Composition and susceptibility to chlorhexidine of multispecies biofilms of oral bacteria

Abstract

Using a constant-depth film fermentor, we have grown a six-membered biofilm community with a bacterial composition similar to that found in supragingival dental plaque. Cryosectioning revealed the distribution of bacteria throughout the biofilm. Exposure to 0.2% chlorhexidine for up to 5 min had little effect on biofilm viability.

FIG. 1

Growth of individual species comprising a multispecies biofilm formed on bovine enamel discs with CM as the sole nutrient source. Error bars represent standard deviations (n = 4).

FIG. 2

Viable counts of constituent bacteria in 30-μm sections of the 300-μm-thick biofilms. Numbers on the x axis are CFU per square millimeter.

FIG. 3

Transmission electron micrographs of a transverse section of biofilm (216 h) at the biofilm-air interface (a) and at the biofilm-substratum interface (b). Bars represent 2 μm.

FIG. 4

Relative proportions of live and dead bacteria in 30-μm sections of a 300-μm-thick biofilm at 216 h.

FIG. 5

Response of individual species comprising multispecies biofilms to various periods of exposure to 0.2% CHG. Error bars represent standard deviations (n = 4).