Active immunization using exotoxin A confers protection against Pseudomonas aeruginosa infection in a mouse burn model.
BACKGROUND
Pseudomonas 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.


METHODS
The 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 x 10(8) 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.


RESULTS
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 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.


CONCLUSIONS
Active 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.
Manafi
Ali
A
Department of Plastic Surgery, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. dramanafi@yahoo.com
Kohanteb
Jamshid
J
Mehrabani
Davood
D
Japoni
Aziz
A
Amini
Masoud
M
Naghmachi
Mohsen
M
Zaghi
Ahmad Hosseinzadeh
AH
Khalili
Nazanin
N
D036002:ADP Ribose Transferases / Q000008:administration & dosage / Q000276:immunology; D000818:Animals; D021461:Animals, Outbred Strains; D000907:Antibodies, Bacterial / Q000097:blood; D001427:Bacterial Toxins / Q000008:administration & dosage / Q000276:immunology; D002056:Burns / Q000382:microbiology / Q000401:mortality / Q000517:prevention & control; D004195:Disease Models, Animal; D005098:Exotoxins / Q000008:administration & dosage / Q000276:immunology; D006801:Humans; D007114:Immunization; D008099:Liver / Q000382:microbiology; D051379:Mice; D011552:Pseudomonas Infections / Q000382:microbiology / Q000401:mortality / Q000517:prevention & control; D054406:Pseudomonas Vaccines / Q000008:administration & dosage / Q000276:immunology; D011550:Pseudomonas aeruginosa / Q000276:immunology* / Q000302:isolation & purification / Q000472:pathogenicity; D011817:Rabbits; D013154:Spleen / Q000382:microbiology; D037521:Virulence Factors / Q000008:administration & dosage / Q000276:immunology; D000097668:Pseudomonas aeruginosa Exotoxin A
D036002:ADP Ribose Transferases; D000907:Antibodies, Bacterial; D001427:Bacterial Toxins; D005098:Exotoxins; D054406:Pseudomonas Vaccines; D037521:Virulence Factors; D000097668:Pseudomonas aeruginosa Exotoxin A