Dual-Species Biofilm Model: Advancing Antibiofilm Testing for Wound Care
Summary: This study introduces a biorelevant in vitro dual-species biofilm model using an electrospun gelatin-glucose (Gel-Gluc) matrix to mimic chronic wound environments and test antibiofilm wound dressings. Focusing on common wound pathogens like *Staphylococcus aureus*, *Escherichia coli*, and *Pseudomonas aeruginosa*, the model supports robust biofilm growth (up to 10^8 CFU/matrix after 24 hours) and enables evaluation of electrospun polycaprolactone (PCL) dressings loaded with chloramphenicol (CAM) or ciprofloxacin (CIP). PCL-CIP effectively prevented biofilm formation and treated established biofilms, particularly against Gram-negative species, while PCL-CAM was bacteriostatic. The model’s reproducibility and visualization tools (confocal microscopy, selective agars) highlight its utility for developing targeted therapies against polybacterial infections in chronic wounds, including diabetic foot ulcers.
Key Highlights:
- Dual-species biofilms (*S. aureus* + *E. coli* or *P. aeruginosa*, *E. coli* + *P. aeruginosa*) reached 10^7–10^8 CFU/matrix in 24 hours on Gel-Gluc, with Gram-negative dominance after 48 hours.
- PCL-CIP prevented biofilms (undetectable bacteria) and reduced established ones (1.8–3.9 log CFU decrease), outperforming PCL-CAM, which only inhibited growth.
- Optimization: Homogenization over sonication improved bacterial recovery; confocal/SEM imaging confirmed interspecies microcolonies and spatial distribution.
- Challenges: *S. aureus* survival in *P. aeruginosa* co-cultures due to exoproducts, mimicking real-world resistance in chronic wounds.
- Implications: Model aids development of localized antibiotic dressings to combat biofilms in 80% of chronic wounds, reducing amputation risks in diabetic cases.
Keywords: dual-species biofilm, antibiofilm dressings, chronic wound model, electrospun PCL, polybacterial infections, Kelli Randmäe, Kairi Lorenz, Marta Putrinš