"The world of medicine and infectious diseases is going to have to change to deal with our old foes--the bacteria," said David Henderson, M.D., Deputy Director for Clinical Care at the NIH Clinical Center, who spoke at a lecture at the National Institutes of Health in Bethesda, Maryland.

He stated that the major factor in the increase in drug-resistant bacteria is that sometimes people don't take the full course of the antibiotic that the doctor prescribed. Often, if a patient starts to feel better while taking an antibiotic, he or she will decide to not finish the rest of the prescription. Or a patient stops taking the drug because it may be too expensive. (For example, when someone has tuberculosis, they need to take two or three expensive medicines for 6 months). The bacteria that remain after partial treatment are the ones that are more resistant to that drug or combination of drugs. They attack with a vengeance once the treatment stops, becoming even more resistant and tougher to treat than when the antibiotic was first started.

Another factor in the increased amount of drug resistance is the overuse or misuse of antibiotics. Often doctors prescribe them--at the insistence of a patient or a parent--for viral infections like a cold or the flu. Experts stress that antibiotics have no effect on viruses; they only work on bacteria. This overuse or overexposure to the same antibiotic contributes to resistance: As bacteria begin recognizing the same agent, they toughen their line of defense, ultimately becoming more elusive and resistant to the drug.

As Dr. Henderson explained, bacteria have a variety of mechanisms to get around the high-powered antibiotics of the 1980s. Some organisms can "crank out substances that will break down the drug...." Or they can fool the drug by modifying the substance on them that is the target for the drug. "They can send out lots and lots of targets so the antibiotic won't know which one is the real target." Then the antibiotic binds to the "wrong" one and the organism is safe.

Ironically, hospitals contribute to the problem of drug resistance "because they don't follow good infection control strategies. Particularly problematic is handwashing," noted Dr. Henderson. It was shown back in the 1800s that handwashing prevents the transmission of hospital-acquired infections. Unfortunately, diligent handwashing is not adhered to at most health care facilities. Dr. Henderson pointed out, "The hospital is not a very safe place. Five percent of the patients who come to the hospital get a hospital-acquired infection." The big problem, he explained, is that you can get infected with an organism that's highly resistant, and thus very dangerous.

Antibiotics have been used inappropriately not only by doctors but also by veterinarians who, for example, give the drugs to calves for stress. There is no scientific evidence that antibiotics help with stress. Also, 80 percent of the antibiotics given to farm animals are as "nutritional supplements" to make them fatter quicker. In time, the bacteria in these animals develop resistance to these drugs and that resistance is passed on to the people who come in contact with these animals. Eventually the resistant bacteria spread throughout the community.

There is no easy solution to the problem of drug-resistant bacteria. Both health consumers and practitioners share the responsibility for limiting the factors that are contributing to what some feel is a near-crisis situation. Dr. Henderson believes that we may, in the near future, have to move past today's commonly-prescribed antibiotics and perhaps find ways to help the immune system overcome bacterial infections that will help us get into the next century of medicine and take us away from our reliance on antibiotics.--an NIH HEALTHWise report, January 1998

For more information on this Medicine for the Public Lecture, reporters can contact:

Jan Ehrman
Pubilc Affairs Specialist, NIH
Phone: 301-496-4143
Fax: 301-402-1485
E-mail: je48b@nih.gov

NIH Clinical Center
Information Office
Phone: 301-496-2563
Fax: 301-402-2984