Fluorescent in situ hybridization - bacterial detection and identification

Fluorescent in situ hybridization (FISH) with ribosomal RNA (rRNA) targeted fluorescent oligonucleotide probes is a culture-independent technique for the detection and identification of bacteria. The cells remain morphologically intact allowing the visualization and enumeration of cells. Briefly, bacterial cells are first fixed and permeabilized if necessary, hybridized with specific probes under stringent conditions, and detected either by epifluorescent microscope or by flow cytometry (FCM). The technique is suitable for species-specific detection of pathogens and for the analysis of complex microbial populations. Multiplexed detection can be achieved by selecting unique fluorochromes for different specific probes. Fluorescent in situ hybridization provides information about the presence, number, morphology, and spatial distribution of bacteria. It can be performed in a few hours and therefore holds great promise for medical microbiology. This review summarizes methodological aspects and diagnostic applications of FISH.