Distinct Function of Pseudomonas aeruginosa Type IV Pili Disclosed in the Bacterial Pass-Through of Membrane Filter with Smaller Pore Sizes

Membrane filter pass-through ability of Pseudomonas aeruginosa was analyzed with isogenic mutants. A flagellum-deficient fliC mutant required two-times longer time (12 hr) to pass through a 0.45-μm pore size filter. With 0.3- and 0.22-μm filters, however, the fliC mutant showed no remarkable disability. Meanwhile a pilA mutant defective in twitching motility failed to pass through the 0.22-μm filter. Complementation of the mutant with pilA gene on a plasmid restored the twitching motility and the 0.22-μm filter pass-through activity. Thus, the distinctive role of P. aeruginosa type IV pili in infiltration into finer reticulate structures was indicated.