Biofilm formation as a virulence factor of Acinetobacter baumannii: An emerging pathogen in critical care units

Abstract

Acinetobacter baumannii, an emerging nosocomial pathogen, is increasingly associated with serious infections among hospitalized patients, especially those on life-support systems. A. baumannii has become resistant to almost all currently available antibacterial agents, including carbapenems, which were once considered the drug of choice for the treatment of infections with multidrug-resistant (MDR) organisms. A. baumannii is notorious in its ability to spread among hospitalized patients and causes outbreaks which have been reported worldwide. The capability of these strains to circulate widely seems to depend on the expression of virulence factors that allow bacterial colonization as well as on the expression of antibiotic resistance. Biofilm production by A. baumannii appears to be one of the major contributing factors in colonization, notably of medical devices. This review explores published literature on the association of biofilms and MDR A. baumannii in hospitalized patients. An online search was made for articles of original work and reviews on biofilms production among Acinetobacter and their association with virulence. The articles were reviewed and results were analyzed based on biofilm production and the factors associated with it, namely biofilm cycle, biofilm-associated protein, chaperone-usher secretion system, and quorum sensing.