Bacteriophages and biotechnology: a review

Bacteriophages are viruses whose hosts are bacterial cells. Like all viruse s, phages are metabolically inert in their extra-cellular form, reproducing only after infecting suitable host bacteria. Discovered over 80 years ago, they have played a key role in the development of modern biotechnology. Th eir initial isolation appeared to offer the first therapeutic for the contr ol of infectious disease. The discovery of antibiotics in the 1940s eclipse d bacteriophage-based therapies although, with the increase in multiply dru g-resistant pathogens, bacteriophages are being re-evaluated as the basis o f new therapeutic strategies. Their defined host specificity facilitated th eir application in the typing and identification of a wide range of bacteri a. Bacteriophage typing schemes were developed for most groups of pathogeni c of bacteria and more recently their host specificity has been applied to the development of bacterial detection and diagnostic strategies. The advan ce in molecular biology over the past 30 years has been built on the study of phage structure and genetics carried out through the 1950s and 1960s. Re striction endonucleases which form the basis of molecular cloning were deve loped following studies of phage infection and many phage enzymes provide t ools for the molecular biologist. The technique ofphage display has more re cently provided a powerful technique for the identification and optimisatio n of ligands for antibodies and other biomolecules. In the environment they have been widely applied as tracers, as indicators of pollution and in the monitoring and validation of biological filters. While providing a valuabl e resource to the development of modern biotechnology, their ability to mob ilise and transfer toxin genes in the environment is viewed with concern. T hey also present a continuing challenge to the fermentation and in particul ar, the dairy industry, where phage infection can prove commercially disast rous. (C) 2000 Society of Chemical Industry.