Building blocks of biofilms - an engaging and hands-on microbiology outreach activity for school children and the general public.

Biofilms are naturally occurring communities of micro-organisms, attached to a surface and often embedded in a matrix of self-produced polymeric substances. Biofilms are widely implicated in human infections, particularly on prostheses and medical implants. Such biofilms are difficult to eradicate, often leading to replacement of the prosthesis and resulting in a significant burden to healthcare. Here we present a fun and engaging interactive activity targeted toward primary school/early secondary school children, introducing the concept of natural and healthcare-associated biofilms, using dental plaque as an archetypal example. Dental plaque forms as a result of poor oral/dental hygiene, and develops according to a typical series of defined stages: attachment and adherence to the surface, followed by colonization and maturation of the biofilm structure, and eventually, dispersal. This activity uses dental disclosing tablets to visualize real biofilms (plaque) on the participants teeth, and uses interlocking building-blocks to represent microorganisms, where children build three-dimensional 'biofilms' of varying shapes and structural integrities. Each of the stages of development are discussed in detail, and after building the biofilms, balls of different shapes, sizes and weights can be used as 'antimicrobials' to disrupt the biofilm structure. The outcomes of the activity are to enhance knowledge and general understanding of biofilms; their ubiquitous presence in the natural environment, development, implications in healthcare, and challenges of treatment. The various 'antimicrobial' balls also provide a basis to introduce and discuss drug selection for infections, and the importance of using the correct antimicrobial for different infections to avoid development of resistance.