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From Normal Flora to Brain Abscesses: A Review of Streptococcus intermedius
Elio Issa1, Tamara Salloum1, Sima Tokajian1
1Department of Natural Sciences, School of Arts and Sciences, Lebanese American University, Byblos, Lebanon.
Abstract:
Streptococcus intermedius is a β-hemolytic Gram-positive member of the Streptococcus anginosus group (SAG). Despite being a part of the normal microbiota, it is one of the most common pathogens associated with brain and liver abscesses and thoracic empyema, increasing as a result the morbidity and mortality rates in affected patients. Though there are numerous published case reports on S. intermedius infections, it is still understudied compared to other SAG members. Our knowledge of the genomic factors contributing to its dissemination to the brain and abscess development is also limited to few characterized genes. In this review, we summarize our current knowledge on S. intermedius identification methods, virulence factors, and insight provided by the whole-genome and correlate patients' metadata, symptoms, and disease outcome with S. intermedius infections in 101 recent case reports obtained from PubMed. This combined information highlights the gaps in our understanding of S. intermedius pathogenesis, suggesting future research directions to unveil the factors contributing to abscess development.
Insights
Streptococcus intermedius, a common pathogen, causes serious abscesses. This review details its identification, virulence, and genomic factors, highlighting knowledge gaps in its pathogenesis.
Area of Science:
- Microbiology
- Infectious Diseases
- Genomics
Background:
- Streptococcus intermedius (S. intermedius) is a Gram-positive bacterium belonging to the Streptococcus anginosus group (SAG).
- While part of the normal microbiota, S. intermedius is a significant pathogen causing brain and liver abscesses, and thoracic empyema.
- Despite numerous case reports, S. intermedius infections remain understudied compared to other SAG members, with limited understanding of its genomic virulence factors.
Purpose of the Study:
- To review current knowledge on S. intermedius identification, virulence factors, and genomic insights.
- To correlate patient metadata, symptoms, and outcomes with S. intermedius infections using 101 PubMed case reports.
- To identify research gaps in S. intermedius pathogenesis and abscess development.
Main Methods:
- Literature review of S. intermedius identification methods and virulence factors.
- Analysis of whole-genome data for insights into S. intermedius pathogenesis.
- Systematic correlation of patient data, symptoms, and disease outcomes from 101 recent case reports.
Main Results:
- Summarized current understanding of S. intermedius identification and virulence.
- Provided genomic insights into S. intermedius dissemination and abscess formation.
- Highlighted correlations between patient metadata, symptoms, and disease outcomes in S. intermedius infections.
Conclusions:
- Current knowledge on S. intermedius pathogenesis is limited, particularly regarding genomic factors.
- Further research is needed to understand the factors contributing to S. intermedius-associated abscess development.
- This review identifies critical gaps and suggests future research directions for S. intermedius infections.
