Publications

Despite advances in bone graft design and surgical techniques, bacterial infection remains a major cause of graft failure, exacerbated by the global rise in antimicrobial resistance. This has intensified the pursuit of antibioticfree strategies to prevent bacterial colonization. Among these, antibacterial surface nanotopographies have emerged as promising tools, leveraging nanoscale geometries to physically disrupt bacteria upon contact. In this study, we engineered the surface of a calcium phosphate bone graft to confer antimicrobial functionality through a dual approach: the creation of high-aspect-ratio nanotopographies and ionic doping with fluoride. Through controlled hydrolysis of alpha-tricalcium phosphate by biomimetic and hydrothermal treatments, we generated calcium deficient hydroxyapatite nanoneedle structures whose morphology and biofunctionality were tuned via fluoride incorporation. XRD and Raman spectroscopy confirmed the formation of hydroxy-fluorapatite, with phase composition and surface morphology dependent on fluoride concentration and processing parameters. Fluoride doping significantly altered nanoneedle dimensions and spacing and enhanced bactericidal activity, particularly against P. aeruginosa, and to a lesser extent S. aureus. Notably, fluoride-doping alone showed no antibacterial effects; however, when combined with nanotopography, a synergistic increase in efficacy was observed. Importantly, the antimicrobial surfaces supported the proliferation and osteogenic differentiation of SaOS-2 cells. Co-culture assays modeling pre- and post-implantation infection scenarios demonstrated robust cell adhesion and markedly reduced bacterial colonization. In conclusion, our findings present a multifunctional, synthetic bone graft with both physical and chemical antibacterial properties, offering a promising strategy to mitigate infection risks while supporting osteointegration.

JTD Keywords: Antibacterial nanotopography, Bactericidal surfaces, Biomaterials, Bone regeneration, Calcium phosphate, Cements, Coatings, Cytokines, Fluoride, Hydroxyapatite, Infections, Magnesium, Pseudomonas-aeruginosa, Setting reaction

The bacterium Pseudomonas aeruginosa is involved in chronic infections of cystic fibrosis lungs and chronic wounds. In these infections the bacteria are present as aggregates suspended in host secretions. During the course of the infections there is a selection for mutants that overproduce exopolysaccharides, suggesting that the exopolysaccharides play a role in the persistence and antibiotic tolerance of the aggregated bacteria. Here, we investigated the role of individual P. aeruginosa exopolysaccharides in aggregate-associated antibiotic tolerance. We employed an aggregate-based antibiotic tolerance assay on a set of P. aeruginosa strains that were genetically engineered to over-produce a single, none, or all of the three exopolysaccharides Pel, Psl, and alginate. The antibiotic tolerance assays were conducted with the clinically relevant antibiotics tobramycin, ciprofloxacin and meropenem. Our study suggests that alginate plays a role in the tolerance of P. aeruginosa aggregates toward tobramycin and meropenem, but not ciprofloxacin. However, contrary to previous studies we did not observe a role for Psl or Pel in the tolerance of P. aeruginosa aggregates toward tobramycin, ciprofloxacin, and meropenem.Copyright © 2023 Liang, Nilsson, Kragh, Hedal, Alcàcer-Almansa, Kiilerich, Andersen and Tolker-Nielsen.

JTD Keywords: aggregates, antibiotic tolerance, biofilm formation, extracellular matrix, genome, growth, lungs, molecular-mechanisms, mutations, polysaccharide, pseudomonas aeruginosa, psl, system, Aggregates, Antibiotic tolerance, Biofilm, Extracellular matrix, Pseudomonas aeruginosa, Small-colony variants

Background and aims: In this work, breath samples from clinically stable bronchiectasis patients with and without bronchial infections by Pseudomonas Aeruginosa- PA) were collected and chemically analysed to determine if they have clinical value in the monitoring of these patients. Materials and methods: A cohort was recruited inviting bronchiectasis patients (25) and controls (9). Among the former group, 12 members were suffering PA infection. Breath samples were collected in Tedlar bags and analyzed by e-nose and Gas Chromatography-Mass Spectrometry (GC-MS). The obtained data were analyzed by chemometric methods to determine their discriminant power in regards to their health condition. Results were evaluated with blind samples. Results: Breath analysis by electronic nose successfully separated the three groups with an overall classification rate of 84% for the three-class classification problem. The best discrimination was obtained between control and bronchiectasis with PA infection samples 100% (CI95%: 84–100%) on external validation and the results were confirmed by permutation tests. The discrimination analysis by GC-MS provided good results but did not reach proper statistical significance after a permutation test. Conclusions: Breath sample analysis by electronic nose followed by proper predictive models successfully differentiated between control, Bronchiectasis and Bronchiectasis PA samples. © 2021 The Author(s)

JTD Keywords: biomarkers, breath analysis, bronchiectasis, diagnosis, e-nose, fingerprints, gc-ms, identification, lung-cancer, partial least-squares, pseudomonas-aeruginosa, signal processing, validation, volatile organic-compounds, Airway bacterial-colonization, Breath analysis, Bronchiectasis, E-nose, Gc-ms, Signal processing

The snore is a breathing sound that originates during sleep, either nocturnal or diurnal. Many procedures have been used for its analysis, from simple interrogation, going through acoustic methods that have been developed thanks to the advance of biomedical techniques in recent years. So far a procedure homologated by different laboratories for its study doesn’t exist. The present editorial describes the current state of the art in the snoring analysis procedures.

JTD Keywords: Snoring, Sleep apnea, OSAS