Streptococcus intermedius: an underestimated pathogen in brain infection?

Area of Science:

• Microbiology
• Infectious Diseases
• Neuroscience

Background:

• Streptococcus intermedius is an oral commensal within the Streptococcus anginosus group (SAG).
• S. intermedius causes periodontitis and invasive pyogenic infections, notably intracranial suppuration (ICS).
• ICS presents as brain abscesses or subdural/extradural empyema, requiring neurosurgery and prolonged antibiotics.

Purpose of the Study:

• To evaluate current knowledge on the clinical features and pathogenesis of S. intermedius-associated ICS.
• To explore potential reasons for the increasing incidence of these infections.
• To highlight the need for further research into S. intermedius virulence factors and molecular epidemiology.

Main Methods:

• Literature review and synthesis of existing data on S. intermedius ICS.
• Analysis of clinical presentations, treatment outcomes, and epidemiological trends.
• Hypothetical exploration of pathogenic mechanisms and host-pathogen interactions.

Main Results:

• S. intermedius exhibits higher mortality and a predilection for intracranial infections compared to other SAG species.
• The incidence of ICS due to S. intermedius is rising, with a growing proportion attributed to SAG species.
• Mechanisms underlying S. intermedius neurotropism and virulence remain poorly understood.

Conclusions:

• S. intermedius poses a significant threat due to its propensity for causing severe ICS.
• Further research into S. intermedius pathogenesis, virulence factors, and genomic data is essential.
• Understanding these factors may help mitigate the increasing burden of these infections.