FISH in Suspension or in Adherent Cells

Fluorescence in situ hybridization (FISH) enables the detection and enumeration of microorganisms in a diversity of samples. Short-length oligonucleotide DNA probes complementary to 16S or 23S rRNA sequences are generally used to target different phylogenetic levels. The protocol for the application of FISH to aggregated or suspended cells in mixed microbial communities is described in this chapter, with a special emphasis on environmental samples.