Active immunization using exotoxin A confers protection against Pseudomonas aeruginosainfection in a mouse burn model

Abstract

BackgroundPseudomonas aeruginosa is an important cause of nosocomial infection and may lead to septicemia and death. We evaluated the immunogenicity of semi-purified exotoxin A from the bacterium in a mouse burn model.MethodsThe toxoid was prepared from exotoxin A taken from toxigenic strains of P. aeruginosa (PA 103). 50 mice were immunized with the toxoid, burned with hot metal and infected with 1 × 108 CFU of toxigenic strains of P. aeruginosa (experimental group); 25 non-immunized mice were also burned and infected (control group). The mortality rate and presence of any exotoxin and P. aeruginosa in the sera, liver and spleen were determined.ResultsIn the experimental group, 2 mice died before the burns were administered and were excluded from the study. The remainder (48 mice) were challenged with a lethal dose of P. aeruginosa and followed for 70 days. 3 of these mice died. Neither P. aeruginosa nor exotoxin A was not detected in the liver, spleen or sera of the surviving mice. The protective efficacy of toxoid vaccination was therefore 93.8%. In the control group, all mice died from bacteremia and septicemia, most (80%) within 6 days, and P. aeruginosa and exotoxin A were isolated from sera, spleen and liver.ConclusionActive immunization of mice using a semi-purified exotoxin A derived from P. aeruginosa was 93.8% effective at protecting mice from subsequent P. aeruginosa infections in a mouse burn model.

Triplex PCR for the Simultaneous Detection of Pseudomonas aeruginosa, Helicobacter hepaticus, and Salmonella typhimurium

“…3). Recently, after toxigenic strains of P. aeruginosa (PA 103) were inoculated subcutaneously into a burned area, P. aeruginosa were isolated from sera, spleen, and liver [6]. However, we did not detect P. aeruginosa in liver samples.…”

Animal models of external traumatic wound infections

“…For the introduction of the burn infections, to apply the infecting microorganism topically 64,70,71,74,83 is more clinically relevant than to inject the microorganism under the burn eschar. 58,59,68,69,82 Apparently, the minimum inoculum of microorganism required to induce infection by use of subcutaneous injection in lower than that using topical application. Similar to the models SSI and skin abrasion infection, lethal infections can be developed in animals by use of lethal microorganisms (e.g., P. aeruginosa), 49,59,71 while chronic infections can be produced using less lethal microorganisms (e.g., S. aureus).…”

Effect ofPlantago majoron Burn Wound Healing in Rat

“…A standard 3rd degree burn wound was produced using a hot plate with the same size about 20% total body surface area (TBSA) and at identical t e m p e r a t u r e as described by Manafi et al (2009). Rats of groups of A, B and C were treated with silver sulfadiazine (SSD), 20% or 50% Plantago major ointment.…”