The Effects of Triclosan and Zinc Citrate, Alone and in Combination, on a Community of Oral Bacteria Grown in vitro

Abstract

A mixed-culture chemostat system has been used as a more stringent laboratory system for evaluation of the antimicrobial effects of Triclosan and zinc citrate. The inhibitors were added alone, and in combination, as a pulse (a high initial inhibitor concentration which decreased with time) or as a dose (concentration of inhibitor increased with time) to give maximum concentrations of 34.5 mumol/L Triclosan and 39.8 mumol/L zinc citrate. When dosed, Triclosan inhibited A. viscosus and all five Gram-negative species, whereas zinc citrate had less effect, probably due to complexation by media components. Similar effects were seen when Triclosan was pulsed, except that S. mutans was the most sensitive Gram-positive species and V. dispar was unaffected. However, when the inhibitors were dosed or pulsed in combination, marked complementary and additive inhibitory effects were observed, particularly against Gram-negative species, although S. gordonii and S. oralis were relatively unaffected. The data confirm that increased effects can be obtained with suitable combinations of antimicrobial agents and suggest that, under certain conditions, apparently broad-spectrum antimicrobial agents may be acting more selectively than hitherto suspected.

Effects of a Chlorhexidine Gluconate-Containing Mouthwash on the Vitality and Antimicrobial Susceptibility of In Vitro Oral Bacterial Ecosystems

“…This variation is presumably due to interindividual variation in bacterial carriage, represented in the microcosms. Comparable specificity and variation in effects have been shown in many previous studies, including an investigation using a novel supragingival-plaque model (13), in human volunteer studies (38), and in a defined bacterial ecosystem (3,30). Considerable variation in the extent of effects is also apparent between laboratories and is probably due to variation in experimental parameters or among individual donors.…”

“…CHX susceptibilities (MICs and MBCs) were determined for 10 dental bacteria, comprising a consortium of organisms used extensively for studies of mixed cultures of plaque bacteria (3,26,30). These data are shown in Table 1.…”

Effects of Triclosan-Containing Rinse on the Dynamics and Antimicrobial Susceptibility of In Vitro Plaque Ecosystems

“…Table 3 shows the MICs and minimal bactericidal concentrations (MBCs) for 10 dental bacteria which comprise the Marsh consortium (4,29). These data show that N. subflava was the most susceptible bacterium, followed by the gram-negative anaer- The values are presented as the mean, median; standard deviations of the data for multiple cell clones are given in parentheses.…”

Contemporary perspective on plaque control

“…For example, although displaying similar MIC values against Triclosan, Gram negative obligately anaerobic bacteria implicated in gingivitis and periodontal diseases are more susceptible than the Gram positive bacteria (streptococci and Actinomyces species) found in health when exposed to this agent for only short periods. 24 Many Antimicrobial concentration Fig. 1 Pharmacokinetics of antimicrobial agents delivered to the mouth.…”