Fig. 5: ReacSight-based assembly of an automated platform enabling reactive control and characterization of bacterial cultures in low-volumes.
From: Enhancing bioreactor arrays for automated measurements and reactive control with ReacSight
a Platform overview. The Opentrons OT-2 pipetting robot is used to enhance the capacities of a plate-reader (Spark, Tecan). The robot is used to treat cultures in the plate-reader at predefined ODs. b Left: an E. coli clinical isolate can be maintained in growing conditions by renewing the media in an OD-controlled manner. Care must be taken to compensate for evaporation over extended time scales. Right: cells in rich media (glucose + casamino acids vs glucose alone) grow faster and yet resist better sub-MIC antibiotic treatments. c Left: A bacterial population may exhibit resilience to treatments thanks to the combination of two effects. At the single-cell level, cells may tolerate an antibiotic concentration exceeding their MIC through filamentation. Filamentation-based tolerance allows to increase biomass before cell death. At the population level, the antibiotic is degraded by enzymes released upon cell death in the environment. The final outcome depends on a race between cell death and antibiotic degradation. Middle: the respective role of these two effects can be investigated by means of repeated antibiotic treatments. Right: an E. coli clinical isolate is treated with different concentrations of CTX (legend) at an initial of OD of 5 10−4, and a second time with either 16 mg/L of CTX (red) or media alone (blue) at a user-defined OD (2.5 10−3 or 5 10−3). Because of instrument limitations, OD readouts below 10−3 are poorly reliable. Source data are provided as a Source Data file.
