Community-acquired Acinetobacter baumannii: clinical characteristics, epidemiology and pathogenesis

Abstract

Community-acquired Acinetobacter baumannii (CA-Ab) is a rare but serious cause of community-acquired pneumonia in tropical regions of the world. CA-Ab infections predominantly affect individuals with risk factors, which include excess alcohol consumption, diabetes mellitus, smoking and chronic lung disease. CA-Ab pneumonia presents as a surprisingly fulminant course and is characterized by a rapid onset of fever, severe respiratory symptoms and multi-organ dysfunction, with a mortality rate reported as high as 64%. It is unclear whether the distinct clinical syndrome caused by CA-Ab is because of host predisposing factors or unique bacterial characteristics, or a combination of both. Deepening our understanding of the drivers of overwhelming CA-Ab infection will provide important insights into preventative and therapeutic strategies.

Keywords:

• A. baumannii
• CA-Ab
• community-acquired pneumonia
• ethanol

Financial & competing interests disclosure

AY Peleg was supported by an Australian National Health and Medical Research Council Career Development Fellowship. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Community-acquired Acinetobacter baumannii (CA-Ab) is a rare but serious cause of community-acquired pneumonia.

• The majority of CA-Ab infections occur in regions with hot and humid climates.

• Risk factors for developing CA-Ab infections include excess alcohol consumption, smoking, diabetes mellitus and chronic lung disease.

• CA-Ab infections are caused by a diverse range of strains and are distinct from hospital strains.

• Without appropriate initial antibiotic therapy, mortality rate has been reported to be as high as 64%.

• Implementation of treatment protocols to include antibiotics that cover Acinetobacter species in Northern Australia has considerably reduced the mortality rate from CA-Ab pneumonia.