Microbiological appraisal of levofloxacin activity against Pseudomonas aeruginosa biofilm in combination with different calcium chanel blockers in vitro.

Chronic multi-drug resistant Pseudomonas aeruginosa infections among hospitalized elderly patients are nearly epidemic in some institutions and biofilms are now recognized as the root cause of such chronic infections such as with cystic fibrosis patients. We address the potential risks and advantages of combining commonly prescribed calcium channel blockers (CCBs) with the fluoroquinolone levofloxacin in the treatment of P. aeruginosa biofilms by using in vitro real-time monitoring of biofilm growth/inhibition over time. while mibefradil and diltiazem appear to be strongly antagonistic toward antimicrobial activity of levofloxacin, amlodipine and bepridil appear to have significant synergistic effects.