Collagen Enhances Lactobacillus Biofilm Formation

Objectives: To determine the correlation between collagen presence and biofilm production of a clinically isolated Lactobacillus sp. strain; to determine whether the strain has collagenase activity.

Methods: 24-well polystyrene dishes were coated with 0.1% type I collagen overnight. After drying, 1 mL of Lactobacillus sp. cultures diluted in MRS medium to an OD600 of 0.3 were added to the wells. Biofilm formation was quantified by crystal violet staining every 24 hours for 4 days. Collagenase activity was assayed by incubating TCA-concentrated proteins from supernatants of spent liquid cultures (100 mL) with 0.1% collagen, followed by SDS-PAGE.

Results: The collagen coated wells show significantly greater amounts of Lactobacillus biofilm after four days than polystyrene only wells at both pH 6.5 and 4.5 (n=9, ANOVA, Student-Newman-Kuels, p<0.05). No collagenase activity was detected.

Conclusions: The presence of collagen increases the amount of Lactobacillus biofilm formation at both pH 6.5 and 4.5, which suggests a mode of action for proliferating deep dentinal caries.

Support: UCSF COHORT Training Grant no. T32 DE07306.