Supplementary Material for: A Rare Case of Capnocytophaga canimorsus Meningitis in an immunocompetent Patient: A successful Outcome with a Short course of Antibiotics

Introduction: Capnocytophaga canimorsus is a gram-negative bacterium found in the oral flora of dogs and cats, transmitted to humans through bites, licks, or scratches. Infections can lead to severe manifestations, including meningitis, particularly in immunocompromised individuals.
Case presentation: A 46-year old immunocompetent man presented with somnolence, headache, and fever after being licked by his dog. Neurological examination revealed signs of meningeal irritation, and cerebrospinal fluid analysis showed an elevated white cell count and protein levels consistent with bacterial meningitis. Treatment followed Dutch guidelines with amoxicillin, ceftriaxone, and dexamethasone, resulting in rapid clinical improvement. Microbiological confirmation of C. canimorsus followed later. The patient was treated with antibiotics for the duration of one week, and remained symptom-free after being discharged.
Conclusion: C. canimorsus meningitis, although rare, poses diagnostic challenges due to its variable presentation and slow growth in culture. Empirical therapy guided by susceptibility testing contributes to favorable outcomes. This case underscores the importance of considering a C. canimorsus infection in patients with animal exposure and of taking diagnostic findings, precedent, and clinical response into account when determining the treatment duration.

引言：犬咬二氧化碳嗜纤维菌（Capnocytophaga canimorsus）是一种定植于猫狗口腔菌群的革兰氏阴性菌，可通过叮咬、舔舐或抓伤传播给人类。该菌感染可引发严重临床表现，以脑膜炎最为典型，免疫功能受损人群为高发群体。
病例报告：一名46岁免疫功能正常的男性在被其宠物狗舔舐后，出现嗜睡、头痛与发热症状。神经系统检查可见脑膜刺激征，脑脊液分析显示白细胞计数及蛋白水平升高，符合细菌性脑膜炎的实验室特征。治疗方案遵循荷兰临床指南，联合使用阿莫西林、头孢曲松与地塞米松，患者临床症状迅速得到改善。后续经微生物学检测证实为C. canimorsus感染。患者接受为期一周的抗生素治疗，出院后未再出现相关症状，随访无复发。
结论：犬咬二氧化碳嗜纤维菌脑膜炎虽属罕见病症，但因其临床表现多样且体外培养生长缓慢，常给临床诊断带来挑战。基于药敏试验的经验性抗菌治疗有助于获得良好预后。本病例提示，对于有动物接触史的患者，需将犬咬二氧化碳嗜纤维菌感染纳入鉴别诊断范畴；同时在确定抗菌治疗疗程时，应综合考量诊断结果、既往临床参考与临床应答情况。