Doctors have a faster way to determine if a child has a deadly type of meningitis,an inflammation of the membranes covering the brain and spinal cord.

It is relatively simple to treat viral meningitis, but the rare bacterial form that occurs in about one in 25 cases can be deadly. Patients must receive intravenous antibiotics as soon as they are admitted to hospital, saidstudyauthor Dr. Lise Nigrovic of the Children's Hospital of Boston.

Many doctors start children on antibiotics while they wait for bacterial test results to show what kind of meningitis is causing the inflammation, but the results can take two to three days.

In Wednesday's Journal of the American Medical Association, Nigrovic and her colleagues report the results of their study on nearly 3,300 cases of meningitis in children who went to emergency departments between January 2001 and June 2004. Participants were between29 days and 19 years of age.

"The absence of a seizure as well as defined blood and spinal fluid tests identified a low-risk group for bacterial meningitis," Nigrovic said. "And in that group, the risk of bacterial meningitis was one in a thousand."

The set of information they testedpredicted which cases are likely not bacterial with 98 per cent accuracy.

Of the patients, 121, or 3.7 per cent, had bacterial meningitis and 3,174, or 96.3 per cent, had the nonbacterial form, the team found.

The findings could help to reduce unnecessary use of antibiotics, said Dr. Gary Fleisher, a pediatrician at the Children's Hospital of Boston, who was not part of the study.

As the test is adopted clinically, more research will show how the guidelines help in caring for children with bacterial meningitis, the researchers said.

In 2000, public health experts in the U.S. began recommending a vaccine to prevent bacterial meningitis in at-risk children younger than two. The incidence of bacterial meningitis has fallen since then, the team noted.

Health Canada approved a newer vaccinefor bacterial meningitis in 2001.