The use of microorganisms for the study of drug metabolism.

The potential for the use of microorganisms as tools in the study of drug metabolism appears to be unlimited. The selected examples cited here are only the beginning of what could develop into a widely accepted alternative in vitro model system for studying drug metabolism in humans. As with any other in vitro model system, it is not expected that microbial systems could ever replace animals in biomedical research. The acquisition of data regarding absorption, distribution, and excretion will still require whole animal systems. However, it is clear from the examples cited that microbial systems offer a reliable, reproducible alternative to small animal models for preliminary drug metabolism studies. Due to significant species variation, small animal models may, in many cases, be less reliable than microorganisms as predictive models of human metabolism. It has been estimated that approximately 70 million animals are used each year in the U.S. for biomedical research. The development of any techniques which curtail the sacrifice of such large numbers of animals is welcomed both by animal welfare groups who wish to ensure the humane treatment of laboratory animals and by researchers who additionally appreciate the more practical and economical benefits of such alternatives.