Bacterial and fungal growth conditions.

The following strains used in this study were acquired from the American Type Culture Collection (ATCC): Streptococcus salivarius ATCC 13419, Streptococcus agalactiae ATCC 13813, Streptococcus mitis ATCC 6249, Streptococcus sanguinis ATCC 49296, Streptococcus parasanguinis ATCC 15912, Streptococcus pyogenes ATCC 10782, and Candida guilliermondii ATCC 6220. Candida albicans NCYC 1363 and Candida dubliniensis NCPF 39349 were obtained from Fisher Scientific, while Saccharomyces cerevisiae CB was acquired from Carolina Biological Supply Company. Streptococcus cultures were maintained by culturing strains on brain heart infusion (BHI) agar and isolating single colonies. Colonies were grown in BHI broth aerobically at 37°C, shaking at 120 rpm overnight, and then all strains were subcultured into ZMB1 fully defined medium, lacking glucose (41), at an optical density (OD₆₀₀) of 0.1. Glucose, yeast extract (Sigma-Aldrich; no. Y1625), or purified mannan was added to ZMB1, and the cultures were incubated in 96-well plates (VWR) for 18 h aerobically at 37°C on a Synergy HT microplate reader (Biotek) with OD₆₀₀ values recorded every 10 min (n = 3 replicates; repeated 2 independent times). Fungal strains were maintained by culturing strains on yeast-peptone-dextrose (YPD) agar and isolating single colonies. Colonies were grown in YPD broth aerobically at 37°C overnight and used to seed 1-L cultures for mannan preparation. For heat inactivation, live C. albicans NCYC 1363 isolates were washed and resuspended at 2.0 × 10⁷ cells/ml in phosphate-buffered saline (PBS) and incubated at 100°C for 1 h as previously described (42). The completeness of killing was confirmed by plating on YPD agar. The presence of mannan was confirmed by staining with concanavalin A (ConA), a lectin that specifically binds to terminal mannose residues (Vector Labs; catalog no. FLK-2100) (data not shown).