RESUMEN
BACKGROUND: To evaluate whether histopathologic findings of skin in sepsis by Pseudomonas aeruginosa correlate with the clinical course. METHODS: Histological alterations after bacterial challenge by one susceptible (A) and two multidrug-resistant isolates (B and C) of P. aeruginosa were studied in 18 rabbits. Sepsis was induced by the intravenous infusion of 1 x 10(8) CFU by a catheter in the right jugular vein; blood was sampled for the estimation of tumor necrosis factor alpha (TNF-alpha) and malondialdehyde (MDA). Skin biopsies were collected along with a subcutaneous fat specimen for culture. RESULTS: The mean survival was 0.85, 1.75 and 11.00 days after challenge by isolates A, B and C, respectively. The main histologic findings of skin were: inflammation and swelling of the dermis; thickening of the endothelium and infiltration of vessel wall and lumen by polymorphonuclear leukocytes; extravasation of red blood cells, and necrobiotic changes of the hair follicles. Serum TNF-alpha was elevated in animals challenged by isolate A compared to challenge by isolates B and C. Concentrations of MDA were similar for all isolates. Mean log(10) of viable cells isolated from subcutaneous fat were 5.74, 2.74 and 1.40 after challenge by isolates A, B and C, respectively. CONCLUSIONS: Prolongation of survival was accompanied by lower serum TNF-alpha, decreased viable cells from subcutaneous fat and intensified inflammatory response in the dermis and subcutaneous tissue. These findings might be of importance for immunomodulatory intervention.