Molecular diagnostics for existing and emerging infections. Complementary tools for a new era of clinical microbiology.

Diagnostic molecular methods have had a large effect on diagnosis and management of infectious diseases. These tools have been developed in response to diagnostic methods that lack sensitivity, specificity, or rapid turnaround time, to assist with identification of agents that are difficult to cultivate or classify or as methods for assessing the effects of antiviral or antimicrobial agents in chronic infection. Molecular methods have also enabled microbiologists to define disease by the presence of virulence, toxin, or antimicrobial resistance genes and to identify potentially important clones of organisms responsible for outbreaks of infection. Early outcome-based studies suggest that molecular methods may provide substantial reductions in per patient costs. Nucleic acid diagnostic methods will continue to be used in infectious disease and microbiology, and increasingly appear to be complementary tools with important diagnostic, patient management, and health care cost benefits for the laboratory and health care systems.