DNA probes in microbiology

Abstract

The successful diagnosis of a microbial infection is dependent on the ability to confirm the presence of material from pathogenic microorganisms in clinical samples. The diagnostic approaches will vary according to the clinical situation but any test must be able to identify a potential pathogen, or material from that pathogen, amongst complex biological material. In order to identify a particular microorganism it is necessary to take advantage of special characteristics which are unique or commonly associated with that micro-organism. In addition, to be clinically and commercially successful, tests should in general be reliable, economic and easy to perform by trained personnel. A variety of approaches have been used routinely to identify infectious agents in the clinical diagnostics laboratory. Simple bacteriological techniques including cultivation of samples on selective or differential growth media and biotyping have been in successful use for decades. These approaches take advantage of particular metabolic traits associated with individual pathogens. Since specificity is one of the main requirements of a diagnostic reagent, immunological techniques have proved to be of immense value. Indeed, most of the recently developed diagnostic kits employ antibodies which bind specifically to particular bacterial or viral associated antigens. Since all micro-organisms possess unique as well as cross-reactive antigens, an immunological approach can be used at some stage in their identification.