2.4. The Minimum Bactericidal Concentration (MBC) Assay

The untreated biofilms and biofilms treated with LTGP were cultured in TSB with 1% glucose and 20–2500 μg/mL ciprofloxacin, norfloxacin, vancomycin, or rifampicin for 24 h. The medium was carefully removed, and the biofilms were solubilized in 1 mL of saline in 1.5-mL Eppendorf tubes by sonication for 5 min and vortexing for 1 min. Serial dilutions of each biofilm were performed, and 10 μL of each dilution was spotted onto TSB plates and incubated overnight at 37 °C.