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[Mycoplasma pneumoniae respiratory tract infection prevailing among infants at a nursery school]
Abstract:
Mycoplasma pneumoniae (M. pneumoniae) infection in infants had been considered to be very rare, but recently some clinical cases have been reported. We experienced an epidemic of M. pneumoniae infection in a nursery school, and compared M. pneumoniae infection in infants with that in preschool and school children to investigate the features of infantile M. pneumoniae infection. We obtained the following clinical findings in 15 infantile patients with M. pneumoniae infection: The maximum body temperature scarcely increased to 38.5 degrees C or more and the period of high temperature and cough was shorter in infant patients than in preschool and school aged patients. Stridor occurred in 4 patients but skin disorder was not observed. In the laboratory findings, the white blood cell count tended to increase with no changes in neutrophil/lymphocyte ratio and CRP increased slightly. M. pneumoniae antibody was negative in all the patients except 3 and old hemagglutination tests were positive in only 4 patients. The chest X-ray examinations showed a mild increase in the hilar shadow. However, the sequentially located homogeneous shadow which is commonly seen in preschool and school aged patients was not detected. M. pneumoniae antibody scarcely increased in infantile patients but M. pneumoniae was isolated by throat culture from 14 of the 15 patients who were diagnosed as having M. pneumoniae infection.
Insights
Mycoplasma pneumoniae infections present milder symptoms in infants compared to older children, with lower fevers and shorter illness durations. Diagnosis can be challenging due to minimal antibody response in infants.
Area of Science:
- Pediatrics
- Infectious Diseases
- Microbiology
Background:
- Mycoplasma pneumoniae infections were historically considered rare in infants.
- Recent case reports suggest an increasing incidence in this age group.
- Understanding infantile M. pneumoniae infection features is crucial for accurate diagnosis and management.
Purpose of the Study:
- To investigate the clinical features of Mycoplasma pneumoniae infection specifically in infants.
- To compare infantile M. pneumoniae infection with that in preschool and school-aged children.
- To identify diagnostic challenges and characteristics of M. pneumoniae in infants.
Main Methods:
- Retrospective analysis of 15 infant cases during a nursery school epidemic.
- Comparison of clinical and laboratory findings between infants and older children.
- Throat culture for M. pneumoniae isolation and serological testing for antibodies.
Main Results:
- Infants exhibited lower maximum body temperatures (<38.5°C) and shorter durations of fever and cough compared to older children.
- Stridor was observed in some infants, but skin disorders were absent.
- Laboratory findings included mild leukocytosis, normal neutrophil/lymphocyte ratios, and slight CRP elevation.
- M. pneumoniae antibodies were rarely elevated in infants, and chest X-rays showed only mild hilar shadowing without typical lobar pneumonia patterns.
- M. pneumoniae was successfully isolated from throat cultures in 14 out of 15 infants.
Conclusions:
- Mycoplasma pneumoniae infection in infants presents with distinct, milder clinical manifestations compared to older children.
- Diagnostic methods relying on antibody detection may be less reliable in infants due to poor serological response.
- Throat culture is a valuable tool for diagnosing M. pneumoniae infection in infants.
- Further research is needed to elucidate the long-term implications of M. pneumoniae in this age group.