Related Experiment Video
Updated: Jan 14, 2026
06:32
Assessing Respiratory Immune Responses to Haemophilus Influenzae
Published on: June 29, 2021
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Intrahost Genomic Variation of Haemophilus influenzae Isolates from Asymptomatic Nasopharyngeal Carriers Involves
Randall J Olsen1, S Wesley Long1, Yuvanesh Vedaraju2
1Laboratory for Molecular and Translational Human Infectious Diseases Research, Center for Infectious Diseases, Houston Methodist Research Institute, and Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas; Departments of Pathology and Laboratory Medicine and Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York.
The American Journal of Pathology
|October 17, 2025
Summary
This study identified genes that frequently change in Haemophilus influenzae during asymptomatic nasopharyngeal carriage in children. These genomic variations impact bacterial fitness and host interactions.
Area of Science:
- Microbiology
- Genomics
- Human Pathogens
Background:
- Haemophilus influenzae is a human pathogen causing various infections and asymptomatically colonizing the upper respiratory tract.
- Understanding intrahost genomic variation during asymptomatic carriage is crucial for identifying adaptive mechanisms.
- Previous studies have not fully identified genes acquiring mutations during human nasopharyngeal colonization.
Purpose of the Study:
- To investigate intrahost genomic variation of Haemophilus influenzae during asymptomatic carriage in the nasopharynx.
- To identify genes frequently acquiring single-nucleotide polymorphisms (SNPs) during human colonization.
- To understand the functional implications of these genomic changes.
Main Methods:
- Sequencing of 805 Haemophilus influenzae isolates from 24 healthy Icelandic children.
- Analysis of intrahost genomic variation, including nonsynonymous and nonsense SNPs.
- Identification of recurrently polymorphic genes and SNPs across individuals and within the same individual.
Main Results:
- Intrahost genomic variation was observed in 120 genes.
- Sixty-nine genes were recurrently polymorphic across multiple children.
- Seventy-two SNPs occurred in multiple isolates from the same child, affecting genes involved in transcription regulation and virulence.
Conclusions:
- Haemophilus influenzae acquires significant intrahost genomic variation during asymptomatic nasopharyngeal carriage.
- Polymorphic genes are involved in bacterial fitness, virulence, and host-pathogen interactions.
- This study provides a model for understanding genomic diversity in H. influenzae during human colonization.
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