A new study of pediatricians’ prescribing habits told us something old and something new. It told us that antibiotics are overused. It also told us -- and this is the new part -- that doctors are using the wrong antibiotics, even when the bacteria-killing drugs are called for.

According to the study, which looked at tens of thousands of visits to pediatricians outside hospitals from 2006 to 2008, in more than 1 in 5 cases doctors gave their young patients antibiotics. Very often (23 percent of the time), the prescriptions were written when the children had respiratory conditions that antibiotics can’t help -- asthma, for example, or colds caused by a virus.

What’s more, about half of the antibiotic prescriptions were for broad-spectrum drugs such as azithromycin (Zithromax or Zmax). Because broad-spectrum drugs affect many types of bacteria inside the body, they make it that much easier for germs to develop immunity.

Increasing bacterial resistance leaves everyone more vulnerable to infection by superbugs capable of causing ever longer, more serious illness. The cost to the U.S. health-care system: upward of $20 billion a year, and untold thousands of lives, according to a 2009 study.

Doctors have scaled back somewhat on using antibiotics to treat upper-respiratory-tract infections and, in small children, ear infections. Still, we need to find ways to fight overuse and to encourage the development of fresh antibiotics capable of killing bacteria that have become resistant to the old drugs.

For starters, the federal government could require, as a condition of Medicare funding, that hospitals, long-term-care facilities, clinics and private medical practices set up programs that monitor and review every antibiotic prescription written. When patterns of overuse appear, doctors would be counseled to change their practice.

The use of electronic health records can make such monitoring easier -- and also provide doctors with “best practice” advice at the moment they consider writing a prescription. The program to pay Medicare doctors up to $44,000 over five years to adopt health-care information technology can help in the fight against antibiotic resistance.

The second challenge is to persuade drug companies to create new antibiotics. It’s not something the market naturally encourages them to do, because antibiotics, used irregularly and only for a week or two at a time, aren’t as profitable as medicines for chronic health problems. What’s more, the antibiotics we have still work pretty well for most patients. And drug companies understandably grouse that the Food and Drug Administration’s requirements for approval are onerous and unclear. Since the 1980s, the number of new antibiotics approved by the FDA has been falling steadily. From 1983 to 1987, 16 received the go-ahead; since 2008, only two have.

Pharmaceutical companies should be given inducements to invest in new antibiotics. The research and development they engage in should be supported with research grants and rewarded with tax credits. Any new drugs they develop should be given patent extensions and reasonable protection from lawsuits. All such incentives are recommended by the Infectious Diseases Society of America, an organization of doctors.

We also hope Congress will soon pass the bipartisan GAIN bill (Generating Antibiotic Incentives Now), which would direct the FDA to streamline and clarify its process for approving new antibiotics.

The IDSA also recommends creating public-private research partnerships, where government and private industry share the cost of research to find new antibiotics.

Finally, federal health officials should strengthen their ability to monitor emerging resistant germs. The IDSA proposes setting up a central repository of specimens of disease-causing bacteria. That would allow for tracking of microbial resistance and, at least as importantly, it would help researchers develop rapid-diagnostic tests to enable doctors need to write fewer, smarter prescriptions.

Since the advent of antibiotics seven decades ago, we’ve generally held the upper hand against bacterial infections. To keep our advantage, it’s become essential to know exactly which germs we’re up against, to watch and resist their progress in evading the drugs we have, and to continually bring new weapons to the fight.

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