(September 9, 2009 - Insidermedicine)

Guiding the treatment of even the most severe lower respiratory tract infections based on blood levels of a substance known as procalcitonin or PCT can help limit unnecessary use of antibiotics, according to research published in the September 9 issue of the Journal of the American Medical Association.

Here is some information about lower respiratory tract infections:

•    Some of the most common ones are bronchitis and pneumonia

•    They are one of the most frequent reasons for the use of antibiotics, but they are usually caused by viruses, which do not respond to antibiotics

•    It is impossible to reliably differentiate a lower respiratory tract infection caused by a virus from one caused by a bacterial infection from symptoms alone

Researchers from University Hospital Basel randomly assigned over 1,300 individuals with mainly severe lower respiratory tract infections to one of two groups. The first group received antibiotic treatment that was guided by blood levels of PCT, while the second group received care based on standard guidelines.

While the overall rate of adverse outcomes was similar between the two groups, those whose care was guided by PCT received antibiotics for fewer days, on average, than those who received standard care. The PCT group also experienced fewer side effects related to antibiotics than the standard care group.

Today's research demonstrates how using blood levels of PCT to guide care can help physicians use antibiotics more appropriately in patients with lower respiratory tract infections.