RESUMO
The effect of zinc sulfate on the in vitro activities of cefoperazone, ciprofloxacin and tobramycin was evaluated against 10 clinical isolates of Pseudomonas aeruginosa isolated from patients of cystic fibrosis associated with pulmonary pneumonia. Adding zinc of commercial media deficient to this cation increased the MICs and MBCs of the three tested antibiotics. Concurrent administration of zinc with each of the three antibiotics resulted in significant reduction in the antipseudomonal activity of both cefoperazone and tobramycin, while the activity of ciprofloxacin did not significantly altered. The response of pulmonary arterial rings isolated from Pseudomonas aeruginosa infected rabbits to serotonin was significantly reduced when compared to those isolates from control rabbits. Cefoperazone potentiates the response of the pulmonary arterial rings isolated from infected rabbits to serotonin when compared to control rings. Zinc either alone or in combination with cefoperazone significantly reduced the response of the pulmonary rings isolated from infected rabbits to serotonin when compared with control. The results of the present study showed that, zinc reduced the antipseudomonal activities of cefoperazone and tobramycin and did not altered the activity of ciprofloxacin in vivo