Fluorescence enlightens RND pump activity and the intrabacterial concentration of antibiotics

Muriel Masi (1) , Estelle Dumont (1) , Julia Vergalli (1) , Jelena Pajovic (2) , Matthieu Réfrégiers (2) , Jean-Marie Pages (1)

1 MCT - Membranes et cibles thérapeutiques
2 SSOLEIL - Synchrotron SOLEIL

To understand the antibiotic resistance in Gram-negative bacteria, a key point is to investigate antibiotic accumulation which is defined by influx and efflux. Several methods exist to evaluate the membrane permeability and efflux pump activity but they present some disadvantages and limitations. An optimized spectrofluorimetric method using the intrinsic tryptophan fluorescence as internal standard as well as a complementary microfluorimetric assay following the time-course accumulation in intact individual cells have been developed. Comparing the latter population and single cell approaches can lead to the understanding of the phenotypic heterogeneity within a population. The two methodologies lead to the determination of parameters, concentration, accumulation rates, localization that contribute to emerging concepts (RTC2T, SICAR) with the aim to identify and detail the antibiotic chemotypes that are involved in influx/efflux.

Keywords: Antibiotic; bacterial imaging; drug efflux pumps; Gram-negative bacteria; multidrug resistance; transporters

Domains: Life Sciences [q-bio]; Life Sciences [q-bio]; Microbiology and Parasitology

Muriel Masi, Estelle Dumont, Julia Vergalli, Jelena Pajovic, Matthieu Réfrégiers, et al.. Fluorescence enlightens RND pump activity and the intrabacterial concentration of antibiotics. Research in Microbiology, 2018, 169 (7-8), pp.432-441. ⟨10.1016/j.resmic.2017.11.005⟩. ⟨hal-02110917⟩