Erysipelothrix rhusiopathiae-associated bloodstream infection in a patient with systemic lupus erythematosus: a case report and literature review

Introduction. Systemic human infections caused by Erysipelothrix rhusiopathiae have been increasingly reported especially within immunocompromised hosts and those with significant occupational exposure to livestock and aquatic animals. We report a case of E. rhusiopathiae bacteraemia in a patient with systemic lupus erythematosus (SLE) and present a literature review on clinical outcomes and microbiologic diagnosis for this organism.

Case presentation. A 43-year-old female patient was reporting a 1-month history of intermittent fevers. She recently increased her immunosuppression medication for her underlying SLE on the advice of her rheumatologist. The patient sustained a finger laceration from butchering cattle meat 2 weeks after the onset of her initial symptoms, with worsening index finger swelling and increased febrile episodes. Two weeks post-injury, multiple blood cultures were drawn, and each isolated Gram-positive bacilli. Given her recurrent intermittent fevers, there was a concern for ongoing infection, and therefore, intravenous vancomycin was started with prompt referral to an outpatient parenteral antibiotic therapy clinic. The Gram-positive bacillus was confirmed as E. rhusiopathiae via matrix-assisted laser desorption/ionization-time of flight analysis. Given intrinsic resistance to vancomycin, vancomycin was switched to intravenous ceftriaxone as targeted antimicrobial therapy for 2 weeks. Reassuringly, there was no echocardiographic evidence of infective endocarditis, warranting the prolonged treatment course. Post-treatment, she remained symptom-free with the resolution of joint symptoms and fevers.

Conclusion. Our report illustrates a case of E. rhusiopathiae bacteraemia from an immunodeficient host, with prompt microbiologic diagnosis and intervention with appropriate antimicrobial coverage. Literature reflects the rarity of this infection, predilections to specific susceptible hosts and the importance of raising awareness of zoonotic infections.