FIG. 1.

Bacterial density in vegetations infected with S. gordonii DL1 (filled dots) or EM230 (open dots). Each dot in a column represents the bacterial density in a vegetation (log₁₀ CFU/mg of vegetation) in a single rat. Dots below the zero level represent culture-negative vegetations. Differences in median vegetation bacterial densities and differences in rates of valve infections were evaluated by the Mann-Whitney U test and Fisher's exact probability test, respectively. N.S., not significant.