If you just enter 'Tuberculosis' in the search box, you get results. Did you try to enter ' Mycobacterium Tuberculosis' ? I think Mycobacterium Tuberculosis does not qualify as being a 'trait' - rather it is the bacterium responsible for the trait Tuberculosis.
Quoting from the help page:
What can I type into the search bar? You can type any text you wish into the search bar. This will then return any exact string matches within a number of data fields in the Catalog, including title, author, journal, reported trait, mapped (ontology) trait, mapped trait’s synonyms, mapped trait’s parents, sample descriptions, genes and SNPs.