ColorFlux: a colored indicator for bacterial efflux

Bacterial resistance to antibiotics is sometimes directly linked to the activity of their efflux pumps. As a result, this capacity is becoming very interesting to measure in order to understand the resistance mechanisms of certain bacteria.

ColorFlux is a cationic compound that rapidly penetrates Gram+ bacteria by passive diffusion and is then efficiently expelled out from the cell via efflux pumps.

Available as a solution, ColorFlux  simply must be add to the bacterial culture medium. After incubating the bacteria for only 15 minutes, an equilibrium level is reached and the relative levels of efflux activity can be quickly assessed by observing the color of the cell pellet. If the cell expels little of the colored compound, it becomes colored itself. In this way, the intensity of the color of the bacterial pellet obtained after centrifugation is directly correlated with the activity of the efflux pumps. This visual analysis method has the advantage of being very simple to interpret and very fast.

In addition, the fluorescent quality of ColorFlux also allows accurate quantification of efflux levels through fluorescence measurements. Alternatively, the kinetics of ColorFlux accumulation can also be monitored by flow cytometry.

Previously used with:

ColorFlux staining has been shown to reflect the activity of well-characterised efflux pumps belonging to the major facilitatory transporter superfamily and ATP-binding cassette families in a variety of Gram + bacteria:

• NorA, MepA, MepB, PatA, PatB (Staphylococcus aureus & Streptococcus pneumoniae)
• BmrA (Bacillus subtilis)

The list is regularly updated based on feedback from users.

How does it work?

Features we like:

ColorFlux is a fast, reliable and non-toxic solution for assessing bacterial efflux as part of antibiotic resistance research.

• Qualitative and quantitative measurement: with the naked eye or by fluorescence measurement
• Reliable: indicator directly correlated with efflux
• Fast and easy to use: the entire protocol should take less than 30 minutes
• Safe: no harmful products

Technology transfer the way we like it: it all started with…

Olivier Siri, Jean-Michel Bolla, Michel Camplo and Mrunal Patil and their meeting with Idylle, a French start-up specialized in technology transfer between researchers around the world.