Staphylococcus aureus is a microorganism frequently associated with implant-related infections, owing to its ability to produce biofilms. These infections are difficult to treat because antimicrobials must cross the biofilm to effectively inhibit bacterial growth. Although some antibiotics can penetrate the biofilm and reduce the bacterial load, it is important to understand that the results of routine sensitivity tests are not always valid for interpreting the activity of different drugs. In this review, a broad discussion on the genes involved in biofilm formation, quorum sensing, and antimicrobial activity in monotherapy and combination therapy is presented that should benefit researchers engaged in optimizing the treatment of infections associated with S. aureus biofilms.

Introduction: Infections associated with medical implants pose significant challenges to healthcare, demanding the development of new effective antimicrobial strategies. This study focuses on the creation of a novel biological membrane with enhanced antimicrobial properties by with the incorporation of either vancomycin or silver nanoparticles. Methods: Pericardium samples were impregnated with either silver nanoparticles (AgNPs) or vancomycin (VAN). The antimicrobial activity of the membranes was assessed through qualitative microbiological analysis, biofilm production and animal in vivo model of infection. Histological analysis was performed on the pericardium samples, and quantitative microbiological analysis was conducted on the tissue from the animal model and biocompatibility evaluation. Statistical analyses were carried out using appropriate tests. Results: Microbiological tests confirmed both VAN and AgNP showed inhibition halos against bacteria. Histological analysis indicated minimal inflammatory response and bacterial presence in VAN and AgNP groups compared to the control group revealed reduced bacterial presence. Biomechanical testing showed that polypropylene had the lowest tensile strength, while AgNP-impregnated pericardium exhibited lower resistance than VAN-impregnated and control pericardium. Conclusion: Lyophilized and decellularized bovine pericardium as a substrate, combined with the incorporation of vancomycin or silver nanoparticles, provides a versatile platform for combating infections associated with medical implants.

This study introduces a novel approach by proposing a dressing impregnated with vancomycin and chlorhexidine for postoperative care, specifically targeting patients undergoing orthopedic surgeries. The research design involved a pilot study with a randomized control group, aiming to evaluate the vancomycin with chlorhexidine dressing's efficacy and safety. A total of 12 patients used impregnated dressing and 9 used the same dressing without impregnation. Despite limitations, including the small sample size and single-center study location, our findings demonstrate the safety of the impregnated dressing in trauma surgeries, indicating potential applicability in broader surgical contexts. In conclusion, this study contributes to the discourse on preventive strategies for SSIs, presenting a pioneering approach with the vancomycin and chlorhexidine-impregnated dressing. Future research endeavors, incorporating larger-scale studies and addressing study limitations, are crucial for advancing the understanding and implementation of effective postoperative care strategies.

Background: Antibiofilm activity of silver nanoparticles has been extensively investigated in common bacteria. Metallo-β-lactamase producing Gram-negative bacteria are hard-to-treat microorganisms with few therapeutic options, and silver nanoparticles were not evaluated on the biofilm of these bacteria. Objectives: The aim of this study was to evaluate the antibiofilm activity of a bone scaffold impregnated with silver nanoparticles in NDM-producing Gram-negative bacilli. Methods: Bone scaffolds from bovine femur were used for the tests and impregnated with silver nanoparticles (50 nm) by physical adsorption. Silver nitrate minimal inhibitory and bactericidal concentrations (MIC and MBC) were performed on NDM-producing Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Disc diffusion tests for silver nanoparticles susceptibility and quantification of biofilm production on plate and bone with sessile cell count were performed. Results: The MIC results demonstrated that silver nitrate had an antimicrobial effect on all microorganisms, inactivating the growth of isolates from a concentration of 8 µg/mL. MBC results showed that E. coli 16.211 was the only isolate to present MIC different from MBC, with a value of 16 µg/mL. Conclusion: Bone scaffolds impregnated with silver nanoparticles can significantly reduce biofilm, and it can be a strategic material to be used as an implant for different approaches.

Background: Staphylococcus aureus is a major contributor to biofilm-associated infections, which complicate the treatment of chronic conditions like osteomyelitis and prosthetic infections. Bio-films, characterized by bacterial communities encased in a protective matrix, hinder the effec-tiveness of antimicrobial agents and contribute to persistent infections. Objective: This study aimed to evaluate the activity of delafloxacin, a novel fluoroquinolone, against biofilm-forming S. aureus strains, including methicillin-resistant (MRSA) and methicillin-sensitive (MSSA) isolates. Methods: Delafloxacin’s efficacy was compared with traditional antibiotics (vancomycin, line-zolid, doxycycline, sulfamethoxazole/trimethoprim, and rifampicin) using minimal inhibitory concentration (MIC) assays, including testing at different pH levels to simulate acidic biofilm conditions. Synergistic interactions between delafloxacin and other antimicrobials were assessed using the checkerboard method. Biofilm eradication was tested through minimal biofilm eradi-cation concentration (MBEC) assays, biomass quantification, and cell viability (MTT assay). Re-sults: The results showed that all isolates were susceptible to vancomycin and linezolid, with varying resistance to other antibiotics. Delafloxacin demonstrated potent activity, with MIC re-ductions observed in acidic conditions. Synergistic effects were minimal, with only a few isolates showing synergy with vancomycin and doxycycline. Biofilm eradication tests revealed limited success in eradicating biofilms at breakpoint concentrations. However, rifampicin in combination with delafloxacin significantly reduced biofilm biomass in some isolates. No significant changes in cell viability were noted across treatments. Conclusion: This study highlights delafloxacin's potential against biofilm-associated infections, particularly in acidic environments. Despite the challenges in biofilm eradication, delafloxacin combined with rifampicin shows promise for im-proved treatment strategies.