The Concept of Biofilm-Related Implant Malfunction and "Low-Grade Infection".

Biofilms have a tremendous impact on industrial machines working in moist environments, while in biological systems their effect is further complicated by the host's response.Implant-related infections are a complex process, starting with bacterial adhesion and biofilm formation, followed by the variable interaction between host, implant, microorganisms and their by-products. Depending on the balance of these factors, different clinical presentations are observed, which may eventually, at times, shift from one into the other.-"Implant malfunction" displays only mild clinical signs/symptoms - light pain and/or slight soft tissue contracture or functional impairment - with negative infection/inflammatory markers; it requires prolonged cultures, antibiofilm and eventually genomic investigations for pathogen detection;-"Low-grade infection" features recurrent or persistent pain and/or soft tissue contracture with various functional impairment and mixed positive/negative markers of infection/inflammation; pathogen identification requires prolonged cultures and antibiofilm techniques;-"High-grade infection" displays classical signs/symptoms of infection/inflammation with positive tests; pathogen identification is often possible with traditional microbiological techniques, but is better achieved with prolonged cultures and antibiofilm processing.Understanding biofilms-related clinical presentations is crucial for physicians, to implement the best diagnostic and therapeutic measures, and for regulatory bodies, to define the evaluation process of technologies aimed at reducing implants' malfunctions and infections, like anti-adhesive and antibiofilm coatings, that should be regulated as (part of) medical devices, requiring a suitable post-marketing surveillance.Only an effective antibiofilm-targeted approach from all players will hopefully allow the medical community to mitigate the current unacceptable social and economical burden of implant-related infections and malfunctions.