Person: Echeverz SarasĂșa, Maite
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Echeverz SarasĂșa
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Maite
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Ciencias de la Salud
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0000-0002-4153-4549
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810062
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Publication Open Access Salmonella biofilm development depends on the phosphorylation status of RcsB(American Society for Microbiology, 2012) Latasa Osta, Cristina; GarcĂa MartĂnez, Begoña; Echeverz SarasĂșa, Maite; Toledo Arana, Alejandro; Valle Turrillas, Jaione; Campoy SĂĄnchez, Susana; GarcĂa del Portillo, Francisco; Solano Goñi, Cristina; Lasa Uzcudun, Ăñigo; IdAB. Instituto de AgrobiotecnologĂa / Agrobioteknologiako Institutua; Gobierno de Navarra / Nafarroako Gobernua: IIM13329.RI1The Rcs phosphorelay pathway is a complex signaling pathway involved in the regulation of many cell surface structures in enteric bacteria. In response to environmental stimuli, the sensor histidine kinase (RcsC) autophosphorylates and then transfers the phosphate through intermediary steps to the response regulator (RcsB), which, once phosphorylated, regulates gene expression. Here, we show that Salmonella biofilm development depends on the phosphorylation status of RcsB. Thus, unphosphorylated RcsB, hitherto assumed to be inactive, is essential to activate the expression of the biofilm matrix compounds. The prevention of RcsB phosphorylation either by the disruption of the phosphorelay at the RcsC or RcsD level or by the production of a nonphosphorylatable RcsB allele induces biofilm development. On the contrary, the phosphorylation of RcsB by the constitutive activation of the Rcs pathway inhibits biofilm development, an effect that can be counteracted by the introduction of a nonphosphorylatable RcsB allele. The inhibition of biofilm development by phosphorylated RcsB is due to the repression of CsgD expression, through a mechanism dependent on the accumulation of the small noncoding RNA RprA. Our results indicate that unphosphorylated RcsB plays an active role for integrating environmental signals and, more broadly, that RcsB phosphorylation acts as a key switch between planktonic and sessile life-styles in Salmonella enterica serovar Typhimurium.Publication Open Access Role of sodium salicylate in Staphylococcus aureus quorum sensing, virulence, biofilm formation and antimicrobial susceptibility(Frontiers Media, 2022) Turner, Adam Benedict; Gerner, Erik; Firdaus, Rininta; Echeverz SarasĂșa, Maite; WerthĂ©n, MarĂa; Thomsen, Peter; Almqvist, SofĂa; Trobos, Margarita; Ciencias de la Salud; Osasun ZientziakThe widespread threat of antibiotic resistance requires new treatment options. Disrupting bacterial communication, quorum sensing (QS), has the potential to reduce pathogenesis by decreasing bacterial virulence. The aim of this study was to investigate the influence of sodium salicylate (NaSa) on Staphylococcus aureus QS, virulence production and biofilm formation. In S. aureus ATCC 25923 (agr III), with or without serum, NaSa (10 mM) downregulated the agr QS system and decreased the secretion levels of alpha-hemolysin, staphopain A and delta-hemolysin. Inhibition of agr expression caused a downregulation of delta-hemolysin, decreasing biofilm dispersal and increasing biofilm formation on polystyrene and titanium under static conditions. In contrast, NaSa did not increase biofilm biomass under flow but caused one log10 reduction in biofilm viability on polystyrene pegs, resulting in biofilms being twice as susceptible to rifampicin. A concentrationdependent effect of NaSa was further observed, where high concentrations (10 mM) decreased agr expression, while low concentrations (â€0.1 mM) increased agr expression. In S. aureus 8325-4 (agr I), a high concentration of NaSa (10 mM) decreased hla expression, and a low concentration of NaSa (â€1 mM) increased rnaIII and hla expression. The activity of NaSa on biofilm formation was dependent on agr type and material surface. Eight clinical strains isolated from prosthetic joint infection (PJI) or wound infection belonging to each of the four agr types were evaluated. The four PJI S. aureus strains did not change their biofilm phenotype with NaSa on the clinically relevant titanium surface. Half of the wound strains (agr III and IV) did not change the biofilm phenotype in the 3D collagen wound model. In addition, compared to the control, ATCC 25923 biofilms formed with 10 mM NaSa in the collagen model were more susceptible to silver. It is concluded that NaSa can inhibit QS in S. aureus, decreasing the levels of toxin production with certain modulation of biofilm formation. The effect on biofilm formation was dependent on the strain and material surface. It is suggested that the observed NaSa inhibition of bacterial communication is a potential alternative or adjuvant to traditional antibiotics.Publication Open Access Insights into c-di-GMP signaling and the PGA exopolysaccharide biological functions using Salmonella as a model organism(2017) Echeverz SarasĂșa, Maite; Lasa Uzcudun, Ăñigo; Solano Goñi, Cristina; ProducciĂłn Agraria; Nekazaritza EkoizpenaSalmonella es un patĂłgeno alimentario de gran relevancia clĂnica capaz de adherirse a superficies y formar comunidades bacterianas embebidas en una matriz que ellas mismas producen denominadas biofilms. Esta matriz confiere a las bacterias protecciĂłn frente a agentes externos, aumentando su tolerancia frente a condiciones ambientales adversas, agentes antimicrobianos o el sistema inmune del hospedador. Existe una vĂa de señalizaciĂłn, mediada por el dinucleĂłtido cĂclico, c-di- GMP, que controla en muchas especies bacterianas la sĂntesis de diversos componentes de la matriz del biofilm, de manera que concentraciones elevadas de este nucleĂłtido activan la producciĂłn de la matriz y por lo tanto del biofilm. La formaciĂłn de biofilms en explotaciones agropecuarias y lugares donde se procesan alimentos es una fuente potencial de contaminaciĂłn y de transmisiĂłn de este patĂłgeno. Diversas medidas de higiene y seguimiento han sido implementadas por las autoridades para el control de esta bacteria; sin embargo alrededor de 93 millones de personas en todo el mundo sufren salmonelosis cada año. Por ello, la bĂșsqueda de medidas alternativas de control, basadas en la vacunaciĂłn animal, asĂ como el estudio de los mecanismos de patogenicidad y formaciĂłn de biofilm de Salmonella han sido el objeto de este trabajo.Publication Open Access Functional analysis of intergenic regulatory regions of genes encoding surface adhesins in Staphylococcus aureus isolates from periprosthetic joint infections(Elsevier, 2022) Morales Laverde, Liliana Andrea; Trobos, Margarita; Echeverz SarasĂșa, Maite; Solano Goñi, Cristina; Lasa Uzcudun, Ăñigo; Ciencias de la Salud; Osasun ZientziakStaphylococcus aureus is a leading cause of prosthetic joint infections (PJI). Surface adhesins play an important role in the primary attachment to plasma proteins that coat the surface of prosthetic devices after implantation. Previous efforts to identify a genetic component of the bacterium that confers an enhanced capacity to cause PJI have focused on gene content, kmers, or single-nucleotide polymorphisms (SNPs) in coding sequences. Here, using a collection of S. aureus strains isolated from PJI and wounds, we investigated whether genetic variations in the regulatory region of genes encoding surface adhesins lead to differences in their expression levels and modulate the capacity of S. aureus to colonize implanted prosthetic devices. The data revealed that S. aureus isolates from the same clonal complex (CC) contain a specific pattern of SNPs in the regulatory region of genes encoding surface adhesins. As a consequence, each clonal lineage shows a specific profile of surface proteins expression. Co-infection experiments with representative isolates of the most prevalent CCs demonstrated that some lineages have a higher capacity to colonize implanted catheters in a murine infection model, which correlated with a greater ability to form a biofilm on coated surfaces with plasma proteins. Together, results indicate that differences in the expression level of surface adhesins may modulate the propensity of S. aureus strains to cause PJI. Given the high conservation of surface proteins among staphylococci, our work lays the framework for investigating how diversification at intergenic regulatory regions affects the capacity of S. aureus to colonize the surface of medical implants.