FIG. 6.

Biofilm formation by additional ETSU-9 mutant strains. (A) The ETSU-9 parent strain and the ETSU-9.222cat, ETSU-9.714cat, and ETSU-9.988cat mutants were grown in broth (black columns) or on agar plates (gray columns) and then used to inoculate a 24-well plate. Biofilm development was measured as described in Materials and Methods. These data represent the means and standard errors from three independent experiments. A two-tailed t test was used to compare biofilm formation by each of the mutants to biofilm formation by the parent strain with a given inoculum (i.e., broth grown or agar plate grown); *, P < 0.05; **, P < 0.01. (B) Growth of the same four strains in TH broth.