TUESDAY, May 15 (HealthDay News) -- The use of antimicrobials against atypical disease-causing germs in hospitalized patients with community-acquired pneumonia results in patients reaching clinical stability sooner, shorter hospital stays, and lower death rates, a large U.S. study says.

Atypical pneumonias are caused by organisms other than the so-called "typical" bacteria, viruses or fungi. The study authors defined atypical treatment as the use of any antibiotic regimen that included a macrolid, fluoroquinolone or tetracycline, which are all broad-spectrum antibiotics.

The researchers analyzed data on thousands of hospitalized patients with community-acquired pneumonia (CAP) who received atypical treatment in North America, Europe, Latin America, and Africa and Asia.

The researchers found that treatment with antimicrobials against atypical pathogens reduced the time from clinical stability from 3.7 days to 3.2 days, shortened the hospital stay from 7.1 days to 6.1 days, reduced the overall death rate from 11.1 percent to 7 percent, and the CAP-related death rate from 6.4 percent to 3.8 percent.

The findings are published in the second issue for May of the American Journal of Respiratory and Critical Care Medicine.

"This study indicates that, although the incidence of atypical pathogens is relatively similar in all regions of the world, there are significant differences in the proportion of patients who are treated with an empiric regimen that cover for atypical pathogens," study author Dr. Forest W. Arnold, of the division of infectious diseases at the University of Louisville, said in a prepared statement.

The researchers found that the atypical treatment rates were 91 percent in North America, 74 percent in Europe, 53 percent in Latin America, and 10 percent in Africa and Asia.

More information

The U.S. National Library of Medicine has more about atypical pneumonia.