This is the status of a designated strain : "The type strain is made up of living cultures of an organism, which are descended from a strain designated as the nomenclatural type" .
Since August 2002 "authors of papers in which new names and/or new combinations are proposed provide evidence that types are deposited in two publicly accessible recognized culture collections in two different countries"
The Type Strain being a "prototype strain" and fully recognized as a member of the taxon species level, other strains of the species have to share a common ancester and a high level of similarities with it. Even if this strain is not the "mean" or "gravity point" of the species, a strain of the species must not have important differences. Thus the DNA sequence of a Type Strain has a big "confidence weigth" to position the species in a phylogenetic tree.
In Bibi Le the status is identified by T and Bibi Le tries to inform the user that a sequence of a Type Strain is missing in the tree (it may ask if you want to add it to the tree if this is possible).