# Streptococcus suis meningitis in an elderly man: a case report

## TL;DR

An elderly man developed Streptococcus suis meningitis and was successfully treated with vancomycin, including an intrathecal injection, after initial treatments failed.

## Contribution

The case highlights the effectiveness of vancomycin and intrathecal administration for treating drug-resistant Streptococcus suis meningitis.

## Key findings

- Vancomycin treatment, including intrathecal injection, improved the patient's condition effectively.
- Metagenomic Capture sequencing helped confirm the diagnosis by increasing pathogen detection accuracy.
- The patient's recovery suggests a potential treatment approach for drug-resistant central nervous system infections.

## Abstract

Streptococcus suis is a zoonotic pathogen that resides in pigs. It can be transmitted to humans through several routes, including contact with sick or carrier pigs via broken skin or mucous membranes and consumption of undercooked pork products. Streptococcus suis often causes severe clinical symptoms such as meningitis, sepsis, and shock.

A 66-years-old male butcher was admitted to the hospital with a sudden high fever and disturbance of consciousness, and he remained in a state of persistent restlessness. The neurological examination findings were as follows: he was poorly cooperative with the examinations of higher cortical functions and cranial nerves, uncooperative with the examination of limb muscle strength, and unable to cooperate with the examinations of sensation and ataxia. He presented with nuchal rigidity, with a distance of four finger breadths between the chin and chest, and Kernig’s sign was positive. The patient was diagnosed with Streptococcus suis meningitis based on the results of Metagenomic Capture sequencing, cerebrospinal fluid culture, and blood culture. Considering the patient’s critical condition, he had received empirical treatment with cephalosporin in the previous hospital, but the therapeutic effect was not satisfactory. Moreover, in this region, there is a phenomenon of decreased sensitivity in Streptococcus pneumoniae to penicillin and third-generation cephalosporins. Therefore, the patient received antibiotic treatment with vancomycin (1 g) intravenously every 12 h. Concurrently, he was administered mannitol to reduce intracranial pressure and ulinastatin for anti-inflammatory effects and immune enhancement. Subsequently, vancomycin 20 mg was administered by intrathecal injection. The patient’s condition improved, and he was discharged from the hospital. There was no special discomfort during follow-up.

This case report describes the diagnosis and treatment process of Streptococcus suis meningitis. It proposes an antibiotic treatment plan centered on vancomycin. Intrathecal injection of antibiotics may provide an effective treatment option for severe patients and offer a treatment choice for drug-resistant bacterial infections in the central nervous system. It was also pointed out that Metagenomic Capture sequencing can reduce host gene interference and increase the detection rate of pathogens. This case aims to enhance clinicians’ understanding of the disease and provide a reference for early identification and standardized treatment.