Bioengineering Approaches to Fight against Orthopedic Biomaterials Related-Infections

Recent advancements and future directions in fracture related infections: A scoping review

Fracture-related infections (FRIs) are complex challenges in orthopedic and trauma surgery, driving ongoing advancements in diagnostics, therapeutics, and management strategies. This scoping review examines recent progress and future directions in FRI management. Diagnostic enhancements encompass standardized definitions, improved biomarkers, advanced microbiological techniques, and innovative imaging modalities. Promising future diagnostics may include point-of-care testing, advanced imaging with enhanced specificity, and machine learning algorithms. Advancements in implant technology emphasize materials science, surface modifications, and personalized 3D printing, enhancing durability and antimicrobial efficacy. Immunomodulatory therapies targeting T cell dysfunction offer potential in addressing FRI chronicity. Enzybiotics and phages present promising alternatives to combat antibiotic resistance, with enzybiotics demonstrating effectiveness against biofilm-associated infections. Patient optimization, multidisciplinary approaches and specialized reference centers play vital roles in comprehensive FRI management, particularly crucial in resource-constrained settings. Collaboration and investment in research and technology are imperative for harnessing the full potential of these advancements and improving global FRI management outcomes. Addressing these complexities necessitates a multifaceted approach integrating clinical expertise, technological innovation, and global cooperation to optimize patient care and mitigate the burden of FRI worldwide.

Progress in Designing Therapeutic Antimicrobial Hydrogels Targeting Implant-associated Infections: Paving the Way for a Sustainable Platform Applied to Biomedical Devices

Implantable biomedical devices have found widespread use in restoring lost functions or structures within the human body, but they face a significant challenge from microbial-related infections, which often lead to implant failure. In this context, antimicrobial hydrogels emerge as a promising strategy for treating implant-associated infections owing to their tunable physicochemical properties. However, the literature lacks a comprehensive analysis of antimicrobial hydrogels, encompassing their development, mechanisms, and effect on implant-associated infections, mainly in light of existing in vitro, in vivo, and clinical evidence. Thus, this review addresses the strategies employed by existing studies to tailor hydrogel properties to meet the specific needs of each application. Furthermore, this comprehensive review critically appraises the development of antimicrobial hydrogels, with a particular focus on solving infections related to metallic orthopedic or dental implants. Then, preclinical and clinical studies centering on providing quantitative microbiological results associated with the application of antimicrobial hydrogels are systematically summarized. Overall, antimicrobial hydrogels benefit from the tunable properties of polymers and hold promise as an effective strategy for the local treatment of implant-associated infections. However, future clinical investigations, grounded on robust evidence from in vitro and preclinical studies, are required to explore and validate new antimicrobial hydrogels for clinical use.

Antimicrobial Biomaterials Based on Physical and Physicochemical Action

Developing effective antimicrobial biomaterials is a relevant and fast-growing field in advanced healthcare materials. Several well-known (e.g., traditional antibiotics, silver, copper etc.) and newer (e.g., nanostructured, chemical, biomimetic etc.) approaches have been researched and developed in recent years and valuable knowledge has been gained. However, biomaterials associated infections (BAIs) remain a largely unsolved problem and breakthroughs in this area are sparse. Hence, novel high risk and potential high gain approaches are needed to address the important challenge of BAIs. Antibiotic free antimicrobial biomaterials that are largely based on physical action are promising, since they reduce the risk of antibiotic resistance and tolerance. Here, selected examples are reviewed such antimicrobial biomaterials, namely switchable, protein-based, carbon-based and bioactive glass, considering microbiological aspects of BAIs. The review shows that antimicrobial biomaterials mainly based on physical action are powerful tools to control microbial growth at biomaterials interfaces. These biomaterials have major clinical and application potential for future antimicrobial healthcare materials without promoting microbial tolerance. It also shows that the antimicrobial action of these materials is based on different complex processes and mechanisms, often on the nanoscale. The review concludes with an outlook and highlights current important research questions in antimicrobial biomaterials.

Disability-adjusted life years from bone and joint infections associated with antimicrobial resistance: an insight from the 2019 Global Burden of Disease Study

PURPOSE

Bone and joint infections, complicated by the burgeoning challenge of antimicrobial resistance (AMR), pose significant public health threats by amplifying the disease burden globally. We leveraged results from the 2019 Global Burden of Disease Study (GBD) to explore the impact of AMR attributed to bone and joint infections in terms of disability-adjusted life years (DALYs), elucidating the contemporary status and temporal trends.

METHODS

Utilizing GBD 2019 data, we summarized the burden of bone and joint infections attributed to AMR across 195 countries and territories in the 30 years from 1990 to 2019. We review the epidemiology of AMR in terms of age-standardized rates, the estimated DALYs, comprising years of life lost (YLLs) and years lived with disability (YLDs), as well as associations between DALYs and socio-demographic indices.

RESULTS

The GBD revealed that DALYs attributed to bone and joint infections associated with AMR have risen discernibly between 1990 and 2019 globally. Significant geographical disparities and a positive correlation with socio-demographic indicators were observed. Staphylococcus aureus infections, Group A Streptococcus, Group B Streptococcus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Enterobacter-related bone and joint infections were associated with the highest DALYs because of a high proportion of antimicrobial resistance. Countries with limited access to healthcare, suboptimal sanitary conditions, and inconsistent antibiotic stewardship were markedly impacted.

CONCLUSIONS

The GBD underscores the escalating burden of bone and joint infections exacerbated by AMR, necessitating urgent, multi-faceted interventions. Strategies to mitigate the progression and impact of AMR should emphasize prudent antimicrobial usage and robust infection prevention and control measures, coupled with advancements in diagnostic and therapeutic modalities.

A biodegradable PVA coating constructed on the surface of the implant for preventing bacterial colonization and biofilm formation

BACKGROUND

Bone implant infections pose a critical challenge in orthopedic surgery, often leading to implant failure. The potential of implant coatings to deter infections by hindering biofilm formation is promising. However, a shortage of cost-effective, efficient, and clinically suitable coatings persists. Polyvinyl alcohol (PVA), a prevalent biomaterial, possesses inherent hydrophilicity, offering potential antibacterial properties.

METHODS

This study investigates the PVA solution's capacity to shield implants from bacterial adhesion, suppress bacterial proliferation, and thwart biofilm development. PVA solutions at concentrations of 5%, 10%, 15%, and 20% were prepared. In vitro assessments evaluated PVA's ability to impede bacterial growth and biofilm formation. The interaction between PVA and mCherry-labeled Escherichia coli (E. coli) was scrutinized, along with PVA's therapeutic effects in a rat osteomyelitis model.

RESULTS

The PVA solution effectively restrained bacterial proliferation and biofilm formation on titanium implants. PVA solution had no substantial impact on the activity or osteogenic potential of MC3T3-E1 cells. Post-operatively, the PVA solution markedly reduced the number of Staphylococcus aureus and E. coli colonies surrounding the implant. Imaging and histological scores exhibited significant improvements 2 weeks post-operation. Additionally, no abnormalities were detected in the internal organs of PVA-treated rats.

CONCLUSIONS

PVA solution emerges as an economical, uncomplicated, and effective coating material for inhibiting bacterial replication and biofilm formation on implant surfaces, even in high-contamination surgical environments.

A Cyclam Salt as an Antifungal Agent: Interference with Candida spp. and Cryptococcus neoformans Mechanisms of Virulence

The importance of fungal infections, particularly those caused by yeasts, is increasing among the medical community. Candida albicans and Cryptococcus neoformans are amongst the high-priority fungal species identified by the World Health Organization (WHO) and are considered in the critical group, while Candida krusei is included in the medium-priority group. The cyclam salt H4[H2(4-CF3PhCH2)2Cyclam]Cl4 proved to be active against the growth of these three yeasts, and the aim of this work was to verify its interference with their virulence mechanisms, whether shared or unique. H4[H2(4-CF3PhCH2)2Cyclam]Cl4 significantly inhibited biofilm production and catalase activity, being able to interfere with C. albicans dimorphic transition and C. neoformans melanin production. At the minimal inhibitory concentration (MIC) values, H4[H2(4-CF3PhCH2)2Cyclam]Cl4 had no antioxidant effect, as determined by the DPPH method. When using the RAW264.7 macrophage cell line, H4[H2(4-CF3PhCH2)2Cyclam]Cl4 reduced nitric oxide (NO) detection (the Griess reaction), but this effect was associated with a significant toxic effect on the cells.

Effect of Camel Peptide on the Biofilm of Staphylococcus epidermidis and Staphylococcus haemolyticus Formed on Orthopedic Implants

The increasing bacterial drug resistance and the associated challenges in the treatment of infections warrant the search for alternative therapeutic methods. Hope is placed in antimicrobial peptides, which have a broad spectrum of action and are effective against strains which are resistant to conventional antibiotics. Antimicrobial peptides are also tested for their efficacy in the treatment of infections associated with the formation of biofilm. The aim of the present study was to examine the effect of Camel peptide on S. epidermidis and S. haemolyticus adhesion to and formation of biofilm on steel cortical bone screws and also on the process of reducing mature biofilm in orthopedic implants. The tests were performed on steel implants for osteosynthesis. The MIC value and MBEC values of the peptide were determined using the microdilution method in microtiter plates. The effect of the peptide on adhesion and biofilm formation, as well as on the activity on the preformed biofilm, was evaluated using quantitative methods and confocal microscopy. The presented research results indicate that the peptide exhibits very good antimicrobial properties against the analyzed strains. Concentrations above MIC reduced biofilm in the range of 90-99%.

Bacterial Biofilm Formation on Biomaterials and Approaches to Its Treatment and Prevention

Bacterial biofilms can cause widespread infection. In addition to causing urinary tract infections and pulmonary infections in patients with cystic fibrosis, biofilms can help microorganisms adhere to the surfaces of various medical devices, causing biofilm-associated infections on the surfaces of biomaterials such as venous ducts, joint prostheses, mechanical heart valves, and catheters. Biofilms provide a protective barrier for bacteria and provide resistance to antimicrobial agents, which increases the morbidity and mortality of patients. This review summarizes biofilm formation processes and resistance mechanisms, as well as the main features of clinically persistent infections caused by biofilms. Considering the various infections caused by clinical medical devices, we introduce two main methods to prevent and treat biomaterial-related biofilm infection: antibacterial coatings and the surface modification of biomaterials. Antibacterial coatings depend on the covalent immobilization of antimicrobial agents on the coating surface and drug release to prevent and combat infection, while the surface modification of biomaterials affects the adhesion behavior of cells on the surfaces of implants and the subsequent biofilm formation process by altering the physical and chemical properties of the implant material surface. The advantages of each strategy in terms of their antibacterial effect, biocompatibility, limitations, and application prospects are analyzed, providing ideas and research directions for the development of novel biofilm infection strategies related to therapeutic materials.

Bone Grafts in Dental Medicine: An Overview of Autografts, Allografts and Synthetic Materials

This review provides an overview of various materials used in dentistry and oral and maxillofacial surgeries to replace or repair bone defects. The choice of material depends on factors such as tissue viability, size, shape, and defect volume. While small bone defects can regenerate naturally, extensive defects or loss or pathological fractures require surgical intervention and the use of substitute bones. Autologous bone, taken from the patient's own body, is the gold standard for bone grafting but has drawbacks such as uncertain prognosis, surgery at the donor site, and limited availability. Other alternatives for medium and small-sized defects include allografts (from human donors), xenografts (from animals), and synthetic materials with osteoconductive properties. Allografts are carefully selected and processed human bone materials, while xenografts are derived from animals and possess similar chemical composition to human bone. Synthetic materials such as ceramics and bioactive glasses are used for small defects but may lack osteoinductivity and moldability. Calcium-phosphate-based ceramics, particularly hydroxyapatite, are extensively studied and commonly used due to their compositional similarity to natural bone. Additional components, such as growth factors, autogenous bone, and therapeutic elements, can be incorporated into synthetic or xenogeneic scaffolds to enhance their osteogenic properties. This review aims to provide a comprehensive analysis of grafting materials in dentistry, discussing their properties, advantages, and disadvantages. It also highlights the challenges of analyzing in vivo and clinical studies to select the most suitable option for specific situations.