FIG. 8.

Adherence of wild-type and mutant strains to HeLa cells. HeLa cells (2 × 10⁵) were infected with wild-type and mutant strains at a multiplicity of infection of 10. After 1.5 h, nonadherent bacteria were removed by washing five times with PBS. The monolayers and cell-associated bacteria were then recovered by treatment with 0.2% Triton X-100 for 5 min at room temperature. The recovered bacteria were plated on LB agar plates after dilution. Results are presented as the ratio of the adherence of the tested strains to that of the wild-type controls. Error bars represent standard deviations.