Experimental candidiasis after thermal injury

Abstract

The ability of Candida albicans to infect thermally injured mice was studied. Female mice were either left unburned or given a 20% total body surface area 2-s or 7-s scald burn. The wound or skin surface was then inoculated with a human burn wound isolate of C. albicans. At 4 h postburn, approximately 10(2) to 10(3) CFU/g of tissue could be recovered from the skin of burned and unburned animals. Unburned mice cleared the organisms from the skin by 72 h, whereas in 7-s-burned animals, the candida increased in numbers to approximately 10(7) CFU/g of tissue. The ability of the organisms to invade systemically after wound surface inoculation was examined in mice given either a 2-s or a 7-s scald burn. Each injury was histologically confirmed as a full-thickness (third degree) burn, with slightly deeper tissue damage observed with the 7-s burn. At each time period examined (1, 4, 7, and 10 days), there were significantly fewer organisms in the wounds of mice given the 2-s injury than in wounds of mice burned for 7 s (P less than 0.05). In 3 of 33 mice given a 7-s injury, organisms were recovered from the kidneys at the time of sacrifice, whereas no evidence of invasion into the kidneys was noted in mice given a 2-s thermal injury. This study demonstrated that thermal injury enhances the ability of C. albicans to infect mice and that the depth of burn appears to be an important factor in determining whether the organisms can invade the burn wound to cause systemic infection. This animal model should be valuable in elucidating the virulence factors of C. albicans that play a role in the pathogenesis of candidiasis after thermal injury.