New strategies in microbiological diagnosis.

With the advent of the polymerase chain reaction (PCR), molecular biology is at last poised to enter the clinical microbiology laboratory. We describe this technique, and review its present and future applications in the diagnosis of infectious disease, with particular emphasis on its potential in diagnostic bacteriology. We discuss the suitability of different sequences as targets for DNA amplification. The disadvantages of PCR as a diagnostic strategy are covered, and current technical problems with the method are surveyed. We briefly mention two alternative strategies--the transcript-based amplification system and replicatable RNA reporter systems based on the Q beta replicase.