Caracterización de nuevos factores de virulencia del patógeno nosocomial "Acinetobacter baumannii"

Resumo

Acinetobacter baumannii is an opportunist pathogen that has emerged in the last years as one of the most dangerous microorganisms living in hospital environments. In the present work two new virulence factors, that could partially explain the ability of A. baumannii to cause an infection, have been characterized. The LH92_11085 gene of the A. baumannii MAR002 strain, involved in the formation of a chaperone-usher pilus system, was found as over-expressed in biofilm cells compared to planktonic cells. The inactivation of this gene resulted in a reduction in the capacity of the MAR002 strain to form biofilm and to adhere to human epithelial cells and in a decrease in virulence. The A1S_0242 gene (feoA) from the A. baumannii ATCC 17978 strain, which is involved in iron uptake and that was found as over-expressed during the course of a pneumonia infection, plays a role in adhesion, biofilm formation, resistance to oxidative stress and in virulence. Data obtained in this work demostrate the contribution of both genes to the pathogenesis of A. baumannii.