Rapid flu tests can help doctors decide when patients need antibiotics and when they do not, researchers reported Monday.
They said their findings, published in the Archives of Internal Medicine, might help persuade doctors to ease off on the antibiotics they prescribe for patients in the hospital.
Experts almost universally agree that antibiotics are overused in the United States and elsewhere, and that this overuse has helped new, drug-resistant strains of bacteria to evolve.
Antibiotics are useless against viruses, such as influenza, but bacterial and viral infection often cause very similar symptoms.
“If they are ill enough to come into the hospital, if they have a fever or are elderly, almost all of those people receive an antibiotic,” said Dr. Ann Falsey of Rochester General Hospital and the University of Rochester in New York.
“Our tendency is to use antibiotics to be quite safe. Now that we have some rapid diagnostic methods, we can tell their doctors that your patient has influenza A.”
Falsey’s team reviewed the medical records of 166 Rochester hospital patients with documented influenza between 1999 and 2003.
They saw that 86 of the patients tested positive using the rapid test, which gives an answer within minutes, while the 80 others either did not have the rapid test done, or they tested negative at the time but were later found to have influenza.
Most of the patients got antibiotics anyway — but it was just 86 percent of the patients who tested positive for flu, compared to 99 percent whose flu was not diagnosed right away.
“At least some proportion of doctors is willing to stop antibiotics when patients have a documented viral infection,” said Falsey, whose work was paid for by the National Institutes of Health.
“This is certainly encouraging, but there is a lot more work to do.”
Falsey noted that in half of all cases of pneumonia, doctors never discover if a virus or bacteria was the cause.
“That may mean that our tools are not sensitive enough yet or that there are yet new agents to be discovered,” she said in a telephone interview.
She estimated that about 10 percent of cases of severe respiratory infections are due to influenza, and another 5 percent to 10 percent are caused by respiratory syncytial virus or RSV. “Then there are parainfluenza viruses, coronaviruses, adenoviruses -- all sorts of things,” she said.
Yet as many as 90 percent of people with the flu who see a doctor are given antibiotics, even though the drugs do not help, might cause side effects, and might breed drug-resistant bacteria, she said.
