The rise of multidrug-resistant Gram-negative pathogens has created an urgent need for alternative treatments like enzybiotics, which utilize bacteriolytic enzymes to target bacterial cell walls. However, the topical application of these enzymes is often limited by their instability on the skin surface and the challenge of maintaining effective local concentrations. While seaweed-derived alginates are commonly used as delivery vehicles, their physicochemical variability can lead to instability in pharmaceutical formulations. Bacterial alginate from Azotobacter vinelandii was considered a potential solution because it allows for controlled biotechnological synthesis, ensuring stable properties and effective encapsulation of the novel modified endolysin LysSi3-LK.
Methods
Researchers synthesized bacterial alginate using A. vinelandii and produced the recombinant endolysin LysSi3-LK via E. coli expression. They formulated various sodium alginate gels and calcium alginate hydrogels to evaluate enzyme release kinetics and nanoparticle formation. The study assessed antibacterial activity against ESKAPE pathogens and examined biocompatibility with human HaCaT keratinocytes through cytotoxicity, migration, and proliferation assays.
Key Findings
- Encapsulation in 1–2% bacterial alginate provided sustained release of active LysSi3-LK, with active diffusion observed after 24 hours.
- The enzybiotic compositions demonstrated strong antibacterial efficacy against A. baumannii and P. aeruginosa, though activity against Enterobacteriaceae varied by strain.
- While pure bacterial alginate (>1%) showed moderate cytotoxicity, the addition of the endolysin significantly improved keratinocyte survival and metabolic activity.
- Although cell migration was dose-dependently reduced, the hydrogels stimulated cell proliferation and maintained cell viability above 75% over a seven-day period.
The novelty of this research lies in it being the first investigation into using bacterial alginates for enzybiotic development, confirming that they serve as a safe, controlled alternative to seaweed-derived carriers. The study proves that bacterial alginate effectively preserves endolysin activity while promoting skin cell growth within a matrix, which is essential for wound healing. Future implications involve the potential for these compositions to treat severe skin infections, though subsequent in vivo experiments are required to fully evaluate their safety and efficacy in complex physiological wound environments.
Link to the study: https://www.mdpi.com/1422-0067/27/9/3856
