FIG. 5.

Effects of different amounts of chlorhexidine (■), tetracycline (▤), and penicillin (□) on the light emission (relative light units [RLU]) of the bacteria. Twofold dilutions of each antimicrobial agent were made, starting from 10.0 μg/ml for chlorhexidine, 0.08 μg/ml for tetracycline, and 0.40 μg/ml for penicillin (sample 6), and the antimicrobial agents were incubated with the bacteria for 4 h at 35°C in BHI broth. The sample labelled 0 is the nontreated control. The values are the means of two independent measurements. The variation between the measurements was less than 10%. Arrows indicate the concentrations that inhibited growth on agar plates.