Stuart B. Levy is a professor of medicine at the Tufts University School of Medicine in Boston and the author of The Antibiotic Paradox: How Miracle Drugs are Destroying the Miracle (Plenum, 1992). He replies:

"The problem of resistance actually has been discussed and raised probably for at least the past 20 to 30 years. In 1981, as the result of a meeting in Santa Domingo on resistance, an international organization was established: the Alliance for the Prudent Use of Antibiotics (for those interested in contacting this organization, their mailing address is P.O. Box 1372, Boston, MA 02117). The Alliance, which has a presence in 93 countries, was founded to combat the drug-resistant infectious diseases becoming prevalent in developing countries. At the time, drug resistance already posed a substantial threat in those countries, and people felt a tremendous need to call attention to the danger. It may seem that concerns about drug resistance have only surfaced recently, however, because it has taken longer for the problem to reach the developed world, especially the U.S.

"Years of misuse of antibiotics led to the emergence of infectious bacteria that are resistant not just to one but to many antibiotics. As a result, there are strains of bacteria today for which we have only one effective drug treatment or, in some cases, none at all. For the first time since the discovery of antibiotics, patients in the U.S. are dying of bacterial infections that cannot be treated. The other half of the problem is that medical researchers have not found any fundamentally new antibiotics in the past decade, and we do not expect the discovery of any in the near future--we must rely on the ones we currently have. That limitation is why many of us consider this a true public health crisis. Resistance has been a critical factor in the appearance of 'reemerging infections.' We can no longer effectively treat some diseases that we were treating easily just five to 10 years ago.

"Many of the people writing about the resistance problem now have firsthand experience of the problem. Once they became aware that bacteria are no longer succumbing to treatment, they asked why, and pretty soon there was a media blitz about the risk of drug-resistant diseases. Another reason for the growing awareness is that antibiotic-resistant bacteria have become an everyday problem for people in the community; previously it was confined to very sick people in the hospitals.

"Why are resistant strains more likely to appear if we do not complete a course of treatment? Bacterial infections are caused by hundreds of millions of bacteria, which are not all the same. Some are more susceptible to the antibiotic than others, and the bacteria reside in different parts of the body, some more sheltered than others. Each antibiotic treatment takes care of the most susceptible and exposed bacteria. An incomplete course of treatment will leave behind those that were in a safe place and those that, by mutation, happened to have some level of resistance.

"When that population reestablishes itself, you will again have a large number of bacteria throughout the body, but they are less susceptible to the drug. Consequently, there is a greater likelihood that you will have a population that possesses some resistance to the antibiotic. A full dose of antibiotic keeps diminishing the bacterial population, which allows your body to clean up the modest remnant population. If you stop taking the medicine, the population can increase and re-create the infection, so that the bacteria can then be passed along to others. Those bacteria then can go on to become even more resistant."

Marvin J. Bittner, a staff physician at the Omaha VA Medical Center and an associate professor at Creighton University School of Medicine, adds some information and an alternative description of the dangers of incomplete treatment:

"During the 1940s, attempts to treat tuberculosis with only one drug failed; the result was the emergence of resistance. During the 1950s, hospital nurseries were swept by epidemics of penicillin-resistant staphylococci. By the 1970s, penicillin-resistant gonorrhea had spread around the world.

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