A new test may reduce the overuse of antibiotics. All it takes is a nasal swab and within hours a machine can show if the patient's symptoms are viral or bacterial.

Treating Viral Respiratory Infections
In 2006, more than 50 million Americans sought medical help for respiratory symptoms. Peak incidence is between late winter and early spring.

In most cases, symptoms of a viral respiratory infection can be treated with over-the-counter medications to reduce pain and fever. Patients should see a doctor if the symptoms continue to worsen after seven days or don’t improve within 10 days. In addition, medical care should be sought for patients with a high fever, breathing problems or severe head pain or swelling.

Antibiotics fight bacteria, not viruses. Thus, the medications are inappropriate for viral infections. However, sometimes people with a viral infection develop a secondary bacterial infection. For these patients, an antibiotic may be appropriate. Health experts say inappropriate use of antibiotics increases the risk of bacterial resistance to the drugs. If the bacteria learn to resist the effects of one antibiotic, stronger antibiotics may be needed to fight the infection. In some cases, the bacteria can become resistant to all common antibiotics.

Detecting a Viral Respiratory Illness
In the past, it was common for doctors to prescribe antibiotics to patients with respiratory infections, even if doctors were unsure if the symptoms were caused by a bacteria or virus. To stem the growth of drug-resistant bacteria, health experts now recommend more judicious use of antibiotics. Patients with respiratory symptoms may be advised to treat the symptoms and see a physician if the symptoms get worse or continue to linger.

Now, doctors have a faster way to determine if a respiratory illness is caused by a virus. In January, the FDA approved the xTAG™ Respiratory Viral Panel. The test can screen for 12 different viruses: influenza A, influenza A-H1, influenza A-H3, influenza B, adenovirus, respiratory syncytial virus type A and B, rhinovirus, parainfluenza types 1, 2, and 3 and metapneumovirus (a newly discovered respiratory virus).

To use the test, the physician takes a swab of secretions from the nose or throat. The sample is sent to a lab where the cellular DNA and RNA are separated out. Next, multiple copies of the genetic components are created. The finished sample is mixed with color-coded beads. Each bead color is designed to attach to a specific viral DNA. The beads are then sorted and read by an instrument called the Luminex® xMAP. If one of the 12 viruses is present in the sample, the machine generates a signal that tells a computer the test result is positive for that virus.

Mark Kolins, M.D., Clinical Pathologist with Beaumont Hospital in Michigan, says current laboratory techniques for differentiating and identifying viral or bacterial infections take time, sometimes two to ten days. In addition, the current tests can only detect one or a couple of viruses at a time. The TAG™ Respiratory Viral Panel provides results in just a few hours and can detect up to 12 different viruses. Thus, there is no need for a lab to perform several different tests on the same sample.

Pulmonologist Devang Doshi, M.D., says the TAG™ Respiratory Viral Panel enables doctors to determine the best course of treatment for patients much sooner. If the symptoms are caused by a virus, then doctors avoid inappropriate use of antibiotics. Depending upon the type of virus found, antiviral medications can be given to fight the infection. The test can also help local health officials keep tabs on what viruses are circulating within a community so doctors can be prepared to treat local outbreaks. The TAG™ Respiratory Viral Panel is typically available at larger laboratories and hospitals.

AUDIENCE INQUIRY
For information about the xTAG™ Respiratory Viral Panel:
Luminex®, http://www.luminexcorp.com/technology/xtag/index.html

For general information on respiratory or viral illnesses:
Centers for Disease Control and Prevention, http://www.cdc.gov
Microbe World, http://www.microbeworld.org
National Institute of Allergy and Infectious Diseases, http://www.niaid.nih.gov