The emergence of bacterial strains displaying resistance to the currently available antibiotics is a critical global concern. These resilient bacteria can form biofilms that play a pivotal role in the failure of bacterial infection treatments as antibiotics struggle to penetrate all biofilm regions. Consequently, eradicating bacteria residing within biofilms becomes considerably more challenging than their planktonic counterparts, leading to persistent and chronic infections. Among various approaches explored, essential oils loaded in nanoparticles based on biopolymers have emerged, promising strategies that enhance bioavailability and biological activities, minimize side effects, and control release through regulated pharmacokinetics. Different available reviews analyze nanosystems and essential oils; however, usually, their main goal is the analysis of their antimicrobial properties, and progress in biofilm combat is rarely discussed, or it is not the primary objective. This review aims to provide a global vision of biofilm conformation and describes mechanisms of action attributed to each EO. Furthermore, we present a comprehensive overview of the latest developments in biopolymeric nanoparticles research, especially in chitosan- and zein-based nanosystems, targeting multidrug-resistant bacteria in both their sessile and biofilm forms, which will help to design precise strategies for combating biofilms.

Biofilms, structured communities of microorganisms encased in an extracellular matrix, are a major cause of persistent infections, particularly when formed on medical devices. This study investigated the kinetics of biofilm formation by Escherichia coli and Pseudomonas aeruginosa, two clinically significant pathogens, on two medical-grade polymers: polyether ether ketone (PEEK) and polyamide 12 (PA12). Using a modified crystal violet staining method and spectrophotometric quantification, we evaluated biofilm development over time on polymer granules and catheter segments composed of these materials. Results revealed that PEEK surfaces supported significantly more biofilm formation than PA12, with peak accumulation observed at 24 h for both pathogens. Conversely, PA12 demonstrated reduced bacterial adhesion and lower biofilm biomass, suggesting surface characteristics less conducive to microbial colonization. Additionally, the study validated a reproducible protocol for assessing biofilm formation, providing a foundation for evaluating anti-biofilm strategies. While the assays were performed under static in vitro conditions, the findings highlight the importance of material selection and early prevention strategies in the design of infection-resistant medical devices. This work contributes to the understanding of how surface properties affect microbial adhesion and underscores the critical need for innovative surface modifications or coatings to mitigate biofilm-related healthcare risks.

Proteases play a role in different processes for protozoans and for the free-living amoeba Acanthamoeba. Some of these processes are related to pathogenicity and to encystment. In this study we describe the discovery of a protease with antimicrobial activity produced by Acanthamoeba. To identify it, we developed a novel zymogram using bacteria as an in-gel substrate that can help identify proteins capable of bacterial degradation. We used chromatography to isolate the proteases and showed that it quickly degrades in the environment. Additionally, we identified overexpressed proteases during encystment. The study of proteases from Acanthamoeba can serve several purposes including new antimicrobial proteins that the amoeba can use for potentially predigesting prokaryotes. Secondly, it can help with the identification of potential new therapies against Acanthamoeba infection.

Staphylococcus aureus biofilms are particularly challenging to eradicate due to their protective niche, which increases bacterial resistance. This has encouraged the scientific community to explore new perspectives of control. Polymeric nanotechnology and the use of natural compounds have been emerging as promising tools for treating antimicrobial resistance and preventing biofilms because the nanosize permits the disruption of biofilms, reducing the dose and decreasing the biomolecules’ limitations such as high volatility and low solubility, enhancing their antimicrobial properties. Our research developed nineteen unique formulations, each loaded with a specific Mexican natural compound with antibacterial and antioxidant properties: rosemary essential oil, p‐cymene, oregano essential oil, and carvacrol, all encapsulated within poly(lactic‐co‐glycolic acid) nanoparticles (NPs) and coated with mannitol. The nanosystems were characterized by physicochemical techniques showing an evident spherical morphology and an average size of around 200 nm, enhancing the oils’ stability within the polymeric matrix. Notably, the interaction of phytochemicals, unloaded and loaded NPs with MRSA (in sessile form and mature biofilm conformation), and fibroblast cells was analyzed. The antimicrobial activity of the natural molecules against MRSA was significantly enhanced up to 20 times higher when encapsulated in the nanosystems, with minimum inhibitory concentrations (MICs) observed as low as 0.443 mg/mL for carvacrol‐loaded NPs. A synergistic effect was observed between the materials and the encapsulated natural compounds, resulting in potent antimicrobial properties and reduced bacterial growth and biofilm integrity (biofilm disruption > 50% for the better formulations). The cytotoxicity toward fibroblasts was reduced from 60% to 10% with the formulations showing safe profiles. This is the first study evaluating the effect of these NPs and the mannitol coating on mature MRSA biofilms, demonstrating promising results. Although simple in their approach, the novel nanomaterials proposed here represent multifunctional and comprehensive advancements in enhancing therapeutic efficacy and addressing the global challenge of resistant microorganisms.