Antibiotics, one of the great miracles of modern medicine, are drugs or chemicals, typically of microbial origin, that inhibit the growth or metabolic activities of bacteria and other microorganisms. Selman Waksman, the microbiologist who discovered streptomycin, first applied the word in this fashion in 1943.

Nearly a century earlier, however, "Antibiotic," (which comes from Greek roots for "against life") described an opposition to believing in the presence or possibility of life outside of Earth. Matthew F. Maury (1806-1873), a U.S. Naval officer and founder of the U.S. Naval Observatory, coined the word in his 1860 textbook, Physical Geography of the Sea and its Meteorology. Maury often used a telescope gazed at the stars to chart the seas, winds and currents. Arguing against extra-terrestrial life forms, he declared, "I incline to the antibiotic hypothesis."

Although this use of the word soon fell out of favor, by 1890 antibiotic was revived by the French microbiologist, Pierre Vuillemin. But he used it to describe any compound that was "injurious to or destructive of living matter, especially micro-organisms." In fact, he was riffing on a much different anti-life concept called "antibiosis," a term that both Louis Pasteur and Robert Koch used in 1877 to describe how certain airborne bacteria inhibited the growth of anthrax cultures. The key, of course, was finding out what exactly was causing the inhibition.

In the decades that followed, several scientists searched for agents that could be prescribed to treat patients infected with disease-causing microbes. The catch was that in many cases the substances used were so toxic that they not only killed the microbes; they also seriously harmed those people taking the medication. An early example of one of these drugs was Dr. Paul Ehrlich’s famous "magic bullet" for syphilis, Salvarsan 606, which was essentially a variant of arsenic.

In 1928, Alexander Fleming, a bacteriologist at London’s St. Mary’s Hospital discovered a penicillium fungus that had contaminated his laboratory. Fleming’s "Eureka" moment, of course, when he noticed how well the fungus inhibited the growth of specific types of bacteria he was trying to culture. We know it today as Penicillin, the wonder drug that started the antibiotic revolution. It took many more years, however, to learn how to apply Fleming’s discovery on a wide scale. During World War II, a team of Oxford scientists led by Sir Howard Florey figured out the difficult task of purifying and mass-producing penicillin so that it could be easily prescribed and delivered. This was accomplished during the war but only became available for civilians beginning in 1946. Fittingly, Florey, his colleague Ernst B. Chain, and Fleming won the 1945 Nobel Prize in Medicine for their work.

In the years since, the pharmaceutical industry has developed a wide menu of different types of antibiotics with diverse chemical structures and biological activities. The best ones inhibit the growth of certain strains of bacteria in a highly selective manner that does not harm the cells, tissues and organs of the person taking the drug.

With success, of course, came other serious, if not outright ironic, consequences in these "against life" agents. As doctors prescribed and patients demanded more and more antibiotics, not always appropriately, antibiotic resistance developed. This problem has only grown worse with each passing year rendering some antibiotics all but useless in the war against infection. It is a crisis well worth solving. Indeed, antibiotic resistance threatens to drag us back to the 19th century, when microbes too often outsmarted the human body’s ability to kill them before they killed us.