bloodstream infections, meningitis, skin and bone infections and urinary tract infections. The most common infections are pneumonia and bloodstream infections. Factors that increase the risk of infection include a weak immune system, long hospital stays, hospital ventilators and the tubes used on them, and having an open wound.

It can be difficult to tell the difference between symptoms of _A. baumannii_ infection and symptoms of other hospital infections. Symptoms include fever, rash, confusion, urinating pain, nausea, muscle and chest pains, breathing difficulties, and coughing.

_A. baumannii_ is spread through contact with contaminated surfaces, objects, and skin of contaminated patients. It can survive on surfaces for a long time before infecting new patients making it an effective pathogen.

## Treatment

Carbapenems are a type of antibiotics that have been used to treat _Acinetobacter baumannii_ infections. These antibiotics are effective in treating infection. However, _A. baumannii_ can develop tolerance to this antibiotic. This tolerance makes it harder to treat infections. Carbapenems-resistant _A. baumannii_ can spread their tolerance to other types of bacteria. This is dangerous in healthcare settings because if many bacteria are tolerant to carbapenems, the antibiotic cannot be used to treat infections anymore. _A. baumannii_ can be tolerant to multiple antibiotics making infections difficult to treat.

Polymyxins are another antibiotic used to treat _A. baumannii_ infection. These are effective against infection but polymyxins can be toxic to the kidneys.

Combination therapies can also be used to treat _A. baumannii_ which is tolerant to many different types of antibiotics. This means treating the infection with a combination of different drugs at the same time. Different combinations are still being tested against _A. baumannii_ infections.

## Prevention of infection

Preventing and controlling outbreaks of _A. baumannii_ is very important. Preventing infections will reduce the number of infections in hospitals and help stop the spread of antibiotic resistance.

_A. baumannii_ can be controlled with strict infection control measures such as educating hospital staff about the dangers of spreading hospital infections, proper hand washing, cleaning of hospitals and actively testing surfaces for the presence of _A. baumannii__._ These measures have been shown to reduce the spread of _A. baumannii_ and reduce tolerance to antibiotics. However, all measures must be followed strictly to control infection.

## Related pages

- Influenza