The Wider Contribution of Microbiology to the Pharmaceutical Sciences

THE WIDER CONTRIBUTION OF MICROBIOLOGY TO THE PHARMACEUTICAL SCIENCES

INTRODUCTION

There has long been a tendency, particularly in the medical and pharmaceutical fields, to regard microbes as harmful entities to be destroyed. The exploitation of microorganisms and their products has assumed an increasingly prominent role in the diagnosis, treatment and prevention of human diseases. Non-medical uses are also of significance, e.g. the use of bacterial spores (Bacillus thuringiensis) and viruses (baculoviruses) to control insect pests, the fungus Sclerotinia sclerotiorum to kill some common weeds, and improved varieties of Trichoderma harzianum to protect crops against fungal infections, and these will also be explored.

 
Early Treatment Of Human Disease

The earliest uses of microorganisms to treat human disease can be traced to the belief that the formation of pus in some way drained off noxious humours responsible for systemic diseases. Although the spontaneous appearance of pus in their patients’ wounds satisfied most physicians, deliberate contamination of wounds was also practiced. Bizarre concoctions of bacteria such as ‘ointment of pigs’ dung’ and ‘herb sclerata’ were particularly favoured during the Middle Ages. Early central European and South American civilizations cultivated various fungi for application to wounds. In the 19th century, sophisticated concepts of microbial antagonism were developed following Pasteur’s experiments demonstrating inhibition of anthrax bacteria by ‘common bacteria’ simultaneously introduced into the same culture medium. Patients suffering with diseases such as diphtheria, tuberculosis and syphilis were treated by deliberate infection with what were then thought to be harmless bacteria such as staphylococci, Escherichia coli and lacto-bacilli. Following their discovery in the early part of the last century, bacterial viruses (bacteriophages) were considered as potential antibacterial agents—an idea that soon fell into disuse but has recently been revived.

Present-Day Exploitation

Some of the most important and widespread uses of microorganisms in the pharmaceutical sciences are in the production of antibiotics and vaccines and the use of microorganisms in the recombinant DNA industry. There are a variety of other medicinal agents derived from microorganisms including vitamins, amino acids, dextrans, iron-chelating agents and enzymes. Microorganisms as whole or subcellular fractions, in suspension or immobilized in an inert matrix are employed in a variety of assays. Microorganisms have also been used in the pharmaceutical industry to achieve specific modifications of complex drug molecules such as steroids, in situations where synthetic routes are difficult and expensive to carry out, and more recently microorganisms have been employed in their own right as platforms for the discovery of novel therapeutic peptides and proteins.