Etiology of Community Acquired Pneumonia Among Adult Patients Requiring Hospitalization in Taiwan

Background: There has not been a comprehensive multi-center study investigating the microbial profile of community acquired pneumonia (CAP) in Taiwan.

Methods: A prospective study of adult CAP patients requiring hospitalization between December 2001 and April 2002 was carried out in 13 hospitals in Taiwan. Etiology was determined based on laboratory data from blood and sputum cultures plus serology from paired serum and urine antigen detection tests.

Results: Etiology was assigned to 99 (58.9%) of the 168 patients having the most complete data for etiology determination, with mixed infection in 21 (12.5%) patients. More than half (51.8%) of the patients were>60 years and 63.7% of the patients were males. The most common etiologic agent was Streptococcus pneumoniae (40, 23.8%), the majority (60%, 24 cases) of which was detected by positive urine antigen test. Other common agents included Mycoplasma pneumoniae (24, 14.3%), Chlamydia pneumoniae (12, 7.1%), Influenza A virus (11, 6.5%), Klebsiella pneumoniae (8, 4.8%) and Haemophilus influenzae (8, 4.8%). The prevalence of S. pneumoniae and M. pneumoniae was highest in patients>60 years (25/87, 28.7%), and<44 years (12/59, 19%), respectively; while K. pneumoniae comprised a larger proportion (4/22, 18%) in the 45-59 years group.

Conclusions: S. pneumoniae was the most common etiology agent in adult patients hospitalized due to CAP in Taiwan and the spectrum of other major pathogens was similar to studies conducted elsewhere in the world. Empiric treatment recommendations developed in other parts of the world may be appropriately adapted for local use after taking into account local resistance profiles. Our data also support the recommendation that urine antigen test be added as an adjunct to adult CAP etiology diagnosis protocol.