Abstract: A method of collecting, detecting and enumerating microorganisms in a fluid comprising subjecting a sample of the fluid to dielectrophoresis and collecting the microorganisms onto a microelectrode, scanning the microelectrode using a scanning laser and determining the number of microorganisms present on the microelectrode. Alternatively, the microorganisms may be spun onto a substrate which has been pre-treated with a polycationic electrolyte.