FIG. 8.

Adherence of K. kingae PilC1 and PilC2 mutants. The bars indicate the adherence of K. kingae strains 269-492, 269-492 pilC1 (pilC1), 269-492 pilC2 (pilC2), 269-492 pilC1/pilC2 (pilC1/pilC2), and 269-492 pilA1::aphA3 (pilA1:aphA3) to respiratory epithelial cell lines. The pilC1 mutant and the pilC2 mutant were less adherent than strain 269-492 to all cell lines (P ≤ 0.05, as determined using the unpaired t test). The level of surface-expressed pili on each strain was determined by negative-staining transmission electron microscopy and was scored using a scale ranging from − to +++.