A Classification of the Klebsiella Group

SUMMARY: Klebsiella strains are divided into six categories on the following reactions: fimbriation, production of gas from glucose at 37°, acid from lactose and dulcitol, methyl red test, acetoin production, citrate, urease, gluconate, malonate, lysine decarboxylase, growth in the presence of KCN and ability to produce gas from lactose at 44°. Five of the six categories are assigned specific rank, the sixth subspecific rank. The tests enable Friedländer’s pneumobacillus to be distinguished from Aerobacter aerogenes. A new species, Klebsiella edwardsii, and a new subspecies, K. edwardsii var. atlantae, are named. Neotype strains of old species are proposed, holotypes of the new species and variety designated, and the catalogue numbers in the National Collection of Type Cultures and American Type Culture Collection given.