Spring 2001 Issue
Combatting Drug Failure
Antimicrobial Resistance: An Evolving Threat to Health Care
Antibiotics - drugs that fight infections caused by bacteria - are the heavy artillery in the health care arsenal. Their widespread availability beginning in the 1940s revolutionized medical care and dramatically reduced illness and death from infectious diseases. However, the microorganisms that antibiotics control have, over the past 60 years, developed resistance to these drugs. Today, virtually all important bacterial infections in the United States and throughout the world are becoming resistant - and resistance is rapidly emerging in viral, parasitic and fungal infections as well. For this reason, antimicrobial resistance (AR) is among CDC’s top concerns and is one of the four strategic program priorities for the CDC Foundation.
“We are facing a situation in which existing drugs are losing their usefulness and very few new ones are becoming available to take their place,” says David Bell, M.D., EIS ‘79, assistant to the director for antimicrobial resistance in CDC’s National Center for Infectious Diseases. “We haven’t reached the point yet in the U.S. where lots of people are dying of untreatable infections,” Bell says. However, physicians are commonly forced to use second, third or even fourth choice drugs when the preferred ones fail. These drugs are usually much more expensive and may also be less effective or have toxic side effects. In developing countries, more expensive drugs to treat resistant infections are often not available.
Bell says that a major factor promoting the emergence of AR is overuse and misuse of antibiotics. “It’s not just one problem,” he says. “It’s a group of problems.” In the United States, three types of infections for which AR is a critical issue include infections acquired in healthcare settings, in the community (especially respiratory infections) and through the food supply.
“Forty percent of all infections of Staphylococcus aureus are now resistant to standard treatment,” says Julie Gerberding, M.D., M.P.H., director of the Division of Healthcare Quality Promotion. These are the bacteria responsible for endocarditis (inflammation of the lining of the heart); septicemia (blood poisoning); and respiratory, skin, urinary tract and other infections that are sometimes acquired by hospitalized patients. Gerberding says that in some intensive care units, more than 50 percent of staphylococcal infections are resistant to first-line treatment. To address this problem, CDC is developing new programs for both inpatient and outpatient settings to minimize the risk of infection with resistant bacteria.
Richard Besser, M.D., EIS ‘91, of the Respiratory Diseases Branch, says the 1990s saw a dramatic rise in resistance among bacteria that cause respiratory infections. Up to 30 percent of pneumococci, a leading cause of the bacterial pneumonia cases, no longer respond to the preferred antibiotic, but in the 1970s, virtually 100 percent of these bacteria were responsive. “The biggest problem,” says Besser, “is inappropriate prescribing of antibiotics.” He notes that up to 40 percent of antibiotics prescribed in doctors’ offices are for viral infections, which are not treatable with antibiotics. There are many reasons for this, Besser says, including demand from patients, time pressure on physicians and diagnostic uncertainty.
“The patient wants to get back to work or wants to get the child back in school, and the doctor wants the patient to feel satisfied with treatment,” he says. The result is overprescribing of antibiotics, resulting in the development of resistant bacteria. Besser says that the way to combat this practice is to educate physicians and the public to decrease both demand and overprescribing. In addition, providing clinicians with better means of diagnosing respiratory tract infections may remove some of the uncertainty that promotes overprescribing.
In 1999, CDC joined with the Food and Drug Administration, the National Institutes of Health and seven other federal agencies to form the Interagency Task Force on Antimicrobial Resistance. With input from many sources, including professional societies, state and local government agencies, healthcare organizations, private industry and consumer groups, the Task Force developed A Public Health Action Plan to Combat Antimicrobial Resistance to serve as a blueprint for federal agencies to attack the AR problem at every level.
“Dealing with antimicrobial resistance requires multiple approaches,” says Bell. “Thus the plan consists of four sections: surveillance, prevention and control, research, and product development.” CDC will play a major role in virtually all of the action items in the surveillance, and prevention and control sections. Top priority action items for CDC include conducting public awareness campaigns to inform consumers about the proper use of antibiotics and implementing programs to assist clinicians in appropriate prescribing.
“Drug resistance affects virtually all important human infections,” says Bell, “and unlike in the past, there are very few new drugs coming down the pipeline to replace the ones that are no longer useful because of resistance.” He says that most “new” drugs are relatives of existing drugs - not any real new breakthrough.
“Implementing the action plan will be a massive undertaking that will require working with many partners,” Bell says. “It’s evident that existing resources don’t come anywhere close to meeting funding needs, and we’ll need increasing investment in the coming years.” Bell says some of the necessary funds will come from federal budget allocations, but private organizations and individuals can play an important role in supplementing federal activities to address this important public health problem. “This is a problem that affects everyone,” Bell adds, “and we’re all going to need to work together to solve it.”
- Rosemarie Perrin