title: Pseudomonas aeruginosa exotoxin A: its role in retardation of wound healing: the 1992 Lindberg Award.
abstract: Bacterial concentrations greater than 10(5) colony-forming units/gm of tissue prevent wound healing. However, it has not been determined whether it is the number of bacteria or a toxin produced by these organisms that impedes the wound healing process. Pseudomonas aeruginosa (PSAR), a burn wound pathogen, produces a dermonecrotic toxin, exotoxin A. Studies have indicated a role for exotoxin A in the pathogenicity of PSAR. We investigated the role of exotoxin A in the retardation of contraction. Acute granulating wounds were created on 90 Sprague-Dawley rats. The animals were equally divided into six groups and were treated topically as follows: group 1, sham: no infection, no treatment; group 2, exotoxin A; group 3, exotoxin A and antiexotoxin; group 4, autoclaved PSAR 10(6); group 5, 10(6) viable PSAR inoculated in the wound; group 6, 10(6) viable PSAR and antiexotoxin. Wound contraction was measured with the use of planimetry twice a week. Serial biopsies were performed on all wounds. Contraction rates revealed significantly (p < 0.05) retarded closure in the animals treated with exotoxin A and in the viable PSAR group when compared with the rates of the noninfected control groups. Animals treated with exotoxin A plus antiexotoxin A and those treated with live PSAR and antiexotoxin showed contraction rates identical to the control groups. These data suggest that exotoxin A in PSAR infections retards wound healing and that neutralization of the toxin restores the normal healing process.
authors.affiliation: Department of Plastic Surgery, University of Texas Medical Branch, Shriners Burns Institute, Galvenston 77550.
authors.forename: J P
authors.initials: JP
authors.lastname: Heggers
authors.forename: S
authors.initials: S
authors.lastname: Haydon
authors.forename: F
authors.initials: F
authors.lastname: Ko
authors.forename: P G
authors.initials: PG
authors.lastname: Hayward
authors.forename: S
authors.initials: S
authors.lastname: Carp
authors.forename: M C
authors.initials: MC
authors.lastname: Robson
mesh_terms: D036002:ADP Ribose Transferases; D000818:Animals; D001363:Awards and Prizes; D001427:Bacterial Toxins; D002056:Burns / Q000382:microbiology / Q000503:physiopathology*; D005098:Exotoxins / Q000502:physiology*; D011552:Pseudomonas Infections / Q000382:microbiology / Q000503:physiopathology; D011550:Pseudomonas aeruginosa; D051381:Rats; D017207:Rats, Sprague-Dawley; D037521:Virulence Factors; D014945:Wound Healing / Q000502:physiology*; D000097668:Pseudomonas aeruginosa Exotoxin A
chemical_list: D036002:ADP Ribose Transferases; D001427:Bacterial Toxins; D005098:Exotoxins; D037521:Virulence Factors; D000097668:Pseudomonas aeruginosa Exotoxin A