A quantitative model of invasive Pseudomonas infection in burn injury.

To evaluate newer therapies for wound infections, it becomes necessary to quantify bacteria that invade from the infected wounds into the adjacent tissues. For example, antibody-targeted photolysis targets the invasive Pseudomonas with antibodies carrying photochemical dyes. A full-thickness burn wound was infected with Pseudomonas aeruginosa with a modification of previous methods. In mice, a skin fold was elevated, and two preheated brass blocks at 92 degrees to 95 degrees C were applied for 5 seconds, producing a 5% total body surface area injury with discrete margins. The eschars were immediately inoculated with Pseudomonas. Survival at 10 days was 100% with burn injury alone and 60% with infected burns. Pseudomonas (10(8)/gm) were recovered from the unburned muscle by 24 hours. The method produced uniform and reproducible quantitative bacteriology within the muscle immediately beneath the burn injury (SL < 0.05). Quantitative comparisons can be used to determine the effectiveness of newer modalities to control Pseudomonas burn wound infections.