Reversal of the silver inhibition of microorganisms by agar.

Increasing use of silver in the treatment of water has necessitated an examination of microbiological methods for the measurement of silver inactivation of microorganisms. Three common agar media were tested for their ability to neutralize the bacteriostatic effects of silver. Results suggested that growth media differed in their neutralizing capacity; that is, the non-inhibitory media tryptone glucose agar and Trypticase soy agar showed more neutralizing capacity than eosin methylene blue agar. Furthermore, the neutralizing effect appeared to be a function of the soluble component of the media and not of the agar itself.