Apparatus and process for rapid and ultrasensitive detection and counting of microorganisms by fluorescence

摘要

Apparatus for rapid, ultrasensitive and automatic counting of fluorescent biological cells such as microorganims, carried by a solid support such as a filter and process for said rapid count of said microorganisms by said apparatus. Said process comprises: scanning a solid support on which a sample potentially containing microorganisms has been deposited, with an incident beam from a laser, forming a laser spot on the solid support, said laser spot being substantially greater than the microorganisms to be detected, said laser spot size being comprised between 4 and 14 mu m and simultaneously: detecting the resultant fluorescent light at least at one wavelength; establishing a set of correlated-features by a line-to-line correlation of individual features; comparing said correlated-features on each pair of adjacent lines in time synchrony, at least at two different wavelengths lambda 1 and lambda 2; making a size discrimination of retained events and selecting those having a size corresponding to a microorganism; determining if for retained events after size discrimination, the events energy profile in three dimensions is within predetermined Gaussian shape criteria; and counting said remaining events to determine and to count exclusively the microorganisms present on said solid support.