High-resolution taxonomic profiling and metatranscriptomics identify microbial, biochemical, host, and ecological...

Biofilm-associated diseases like peri-implant mucositis (PIM) and peri-implantitis (PI) are significant clinical challenges affecting millions of dental implant patients globally. Although studies have described the role of microbial, host, or environmental factors in disease development, their complex interplay, particularly during dysbiosis, remains poorly understood. This cross-sectional study characterized the microbiome composition and metatranscriptomes of 125 peri-implant biofilms from 48 individuals, uncovering molecular signatures linked to peri-implant health (PIH), PIM, and PI. Distinct variations were observed in biofilm amount, microbial composition and activity, phage populations, and host response. Biofilms were categorized into four community types (CTs) based on the bacterial transcriptional activity: one linked to PIH, one to PI, and two to PIM. PIH and PIM were primarily characterized by aerotolerant taxa with increased anabolic processes, while PI was dominated by obligate anaerobes with complex biofilm morphology. PIM samples, relative to PIH, were characterized by biofilm expansion with minimal functional changes, except for the Neisseria-rich PIM subtype showing higher pyruvate and lipoic acid metabolism. The phagome mirrored the bacterial compositional variations across disease states. Furthermore, human transcriptome responses varied, indicating increased keratinization in PIH, enhanced expression of ribosome components in PIM, and inflammatory signaling and hypoxia in PI. Additionally, we identified complex species-enzyme, phage-bacterium, and host-microbe associations within the peri-implant ecosystem. Our integrative multi-omics approach provides a comprehensive view of microbial, biochemical, host, and ecological factors associated with dysbiosis, offering novel insights into peri-implant disease dynamics.

Peri-implant mucositis and peri-implantitis are highly prevalent inflammatory conditions that compromise the long-term survival and success of dental implants, yet their underlying biological mechanisms are largely unresolved. The full-length 16S rRNA gene amplicon sequencing (full-16S) allows for high-resolution taxonomic profiling of peri-implant biofilms, thereby advancing our understanding of microbial composition across health and peri-implant diseases. The integration of metatranscriptomics, furthermore, captures actively transcribed genes within the biofilm and offers direct insights into microbial community functions and the broader molecular context of peri-implant dysbiosis. DNA- and RNA-derived abundances were strongly correlated, with only a few microbial classes showing moderate diagnosis-related differences after DNA-based normalization of transcriptional activity. In this study, we integrated full-16S with metatranscriptomic profiling to simultaneously assess microbial taxonomy, functional activity, phage dynamics, and host gene expression in peri-implant biofilms. Importantly, we provide a systems-level view and report previously undescribed associations between different molecular signatures in the peri-implant ecosystem.