A Medium to Suppress the Swarming of Proteus Species

SUMMARY Media containing activated charcoal inhibited the swarming but not the growth of Proteus mirabilis and P. vulgaris. The suppression of swarming depended on the presence of the charcoal in the medium: media pretreated with charcoal gave normal swarming. Charcoal does not interfere with the production of flagella as do some other substances used for the suppression of swarming. Starch and albumin at similar concentrations to the charcoal had no effect on swarming. Charcoal agar does not interfere with the growth of organisms other than Proteus and so facilitates the isolation of organisms contaminated with Proteus spp.