TABLE 5.

Comparison of bacteriocin production by mixed cultures of S. mutans BM71 S. gordonii Challis in broth or biofilmsa

Supernatant from strain(s)% Killing of indicator RP66b
BrothBiofilms
BM71 alone98.3 ± 0.399.6 ± 0.4
BM71 + Challis0 ± 0 (537/406)0 ± 0 (517/353)
BM71 + BYW197.1 ± 1.0 (447/356)52.9 ± 7.0 (479/146)
  • a A 100 μl aliquot from S. mutans BM71 alone or in a mixture with S. gordonii Challis from a broth or biofilm culture was mixed with 5 × 104 CFU of RP666 indicator cells (in 100 μl of THB) and incubated at 37°C for 1 h. Two micro liters of the culture was plated on the surface of a TSA plate and incubated for another 24 h at 37°C under anaerobic conditions.

  • b Values are means ± standard deviations from two experiments. The values in parentheses are the total number of S. mutans cells (106)/total number of S. gordonii cells (106) counted on mitis salivarius plates.