Use of resazurin to detect mefloquine as an efflux-pump inhibitor in Pseudomonas aeruginosa and Escherichia coli.
Multi-drug-resistant bacteria can cause serious infections that are extremely difficult to treat. Bacterial efflux pumps are known to contribute to multi-drug resistance and, thus, constitute a promising target for novel antibacterial agents. Resazurin is widely used to monitor bacterial growth because resazurin is reduced to the fluorescent resorufin by live cells. We have shown by flow cytometric analysis and by accumulation studies with wild type and efflux deficient strains that resazurin is a substrate of efflux pumps in Escherichia coli and Pseudomonas aeruginosa. Our investigations showed that the conversion rate of resazurin to resorufin is affected by efflux pumps. This finding was used to design an assay useful to detect efflux pump activity and to find potential efflux-pump inhibitors in a microtiter plate format. Mefloquine was detected as efflux-pump inhibitor when a panel of selected chemical compounds was tested for assay validation purposes.
Basilea Pharmaceutica International Ltd., Grenzacherstrasse 487, Basel, Switzerland.
Faustino
F
Vidal-Aroca
Alexandra
A
Meng
Tanja
T
Minz
Malcolm G P
MG
Page
Jürg
J
Dreier
D004353:Drug Evaluation, Preclinical / Q000379:methods; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects*; D005434:Flow Cytometry / Q000379:methods; D005456:Fluorescent Dyes / Q000378:metabolism; D006801:Humans; D015767:Mefloquine / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests / Q000379:methods*; D050296:Microbial Viability / Q000187:drug effects; D010078:Oxazines / Q000378:metabolism*; D011550:Pseudomonas aeruginosa / Q000187:drug effects*; D013194:Staining and Labeling / Q000379:methods; D014966:Xanthenes / Q000378:metabolism*
D004791:Enzyme Inhibitors; D005456:Fluorescent Dyes; D010078:Oxazines; D014966:Xanthenes; C005843:resazurin; D015767:Mefloquine