Rapid Flu Tests May Reduce Threat of Antibiotic Resistance

January 22, 2007

New tests to rapidly detect the flu are allowing doctors to cut down on the number of hospital patients who receive antibiotics, helping soften the rapidly worsening threat of antibiotic resistance, according to a study to appear in the Feb. 26 issue of the Archives of Internal Medicine. The study was posted online by the journal Jan. 22 because of the importance of the findings to public health.

The research was done by infection control experts at Rochester General Hospital in Rochester, N.Y., who are on the faculty at the University of Rochester Medical Center.

“I was pleasantly surprised by the results,” said Ann Falsey, M.D., who led the study. “Rapid testing does give physicians evidence to discontinue antibiotics, and some physicians are responding to the evidence.

Falsey’s team analyzed the records of 166 patients who definitely had the flu when hospitalized. Eighty-six of the patients tested positive with 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 the flu. The team checked the subsequent treatment to see if there was a difference in the use of antibiotics, which aren’t effective or useful against viruses like the flu.

They found that 86 percent of the patients whose flu was confirmed early on were treated with antibiotics, compared to 99 percent of the patients whose flu wasn’t identified immediately. It’s not a huge difference in numbers, but the study showed that the difference is significant, demonstrating that the rapid test does reduce the use of antibiotics in the hospital.

“At least some proportion of doctors is willing to stop antibiotics when patients have a documented viral infection,” said Falsey. “This is certainly encouraging, but there is a lot more work to do.”

The issue is important, says Falsey, because the over-use of antibiotics makes patients and the community more vulnerable to dangerous microbes resistant to most treatments. It’s particularly important in hospitals, where people most prone to infection are treated.

Yet, Falsey noted in the study that 61 percent of patients who were generally at low risk for bacterial infection continued to receive antibiotics. She says that the prescription of antibiotics to patients with a viral infection is often done by doctors who believe that their patient may also have a bacterial infection or that antibiotics will prevent subsequent bacterial infections that could occur while the person is weak with the flu or another virus. In the current study, for instance, those patients with the flu who were still receiving antibiotics tended to be older, smokers, and have breathing difficulties. In other words, they were the ones most vulnerable to such an infection.

Nevertheless, Falsey notes that there have been no studies proving that such a practice is effective at preventing infections.

“Doctors are trying to do the right thing by their patients. Sometimes they perceive antibiotics as the safest choice, even though a virus may be the cause of their patient’s illness,” said Falsey, noting that 90 percent of people with the flu who see a doctor are given antibiotics, even though the drugs won’t help.

The simplest solution to antibiotic resistance would be for doctors to not prescribe antibiotics when they’re unlikely to help, such as when a patient definitely has the flu, the common cold, or most cases of sore throat. But when patients don’t feel well, many march into their doctor’s office expecting an answer and feel neglected if they don’t receive a prescription in return for their visit. That leaves doctors caught between prescribing medication that probably won’t help, vs. appearing unhelpful to their patients.

“Oftentimes people get sick, they just want to feel better, and they assume there is a pill that will make them better quickly,” said Falsey. “Unfortunately, that’s not the case for many respiratory illnesses that are caused by viruses. Instead they should rest, drink plenty of fluids, and take over-the-counter medications to help ease their symptoms. But many patients don’t want to hear that, and it can be difficult for a doctor to deliver the news.”

The study, conducted with funding from the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, was conducted by Falsey, Edward Walsh, M.D., and Yoshihiko Murata, M.D., Ph.D. All three are involved in infection control at Rochester General Hospital and are on the faculty of the Infectious Diseases Division of the Department of Medicine at the University of Rochester Medical Center.

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