Patent ID: 11970726

Abstract:
The invention relates to the field of microbiology and detecting micro-organism. Provided is a method for the quantitative analysis of microbial cells in a liquid sample, comprising the steps of (i) contacting the sample with a nucleic acid binding fluorescent dye to stain for nucleic acids in said microbial cells; (ii) subjecting the labelled cells to a fluorescence microscopy imaging method and determining, based on the nucleic acid staining, for a plurality of single cells at least a first parameter reflecting the nucleic acid content of said cell and a second parameter reflecting the extent of stretching of said cell; (iii) classifying based on said at least first and second parameter said cell into one of the following categories: (A) Viable cultivable cells with a nucleic acid content value between >=0.1 and <1.0 and extent of stretching of the cell value between >=1.0 and 10 μιηm2, (B) Viable non-cultivable cells with a nucleic acid content value of >−0.2 and extent of stretching of the cell value of >=0.5 μιηm2 minus (A), (C) Most likely dead cells with a nucleic acid content of <1.0 and extent of stretching of the cell value of <0.50 μιηm2; and (iv) calculating the ratio of the amount of (A) viable cultivable cells, (B) viable non-cultivable cells and (C) most likely dead cells in a microbial sample.