Active immunization using exotoxin A confers protection against <it>Pseudomonas aeruginosa </it>infection in a mouse burn model

• Main Authors: Naghmachi Mohsen, Amini Masoud, Japoni Aziz, Mehrabani Davood, Kohanteb Jamshid, Manafi Ali, Zaghi Ahmad Hosseinzadeh, Khalili Nazanin
• Format: Article
• Language: English
• Published: BMC 2009-02-01
• Series: BMC Microbiology
• Online Access: http://www.biomedcentral.com/1471-2180/9/23

<p>Abstract</p> <p>Background</p> <p><it>Pseudomonas aeruginosa </it>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.</p> <p>Methods</p> <p>The toxoid was prepared from exotoxin A taken from toxigenic strains of <it>P. aeruginosa </it>(PA 103). 50 mice were immunized with the toxoid, burned with hot metal and infected with 1 × 10⁸CFU of toxigenic strains of <it>P. aeruginosa </it>(experimental group); 25 non-immunized mice were also burned and infected (control group). The mortality rate and presence of any exotoxin and <it>P. aeruginosa </it>in the sera, liver and spleen were determined.</p> <p>Results</p> <p>In 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 <it>P. aeruginosa </it>and followed for 70 days. 3 of these mice died. Neither <it>P. aeruginosa </it>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 <it>P. aeruginosa </it>and exotoxin A were isolated from sera, spleen and liver.</p> <p>Conclusion</p> <p>Active immunization of mice using a semi-purified exotoxin A derived from <it>P. aeruginosa </it>was 93.8% effective at protecting mice from subsequent <it>P. aeruginosa </it>infections in a mouse burn model.</p>