(USA TODAY) -- Doctors are giving fewer antibiotics to U.S. children than they did in the mid-1990s, a trend that might slow the increase in germs resistant to those drugs, according to an extensive study out today.

This reversal of a 20-year rise in antibiotic prescriptions is good news to many public health experts, who have long considered many antibiotic prescriptions unnecessary. Health officials around the world have voiced concerns about increasing levels of antibiotic-resistant bacteria.

Surveys by the Centers for Disease Control and Prevention suggested that outpatient prescriptions grew by about 50% from 1980 to 1992.

This study is much more comprehensive than CDC reports in the late 1990s, which showed the start of a decline in antibiotic prescriptions. Those statistics were based only on doctor visits and did not include phoned-in prescriptions.

The new study in Pediatrics tracked all prescriptions for 225,000 children in nine HMOs from 1996 to 2000. Antibiotic use dropped 24% in children younger than 3 and 25% for those from 3 up to 6. For children 6 to 18, the drugs were prescribed much less often, and rates fell by 16%.

"This is very exciting news and shows we're moving in the right direction," says Richard Besser, medical director of a CDC campaign for correct antibiotic use. "It's reassuring to see there's a real drop here."

Children receive the vast majority of antibiotics given to outpatients, Besser says. The drugs don't work for colds, bronchitis and other viruses, and they aren't needed for up to 80% of childhood ear infections.

Nevertheless, evidence shows that doctors often prescribe antibiotics for those conditions, and patients push to get the medicine.

The study's lead author, Jonathan Finkelstein of Harvard Medical School in Boston, says antibiotics usage had increased for several reasons. Among them:

* A growing number of children attend group day care, where colds spread rapidly.

* Employed parents often demand antibiotics so they can return to work more quickly.

Finkelstein says infants and toddlers use the most antibiotics, so declines in this youngest group make the biggest impact.

Doctors' "higher threshold" for diagnosing ear infections looks like the key factor accounting for fewer antibiotic prescriptions among the youngest, Finkelstein says.

"They're seeing mild ear pain and taking a 'watchful waiting' approach. Then the antibiotic often isn't necessary," he says.

Copyright 2003 USA TODAY, a division of Gannett Co. Inc.