Deoxyribonucleic acid typing methods for medically important microorganisms

The ability to type microorganisms to a sub-species level plays an essentia l role in the diagnosis, treatment and control of human infection. Traditio nally, differentiation of microorganisms has involved analysis of phenotypi c markers. However, these methods are not universally applicable to all mic roorganisms, and results may be influenced by environmental factors. Recent developments in DNA analysis, together with the limitations of phenotypic methods, have resulted in an increasing use of procedures based on DNA anal ysis for the typing of clinically important microorganisms. The aim of this review is to provide an overview of the advantages and disadvantages of th e genetic typing techniques currently available.