16S rRNA sequence of saliva-derived multispecies biofilm

Biofilms were formed ex vivo using cell-free saliva as a medium, and total salivary cells pooled from six healthy subjects as an inoculum. Pre-formed multispecies biofilms grown anaerobically for 24 hr were treated with either nisin A (50 ug/mL) or two concentrations of salivaricin 10 (25 and 50 ug/mL) for 20 min. The biofilms were then washed to remove tested compounds and scraped to make a total cell suspension which was inoculated into a fresh growth medium to allow non-inhibited cells to grow overnight. 16S rRNA gene amplicon sequencing was used to profile the species composition of viable cells that survived the peptides' bactericidal action and were able to regrow again post-treatment compared to viable cells derived from the PBS treatment as a negative control.