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

TL;DR

This study shows that Cremophor EL and Cremophor RH40 can reduce antibiotic resistance in Pseudomonas aeruginosa by inhibiting efflux pumps.

Contribution

The novel finding is the synergistic effect of Cremophor EL and Cremophor RH40 with antibiotics against MDR Pseudomonas aeruginosa.

Findings

Six out of 30 P. aeruginosa strains showed high efflux pump activity.

Cremophor RH40 reduced ciprofloxacin MIC by 6-fold, while Cremophor EL reduced it by 4-fold.

Both surfactants synergized with ciprofloxacin, ticarcillin, and meropenem in inhibiting efflux pumps.

Abstract

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

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

Efflux pump-active MDR strains of P. aeruginosa 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.

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.

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

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