There is a need for methods to improve the clinical efficacy of currently available antibiotics against multidrug-resistant bacteria in CF CRS. Ivacaftor was recently identified as having potentially beneficial off-target effects as a weak inhibitor of bacterial DNA gyrase and topoisomerase IV. The researchers conducted this study to evaluate whether ivacaftor enhances the antimicrobial activity of ciprofloxacin against Pseudomonas aeruginosa.

The planktonic growth of the PAO-1 strain of P. aeruginosa was studied in the presence of ciprofloxacin and ivacaftor. Effects were measured according to an optical density of cultured PAO-1 at 600 nm. For a static PAO-1 biofilm assay, the PAO-1 strain was inoculated and cultured for 72 h in the drugs’ presence. Formed PAO-1 biofilms were quantified by crystal violet staining and imaged with CLSM and SEM.

After the anaylsis significant synergism was noted between ciprofloxacin and 16 µg/mL of ivacaftor in reducing planktonic growth and biofilm formation. Quantitative measurements with crystal violet staining were correlated to CLSM and SEM images.

The study concluded that ivacaftor enhanced ciprofloxacin’s antimicrobial activity against P. aeruginosa. Further studies evaluating the efficacy of ivacaftor/ciprofloxacin combination for P. aeruginosa for CF CRS are warranted.

Reference: https://journals.sagepub.com/doi/full/10.1177/1945892418815615

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