title: Molecular mechanisms involved in the response to desiccation stress and persistence in Acinetobacter baumannii.
abstract: Desiccation tolerance contributes to the maintenance of bacterial populations in hospital settings and may partly explain its propensity to cause outbreaks. Identification and relative quantitation of proteins involved in bacterial desiccation tolerance was made using label-free quantitation and iTRAQ labeling. Under desiccating conditions, the population of the Acinetobacter baumannii clinical strain AbH12O-A2 decreased in the first week, and thereafter, a stable population of 0.5% of the original population was maintained. Using label-free quantitation and iTRAQ labeling, 727 and 765 proteins, respectively, were detected; 584 of them by both methods. Proteins overexpressed under desiccation included membrane and periplasmic proteins. Proteins associated with antimicrobial resistance, efflux pumps, and quorum quenching were overexpressed in the samples subjected to desiccation stress. Electron microscopy revealed clear morphological differences between desiccated and control bacteria. We conclude that A. baumannii is able to survive long periods of desiccation through the presence of cells in a dormant state, via mechanisms affecting control of cell cycling, DNA coiling, transcriptional and translational regulation, protein stabilization, antimicrobial resistance, and toxin synthesis, and that a few surviving cells embedded in a biofilm matrix are able to resume growth and restore the original population in appropriate environmental conditions following a "bust-and-boom" strategy.
authors.affiliation: Microbiology Division, INIBIC-Complejo Hospitalario Universitario de la Coruña , Xubias s/n, 3a Planta Ed. Sur 15006 La Coruña, Spain.
authors.forename: Carmen M
authors.initials: CM
authors.lastname: Gayoso
authors.forename: Jesús
authors.initials: J
authors.lastname: Mateos
authors.forename: José A
authors.initials: JA
authors.lastname: Méndez
authors.forename: Patricia
authors.initials: P
authors.lastname: Fernández-Puente
authors.forename: Carlos
authors.initials: C
authors.lastname: Rumbo
authors.forename: María
authors.initials: M
authors.lastname: Tomás
authors.forename: Oskar
authors.initials: O
authors.lastname: Martínez de Ilarduya
authors.forename: Germán
authors.initials: G
authors.lastname: Bou
mesh_terms: D040981:Acinetobacter baumannii / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D001426:Bacterial Proteins / Q000378:metabolism; D018441:Biofilms; D002853:Chromatography, Liquid; D003890:Desiccation; D004591:Electrophoresis, Polyacrylamide Gel; D046529:Microscopy, Electron, Transmission; D025341:Principal Component Analysis; D040901:Proteomics; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013312:Stress, Physiological
chemical_list: D001426:Bacterial Proteins