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Febrile Children with Pneumonia Have Higher Nasopharyngeal Bacterial Load Than Other Children with Fever
Bryndis Bjornsdottir1,2, Ubaldo Benitez Hernandez3, Asgeir Haraldsson1,2
1Faculty of Medicine, University of Iceland, 101 Reykjavik, Iceland.
Insights
High density of Streptococcus pneumoniae and Haemophilus influenzae in the nasopharynx increases pneumonia risk in children. Viral infections may precede and trigger severe respiratory infections.
Area of Science:
- Pediatrics
- Infectious Diseases
- Microbiology
Background:
- Febrile episodes are common in children, often leading to emergency department visits.
- While most childhood infections are self-limiting, severe and life-threatening infections do occur.
- Invasive bacterial infections in children require prompt diagnosis and understanding of contributing factors.
Purpose of the Study:
- To investigate the relationship between nasopharyngeal microbial carriage and infection outcomes in children presenting with suspected invasive bacterial infection.
- To identify specific microbial and viral factors associated with severe infections, particularly pneumonia.
- To explore the role of microbial density in the nasopharynx as a risk factor for pediatric pneumonia.
Main Methods:
- Prospective cohort study of children undergoing blood culture in a pediatric emergency department over two years.
- Nasopharyngeal swabs analyzed for respiratory viruses and three key bacterial species (Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis) using quantitative PCR.
- Statistical analyses including Fisher's exact test, Wilcoxon rank sum, and multivariable models were employed.
Main Results:
- Of 196 enrolled children, 92 had severe infections, with pneumonia being the most common (44/92).
- Presence of respiratory viruses and carriage of Streptococcus pneumoniae and Haemophilus influenzae were linked to increased pneumonia risk.
- Higher nasopharyngeal bacterial density of S. pneumoniae and H. influenzae independently predicted pneumonia, while M. catarrhalis carriage showed a protective association.
Conclusions:
- Higher nasopharyngeal density of S. pneumoniae and H. influenzae may contribute to the development of bacterial pneumonia in children.
- Preceding viral respiratory infections could act as a trigger for severe lower respiratory tract infections.
- Understanding nasopharyngeal microbial dynamics is crucial for predicting and potentially preventing severe pediatric infections.
Abstract:
Febrile episodes are common in children and the most frequent reason for attending emergency services. Although most infections have a benign and self-limiting course, severe and sometimes life-threatening infections occur. This prospective study describes a cohort of children presenting to a single-centre pediatric emergency department (ED) with suspected invasive bacterial infection, and explores the relationships between nasopharyngeal microbes and outcomes. All children attending the ED who had a blood culture taken were offered to participate over a two-year period. In addition to conventional medical care, a nasopharyngeal swab was obtained., which was analysed for respiratory viruses and three bacterial species using a quantitative PCR. Fisher's exact test, Wilcoxon rank sum, and multivariable models were used for statistical analyses of the 196 children (75% younger than four years) who were enrolled and had sufficient data for analysis; 92 had severe infections according to the study protocol, while five had bloodstream infections. Radiologically confirmed pneumonia was the most common severe infection found in 44/92 patients. The presence of respiratory viruses and the carriage of Streptococcus pneumoniae and Haemophilus influenzae were associated with a higher risk of pneumonia. Higher density colonisation with these bacteria were independent risk factors for pneumonia, whereas Moraxella catarrhalis carriage was associated with lower risk. Our data support the hypothesis that higher nasopharyngeal density of pneumococci and H. influenzae could play a role in the development of bacterial pneumonia in children. A preceding viral infection of the respiratory tract may be a trigger and play a role in the progression to severe lower respiratory tract infection.
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