FIG 3.

Comparison of sensitivity and selectivity of C. difficile brucella broth with thioglycolic acid and l-cysteine (CDBB-TC) versus C. difficile brucella broth (CDBB) for the detection of environmental contamination on hospital wards. Swabs were applied to a 5 by 10 cm area of surfaces and incubated at 37°C for 72 h. All specimens with a change from red to yellow were cultured for C. difficile. On the right are cultures negative for C. difficile but positive for other organisms that grew when reinoculated into CDBB with a change in color to yellow (i.e., false-positive cultures for C. difficile).