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Pneumonia due to Chlamydia trachomatis in Japanese infants
Insights
Chlamydia trachomatis (C. trachomatis) infection was detected in 29% of infants with pneumonia using IgM antibody testing. This bacterium was more frequently isolated from infants with positive IgM antibody results, indicating a significant role in infant pneumonia.
Area of Science:
- Pediatrics
- Infectious Diseases
- Microbiology
Background:
- Chlamydia trachomatis (C. trachomatis) is a significant cause of pneumonia in infants.
- Serological and etiological data on C. trachomatis pneumonitis in Asian populations are limited.
- Infant pneumonia presents a substantial public health challenge globally.
Purpose of the Study:
- To investigate the prevalence of C. trachomatis infection in infants with pneumonia in Japan.
- To correlate serological findings (IgM antibodies) with the isolation of C. trachomatis.
- To describe the clinical characteristics of C. trachomatis pneumonitis in infants.
Main Methods:
- Sera from 109 infants with pneumonia were tested for IgM antibodies to C. trachomatis L2 strain using indirect immunofluorescence (IF).
- Nasopharyngeal swabs were collected for C. trachomatis isolation using McCoy and HeLa cell cultures.
- Clinical data from IgM antibody-positive patients were analyzed.
Main Results:
- Twenty-nine percent (32/109) of infants showed positive IgM antibodies (titer ≥ 1:16) to C. trachomatis.
- C. trachomatis was isolated from 66% (21/32) of IgM antibody-positive infants, compared to 7% (5/77) of IgM antibody-negative infants.
- Detectable IgM antibody levels were common in infants under four months of age.
Conclusions:
- C. trachomatis is a significant etiological agent in infant pneumonia in Japan.
- IgM antibody testing is a valuable tool for diagnosing C. trachomatis infection in infants with pneumonia.
- This study provides the first report on the serology and clinical features of C. trachomatis pneumonitis in Japan and potentially other Asian countries.
Abstract:
Sera from 109 Japanese infants with pneumonia were tested for antibody to Chlamydia trachomatis (C. trachomatis) L2 strain by an indirect immunofluorescence (IF) technique. Nasopharyngeal swabs were also collected to isolate C. trachomatis. Clinical specimens were inoculated onto cycloheximide-treated McCoy cells and DEAE-dextran-treated HeLa 229 cells. Of 109 patients, 32 (29%) were positive for IgM antibodies (titer, greater than or equal to 1:16) to C. trachomatis. C. trachomatis was isolated from 21 (66%) of 32 IgM antibody-positive infants as compared with 5 (7%) of 77 IgM antibody-negative infants. Detectable levels of IgM antibody were common in infants during the first four months of life. Clinical characteristics of pneumonia of these IgM antibody-positive patients were also described. This is the first report of serology and clinical characteristics of C. trachomatis pneumonitis from Asian countries including Japan.