Living Probiotics Biofilm Contact Lenses Coating for Drug-resistant Bacterial Keratitis Therapy

Purpose : Ocular drug-resistant bacterial infections like keratitis, have posed a grave threat to human vision health. More than 30 percent of all serious ocular infection belong to Methicillin-resistant Staphylococcus aureus (MRSA), and the incidence is rising annually. In this context we developed the living probiotics biofilm contact lenses coating with potent antibacterial and antibiofilm activity in treating MRSA-induced keratitis.

Methods : The coating was prepared as follow. First, LP and dopamine were dissolved in Tris-HCl solution. Then, the mixed solution was incubated with 100 rpm shaking at 37°C for 1 hour and then wash with PBS three times. The antimicrobial activity of coatings was determined with MRSA suspension (1.0 × 108 CFU/mL). Then the probiotics biofilm coating was submerged above bacterial solution (total volume: 1 mL) and incubated in 37°C overnight.

Results : First, we determined the biofilm production of coatings by CKK8 assay. The group of LP co-cultured with dopamine (PDA@LP) have highest biofilm production (more than 60% amount). In addition, the crystal violet staining and Live/Dead assay also showed the surface have thick biofilm in the PDA@LP group. All the results showed that probiotic biofilm was coated to the surface successfully and the dopamine can accelerate the biofilm formation. Second, we test the antimicrobial activity of the coating towards MRSA. Due to the PDA@LP surface have more living probiotics, the coating showed excellent antimicrobial activity (more than 3 logreduction rate, > 99.9% kill) compared with the others. Meanwhile, the PDA@LP coating also showed anti-biofilm activity to MRSA. The biofilm forms with an abundance of live MRSA cells adhering to the control and PDA surface. However, there is no biofilm formation observed on the surface of LP and PDA@LP group.

Conclusions : 1. Probiotics are more easyily to develp biofilm on the surface when co-culture with dopamine.
2. MRSA were killed by the living probiotics, resulting in effective biofilm inhibition activity.