FIG. 6.

Distribution of the exsA and exoU genotypes, in vitro type III secretion ability, and cytotoxicity to PMNs of 29 P. aeruginosa CF isolates. (A) Percent cytotoxicity calculated from the release of LDH activity. (B) In vitro induction of the type III secretion system, measured by SDS-PAGE analysis of culture supernatants. (C) Southern blot analysis of chromosomal DNAs after digestion with EcoRI. The restriction fragment length polymorphism encountered in exoU-containing strains (CF16, CF17, and CF18) is shown. Molecular sizes markers are indicated on the right.