Ultrafast Evolution\nof Bacterial Antimicrobial Resistance\nby Picoliter-Scale Centrifugal Microfluidics

Experimental\nevolution is a powerful approach for scrutinizing\nand dissecting the development of antimicrobial resistance; nevertheless,\nit typically demands an extended duration to detect evolutionary changes.\nHere, a centrifugal microfluidics system is designed to accelerate\nthe process. Through a simple step of on-chip centrifugation, a highly\ncondensed bacterial matrix of ∼10<sup>12</sup> cells/mL at\nthe enrichment tip of the chip channel is derived, enabling bacteria\nencapsulated to survive in antimicrobial concentrations several times\nhigher than the minimum inhibitory concentration (MIC) and rapidly\ndevelop resistance in the first 10 h. After 48 h of on-chip evolution,\nthe <i>E. coli</i> strain demonstrated a 64 to 128-fold\nreduction in sensitivity to disinfectants (triclosan) as well as antibiotics\n(ciprofloxacin and amikacin), a rate substantially swifter compared\nto conventional continuous inoculation-based experimental evolution.\nThe speed and simplicity of this microfluidic system suggest its broad\napplication for uncovering resistance mechanisms and identifying targets\nof biocides and antibiotics.