Fast Antibiotic Susceptibility Testing based on single cell growth rate measurements

The emergence and spread of antibiotic resistant bacteria is a global threat to human health. The problem is aggravated by unnecessary and incorrect use of broad-spectrum antibiotics. One way to provide correct treatment and to slow down the development of antibiotic resistance is to assay the susceptibility profile of the infecting bacteria before treatment is initiated and let this information guide the choice of antibiotic. However, current methods for Antibiotics Susceptibility Testing (AST) are too slow for point of care application. Here we present a fast AST, fASTest, that rapidly captures individual bacterial cells in nanofluidics channels and monitors their response to different antibiotics based on direct imaging. By averaging the growth rate over many cells, we determined the susceptibility to several antibiotics in less than 25 min even at cell densities as low as 104 CFU/mL. The short time scale, high sensitivity and high specificity make the method practically useful for guiding antibiotic treatment in, for example, urinary tract infections.\n\nOne Sentence SummaryIndividual bacterial cells can be captured and imaged in a microfluidic device to determine how their growth rate responds to antibiotic treatment in a few minutes.