[Polymerase chain reaction (PCR) in microbiology. Value and practical applications].

The gene amplification reaction (PCR) developed in 1985 is a molecular biology instrument which is used to amplify genomic restriction fragment lengths of micro-organisms found in biological samples. At the moment, its applications to direct microbiological diagnosis remain to be determined precisely, and its strict technique is awaiting standardization. However, it is a powerful tool for molecular typing used to follow up an antiviral therapy or to analyse retrospectively paraffin-embedded tissue banks in search of viral or bacterial nucleic acids.