Background:

Since global threat of severe acute respiratory syndrome (SARS) outbreak, originally described as a severe atypical pneumonia in the Guangdong Province of China, has successfully been contained on early July, 2003, many countries remain vigilant for resurgence of SARS. We investigated the causative roles of SARS coronavirus (SARS-CoV) and atypical pathogens in community-acquired pneumonia (CAP) in the post-outbreak period.

Methods:

From September to November 2003, a prospective multicentre study was performed to determine the atypical causes of CAP including SARS-CoV. Clinical samples collected from CAP patients between February and May, 2003 were also examined. To detect SARS-CoV, RT-PCR and Indirect IFA and rapid antibody tests were performed for respiratory specimens and paired sera, respectively. Tests for Mycoplasma pneumoniae, Chlamydia pneumoniae, Legionella species, and respiratory viruses (influenza virus A and B, adenovirus, parainfluenza virus, respiratory syncytial virus) included PCR, urinary antigen test, indirect IFAs and virus culture.

Results:

A total of 134 patients were enrolled in this study (103 patients prospectively and 29 patients retrospectively). SARS-CoV was not detected in any patients. Based on seroconversion, high antibody titre together with the presence of bacterial DNA in respiratory secretions (M. pneumoniae, C. pneumoniae, and L. pneumophila) or bacterial antigen in urine (L. pneumophila), M. pneumoniae, C. pneumoniae, and L. pneumophila were responsible for 12.2, 10.7 and 13.9% of cases, respectively. Respiratory viruses were not detected except for adenovirus in one patient.

Conclusions:

Although SARS-CoV was not detected in this postoutbreak surveillance, we must remain vigilant for reemergence of SARS. Atypical bacterial pathogens appeared more prevalent than the previous reports in South Korea.