INFECTIOUS DISEASES

The emergence of new pathogens, or the concern about bioterrorism, has brought an added urgency to the development of more efficient and rapid methods to detect pathogens and predict their potential virulence. Till date, DNA testing in microbiology has been directed predominantly to the detection of organisms that are difficult to culture in vitro, or for various reasons the growth is unlikely. DNA analysis can be used successfully in infections in which there is a mix of pathogens. Apart from the straightforward diagnostic applications, DNA microbiological testing has been used to detect antimicrobial resistance or toxigenic forms of E. coli. More recently, the availability of DNA technology to quantitate HCV and HIV has been useful in planning and monitoring treatment. The pathogenesis of many infections, particularly viral ones, can also be realized from experimental strategies based on light and electron microscopy, cell culture and immunoassay. The advantages that are provided by DNA techniques include the ability to detect latent (non-replicating) viruses and to localize their genomes to nuclear or cytoplasmic regions within cells. Nucleic acid probe techniques (NAT) can also be manipulated to enable a broad spectrum of serotypes to be detectable. This is particularly valuable in those emerging infections where the underlying serotypes are unknown.