views updated


During and shortly following World War II (1939-1945), new "miracle drugs" revolutionized the medical treatment of infections. These new drugs included several types of substances found to have antibacterial (destructive to bacteria) and antiviral (destructive to viruses) properties. One of these classes of drugs was the tetracyclines. Tetracyclines are a family of antibiotics similar to penicillin that have shown themselves to be both nontoxic (nonpoisonous) and effective against a wide range of infections.

Duggar's Research

Aureomycin, the first of the tetracyclines, was discovered in 1948 by American botanist Benjamin Minge Duggar (1872-1956). Duggar was 76 years old at the time of his discovery. He had graduated from the Mississippi Agricultural and Mechanical College (Mississippi State College) and studied at Alabama's Polytechnic Institute and Harvard University. Duggar later became a professor of botany at the University of Missouri, Washington University, and the Missouri Botanical Garden. He did pioneering research on the tobacco mosaic virus and became widely known for his work with molds and fungi (a group of organisms, such as mushrooms, that lack chlorophyll, roots, stems, or leaves, and reproduce by spores).

Later, as a consultant to the Lederle Division of the American Cyanamid Company, Duggar turned to research on new antibacterial drugs. Although penicillin and streptomycin were being widely used to treat bacterial infections, a number of diseases and strains of bacteria were resistant to the treatments. Duggar focused his research on groups of molds found in soil. He tested more than 3,500 strains of molds before he had a success. In 1945 he tested a sample taken from soil at the University of Missouri campus. A golden-hued (colored) substance produced by the mold exhibited antibiotic properties. After extensive testing, he found it to be active against bacilli, staphylococci, and streptococci (all forms of bacteria). Duggar named the substance aureomycin, from the Latin word "aureus," meaning gold, and the Greek word "mykes," meaning fungus.


Continued testing revealed that aureomycin was effective against 90 percent of bacteria-caused infections. In human trials, the medication was found to be effective against a wide range of infections with minimal side effects. Unlike penicillin and streptomycin, which had to be injected, aureomycin could be taken orally (by mouth). Aureomycin was also effective in treating diseases that did not respond to other antibiotics, such as trachoma, parrot fever, typhus, chlamydias, and mycoplasmas. It was also active against Rocky Mountain spotted fever, an infection which had spread throughout the United States. Caused by a microorganism called rickettsia and transmitted by a tick, the disease was fatal in one out of every five patients. For a time, aureomycin was added to livestock feed to prevent diseases in animals. This practice has been largely discontinued, however, because it breeds bacteria which are immune to the drugs.

Other tetracyclines include terramycin, achromycin and declomycin. Many medical experts consider tetracyclines to be the least toxic and most effective antibiotics next to penicillin. In certain patients, however, they can cause minor side-effects such as nausea, diarrhea, and tooth discoloration. Because the tetracyclines have been used so widely against a variety of diseases, several strains of bacteria have developed resistance to them. As a result, physicians often prescribe other antibiotics for common urinary tract and respiratory (having to do with the lungs and upper chest) infections.