Table I.
Comparison among the zones of inhibition (mm) of ciprofloxacin alone and ciprofloxacin in the presence of sildenafil, tadalafil, or vardenafil against standard bacterial strains
| Standard bacterial strains | Zones of inhibition (mm)* |
|||
|---|---|---|---|---|
| Ciprofloxacin | Ciprofloxacin + sildenafil | Ciprofloxacin + tadalafil | Ciprofloxacin + vardenafil | |
| Escherichia coli | 26.7 (0.6) | 11.3 (1.5) | 11.0 (1.0) | 11. 7 (0.6) |
| Staphylococcus aureus | 21 (1.0) | 9. 7 (1.2) | 9. 7 (0.6) | 9.3 (1.5) |
| Pseudomonas aeruginosa | 23.3 (0.6) | 11 (1.0) | 10. 7 (0.6) | 7.0 (2.0) |
| Staphylococcus epidermidis | 21. 7 (0.6) | 10.3 (1.2) | 10.3 (0.6) | 11.3 (0.6) |
| Acinetobacter baumannii | 17. 7 (0.6) | 8.3 (0.6) | 7. 7 (0.6) | 8.3 (0.6) |
| Proteus mirabilis | 18. 7 (0.6) | 8. 7 (0.6) | 8. 7 (0.6) | 7. 7 (0.6) |
| Klebsiella pneumoniae | 12.0 (1.0) | 4. 7 (0.6) | 6. 7 (0.6) | 5. 7 (0.6) |
⁎
The zones of inhibition values for ciprofloxacin alone were significantly (P < 0.05) lower than those of combination of ciprofloxacin with sildenafil, tadalafil, or vardenafil for all tested bacterial strains. Results are presented as mean (SD) of 3 independent experiments.