The occurrence of twitching motility among gram-negative bacteria.

Almost 1000 strains representing well above 50 different species or groups of gram-negative bacteria were examined for twitching motility. This kind of motility was mainly found in strictly aerobic cocci and rods (viz. Acinetobacter calcoaceticus, Moraxella spp., Neisseria gonorrhoeae, N. meningitidis, Pseudomonas spp., phenon 3 of Thornley that is closely related to Acinetobacter, and marine, yellow-pigmented rods), but also in the facultative Eikenella corrodens and in anaerobic strains presumptively identified as "Bacteroides corrodens" earlier. Strains of species known to possess polar fimbriae were shown to exhibit twitching motility. None of the strains of species known to possess peritrichously arranged fimbriae exhibited twitching motility.