Abstract
BACKGROUND: The repurposing of approved drugs for new activities is gaining widespread attention, including drugs that have antibacterial properties. Nevertheless, besides the benefits of repurposing drugs, the discovery of new antibiotic activity in commonly used medicines raises concerns about inducing antibiotic tolerance and resistance due to the stress produced by the drugs. We found that nebivolol, which is used to treat hypertension, also has antibacterial activity. METHODS: The antibacterial activity of nebivolol was tested by disc diffusion and kinetic O.D. MEASUREMENTS: Antibiofilm activity was determined by crystal violet staining. RESULTS: Nebivolol has antibiotic and antibiofilm activity against several bacteria. However, its effect on Pseudomonas aeruginosa's growth is limited, and it promotes biofilm formation. In addition, P. aeruginosa exposure to nebivolol induces resistance to ciprofloxacin but increases sensitivity to tobramycin. CONCLUSIONS: Nebivolol has antibiotic activity against several bacteria tested but is less effective and possibly detrimental in P. aeruginosa infections. The use of nebivolol, together with other antibiotics, should be further tested and carefully considered.