Cell-adherence properties of K. pneumoniae KR2107 and its isogenic fim and/or fim2 mutants. (A) In vitro adhesion assays to human HCT-8 ileocaecal cells. (B) In vitro adhesion assays to human 5637 bladder epithelial cells. In both cases percentages of bacteria that remained adherent to cell monolayers after 3 h of incubation at 37°C followed by careful washing are shown. Bars represent means and standard deviations.