title: Virulence of different Pseudomonas species in a burned mouse model: tissue colonization by Pseudomonas cepacia.
abstract: The virulence of Pseudomonas aeruginosa and other pseudomonads was examined in a burned mouse model. P. aeruginosa M-2 was highly virulent causing 100% mortality by 38 h with an injection of 10(2) CFU by either a subcutaneous or intraperitoneal route. Subcutaneous injection of 10(2) CFU revealed rapid multiplication of the bacteria at the burn wound with 10(8) CFU/g detectable in the burned skin by 28 h postinjection, 10(5) CFU/g of liver, and 10(3) CFU/ml of blood. Non-P. aeruginosa clinical isolates were markedly less virulent; an injection of greater than or equal to 10(7) CFU caused less than or equal to 60% lethality. P. cepacia SMH colonized the burned skin of thermally injured mice, persisting at levels of 10(7) to 10(8) CFU/g of burned skin after an initial injection of 10(5) CFU. P. cepacia persisted in the burn wound for at least 3 weeks. No organ invasion was detectable throughout this period. Studies with an additional clinical isolate of P. cepacia yielded similar results. An injection of a 10(2) CFU dose revealed that the level of persistence is dose dependent. Results suggest that the tenacious persistence of P. cepacia in the burn wound may provide a model for the study of persistent colonization and infection in a compromised host.
mesh_terms: D000818:Animals; D002056:Burns / Q000382:microbiology* / Q000401:mortality; D003114:Colony-Forming Units Assay; D004195:Disease Models, Animal; D005260:Female; D007114:Immunization; D051379:Mice; D008813:Mice, Inbred ICR; D011549:Pseudomonas / Q000472:pathogenicity*; D012867:Skin / Q000382:microbiology; D013997:Time Factors; D014774:Virulence; D014946:Wound Infection / Q000382:microbiology* / Q000401:mortality