Streptococcus suis is one of the most common zoonotic pathogens, in humans and can cause meningitis, endocarditis, arthritis and sepsis. Human cases of Streptococcus suis infection have been reported worldwide, and most of those cases occurred in Asia. Hearing loss is the most common sequela of Streptococcus suis meningitis. Streptococcus suis infection complicated with acute cerebral infarction has rarely been reported. Therefore, to provide a reference for this disease, we reported a case of acute multiple brain infarctions associated with Streptococcus suis infection. In our report, a 69yearold male patient had Streptococcus suis meningitis and sepsis, which were associated with multiple acute cerebral infarctions in the pons and bilateral frontotemporal parietal occipital lobes. After treatment, the patient exhibited cognitive impairment, dyspraxia and irritability. There are limited case reports of cerebral infarction associated with Streptococcus suis infection, and further research is needed to determine the best treatment method.
Keywords: Streptococcus suis; Cerebral infarction; Cognitive impairment; Meningitis; Sepsis
Streptococcus suis is one of the most common zoonotic pathogens in humans and can cause meningitis, endocarditis, arthritis and sepsis after direct contact with pigs or pork [[
A 69-year-old male patient was admitted to the hospital on 22 September 2022 due to fever lasting for 4 h and coma for 2.5 h. At midnight on 22nd September the patient developed vomiting and loss of consciousness. Then, the spouse called 120 and took him to the emergency department of our hospital. The patient was soon admitted to our Department of Neurology due to an unexplained coma. The patient was a retired corporate executive, and his job was not associated with pigs or pork. The patient cut his left hand with a kitchen knife before onset, and this could have led to an infection. The spouse denied that the patient had any history of hypertension, heart disease, or diabetes. The spouse denied that the patient had a history of substance abuse. Physical examination after admission revealed a body temperature of 39.5℃, pulse rate of 142 beats/minute, respiratory rate of 45 breaths/minute, and blood pressure of 188/102 mmHg. His Glasgow coma scale score was 6 points. There was a 0.5 cm wound on the left index finger. His pupils were equal in size, and his pupillary reflexes were intact. There was no signs of meningeal irritation. The muscle strength of the right upper limb was roughly measured at grade 3. The right lower limb and left limb could not be lifted and could only move on the bed, so the muscle strength of the right lower limb and left limb were roughly measured at grade 2. The extremity tendon reflexes of the patient were normal, and he had a negative bilateral Babinski sign. His National Institutes of Health Stroke Scale (NIHSS) score was 24 points. Because the patient had shortness of breath, the patient was transferred to the intensive care unit (ICU) a few hours after admission. He was mechanically ventilated and underwent lumbar puncture.
His routine blood test results were as follows: white blood cell count, 16.27 × 10
Table 1 Laboratory data
Test Result Normal range of value White blood cell count 16.27 × 109/L (3.5-9.5) × 109/L Neutrophil ratio 90.8% (40-75)% Neutrophil count 14.77 × 109/L (1.8-6.3) × 109/L Hemoglobin 141 g/L (130-175) g/L Platelet count 128 × 109/L (125-350) × 109/L Creatinine 107 µmol/L (59-104) µmol/L Serum procalcitonin 32 ng/mL (0-0.05) ng/mL Lactic acid 10.2 mmol/L (0.5-1.7) mmol/L Glucose 21.3 mmol/L (3.9-6.1) mmol/L Cholesterol 5.24 mmol/L (3.6-5.2) mmol/L Triglyceride 2.59 mmol/L (0.45-1.81) mmol/L Low-density lipoprotein 2.82 mmol/L (2.7-3.1) mmol/L AST 22 U/L (15-40) U/L ALT 24 U/L (9-50) U/L Blood culture S. Suis serotype 2 - Glucose 1.4 mmol/L (2.5-4.5) mmol/L Protein 1.46 g/L (0-0.45) g/L Chlorid 101 mmol/L (120-132) mmol/L White blood cell count 4400 × 106/L (0-5) × 106/L Pressure 330 mmH2O (80-180) mmH2O CSF culture S. Suis serotype 2 -
AST, Aspartateaminotransferase; ALT, Alanine aminotransferase; S. Suis, Streptococcus suis; CSF, Cerebrospinal fluid
Brain computed tomography (CT) revealed lacunar cerebral infarction of the pons, left basal ganglia, and bilateral corona radiata. Computer tomography angiography (CTA) revealed severe stenosis in the M2 segment of the left middle cerebral artery and the P2 segment of the posterior cerebral artery; moreover, moderate stenosis was detected in the basilar artery, the A3 segment of the left anterior cerebral artery and the M2 segment of the right middle cerebral artery. The P2 segment of the posterior cerebral artery and the basilar artery are shown in Fig. 1.
Graph: Fig. 1 Imaging examination of the patient. Diffusion-weighted magnetic resonance imaging of the brain revealed high signals in the pons and bilateral frontotemporal parietal occipital lobes (A, B, C). Computed tomography angiography showed severe stenosis in the P2 segment of the posterior cerebral artery and moderate stenosis in the basilar artery (D)
At first, the patient was empirically given anti-infection treatment with 2 g of meropenem q8h. To reduce intracranial pressure and inflammation, dexamethasone therapy(20 mg qd) were administered. At the same time, the patient was given antiplatelet treatment with clopidogrel, hypolipidemic treatment with atorvastatin, antihypertensive treatment with amlodipine besylate, sugars were controlled with insulin, and cerebral circulation improvement with butyphthalide. For antishock treatment, blood volume was supplemented and norepinephrine was implemented. A clear diagnosis of S. suis meningitis was obtained on 23 September, and the antibiotic treatment was changed to ceftriaxone 3 g q24h combined with penicillin 4.8 million units q6h from 23 September to 26 September. After 5 days of treatment, the patient's condition was stable, but he was still unconscious. Considering the delayed appearance of cerebral infarction lesions on CT, brain magnetic resonance imaging was performed, which revealed multiple acute cerebral infarctions in the pons and bilateral frontotemporal parietal occipital lobes (Fig. 1). After being weaned off the ventilator and after his state of shock improved, the patient was transferred to the Department of Neurology on 4 October. His temperature decreased to normal from 17 October. Antibiotics were discontinued on 24 October. After treatment, the patient gradually became conscious but showed symptoms of irritability, aggression, and insomnia, and was verbally abusive. He could execute simple commands, such as raising his hands and closing his eyes. He always answered questions wrong and often talked to himself. Olanzapine and alprazolam were initiated to alleviate the symptoms. The patient was transferred to the rehabilitation department on 11 November, and he was discharged on 2 December. At the time of discharge, the patient exhibited cognitive impairment and irritability. The muscle strength of the limbs was grade 4. Due to his cognitive impairment, the patient's hearing in both ears and Mini-Mental State Examination (MMSE) score could not be checked. His NIHSS score was 4 points, and his modified Rankin scale (mRS) score was 3 points.
Streptococcus suis, a heterogeneous Gram-positive bacterium, can cause zoonotic diseases. People who are occupationally exposed to pigs and/or pork are the main risk groups. Contact with pigs or pork products and consuming raw pig meat or blood are important routes of infection. Many reported human cases of S. suis infection have been reported worldwide, with approximately 83.6% occurring in Vietnam, Thailand, and China. This has created serious health problems for China [[
The most common sequela of patients who have recovered from purulent meningitis caused by S. suis infection is hearing loss. Up to one-half of patients indicate hearing loss can occur at presentation or a few days later.
The use of dexamethasone may improve hearing impairment [[
In this case, after considering that the patient had meningitis and sepsis, combination therapy with ceftriaxone and penicillin was given. Streptococcus suis is generally susceptible to a variety of antibiotics, such as penicillin, ampicillin, amoxicillin, flucloxacillin, cephalosporin and ceftriaxone [[
Ischemic stroke is a common complication of bacterial meningitis and occurs in 10–29% of cases [[
In the present study, we reported a case of cerebral infarction associated with S. suis infection. For anti-infection treatment, meropenem, penicillin, and ceftriaxone were used and the treatment lasted from September 22 to October 24. After treatment, the patient exhibited cognitive impairment, dyspraxia and irritability. There are limited case reports of cerebral infarction associated with S. suis infection, and further research is needed to determine the best treatment method.
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Wenxin Wei (First Author): Investigation, Project administration, Writing - Original Draft; Zhenhu Qiao: Investigation, Writing - Original Draft; Donghua Qin: Supervision, Investigation; Yu Lan (Corresponding Author): Supervision, Writing - Review & Editing.
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Data are available on request from the corresponding author upon reasonable request.
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of Committee of Medical Ethics of the Minzu Hospital Affiliated of Guangxi Medical University and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. This article does not contain any studies with animals performed by any of the authors. Informed consent was obtained from all individual participants included in the study.
Written informed consent was obtained from the patient for the publication of this case report and any accompanying images.
The authors declare no competing interests.
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By Wenxin Wei; Zhenhu Qiao; Donghua Qin and Yu Lan
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