Drug-resistant microbes are evolving into a public health problem too widespread to ignore.
Usually, it's just a mild skin infection, an irritating outbreak of pimples. But it can get much worse: The pimples can become painful lesions or boils that resemble infected spider bites. Sometimes blood poisoning sets in; sometimes pneumonia. That can make the disease fatal.
The disease is methicillin-resistant Staphylococcus aureus (MRSA), a strain of staph bacteria that, in only a few decades, has become resistant to the antibiotics that once were counted on to destroy it. And it's on the rise. Thirty-five years ago, only 2 percent of staph infections were resistant to methicillin, according to the Centers for Disease Control and Prevention. Today, that figure is 63 percent. In some places, the number is even higher. A national study last fall found some locations where MRSA was responsible for as many as 74 percent of skin infections treated in emergency rooms.
MRSA and other antibiotic-immune bacteria are an increasingly familiar topic in the public health arena, and they should be. They threaten to become immune to every known antibacterial drug. They cost billions of dollars a year to treat. Several states and a few localities have programs aimed at reducing infection rates both in health care facilities and in the community at large. But those efforts have so far been unable to stem the tide of the so-called "superbugs."
"These microbes lived long before we did," says Jennifer Morcone, a spokeswoman with the CDC. "They want to keep living; that's what all living things do. So these pathogens have grown smart."
Antimicrobial resistance is not a new phenomenon. The very moment any antibiotic drug is introduced, bacteria begin to evolve and form a resistance to it. Penicillin was first mass-produced in 1943, and by 1947, the first strain of penicillin-resistant staph had been identified. Since then, epidemiologists have found antibiotic-resistant forms of tuberculosis, head lice, malaria, gonorrhea, typhoid fever and pneumonia.
For several decades, though, antimicrobial resistance didn't strike researchers as a major public health problem. Virtually all the cases were confined to hospitals and didn't work their way into the population at large.
Even now, most of the cases occur in hospitals. But the public health implications are hard to ignore. According to the CDC, 70 percent of the bacteria that cause infections in hospitals are resistant to at least one antibiotic. In the past few years, drug-resistant diseases have increasingly been showing up in the community, among people who haven't set foot inside a hospital.
The causes of these stronger, more prevalent infections are clear. Whenever a person takes antibiotics, the drugs kill sensitive germs. But some resistant bacteria may be left to grow and reproduce. If a patient takes antibiotics incorrectly - fails to take the full dose, for example, or takes antibiotics that were not prescribed - the bacteria have a greater opportunity to develop a resistance. As physicians have prescribed antibiotics more freely in recent years, the problem has worsened.
"Through the inappropriate use of antibiotics - and in some cases unnecessary prescriptions - you end up pressuring the disease to adapt and become stronger," says Dr. Ellen Mangione, of the Colorado Public Health Department and the former chair of the infectious disease committee at the Council of State and Territorial Epidemiologists. "Then it becomes a real public health issue."
Resistant staph has exemplified the spread of antimicrobial resistance from hospitals out into the community. Since 2000, outbreaks have appeared in close-contact places such as jails, day care centers, sports facilities and military installations. In a 2005 study, CDC researchers were surprised to find that nearly one-fifth of drug-resistant staph infections had been caught in the community and had no connection to hospitals or other medical facilities.
SPREADING THE WORD
All totaled, antimicrobial resistance results in thousands of lives lost each year and $5 billion in annual health care costs, according to the Institute of Medicine at the National Academy of Sciences. But combating these pathogens remains relatively low on states' lists of priorities. "When you talk to state legislators, it's not something they typically recognize unless they've personally been affected," says Mangione. "You're competing against funding for roads and money for schools. Drug-resistant organisms don't tend to get much traction."
Still, states are making some efforts to curb infection rates. In the past three years, 16 states have passed legislation to require public reporting of hospital infection data. Fourteen of those will publish numbers for each hospital in the state. In November, Pennsylvania released the nation's first report on infection rates on a hospital-by-hospital basis, and Florida and Missouri have since produced similar reports. Right now, infection-disclosure bills are being considered in 14 states. Although none of these bills is aimed specifically at drug-resistant diseases, disclosing - and reducing - hospital-acquired infections of all kinds would curb the spread of antimicrobial resistance.
A number of states have programs to inform hospitals about the importance of proper hygiene in stopping the spread of drug-resistant diseases. Some of these initiatives also focus on educating patients and physicians about when it's appropriate to take an antibiotic - and when it's unnecessary. Most of these education programs are funded by grants from the CDC. Begun in 2000 at just eight sites, the CDC's "Get Smart" campaign had expanded to 43 state and local sites by last year.
One of those grant recipients is Los Angeles County, which has one of the most advanced antimicrobial-resistance units in the country. The county health department works closely with hospitals' infection-control practitioners to train health personnel. When the health department identifies an occurrence of drug-resistant infection, county workers discuss the risks with physicians, including the dangers of over-prescribing antibiotics. And L.A. County has one of the nation's few hospital infection investigation units. "It's a growing public health issue," says Dr. Jonathan Fielding, the county's public health director.
But, he adds, "we also have to accelerate the pace of development of more effective drugs. The development of new antibiotics hasn't kept pace with these new diseases."
Indeed, the number of new antibacterial drugs introduced has fallen sharply over the past two decades, from about 16 new antibiotics per year in the mid-1980s to only a handful in 2004. In the four-year period ending in 2002, antibacterial agents made up only 3 percent of all the new drugs approved by the Food and Drug Administration. The research and development costs of bringing one new drug to the market can approach $1 billion. Spending that kind of money on an antibiotic simply isn't cost-effective for large pharmaceutical companies.
"If they develop a new drug for diabetes or high blood pressure, the company will make money on that for years and years because the patient takes it for the rest of his life," says Dr. David Gilbert, a past president of the Infectious Disease Society of America and a member of the group's "Bad Bugs, No Drugs" task force. "But if you've got pneumonia, you're going to take a drug for seven to 10 days. Plus, you've got all the people like me urging people not to overuse these new drugs. Basically, everything's working against the development of new antibiotics."
The "Bad Bugs, No Drugs" campaign is lobbying Congress to create incentives for the development of new bacteria-fighting drugs. Those incentives might include funding for "orphan drugs" to treat diseases that affect fewer that 50,000 people per year. The government could offer longer patent protection for new antibiotics - or longer patents on other existing medications in exchange for the development of a new antibacterial agent.
But even if big pharmaceutical companies began an aggressive research and development program for antibiotics tomorrow, it could take as long as a decade to bring just one new drug to the market. State and local education efforts can be effective at slowing the rate of antimicrobial resistance, but they will never eradicate it. And as more and more pathogens develop immunities to treatment, the problem will continue to get worse. Without new drugs, some of these infections could, in a matter of years, become incurable. "We're on a path that's leading to the edge of a cliff where we will have no drugs to treat these diseases," says Gilbert. "And the bugs are smarter than we are."