A Method for Quantitative Determination of Biofilm Viability

Abstract

In this study we present a scheme for quantitative determination of biofilm viability offering significant improvement over existing methods with metabolic assays. Existing metabolic assays for quantifying viable bacteria in biofilms usually utilize calibration curves derived from planktonic bacteria, which can introduce large errors due to significant differences in the metabolic and/or growth rates of biofilm bacteria in the assay media compared to their planktonic counterparts. In the presented method we derive the specific growth rate of Streptococcus mutans bacteria biofilm from a series of metabolic assays using the pH indicator phenol red, and show that this information could be used to more accurately quantify the relative number of viable bacteria in a biofilm. We found that the specific growth rate of S. mutans in biofilm mode of growth was 0.70 h−1, compared to 1.09 h−1 in planktonic growth. This method should be applicable to other bacteria types, as well as other metabolic assays, and, for example, to quantify the effect of antibacterial treatments or the performance of bactericidal implant surfaces.

Reduced Glutathione Mediates Resistance to H 2 S Toxicity in Oral Streptococci

“…2C and D). Since the crystal violet assay cannot differentiate between the extracellular polymeric substances (EPS) and bacterial cells (15), the viability of bacteria in biofilm was additionally investigated by plating. Viable counts of S. mitis and S. oralis in biofilms were significantly affected in the presence of H 2 S (Fig.…”

An Assay for Detection of Uropathogenic Escherichia coliBiofilm using Calcofluor

“…The violet crystal provides a good measure of biofilm mass. However, it does not give a measure of biofilm viability (Welch et al, 2012). In this paper, the production of bacterial exopolysaccharides was indicative of the viability of bacteria forming biofilm.…”

Conditions that induce biofilm production byOrnithobacterium rhinotracheale

“…In this research, we were able to confirm the capacity of ORT to form biofilm, as occurred with S. mutans, which was the strain used as the positive control for biofilm formation. It has been described that S. mutans is able to produce biofilm under diverse pH values, as well as under aerobiosis or elevated CO 2 conditions and at different temperatures (Shumi et al, 2010;Nishimura et al, 2012;Welch et al, 2012).…”