Case Presentation: A 74 year old male with prostate cancer with spinal and epidural metastases and recently treated pneumonia was transferred to our hospital for initiation of palliative radiation. His hospital course was complicated by acute kidney injury and atrial fibrillation that delayed initiation of radiation. During the course of his treatment he developed worsening abdominal pain and distention associated with watery diarrhea and hypotension requiring vasopressors. Though blood cultures remained negative, serology revealed new leukocytosis, and abdominal radiography showed gaseous distention of the stomach with multiple dilated bowel loops. Stool studies were positive for Clostriudium difficile, and he was started on oral vancomycin. Additionally, chest radiography revealed bilateral interstitial opacities, and he was started on intravenous (IV) Vancomycin and Piperacillin-Tazobactam. Four days after initiation of antibiotics, he developed new fevers with maximal temperature of 102 °F and remained pressor-dependent. Repeat blood cultures grew Leuconostoc citreum, Weisella confusa, and Staphylococcus epidermididis. IV Vancomycin and Piperacillin-Tazobactam were discontinued, and IV Ceftriaxone was initiated. Despite this, he complained of worsening abdominal pain, and Computed Tomography (CT) imaging of the abdomen revealed pneumoperitoneum concerning for bowel perforation. He underwent emergent exploratory laparotomy with subtotal colectomy with end ileostomy, with intra-operative findings of a dilated cecum with punctate areas of perforation. Post-operatively, he was continued on oral and rectal Vancomycin, with IV Piperacillin-Tazobactam. Though he had decreasing pressor requirements post-procedurally, he was unable to ventilate adequately post-extubation. Given his poor prognosis, he was placed on comfort measures and he died on his 24th hospital day.

Discussion: The Leuconostoc spp. and Weisella spp. are vancomycin-resistant gram-positive cocco-bacilli. Bacteremia from these organisms is rare and usually develops in immunocompromised hosts. To date, there has been no report of Leuconostoc citreum bacteremia. Microbiologic diagnosis can be difficult, occasionally leading to misidentification as Enterococcus species or Streptococcus species. Additionally, no standardized guidelines for interpretation of antibiotic susceptibility are available, making treatment decisions difficult. Further challenges arise in managing antibiotic therapy in patients with complications from previous antibiotic use, as in this case of severe C. difficile colitis.

Conclusions: This is the first case of Leuconostoc citreum bacteremia, presenting in an immunosuppressed patient with metastatic prostate cancer and severe C. difficile colitis. Challenges to diagnosis and selection of appropriate antibiotic treatment include its rarity and lack of established guidelines.