What Are Antimicrobials?

The antibiotic give you by a doctor falls into a class of medicines called antimicrobials. These come under the general heading "Chemotherapy," which refers to the treatment of disease with chemicals. While the term "chemotherapy" is often used in connection with treating cancer, it originally applied -and still does - to the treatment of infectious diseases. In such cases it is called antimicrobial chemotherapy.

Microbes, or microorganisms, are tiny organisms that can be seen only with the help of a microscope. Antimicrobials are chemicals that act against microbes that cause illness. Unfortunately, antimicrobials can also act against microbes that are beneficial.

In 1941, Selman Waksman, codiscoverer of streptomycin, appllied the term "antibiotic" to antibacterials that come from microorganisms. Antibiotics as well as other antimicrobials used in medical treatment are valuable because of what is called selective toxicity. This means that they can poison germs without seriously poisoning you.

Actually, however, all antibiotics are at least somewhat poisonous to us too. The margin of safety between the dosage that will affect the germs and the dosage that will harm us is called the theraputic index. the larger the index, the safer the drug; The smaller, the more dangerous. In fact, thousands of antibiotic substances have been found, but most are not useful in medicine because of being too toxic to people or to animals.

The first natural antibiotic that could be uses internationally was penicillin, which came from a mold called Penicillium notatum. Penicillin was employed intravenously for the first time in 1941. Shortly thereafter, in 1943, streptomycin was isolated from Streptomyces griseus, a soil bacteria. In time, scores of additional antibiotics were developed, both those that are derived from living things and those that are made synthetically. Yet, bacteria have developed ways of resisting many of these antibiotics, causing a global medical problem.

Next time: A Foreboding Future