Managing Acinetobacter Baumannii Infections

José Garnacho-Montero; Jean-François Timsit


Curr Opin Infect Dis. 2019;32(1):69-76. 

In This Article

Abstract and Introduction


Purpose of review: We reviewed recent data about epidemiology of Acinetobacter baumannii, resistance mechanisms, and therapeutic options for severe infections caused by multidrug-resistant strains.

Recent findings: A. baumannii is a major cause of nosocomial infections affecting mainly to debilitating patients in the ICU, although the spread to regular wards and to long-term care facilities is increasing. It is characterized by its great persistence in the environment and to have an extraordinary capability to develop resistance to all antimicrobials. Carbapenems may not be considered the treatment of choice in areas with high rates of carbapenem-resistant A. baumannii. Nowadays, polymyxins are the antimicrobials with the greatest level of in-vitro activity against A. baumannii. Colistin is the most widely used in clinical practice although polymyxin B seems to be associated with less renal toxicity. Colistin is administered intravenously as its inactive prodrug colistimethate. A loading dose of 9 million IU and subsequently high, extended-interval maintenance doses (4.5 million IU/12 h) are recommended. Combination therapy instead of monotherapy increases the rates of microbiological eradication although no clinical study has demonstrated a reduction in clinical outcomes (mortality or length of stay).

Summary: The optimal treatment for multidrug-resistant A. baumannii nosocomial infections has not been established. There are no compelling data to recommend combination therapy for severe A. baumannii infections.


Acinetobacter baumannii is a gram-negative aerobic bacillus that primarily causes hospital-acquired infections affecting specially to debilitated patients with prolonged hospitalization and with long-term exposition to antimicrobials. Until now, the ICUs have been considered as the epicenters of A. baumannii infections. Nevertheless, spread to general wards and long-term care facilities have also been shown to play an important role.

A. baumannii exhibits a wide variety of mechanisms of resistance to antimicrobial agents. This phenomenon has increasingly become a cause for serious concern for stakeholders and the scientific community worldwide. Thus, the WHO published its first list of 'priority pathogens' resistant to antibiotics, which includes the 12 families of bacteria most dangerous for human health and for that new antibiotics are urgently needed. In this list, A. baumannii is considered as 'priority 1' (critical).[1]