IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
PHYSIOLOGICAL ROLE OF AN OUTER MEMBRANE PROTEIN OF Acinetobacter baumannii ASSOCIATED TO CARBAPENEM RESISTANCE
Autor/es:
MUSSI, A.; RELLING. V.; ADRIANA LIMANSKY; VIAL
Lugar:
Rosario
Reunión:
Congreso; SAIB 2006; 2006
Resumen:
We previously demonstrated that acquisition of resistance to b-lactam carbapenems among multidrug-resistant isolates of the Gram-negative nosocomial pathogen A. baumannii is associated to the loss of an outer membrane protein (OMP) of 29 kDa designated CarO. DNA sequence determination and OM analysis including SDS-PAGE, immunoblotting, and MALDI-TOF revealed two mechanisms responsible for the absence of CarO in carbapenem resistant strains: 1) disruption of the carO gene by insertion elements (IS) and, 2) the existence of allelic variants of CarO with distinctive immunogenic properties. Also, two-dimensional SDS-PAGE and immunoblotting of OM fractions of both carbapenem-sensititive and carbapenem-resistant A. baumannii strains indicated that all CarO variants formed stable oligomers, a property distinctive of OM channels. We also provided evidence that CarO represents a selective channel for basic amino acids. The overall data support the hypothesis that CarO represents a novel and selective OM channel for compounds structurally related to basic amino acids such as the carbapenems through the A. baumannii OM, and that the evolution of resistance to these b-lactams in the clinical setting could result from either the natural deletion of the carO gene by endogenous IS or the accumulation of specific mutations that result in substantial restrictions to the entrance of these antibiotics.