Intracranial infection caused by <i>Streptococcus intermedius</i> and torque teno virus: A case report

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 <i>Streptococcus intermedius</i> 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 <i>Streptococcus intermedius</i> 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.