Rapid Detection of E. coli Immobilized in Gel Microdroplets.

摘要

Rapid detection and enumeration of viable cells is of general importance to a variety of fields. However, a well known attribute of conventional cultivation is slowness. Here we report on progress concerning a rapid method for metabolic detection of cell viability employing gel microdroplets (GMDs). This new method provides a rapid means for detecting single cells (or a microcolony derived from a single cell), using E. coli as model organism. The GMD involves statistically immobilizing individual E. coli cells in agarose particles ranging in size from 10 to 100 microns in diameter. The immobilization is followed by incubation wherein the GMDs are surrounded by a liquid hydrocarbon phase (mineral oil). Incubation of immobilized E. coli under these conditions results in retention of metabolic acids, which lowers the pH within each occupied GMD. Because the volume of the GMD is small, the effective cell density is high even if one cell is present. This, in combination with a weakly buffered medium, results in a rapid decrease in the pH in the occupied GMDs. Keywords: Bacteriology. (jes)