Background: Pseudomonas aeruginosa (PA) is a leading cause of morbidity and mortality in patients with infected burns. In an era of increasing drug resistance, alternative treatment modalities are sought. PA flagellum is an important virulence factor, and therefore may serve as a target for immune therapy. We evaluated the efficacy of polyclonal IgG raised against PA flagellin type-b (anti-bFla), in a murine-infected burn model.
Methods: A full thickness scald burn involving 6-8% of the murine body surface area was induced. Infection was caused by sub-eschar injection of PA. Study groups included: 1.Immune therapy (intra-peritoneal): 1a. Polyclonal anti-bFla, 1b. Non-specific IgG (NS IgG); 2. Conventional antibiotics: 2a. Imipenem (IMP), 2b. Topical silver sulfadiazine (SSD); 3. Model control: Untreated infected-burn. Mortality and morbidity (weight change and functional score) follow-up was 2 weeks.
Results: Burn wound infection with PA (2x106 and 5x106 CFU) resulted in 58-83% mortality rate. Mice treatment with IMP or SSD reduced the mortality rate to 8%. The mortality rate in anti-bFla treated mice ranged between 0-17% (P<0.05). Treatment with different anti-bFla regimens (pre-infection, post-infection, or combined) resulted in similar results. Morbidity paralleled survival results. Conclusion:Anti-bFla IgG is effective in reducing mortality and morbidity in murine PA infected burn model.