Comprehensive exploration and structured study of the microbial diversity implies access to huge numbers of specimens of which some are referred to as "type strains" when they constitute the archetype of a species, and as "reference strains" when they are representative of a lineage with well identified properties.Type strains constitute the primary elements of taxonomy, reference strains are essential parts of coherent R&D processes.These assets of fundamental scientific importance must be conserved and provided with the highest level of reliability to ensure consistent research and knowledge build-up.