Flow cytometric techniques for the detection of microorganisms.

Flow cytometry (FCM) is a technique, which allows one to analyse cells rapidly and individually, and permits the quantitative analysis of distributions of a property or properties in a population. It therefore offers many advantages over conventional measurements for the analysis of biological cells. Historically the technique has been widely applied for the study of mammalian cells, but its use in microbiology has been more limited; this is mainly a consequence of the smaller size of microbes, which results in the smaller optical signals that can be obtained from them. Developments in light sources and optics, together with brighter, spectrally-diverse dyes have reduced this barrier over recent years and the flow cytometer is now an essential tool in many microbiological research establishments. FCM has an increasing role to play in the detection of microbes in both industrial and clinical settings. Environmental monitoring to prevent outbreaks of human diseases such as cryptosporidiosis and Legionnaires' disease and to detect acts of biowarfare or bioterrorism are all amenable to flow cytometric study. This review seeks to highlight the role of the flow cytometer in the detection of microbial cells.