Determination of ammonia inhibition in fabric impregnated with antimicrobials

A new method is described for determining the presence or absence of ammonia produced by urealytic microorganisms, using fabric which has been treated with an antimicrobial. Circular disks of fabric treated with various concentrations of an antimicrobial are placed in the bottoms of snap-on lid petri dishes. Nutrient medium containing urea, an indicator, and a dilution of an overnight culture of Proteus mirabilis is applied to the fabric disks. The lids are snapped on and the dishes are incubated at 37 degrees C. By examination of the fabric disks at regular intervals of time for a color change from white to red, one may determine whether the concentration of antimicrobial in the fabric is sufficient to inhibit the production of ammonia by a urealytic microorganism.