AUTHOR=Thurnheer Thomas , Karygianni Lamprini , Flury Manuela , Belibasakis Georgios N. 

TITLE=Fusobacterium Species and Subspecies Differentially Affect the Composition and Architecture of Supra- and Subgingival Biofilms Models

JOURNAL=Frontiers in Microbiology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2019.01716

DOI=10.3389/fmicb.2019.01716

ISSN=1664-302X

ABSTRACT=<p>Fusobacteria are common obligately anaerobic Gram-negative bacteria of the oral cavity that may act as a bridge between early and late colonizing bacteria in dental plaque and have a role in oral and extra-oral infections. <italic>Fusobacterium nucleatum</italic> has a crucial role in oral biofilm structure and ecology, as revealed in experimental and clinical biofilm models. The aim of this study was to investigate the impact of various <italic>Fusobacterium</italic> species on <italic>in vitro</italic> biofilm formation and structure in three different oral biofilm models namely a supragingival, a supragingival “feeding”, and a subgingival biofilm model. The standard six-species supragingival and “feeding” biofilm models employed contained <italic>Actinomyces oris</italic>, <italic>Candida albicans</italic>, <italic>Streptococcus mutans</italic>, <italic>Streptococcus oralis</italic>, <italic>Veillonella dispar</italic>, and <italic>Fusobacterium</italic> sp. The subgingival biofilm model contained 10 species (<italic>A. oris</italic>, <italic>Campylobacter rectus</italic>, <italic>F. nucleatum</italic> ssp. <italic>nucleatum</italic>, <italic>Porphyromonas gingivalis</italic>, <italic>Prevotella intermedia</italic>, <italic>Streptococcus anginosus</italic>, <italic>S. oralis</italic>, <italic>Tannerella forsythia</italic>, <italic>Treponema denticola</italic>, and <italic>V. dispar</italic>). Six different <italic>Fusobacterium</italic> species or subspecies, respectively, were tested namely <italic>F. nucleatum</italic> ssp. <italic>fusiforme</italic>, <italic>F. nucleatum</italic> ssp. <italic>nucleatum</italic>, <italic>F. nucleatum</italic> ssp. <italic>polymorphum</italic>, <italic>F. nucleatum</italic> ssp. <italic>vincentii</italic>, <italic>F. naviforme</italic>, and <italic>F. periodonticum</italic>). Biofilms were grown anaerobically on hydroxyapatite disks in 24-well culture dishes. After 64 h, biofilms were either harvested and quantified by culture analysis or proceeded to fluorescent <italic>in situ</italic> hybridization (FISH) and confocal laser scanning microscopy (CLSM). All <italic>Fusobacterium</italic> species tested established well in the biofilms, with CFUs ranging from 1.4E+04 (<italic>F. nucleatum</italic> ssp. <italic>fusiforme</italic>) to 5.6E+06 (<italic>F. nucleatum</italic> ssp. <italic>nucleatum</italic>). The presence of specific <italic>Fusobacterium</italic> sp./ssp. induced a significant decrease in <italic>C. albicans</italic> levels in the supragingival model and in <italic>V. dispar</italic> levels in the “feeding” supragingival model. In the subgingival model, the counts of <italic>A. oris</italic>, <italic>S. oralis</italic>, <italic>P. intermedia</italic>, <italic>P. gingivalis</italic>, and <italic>C. rectus</italic> significantly decreased in the presence of specific <italic>Fusobacterium</italic> sp./ssp. Collectively, this study showed variations in the growing capacities of different fusobacteria within biofilms, affecting the growth of surrounding species and potentially the biofilm architecture. Hence, clinical or experimental studies need to differentiate between <italic>Fusobacterium</italic> sp./ssp., as their biological properties may well vary.</p>