Role of pili in the pathogenesis of Pseudomonas aeruginosa burn infection.
The present study using three isogenic mutants (F+P-, F-P+, F-P-) of Pseudomonas aeruginosa indicates that the presence of pili enhances the virulence of the organisms in experimental P. aeruginosa burn infection of mice. The 50% lethal dose (LD50) value for burned mice inoculated with non-piliated (P-) mutant was at least ten times higher than those inoculated with piliated (P+) bacteria. Meanwhile the LD50 value for burned mice inoculated with non-flagellated (F-) mutant was at least 10(5) times higher than those inoculated with flagellated (F+) bacteria. At 24 hr after inoculation, the bacterial counts in burned skin of mice inoculated with P+ bacteria were ten times higher than those inoculated with P- bacteria; and at 48 hr the bacterial counts became a hundred times higher in the former mice than the latter. At 24 hr after inoculation, P+ bacteria were isolated from blood, liver (F+P+), lung (F+P+), and kidney, while P- bacteria were not present in these tissues. And at 48 hr after inoculation, P+ bacteria were isolated from all tissues, while P- bacteria were isolated from some sites only. These results suggested that pili and flagella each play an important role as virulence factors independently, and that pili-mediated enhancement of virulence of P. aeruginosa was attributed to pili-mediated enhanced colonization of the organisms at the burned skin surfaces.
D000818:Animals; D002056:Burns / Q000150:complications* / Q000382:microbiology; D005260:Female; D010861:Fimbriae, Bacterial / Q000502:physiology*; D005407:Flagella / Q000502:physiology; D051379:Mice; D009154:Mutation; D011552:Pseudomonas Infections / Q000209:etiology* / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000472:pathogenicity; D012874:Skin Diseases, Infectious / Q000209:etiology* / Q000382:microbiology; D014774:Virulence