This article describes plug-based microfluidic technology that enables rapid detection and drug
susceptibility screening of bacteria in samples, including complex biological matrices, without preincubation. Unlike conventional bacterial culture and detection methods, which rely on incubation
of a sample to increase the concentration of bacteria to detectable levels, this method confines individual bacteria into droplets nanoliters in volume. When single cells are confined into plugs of small
volume such that the loading is less than one bacterium per plug, the detection time is proportional
to plug volume. Confinement increases cell density and allows released molecules to accumulate
around the cell, eliminating the pre-incubation step and reducing the time required to detect
the bacteria. We refer to this approach as ‘stochastic confinement’. Using the microfluidic hybrid
method, this technology was used to determine the antibiogram – or chart of antibiotic sensitivity
– of methicillin-resistant Staphylococcus aureus (MRSA) to many antibiotics in a single experiment
and to measure the minimal inhibitory concentration (MIC) of the drug cefoxitin (CFX) against
this strain. In addition, this technology was used to distinguish between sensitive and resistant
strains of S. aureus in samples of human blood plasma. High-throughput microfluidic techniques
combined with single-cell measurements also enable multiple tests to be performed simultaneously
on a single sample containing bacteria. This technology may provide a method of rapid
and effective patient-specific treatment of bacterial infections and could be extended to a variety
of applications that require multiple functional tests of bacterial samples on reduced timescales
