FIG. 3.
Antagonistic exclusion activity of bacterial pharyngeal isolates against bioluminescent Streptococcus pyogenes C11LucFF on FaDu hypopharyngeal carcinoma cells (A) and HaCaT keratinocytes (B). Data reported as percent variation of light emission, which referred to the cell layer treated with only PBS buffer before incubation with S. pyogenes. Numerical results are given as arithmetic means ± standard deviations. Each sample was processed in triplicate in at least two independent experiments. Strains belonging to species S. salivarius are indicated in boldface. Statistically significant differences compared to strain K12 were calculated according to an unpaired Student's t test (**, P < 0.001; *, P < 0.05).