Critical analysis of methods to determine growth, control and analysis of biofilms for potential non-submerged antibiofilm surfaces and coatings

The potential uses for antibiofilm surfaces reach across different sectors with significant resultant economic, societal and health impact. For those interested in using antibiofilm surfaces in the built environment, it is important that efficacy testing methods are relevant, reproducible and standardised where possible, to ensure data outputs are applicable to end-use, and comparable across the literature. Using pre-defined keywords, a review of literature reporting on antimicrobial surfaces (78 articles), within which a potential application was described as non-submerged/non-medical surface or coating with antibiofilm action, was undertaken. The most used methods utilized the growth of biofilm in submerged and static systems. Quantification varied (from most to least commonly used) across colony forming unit counts, non-microscopy fluorescence or spectroscopy, microscopy analysis, direct agar-contact, sequencing, and ELISA. Selection of growth media, microbial species, and incubation temperature also varied. In many cases, definitions of biofilm and attempts to quantify antibiofilm activity were absent or vague. Assessing a surface after biofilm recovery or assessing potential regrowth of a biofilm after initial analysis was almost entirely absent. It is clear the field would benefit from widely agreed and adopted approaches or guidance on how to select and incorporate end-use specific conditions, alongside minimum reporting guidelines may benefit the literature

Methods for dynamic investigations of surface-attached in vitro bacterial and fungal biofilms.

Three dynamic models for the investigation of in vitro biofilm formation are described in this chapter. In the 6-well plate assay presented here, the placing of the plate on a rotating platform provides shear, thereby making the system dynamic with respect to the static microtiter assay. The second reported model, especially suitable for harvesting high amounts of cells for transcriptomic or proteomic investigations, is based on numerous glass beads placed in a flask incubated with shaking on a rotating platform, thus increasing the surface area for biofilm formation. Finally, the flow-cell system, that is the driving model for elucidating the biofilm-forming process in vitro as well as the biofilm tolerance towards antibiotics and host defense components, is illustrated here

Study of in vivo catheter biofilm infections using pediatric central venous catheter implanted in rat

International audienceVenous access catheters used in clinics are prone to biofilm contamination, contributing to chronic and nosocomial infections. So far, biofilm physiology was mostly studied in vitro, due to a relative lack of clinically relevant in vivo models. Here, we provide a relevant protocol of totally implantable venous access port (TIVAP) implanted in rats. This model recapitulates all phenomena observed in clinic and allows studying bacterial biofilm development and physiology. After TIVAP implantation and inoculation with luminescent pathogens, in vivo biofilm formation can be monitored in situ and biofilm biomass can be recovered from contaminated TIVAP and organs. We used this protocol to study host responses to biofilm-infection, to evaluate preventive and curative anti-biofilm strategies, and to study fundamental biofilm properties. For this procedure, one should expect ~3h00 of hands-on time including the implantation in one rat followed by in situ luminescence monitoring and bacterial load estimation