(NaturalNews) Although many health researchers and professionals have recommended that doctors stop prescribing antibiotics for sinus infections, the practice is still widespread.A new study, conducted by Swiss researchers and published in the, found that a third of all doctor's visits for upper respiratory infections in the United States end in a diagnosis of rhinosinusitis, or nasal/sinus inflammation. Approximately 80 percent of these patients are prescribed antibiotics.But most rhinosinusitis infections are caused by viruses, which are not affected by antibiotics. In thestudy, researchers found that for every 15 adult rhinosinusitis patients treated with antibiotics, only one would receive any benefit from the drug. Antibiotics were equally ineffective regardless of the patients' age or the length or severity of their symptoms."Antibiotics offer little benefit for patients with acute rhinosinusitis-like complaints," the researchers wrote. "Antibiotics are not justified even if a patient reports symptoms for longer than 7-10 days."In addition to placing patients at risk of side effects, the unnecessary use of antibiotics contributes to the development of drug-resistant bacterial strains.An earlier study, published in the, found that 83 percent of acute and 70 percent of chronic rhinosinusitis infections in the United States are treated with at least one antibiotic.According to Donald A. Leopold, chairman of the department of otolaryngology at the University of Nebraska Medical Center, many doctors prescribe antibiotics simply because they can't think of anything more effective to use."We as physicians don't have very good medications for chronic rhinosinusitis," he said. "The only other drugs in contention are topical steroids, and they are not great. As a group, I suggest we are frustrated at not having good drugs."In addition, many patients insist on being given drugs and doctors are reluctant to stand up to them."Many patients call up and ask for specific antibiotics," he said. "The patients know these names. They have been marketed to them, so they know the drugs are available. And antibiotics do give some relief."