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Updated: Jan 29, 2026

Bronchoalveolar Lavage BAL for Research; Obtaining Adequate Sample Yield
Published on: March 24, 2014
[Pathogens in bronchoalveolar lavage fluid of children with lower respiratory tract infection]
Ya-Lin Guo1, Yu-Xia Yang, Peng-Peng Dong
1Department of Pediatrics, Third Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China. yyx6873@sina.com.
Insights
Mycoplasma pneumoniae is the most frequent pathogen in pediatric lower respiratory tract infections, followed by Streptococcus pneumoniae and Haemophilus influenzae. Pathogen detection varies by age and infection type in children.
Area of Science:
- Pediatric infectious diseases
- Respiratory medicine
- Microbiology
Background:
- Lower respiratory tract infections (LRTIs) are a significant cause of childhood morbidity.
- Identifying causative pathogens is crucial for effective treatment and management of pediatric LRTIs.
Purpose of the Study:
- To investigate the spectrum and features of pathogens identified in children diagnosed with lower respiratory tract infections.
- To analyze pathogen prevalence based on patient demographics and specific clinical presentations of LRTIs.
Main Methods:
- Prospective enrollment of 108 children hospitalized with LRTIs between January 2017 and June 2018.
- Collection of bronchoalveolar lavage fluid samples for pathogen analysis.
- Utilized multiple quantitative real-time polymerase chain reaction (PCR) for sensitive pathogen detection.
Main Results:
- Pathogens were detected in 78.7% of children, with single infections in 48.1% and multiple infections in 30.6%.
- Mycoplasma pneumoniae was the most prevalent pathogen (35.2%), particularly in children aged 36–72 months.
- Streptococcus pneumoniae (26.9%) and Haemophilus influenzae (26.9%) were also common, with distinct age distributions and associations with specific pneumonia types.
Conclusions:
- Mycoplasma pneumoniae is the leading pathogen in pediatric LRTIs, followed by Streptococcus pneumoniae and Haemophilus influenzae.
- Pathogen detection rates demonstrate significant variability influenced by the child's age and the specific type of lower respiratory tract infection.
Objective:
To study the features of pathogens in children with lower respiratory tract infection.
Methods:
A total of 108 children who were hospitalized due to lower respiratory tract infection and underwent fiber bronchoscopy between January 2017 and June 2018 were enrolled. Bronchoalveolar lavage fluid samples were collected. Multiple quantitative real-time PCR was performed to detect pathogens.
Results:
Of the108 children, 85 (78.7%) were found to have pathogens, among whom 52 (48.1%) had single pathogen infection and 33 (30.6%) had multiple pathogen infections. Mycoplasma pneumoniae was detected in 38 children (35.2%), and was the most common pathogen. The children aged 36 - <72 months had the highest detection rate of Mycoplasma pneumoniae. Both Streptococcus pneumoniae and Haemophilus influenzae were detected in 29 children (26.9%) and Streptococcus pneumoniae was mainly detected in children aged <24 months. Each of Acinetobacter baumannii, Candida albicans and Klebsiella pneumoniae was detected in 3 children. Among the 31 children with bronchopneumonia, 9 were found to have Haemophilus influenza, with the highest detection rate of 29%. Among the 34 children with lobar pneumonia, 22 were found to have Mycoplasma pneumoniae, with the highest detection rate of 65%. Among the 22 children with bronchial foreign bodies and bronchopneumonia, 10 were found to have Streptococcus pneumoniae, with the highest detection rate of 45%.
Conclusions:
In children with lower respiratory tract infection, Mycoplasma pneumoniae is the most common pathogen, followed by Streptococcus pneumoniae and Haemophilus influenzae. There are differences in the detection rates of pathogens between children with different ages and different types of lower respiratory tract infection.
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