Study objective: To investigate the prevalence of
asymptomatic infection with Chlamydia pneumoniae in
subjectively healthy adults.
Setting: Kawasaki Medical School Hospital in
Participants: Total of 1,018
asymptomatic healthy adults (age range, 22 to 50 years; mean age, 32.4
years; 482 men and 536 women).
results: Nasopharyngeal swab specimens were obtained from all
subjects and analyzed by isolation in cell cultures and polymerase
chain reaction (PCR) test for C pneumoniae. Serum
samples were also obtained and tested for C
pneumoniae-specific antibodies by the microimmunofluorescence
test. Of 1,018 specimens tested, 14 specimens (1.4%) were judged
positive by culture and/or the PCR. Thirteen specimens were PCR
positive, and 4 specimens were culture positive. There were three
specimens positive by both tests and 11 specimens positive with
discrepancies in culture and PCR results. None of the individuals met
the serologic criteria for acute infection. Of 1,018 sera tested,
64.1% of men and 58.0% of women had antibody to C
pneumoniae. The overall prevalence of antibody was 60.9%.
Forty individuals (3.9%) had an IgG titer of ≥ 1:512 or IgM titer of≥
Conclusions: Our data suggest that
asymptomatic infection with Cpneumoniae
may occur in subjectively healthy adults.