Effect of adjunctive treatment with gamma interferon against Pseudomonas aeruginosa pneumonia in neutropenic and non-neutropenic hosts

To evaluate the adjunctive effect of interferon-gamma (IFN-gamma) in treatment of Pseudomonas aeruginosa pneumonia, neutropenic and non-neutropenic mice received LD(100) of the organism intratracheally, followed by subcutaneous administration of IFN-gamma, ceftazidime (TAZ) or a combination of both agents 2 h post-inoculation. Treatment with IFN-gamma alone showed no significant increase in survival when compared with control. Addition of IFN-gamma to TAZ resulted in no significant change in survival compared with TAZ alone. Survival in TAZ and TAZ + IFN-gamma groups, was significantly higher than in control and IFN-gamma groups. This suggests that adjunctive treatment with IFN-gamma in combination with ceftazidime may not be more beneficial than the antibiotic alone when managing acute P. aeruginosa pneumonia in both immunocompromised and immunocompetent hosts.