Investigation of the role of Cremophor RH 40 and Cremophor EL in the inhibition of efflux pump of .

BACKGROUND

There is increasing emphasis on restoring the efficacy of existing antibiotics instead of developing new ones.

OBJECTIVES

This study aimed to determine the role of Cremophor EL and Cremophor RH40 in the inhibition of efflux pumps in MDR strains.

METHODS

Efflux pump-active MDR strains of were identified and confirmed by flow cytometry. The identified efflux-active strains were further subjected to determination of the MIC of ciprofloxacin and the synergistic role of non-ionic surfactants (Cremophor EL and Cremophor RH40) along with ciprofloxacin.

RESULTS

Out of 30 samples, 6 strains displayed high efflux pump activity. Both Cremophor EL and Cremophor RH40 showed efflux pump inhibitory roles. A 4-fold reduction in the MIC values of ciprofloxacin was observed when Cremophor EL was used along with ciprofloxacin, while a 6-fold reduction was observed when Cremophor RH40 was used along with ciprofloxacin. Both compounds showed synergistic effects with ciprofloxacin, ticarcillin and meropenem when used in a 24-well plate efflux pump inhibitory assay.

CONCLUSION

The inhibition of the efflux pump of MDR by non-ionic surfactants, namely, Cremophor RH40 and Cremophor EL, provided the best strategy to restore the efficacy of ciprofloxacin.