Lactobacillus acidophilus impairs the establishment of pathogens in a subgingival multispecies biofilm.

The present study evaluated the antibiofilm effects of Lactobacillus acidophilus within a subgingival multispecies biofilm. Lactobacillus acidophilus (La5) at 1 × 10², 1 × 10⁴, and 1 × 10⁶ were included at the beginning of biofilm formation, which lasted 7 days. The biofilms comprised 33 periodontitis-related bacterial species and the Calgary Biofilm device was used. At the end, DNA-DNA hybridization (checkerboard) was performed. A Kruskal-Wallis test followed by a Dunn post hoc test were performed (p ≤ 0.05). La5 at 1 × 10⁴ and 1 × 10⁶ reduced the total counts of biofilm and the proportions of red and green complexes when compared to the control biofilm without La5 (p ≤ 0.05). La5 at 1 × 10⁴ increased the proportions of Actinomyces complex compared to the controls (p ≤ 0.05). Both La5 at 1 × 10⁴ and 1 × 10⁶ decreased levels of 20 and 14 distinct species, respectively, including Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum polymorphum, and Parvimonas micra compared to the control (p ≤ 0.05). Only La5 at 1 × 10⁴ reduced the levels of Tannerella forsythia, Fusobacterium periodonticum, and Aggregatibacter actinomycetencomytans compared to the control (p ≤ 0.05). L. acidophilus inhibited establishing periodontic pathogens from red complex such as P. gingivalis and T. forsythia in a subgingival multispecies biofilm.