The present study aimed to evaluate the in vitro antibacterial and antibiofilm activity of bacterial cellulose hydrogel produced by Zoogloea sp. (HYDROGEL) containing vancomycin (VAN) against bacterial strains that cause wound infections, such as multidrug-resistant (MDR) Staphylococcus aureus and Staphylococcus epidermidis. Initially, HYDROGEL was obtained from sugar cane molasses, and scanning electron microscopy (SEM) was performed to determine morphological characteristics. Then, VAN was incorporated into HYDROGEL (VAN-HYDROGEL). The antibacterial activity of VAN, HYDROGEL, and VAN-HYDROGEL was assessed using the broth microdilution method to determine the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) against methicillin-sensitive S. aureus (MSSA) ATCC 25923, methicillin-resistant S. aureus (MRSA) ATCC 33591, S. epidermidis INCQS 00016 (ATCC 12228), five clinical isolates of MRSA, and nine clinical isolates of methicillin-resistant S. epidermidis, following the Clinical and Laboratory Standards Institute (CLSI) guidelines. Additionally, the antibacterial activity of VAN, HYDROGEL, and VAN-HYDROGEL was studied using the time-kill assay. Subsequently, the antibiofilm activity of VAN, HYDROGEL, and VAN-HYDROGEL was evaluated using crystal violet and Congo red methods, as well as SEM analysis. VAN and VAN-HYDROGEL showed bacteriostatic and bactericidal activity against MRSA and methicillin-resistant S. epidermidis strains. HYDROGEL did not show any antibacterial activity. Analysis of the time-kill assay indicated that HYDROGEL maintained the antibacterial efficacy of VAN, highlighting its efficiency as a promising carrier. Regarding antibiofilm activity, VAN and HYDROGEL inhibited biofilm formation but did not demonstrate biofilm eradication activity against methicillin-resistant S. aureus and S. epidermidis strains. However, it was observed that the biofilm eradication potential of VAN was enhanced after incorporation into HYDROGEL, a result also proven through images obtained by SEM. From the methods carried out in this study, it was possible to observe that HYDROGEL preserved the antibacterial activity of vancomycin, aside from exhibiting antibiofilm activity and enhancing the antibiofilm effect of VAN. In conclusion, this study demonstrated the potential of HYDROGEL as a candidate and/or vehicle for antibiotics against MDR bacteria that cause wound infections.

Background/Objectives: The study developed, characterized, and evaluated the toxicity, antibacterial and antibiofilm activity of quercetin encapsulated in chitosan-coated zein nanoparticles (QUER-ZNP-CH). Methods: QUER-ZNP-CH were prepared by the nanoprecipitation method and characterized by physicochemical analyses, stability (12 months), and release kinetics. Toxicity was evaluated through hemocompatibility and a Tenebrio molitor larval model. Antibacterial activity (MIC/MBC, CLSI) and antibiofilm potential (crystal violet assay) were tested against resistant Klebsiella pneumoniae strains. Results: The nanoparticles were prepared, and physicochemical analyses revealed chemical interactions, efficient encapsulation of the drug, and thermal stability. The formulations remained stable over 12 months, and the release kinetics demonstrated controlled release for 72 h. No hemotoxic profile was observed and there was 95% survival of Tenebrio molitor larvae after treatment with QUER-ZNP-CH. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of QUER-ZNP-CH revealed enhanced antibacterial activity of QUER, as indicated by a 32 to 64-fold reduction in the MIC and MBC values. The biofilm inhibition potential of QUER-ZNP-CH showed 60–100% inhibition and 25–95% eradication in concentrations from 0.12 to 62.5 μg/mL. Conclusions: Thus, this nanotechnology-based formulation suggests potential for the treatment of bacterial infections caused by multidrug-resistant K. pneumoniae strains.