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Pathogenic Analysis of the Bronchoalveolar Lavage Fluid Samples With Pediatric Refractory Mycoplasma pneumoniae
Fei Zhao1, Jinrong Liu2, Di Xiao1
1National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing, China.
Abstract:
Background: We conducted a pathogenic analysis in the bronchoalveolar lavage fluid (BALF) samples from refractory Mycoplasma pneumoniae pneumonia (RMPP) children. Methods: A total of 150 BALF samples from 60 RMPP patients were analyzed to investigate pathogenic changes. The characteristics of M. pneumoniae were analyzed through culture, real-time PCR, genotyping, antimicrobial susceptibility testing and proteomics. The other pathogens were determined using culture, sequencing and nucleic acid detection. Results: In 60 RMPP cases, the bacterial co-infection rate was 5%, while that of virus was 33.3%. The poor prognosis rate was 61.7%. The DNA positive rate among the 150 samples was 98.7%, while the culture positive rate was 56.7% for M. pneumoniae. Significant differences were noticed in the positivity of M. pneumoniae culture obtained from samples with a disease course of at least 3 weeks compared with those within 3 weeks. The genotype 1 M. pneumoniae strains showed a macrolide resistant (MLr) rate of 100%, and that for genotype 2 was 90.1%. Proteomics showed that there were 57 proteins up-regulated in the MLs M. pneumoniae, half of which were membrane-associated protein with adhesion or toxicity. Conclusions: Pediatric RMPP usually presented with viral co-infection, but it caused limited effects on the progression and prognosis of RMPP. Persistent presence of viable M. pneumoniae is not necessary in the later stage of RMPP. The expression of virulence factor in the MLr M. pneumoniae was higher than that of the MLs M. pneumoniae, which was more common in the RMPP children.
Insights
Refractory Mycoplasma pneumoniae pneumonia (RMPP) in children often involves viral co-infections, but these don't significantly impact outcomes. Macrolide-resistant M. pneumoniae strains exhibit higher virulence factors.
Area of Science:
- Pediatric Infectious Diseases
- Respiratory Medicine
- Microbiology
Background:
- Refractory Mycoplasma pneumoniae pneumonia (RMPP) in children presents a diagnostic and therapeutic challenge.
- Understanding the pathogenic landscape in RMPP is crucial for improving patient outcomes.
Purpose of the Study:
- To conduct a comprehensive pathogenic analysis of bronchoalveolar lavage fluid (BALF) samples from children with RMPP.
- To investigate the characteristics of Mycoplasma pneumoniae, including genotyping and antimicrobial resistance.
- To identify co-infecting pathogens and their impact on RMPP progression.
Main Methods:
- Analysis of 150 BALF samples from 60 RMPP patients.
- Detection of M. pneumoniae using culture, real-time PCR, and genotyping.
- Antimicrobial susceptibility testing and proteomic analysis of M. pneumoniae.
- Identification of other pathogens via culture, sequencing, and nucleic acid detection.
Main Results:
- High DNA positive rate (98.7%) for M. pneumoniae, with a culture positive rate of 56.7%.
- Viral co-infection detected in 33.3% of cases; bacterial co-infection in 5%.
- Genotype 1 M. pneumoniae strains were 100% macrolide-resistant (MLr), genotype 2 at 90.1%.
- MLr M. pneumoniae strains showed increased expression of virulence-associated proteins.
Conclusions:
- Pediatric RMPP frequently involves viral co-infections, but these have minimal impact on disease progression or prognosis.
- Persistent viable M. pneumoniae is not essential in later stages of RMPP.
- Macrolide-resistant M. pneumoniae strains, common in RMPP, exhibit enhanced virulence factor expression.
