Metagenomic next-generation sequencing confirmed a case of sporadic human infection with Streptococcus suis in an urban area

Abstract

Introduction: Streptococcus suis (S. suis) disease is a zoonotic infection caused by invasive S. suis and can lead to meningitis, septic shock, arthritis, and endocarditis. Early treatment is the key to reducing mortality. However, clinical manifestations of most cases are atypical, severely limiting rapid diagnosis and treatment.

Case report: Here, we report a 74-year-old female patient diagnosed with S. suis infection. The main symptoms were hearing loss, lumbago, and scattered ecchymosis of the lower extremities and trunk. Blood non-specific infection indexes were significantly increased and platelets were significantly decreased; however, no pathogens were obtained from routine blood culture. Finally, the S. suis infection was confirmed by metagenomic next-generation sequencing (mNGS) of blood and cerebrospinal fluid. After antibiotic treatment, the limb and trunk scattered ecchymosis and lumbago symptoms were significantly relieved, but the hearing did not recover.

Conclusions: Human infection with S. suis is rare in central cities, and it is easy to misdiagnose, especially in cases with atypical early symptoms. mNGS technology, combined with clinical observation, is helpful to clarify the direction of diagnosis and treatment, which is conducive to patient recovery.

Keywords: Streptococcus suis; mNGS; meningitis; metagenome; zoonosis.