Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Case Reports
. 2025 Aug;53(8):3000605251363093.
doi: 10.1177/03000605251363093. Epub 2025 Aug 11.

Intracranial infection caused by Streptococcus intermedius and torque teno virus: A case report

Affiliations
Case Reports

Intracranial infection caused by Streptococcus intermedius and torque teno virus: A case report

Huiru Zhou et al. J Int Med Res. 2025 Aug.

Abstract

Infectious diseases of the central nervous system are commonly characterized by delayed diagnosis due to the diversity of pathogens, subtle clinical symptoms, and nonspecific early imaging findings. These diseases are associated with high morbidity and mortality rates. This report presents a rare case of intracranial mixed infection caused by co-infection with Streptococcus intermedius and torque teno virus. This report involves a retrospective analysis of the clinical features, laboratory investigations, and treatment outcomes of intracranial infection, along with diagnostic and therapeutic strategies for such rare mixed infections. The results demonstrated that cerebrospinal fluid metagenomic sequencing plays a crucial role in the microbiological diagnosis of intracranial mixed infection. This report describes the case of a man in his late 30s in whom Streptococcus intermedius and torque teno virus were simultaneously detected in the cerebrospinal fluid. The infection exhibited rapid progression and high aggressiveness, significantly increasing the risk of mortality. This study emphasizes the invasive clinical course of this infection. Despite active and intensive treatment, the patient ultimately succumbed to the illness. It remains unclear whether torque teno virus infection plays a direct role in the pathogenesis or contributes to the severity of the intracranial mixed infection. This case highlights the importance of multidisciplinary collaboration in the diagnosis and treatment of complex intracranial infections, providing clinicians with a novel approach for the differential diagnosis of mixed infections and increasing the clinical awareness and understanding of such rare mixed infections involving the central nervous system.

Keywords: Intracranial central nervous system; Streptococcus intermedius; case report; infection; mixed infection; torque teno virus.

PubMed Disclaimer

Conflict of interest statement

Declaration of conflicting interestsThe authors declare no potential conflicts of interest with respect to the research, authorship, and publication of this article.

Figures

Figure 1.
Figure 1.
Head computed tomography (on June 26 2024) showing a softening lesion in the right frontal lobe, as indicated by the red arrow.
Figure 2.
Figure 2.
High-confidence pathogen genome coverage map. A represents the total genome base pairs of Streptococcus intermedius, and B represents the total genome base pairs of torque teno virus type 22.

Similar articles

References

    1. Issa E, Salloum T, Tokajian S. From normal flora to brain abscesses: a review of Streptococcus intermedius. Front Microbiol 2020; 11: 826–838. - PMC - PubMed
    1. Nedrebø T, Skrede S. Necrotizing soft tissue infections: case reports, from the clinician’s perspectives. In: Bruun T, Madsen MB, Oppegaard O. (eds) Necrotizing Soft Tissue Infections: Clinical and Pathogenic Aspects. Cham: Springer, 2020, pp. 21–37. - PubMed
    1. Ishihara Y, Kaneshiro S, Ikehara Y. Giant liver abscess with Streptococcus intermedius bacteremia treated without any drainage. IDCases 2023; 31: e01662. - PMC - PubMed
    1. Gil E, Hatcher J, Saram S, et al. Streptococcus intermedius: an underestimated pathogen in brain infection? Future Microbiol 2025; 20: 163–177. - PMC - PubMed
    1. Nishizawa T, Okamoto H, Konishi K, et al. A novel DNA virus (TTV) associated with elevated transaminase levels in posttransfusion hepatitis of unknown etiology. Biochem Biophys Res Commun 1997; 241: 92–97. - PubMed

Publication types

MeSH terms

LinkOut - more resources