Background: Mycoplasma pneumoniae is the most frequent cause of respiratory tract infections in school- aged children and adolescents. For appropriate use of antibiotics, diagnosis of M. pneumoniae infection in routine clinical practice has been based on serology using a single serum sample. We evaluated the seroprevalence of anti-M. pneumoniae-specific antibodies in 500 asymptomatic, healthy persons in Jeonnam Province.

Methods: Sera were collected from 500 healthy persons in Jeonnam Province. Anti-M. pneumoniae antibody titer was measured using a microparticle agglutination assay Serodia Myco II (Fujirebio, Japan) and VIRCELL IgM Mycoplasma ELISA kits (Vircell, Granada, Spain).

Results: Anti-M. pneumoniae antibody titers in 500 healthy individuals were 1：20 in 344 (68.8%), 1：40 in 16 (3.2%), 1：80 in 71 (14.2%), 1：160 in 45 (9.0%), 1：320 in 14 (2.8%), and ＞1：320 in 10 (2.0%). The positive rate of M. pneumoniae IgM antibodies was 3.2% (15/473). The prevalence of IgM was 10.0% in the 7∼9 years, 9.1% in the 10∼19 years, and 5.0% in the 20∼29 years old group, which was significantly higher than that in elderly people.

Conclusion: Some of healthy people showed a high anti-M. pneumoniae antibody titer (＞1：160) and positive IgM, and an assessment of current infection with single serum serology has its limitation for the diagnosis of M. pneumoniae infections. (Korean J Clin Microbiol 2007;10:109-113)