Antibiotics

Medical history is filled with stories of primitive healing customs requiring the use of molds, yeasts and mushrooms, all members of the group of plants known as fungi. It was Louis Pasteur who first established the underlying principle of antibiotics when he concluded that it should be possible to use harmless microbes to fight pathogens, an idea that was developed further by other scientists as the science of bacteriology progressed into the 20th century.

In the early 20th century, agricultural bacteriologists were the first to explore the interrelationships among microbes which are basic to the production of antibiotics. In the 1920's, researchers came upon the idea of isolating microbes which can perform a single activity.  Streptomycin was isolated in 1943 and found to be antagonistic to the tuberculosis microbe. It was later administered to guinea pigs infected with tuberculosis and found to be effective. Streptomycin was shown to be effective against tuberculosis in humans in 1945.

In the decade that followed the discovery of streptomycin, three so-called broad-spectrum antibiotics were discovered that are available in almost every town today: terramycin, aureomycin and chloromycetin. The antibiotic griseofulvin was discovered to be active against fungal infections; today, it is one of the most common prescriptions written by veterinarians for the treatment of ringworm in animals.

Also in the early 20th century, British researcher Alexander Fleming discovered  penicillin from an old culture of the deadly bacterium staphylococcus in which mold had grown. Molds are simple, non-flowering plants belonging to the phylum called fungi. They form minute reproductive particles called spores that float about in the air and often find their way into bacterial cultures where they then grow and multiply.

This pioneering work led other scientists to investigate penicillin. As a result, improved methods were developed for growing the penicillium mold, as well as for harvesting the penicillin. Pure penicillin was eventually isolated and tested in healthy mice, rats, rabbits and cats, none of whom showed ill effects. A method had to be found to manufacture it.

The first human trials of penicillin were conducted in 1941. Because there had not been enough animal trials preceding the human tests, the drug was still not effective enough, and most of the patients who volunteered to participate in the first penicillin study did not survive. Once perfected, however, penicillin eventually proved to be effective and safe, and it has since become the most widely-used medicine in the world to fight infectious disease. This drug has few side effects and remains one of the safest medications available.

By curing infectious diseases, especially in children and the elderly, penicillin has substantially lengthened overall human life expectancy. Its use in veterinary medicine is also undisputed.