Margarita Trobos - Academia.edu (original) (raw)

Papers by Margarita Trobos

Journal of materials research and technology, Jul 1, 2023

Frontiers in Bioengineering and Biotechnology, 2016

Microbiology spectrum, Aug 31, 2022

The approach of sequencing or genotyping to characterize the pathogenic potential of staphylococc... more The approach of sequencing or genotyping to characterize the pathogenic potential of staphylococci from orthopedic device-related infection (ODRI) has been applied in recent studies. These studies described the genomic carriage of virulence in clinical strains and compared it with those in commensal strains. Only a few studies have directly correlated genomic profiles to patient outcome and phenotypic virulence properties in periprosthetic joint infections (PJIs). We investigated the association between genomic variations and virulence-associated phenotypes (biofilmforming ability and antimicrobial resistance) in 111 staphylococcal strains isolated from patients with PJI and the infection outcome (resolved/unresolved). The presence of a strong biofilm phenotype in Staphylococcus aureus and an antibiotic-resistant phenotype in Staphylococcus epidermidis were both associated with treatment failure of PJI. In S. epidermidis, multidrug resistance (MDR) and resistance to rifampicin were associated with unresolved infection. Sequence type 45 (ST45) and ST2 were particularly enriched in S. aureus and S. epidermidis, respectively. S. epidermidis ST2 caused the majority of relapses and was associated with MDR and strong biofilm production, whereas ST215 correlated with MDR and non/weak biofilm production. S. aureus agr II correlated with resolved infection, while S. epidermidis agr I was associated with strong biofilm production and agr III with non/weak production. Collectively, our results highlight the importance of careful genomic and phenotypic characterization to anticipate the probability of the strain causing treatment failure in PJI. Due to the high rate of resistant S. epidermidis strains identified, this study provides evidence that the current recommended treatment of rifampicin and a fluoroquinolone should not be administered without knowledge of the resistance pattern. IMPORTANCE This study addresses the presence and frequency of particular genetic variants and virulence factors found in staphylococcal bacteria causing periprosthetic joint infection (PJI) of the hip and knee to ascertain their clinical relevance as predictors of treatment failure. We characterized the genetic virulence traits of a large collection of clinical staphylococci isolated from patients with PJI and evaluated their association with the patient's infection outcome. The results showed that S. aureus strains that produced strong biofilms and S. epidermidis strains with resistance to several antibiotics associated significantly with unresolved infection. Some particular genetic variants associated with biofilm formation and multidrug resistance. These

BMJ Open, Sep 1, 2022

Treatment of periprosthetic joint infections guided by minimum biofilm eradication concentration ... more Treatment of periprosthetic joint infections guided by minimum biofilm eradication concentration (MBEC) in addition to minimum inhibitory concentration (MIC): protocol for a prospective randomised clinical trial. BMJ Open 2022;12:e058168.

Materials advances, 2023

In this work, porous FeMn(-xAg) alloys are fabricated through powder metallurgy methods. The effe... more In this work, porous FeMn(-xAg) alloys are fabricated through powder metallurgy methods. The effects of porosity and Ag addition on the microstructure, biodegradability, magnetic and mechanical properties of the alloys are investigated. Studies on the cytocompatibility, inflammatory cytokine response and antibacterial effect are also conducted. The fabricated alloys exhibit a macro-and nanoporous structure, with uniformly distributed silver particles. The biodegradability tests reveal that the release of Mn to the Hank's solution is higher than that of Fe, without significant differences between the alloys. The degradation products consist mainly of Fe, Mn, O and compounds enriched in Ca, P and Cl. As-sintered alloys show a low saturation magnetization value (below 1 emu g À1), which does not increase significantly with immersion time. The results on biocompatibility indicate that all tested alloys are non-cytotoxic, but the addition of Ag might interfere with cell proliferation. However, the ions released by the FeMn(-xAg) alloys do not induce an inflammatory response in macrophages. The obtained results on microbiological interactions reveal that although no significant bactericidal effect is observed at 4 h between FeMn control and FeMn-5Ag, a significant reduction in the total biofilm biomass of both live and dead bacteria is observed after 24 h in Ag containing FeMn-5Ag surfaces.

Clinical Implant Dentistry and Related Research, Jun 25, 2023

BackgroundNonresorbable membranes promote bone formation during guided bone regeneration (GBR), y... more BackgroundNonresorbable membranes promote bone formation during guided bone regeneration (GBR), yet the relationships between membrane properties and molecular changes in the surrounding tissue are largely unknown.AimTo compare the molecular events in the overlying soft tissue, the membrane, and the underlying bone defect during GBR using dual‐layered expanded membranes versus dense polytetrafluoroethylene (PTFE) membranes.Materials and MethodsRat femur defects were treated with either dense PTFE (d‐PTFE) or dual‐layered expanded PTFE (dual e‐PTFE) or left untreated as a sham. Samples were collected after 6 and 28 days for gene expression, histology, and histomorphometry analyses.ResultsThe two membranes promoted the overall bone formation compared to sham. Defects treated with dual e‐PTFE exhibited a significantly higher proportion of new bone in the top central region after 28 days. Compared to that in the sham, the soft tissue in the dual e‐PTFE group showed 2‐fold higher expression of genes related to regeneration (FGF‐2 and FOXO1) and vascularization (VEGF). Furthermore, compared to cells in the d‐PTFE group, cells in the dual e‐PTFE showed 2.5‐fold higher expression of genes related to osteogenic differentiation (BMP‐2), regeneration (FGF‐2 and COL1A1), and vascularization (VEGF), in parallel with lower expression of proinflammatory cytokines (IL‐6 and TNF‐α). Multiple correlations were found between the molecular activities in membrane‐adherent cells and those in the soft tissue.ConclusionSelective surface modification of the two sides of the e‐PTFE membrane constitutes a novel means of modulating the tissue response and promoting bone regeneration.

Frontiers in Cellular and Infection Microbiology

IntroductionChronic infections are a major clinical challenge in hard-to-heal wounds and implante... more IntroductionChronic infections are a major clinical challenge in hard-to-heal wounds and implanted devices. Pseudomonas aeruginosa is a common causative pathogen that produces numerous virulence factors. Due to the increasing problem of antibiotic resistance, new alternative treatment strategies are needed. Quorum sensing (QS) is a bacterial communication system that regulates virulence and dampens inflammation, promoting bacterial survival. QS inhibition is a potent strategy to reduce bacterial virulence and alleviate the negative impact on host immune response.AimThis study investigates how secreted factors from P. aeruginosa PAO1, cultured in the presence or absence of the QS inhibitor sodium salicylate (NaSa), influence host immune response.Material and methodsIn vitro, THP-1 macrophages and neutrophil-like HL-60 cells were used. In vivo, discs of titanium were implanted in a subcutaneous rat model with local administration of P. aeruginosa culture supernatants. The host immune ...

Surface and Coatings Technology

Microbiology Spectrum

This study addresses the presence and frequency of particular genetic variants and virulence fact... more This study addresses the presence and frequency of particular genetic variants and virulence factors found in staphylococcal bacteria causing periprosthetic joint infection (PJI) of the hip and knee to ascertain their clinical relevance as predictors of treatment failure. We characterized the genetic virulence traits of a large collection of clinical staphylococci isolated from patients with PJI and evaluated their association with the patient’s infection outcome.

Materials Advances

Equiatomic FeMn alloys with varying Ag content (1–5 wt%) and hierarchical porosity show low ferro... more Equiatomic FeMn alloys with varying Ag content (1–5 wt%) and hierarchical porosity show low ferromagnetic response during biodegradation and reduction in the total biofilm biomass upon interaction with S. aureus for 5 wt% Ag containing materials.

Biofilm

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

BMJ Open

IntroductionProsthetic joint infections (PJIs) are disastrous complications for patients and cost... more IntroductionProsthetic joint infections (PJIs) are disastrous complications for patients and costly for healthcare organisations. They may promote bacterial resistance due to the extensive antibiotic use necessary in the PJI treatment. The PJI incidence is estimated to be 1%–3%, but the absolute numbers worldwide are high and increasing as large joint arthroplasties are performed by the millions each year. Current treatment algorithms, based on implant preserving surgery or full revision followed by a semitailored antibiotic regimen for no less than 2–3 months, lead to infection resolution in approximately 60% and 90%, respectively. Antibiotic choice is currently guided by minimum inhibitory concentrations (MICs) of free-living bacteria and not of bacteria in biofilm growth mode. Biofilm assays with relatively rapid output for the determination of minimum biofilm eradication concentrations (MBECs) have previously been developed but their clinical usefulness have not been established...

transfer of sulphonamide and ampicillin resistance between

Frontiers in Microbiology

The widespread threat of antibiotic resistance requires new treatment options. Disrupting bacteri... more The 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 concentration-dependent effect of NaSa was furth...

Frontiers in Neuroscience

PurposeTo investigate the molecular activities in different compartments around the bone-anchored... more PurposeTo investigate the molecular activities in different compartments around the bone-anchored hearing system (BAHS) with either electropolished or machined abutments and to correlate these activities with clinical and microbiological findings.Materials and methodsTwelve patients received machined or electropolished abutments after implant installation of BAHS. Peri-abutment fluid and tissue were collected from baseline to 12 months. Gene expression of cytokines and factors related to tissue healing and inflammation, regeneration and remodelling, as well as bacterial recognition were determined using quantitative-polymerase chain reaction (qPCR). The clinical status was evaluated using the Holgers scoring system, and bacterial colonisation was investigated by culturing.ResultsThe gene expression of inflammatory cytokines (IL-8, IL-1β, and IL-10) and bacteria-related Toll-like receptors (2 and 4) was higher in the peri-abutment fluid than at baseline and in the peri-abutment tissu...

Microorganisms

Staphylococcus aureus is a leading cause of prosthetic joint infections (PJI) characterized by ba... more Staphylococcus aureus is a leading cause of prosthetic joint infections (PJI) characterized by bacterial biofilm formation and recalcitrance to immune-mediated clearance and antibiotics. The molecular events behind PJI infection are yet to be unraveled. In this sense, identification of polymorphisms in bacterial genomes may help to establish associations between sequence variants and the ability of S. aureus to cause PJI. Here, we report an experimental nucleotide-level survey specifically aimed at the intergenic regions (IGRs) of the icaADBCR locus, which is responsible for the synthesis of the biofilm exopolysaccharide PIA/PNAG, in a collection of strains sampled from PJI and wounds. IGRs of the icaADBCR locus were highly conserved and no PJI-specific SNPs were found. Moreover, polymorphisms in these IGRs did not significantly affect transcription of the icaADBC operon under in vitro laboratory conditions. In contrast, an SNP within the icaR coding region, resulting in a V176E cha...

Objective: Autologous bone or inert alloplastic materials are today utilized in cranial reconstru... more Objective: Autologous bone or inert alloplastic materials are today utilized in cranial reconstructions. Recent clinical data report 20-30 % complication rates with these techniques. In this context, new innovations in cranial repair are needed. In the present study we report comprehensive evidence[for full text, please go to the a.m. URL]