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A prescription for tackling antibiotic resistance

September 8, 2009 |  4:48 pm

Antibiotics are great for treating bacterial infections such as bronchitis and pneumonia. They are so great that many doctors prescribe them even when infections are caused by viruses, not bacteria.

MRSA But the overuse of antibiotics has helped spawn the development of antibiotic-resistant bacteria. One obvious solution is to prescribe fewer antibiotics. But that is easier said than done.

Patients with lower respiratory tract infections caused by bacteria have the same clinical symptoms as patients with lower respiratory tract infections caused by viruses. There are tests that can tell them apart, but it can take days to get the results. Sick patients – and the doctors who treat them – simply don’t want to wait.

Wouldn’t it be great if there were some kind of test that could tell you in a matter of minutes whether your infection was caused by a bacterium or a virus?

There is, according to a study published in Wednesday’s edition of the Journal of the American Medical Assn.

Procalcitonin, or PCT, is a substance that circulates in the blood when a patient is fighting a bacterial infection but is rarely released in response to a viral infection. Hospital laboratories can measure the amount of PCT in a blood sample in about 20 minutes.

A group of Swiss researchers wanted to know whether PCT levels could help them figure out when it was appropriate to prescribe antibiotics for lower respiratory tract infections. They recruited 1,359 patients from six hospitals and randomly assigned them to two groups. One group got antibiotics according to their PCT levels; the other group’s prescriptions were determined the old-fashioned way.

It turned out that patients in the PCT group took fewer antibiotics but were just as likely to get better as patients in the control group. Not only did fewer patients in the PCT group receive antibiotics, but those who did took them for fewer days, the study found.

How big was the difference? Overall, the antibiotic prescription rate was 87.7% in the control group and 75.4% in the PCT group, according to the study. Among patients with community-acquired pneumonia, the difference was 99.1% versus 90.7%; for patients with exacerbated chronic obstructive pulmonary disease, it was 69.9% versus 48.7%; and for patients with acute bronchitis, the difference was 50% versus 23.2%.

When patients took fewer antibiotics, they also had fewer adverse events related to antibiotic use, such as nausea, diarrhea and rash, the study found.

-- Karen Kaplan

Photo: Overuse of antibiotics has led to dangerous bugs like methicillin-resistant Staphylococcus aureus, better known as MRSA. Photo credit: Visuals Unlimited