Genome characterisation and comparative analysis of Schaalia dentiphila sp. nov. and its subspecies, S. dentiphila subsp. denticola subsp. nov., from the human oral cavity
Document Type
Article
Publication Date
5-1-2024
Abstract
Background Schaalia species are primarily found among the oral microbiota of humans and other animals. They have been associated with various infections through their involvement in biofilm formation, modulation of host responses, and interaction with other microorganisms. In this study, two strains previously indicated as Actinomyces spp. were found to be novel members of the genus Schaalia based on their whole genome sequences. Results Whole-genome sequencing revealed both strains with a genome size of 2.3 Mbp and GC contents of 65.5%. Phylogenetics analysis for taxonomic placement revealed strains NCTC 9931 and C24 as distinct species within the genus Schaalia. Overall genome-relatedness indices including digital DNA-DNA hybridization (dDDH), and average nucleotide/amino acid identity (ANI/AAI) confirmed both strains as distinct species, with values below the species boundary thresholds (dDDH < 70%, and ANI and AAI < 95%) when compared to nearest type strain Schaalia odontolytica NCTC 9935( T). Pangenome and orthologous analyses highlighted their differences in gene properties and biological functions compared to existing type strains. Additionally, the identification of genomic islands (GIs) and virulence-associated factors indicated their genetic diversity and potential adaptive capabilities, as well as potential implications for human health. Notably, CRISPR-Cas systems in strain NCTC 9931 underscore its adaptive immune mechanisms compared to strain C24. Conclusions Based on these findings, strain NCTC 9931(T) (= ATCC 17982(T) = DSM 43331(T) = CIP 104728(T) = CCUG 18309(T) = NCTC 14978(T) = CGMCC 1.90328(T)) represents a novel species, for which the name Schaalia dentiphila subsp. dentiphila sp. nov. subsp. nov. is proposed, while strain C24(T) (= NCTC 14980(T) = CGMCC 1.90329(T)) represents a distinct novel subspecies, for which the name Schaalia dentiphila subsp. denticola. subsp. nov. is proposed. This study enriches our understanding of the genomic diversity of Schaalia species and paves the way for further investigations into their roles in oral health. Significance This research reveals two Schaalia strains, NCTC 9931( T) and C24(T), as novel entities with distinct genomic features. Expanding the taxonomic framework of the genus Schaalia, this study offers a critical resource for probing the metabolic intricacies and resistance patterns of these bacteria. This work stands as a cornerstone for microbial taxonomy, paving the way for significant advances in clinical diagnostics.
Keywords
Schaalia dentiphila, Schaalia dentiphila subsp denticola, Novel species, Genome analysis, Taxonomy, Oral cavity
Divisions
InstituteofBiologicalSciences
Funders
Wenzhou-Kean University (5000105),Wenzhou Municipal Key Laboratory for Applied Biomedical and the Biopharmaceutical Informatics (WB20211227000125),Zhejiang Bioinformatics International Science and Technology Cooperation Center at Wenzhou-Kean University (WB20210429000008)
Publication Title
BMC Microbiology
Volume
24
Issue
1
Publisher
BioMed Central
Publisher Location
CAMPUS, 4 CRINAN ST, LONDON N1 9XW, ENGLAND