title: Proteomic and functional analyses reveal a unique lifestyle for Acinetobacter baumannii biofilms and a key role for histidine metabolism.
abstract: Biofilm formation is one of the main causes for the persistence of Acinetobacter baumannii, a pathogen associated with severe infections and outbreaks in hospitals. Here, we performed comparative proteomic analyses (2D-DIGE and MALDI-TOF/TOF and iTRAQ/SCX-LC-MS/MS) of cells at three different conditions: exponential, late stationary phase, and biofilms. These results were compared with alterations in the proteome resulting from exposure to a biofilm inhibitory compound (salicylate). Using this multiple-approach strategy, proteomic patterns showed a unique lifestyle for A. baumannii biofilms and novel associated proteins. Several cell surface proteins (such as CarO, OmpA, OprD-like, DcaP-like, PstS, LysM, and Omp33), as well as those involved in histidine metabolism (like Urocanase), were found to be implicated in biofilm formation, this being confirmed by gene disruption. Although l-His uptake triggered biofilms efficiently in wild-type A. baumannii, no effect was observed in Urocanase and OmpA mutants, while a slight increase was observed in a CarO deficient strain. We conclude that Urocanase plays a crucial role in histidine metabolism leading to biofilm formation and that OmpA and CarO can act as channels for L-His uptake. Finally, we propose a model in which novel proteins are suggested for the first time as targets for preventing the formation of A. baumannii biofilms.
authors: Laboratorio de Microbiología, Instituto de Investigación Biomédica de A Coruña (INIBIC), Servicio de Microbiología, Complejo Hospitalario Universitario A Coruña (CHUAC), As Xubias s/n; La Coruña, Spain.
authors: Maria P
authors: MP
authors: Cabral
authors: Nelson C
authors: NC
authors: Soares
authors: Jesús
authors: J
authors: Aranda
authors: José R
authors: JR
authors: Parreira
authors: Carlos
authors: C
authors: Rumbo
authors: Margarita
authors: M
authors: Poza
authors: Jaione
authors: J
authors: Valle
authors: Valentina
authors: V
authors: Calamia
authors: Iñigo
authors: I
authors: Lasa
authors: Germán
authors: G
authors: Bou