Beyond the germ: Rethinking implant-related infections as a host-microbiota-biomaterial ecosystem.

Implant-related infections remain one of the most challenging complications in modern medicine, often leading to implant failure, revision surgery, significant patient morbidity and high rate of patient mortality. Traditionally framed within the germ theory paradigm, their pathogenesis has been attributed primarily to microbial contamination and biofilm formation. However, growing evidence reveals a far more complex picture in which infection susceptibility emerges from the dynamic interplay between host biology, microbiota composition, biomaterial properties, and environmental influences . Host immune tone, metabolic status, and systemic exposures shape the tissue environment in ways that either resist or facilitate microbial colonization. The microbiota contributes to this balance not only by mediating immune responses and providing colonization resistance but also through metabolites and detoxification mechanisms that influence local and systemic immunity. Biomaterials themselves are active participants in this ecosystem: metal ion release, corrosion, and surface properties modulate both host responses and microbial behavior. A particularly intriguing concept is the potential dual role of biofilms - not only as pathogenic reservoirs but also as detoxification systems that sequester metal ions and buffer oxidative stress at the host-implant interface. Recognizing this duality reframes biofilms as biological structures that may, in part, participate in protective containment, albeit at the cost of sustaining low-grade inflammation and risk of septicemia. Looking forward, the integration of systems biology approaches promises to transform our understanding and management of implant-associated infections. Multi-omics profiling, predictive modeling, engineered probiotics, dietary modulation, and novel implant surface designs represent emerging strategies that target the entire host-microbe-material interface. By bridging insights from immunology, microbiome science, biomaterials research, and digital technologies, a new paradigm is emerging - one that views infection prevention and treatment not simply as microbial eradication, but as the cultivation of a resilient biological and material ecosystem around the implant.