Acinetobacter baumannii
Acinetobacter baumannii is an opportunistic pathogen – a bacterial species that does not usually cause disease in healthy people but can cause disease in individuals with weakened immune systems or those with a pre-existing infection or medical condition. It is primarily associated with hospital-acquired infections (nosocomial infections).
Mechanism of transmission: through direct contact from the skin, food, water, soil, or contaminated surfaces (particularly in hospitals)
Number of cases annually: the global incidence of Acinetobacter baumannii infections is estimated to be more than 1 million cases per year1
Acinetobacter baumannii infections
Acinetobacter baumannii can cause serious infections in the lungs, urinary tract, blood, and brain, and at wound sites around the body. It can result in a range of diseases including:
- Urinary tract infections (UTIs) – infection of the ureter, kidneys, or bladder; the bacteria may enter through a catheter that is used to drain urine in hospital
- Pneumonia – infection of the lungs via the mouth or nose; occurs most frequently in ICU patients who are on a ventilator (breathing machine)
- Meningitis – infection of the protective membranes surrounding the brain or spinal cord; may occur following brain or spinal surgery or having a shunt (a hollow tube used to drain fluid from around the brain or spine)
- Bacteraemia – infection of the bloodstream, either directly from a catheter placed into the vein or when infection spreads from other body sites into the blood
Anyone can get an Acinetobacter baumannii infection but there are certain risk factors that massively increase the chance of infection. These include having a pre-existing disease or medical condition, having an open wound(s) due to an accident or injury, and having had recent surgery or a procedure such as insertion of a catheter. A. baumannii infections rarely occur in otherwise healthy individuals or outside of healthcare settings.
Antibiotic resistance
Antibiotic resistance arises when disease-causing bacteria evolve ways to survive exposure to antibiotics. A. baumannii bacteria found in hospital environments are often resistant to one or multiple antibiotics, which means successful treatment can be difficult. Many infections can be very challenging to treat as they are resistant to a powerful group of antibiotics called carbapenems. These infections are referred to as CRAB, carbapenem-resistant Acinetobacter infections.
The World Health Organisation (WHO) considers A. baumannii to be of critical priority for research into AMR and for development of new antibiotics to treat it. It is a member of the ‘ESKAPE’ group of bacteria (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.), which are considered to cause the most problematic nosocomial infections due to their severity and high rates of antibiotic resistance.
Genomics and Acinetobacter baumannii
Acinetobacter baumannii infections are an increasing threat due to the rising rates of resistance against key antibiotics such as carbapenems. Genome data can be used to study the evolution and diversity of genes encoding antibiotic resistance mechanisms, along with other key factors which affect the incidence and severity of infections. This research is critical to increase our understanding of A. baumannii and to help develop strategies that can be used to tackle this disease.
If you are keen to find out more about Acinetobacter baumannii, these websites are good places to go for more information:
