Department of Family Medicine, Queen's University, Kingston, ON, Canada.
Division of General Internal Medicine, University of Toronto, Toronto, ON, Canada.
BMC Infect Dis. 2022 Jul 15;22(1):621. doi: 10.1186/s12879-022-07580-3.
Streptococcus canis is a group G beta-hemolytic Streptococcus species which normally resides on the skin and mucosal surfaces of dogs. Although it rarely causes infection in humans, our case and review of relevant literature demonstrate that this multi-host pathogen may be responsible for metastatic infection. We present an appropriate management strategy in such cases.
A previously healthy 26-year-old male presented to the emergency department with a 2-day history of erythema, pain, and swelling of the left ankle and foot, consistent with acute cellulitis. The patient was initially discharged home with a plan to complete a course of IV cefazolin as an outpatient, but later recalled after two sets of blood cultures grew gram positive cocci. Blood cultures speciated as Streptococcus canis. This was performed by identifying beta hemolytic strep on blood agar, then typed as Lancefield group G, followed by MALDI-TOF which distinguished S. canis. History was unremarkable except for a 2-week history of lower back pain precipitated by a wrestling injury. There was no canine bite or scratch wound, although the patient lives with a dog. CT spine was obtained which demonstrated right piriformis myositis and S1 osteomyelitis. MRI additionally demonstrated right erector spinae myositis, right sacroiliitis, and multiple collections in the right posterior paraspinal soft tissues. Transthoracic echocardiogram did not demonstrate valvular vegetations. The S. canis isolate was pan-susceptible and the patient was ultimately discharged home and completed a 8-week course of IV penicillin G. After completion of therapy, his symptoms, repeat imaging, and biochemical markers suggested resolution of infection on follow-up.
We suggest that management of S. canis bacteremia should involve consideration of screening for metastatic infection and infectious diseases consultation. However, despite its potential for systemic involvement, S. canis is often susceptible to narrow spectrum antibiotics, and may be treated with penicillins.
犬链球菌是一种 G 群β溶血性链球菌，通常存在于狗的皮肤和黏膜表面。尽管它很少在人类中引起感染，但我们的病例和相关文献回顾表明，这种多宿主病原体可能导致转移性感染。我们提出了此类病例的适当治疗策略。
一名 26 岁的既往健康男性因左踝和足部红肿、疼痛和肿胀，出现 2 天的急性蜂窝织炎症状，到急诊科就诊。患者最初被送回家，计划作为门诊患者完成 IV 头孢唑林疗程，但后来在两套血培养中生长出革兰阳性球菌后召回。血培养鉴定为犬链球菌。这是通过在血琼脂上鉴定β溶血性链球菌来完成的，然后鉴定为兰斯菲尔德组 G，然后通过 MALDI-TOF 鉴定为犬链球菌。病史无特殊，除了 2 周前因摔跤受伤导致下腰痛外。患者没有狗咬伤或抓伤伤口，但与一只狗同住。进行 CT 脊柱检查，结果显示右侧梨状肌肌炎和 S1 骨髓炎。MRI 还显示右侧竖脊肌肌炎、右侧骶髂关节炎和右侧后脊柱旁软组织内多个积液。经胸超声心动图未显示瓣膜赘生物。犬链球菌分离株对多种抗生素均敏感，最终患者出院并完成 8 周的 IV 青霉素 G 治疗。治疗完成后，他的症状、重复影像学和生化标志物提示在随访中感染得到了缓解。
我们建议犬链球菌菌血症的治疗应考虑进行转移性感染的筛查和传染病咨询。然而，尽管犬链球菌具有全身感染的潜力，但它通常对窄谱抗生素敏感，可用青霉素类药物治疗。
