Document Type

Conference Proceeding

Publication Date

5-2-2025

Abstract

Introduction: Shewanella algae is a gram-negative, facultatively anaerobic bacterium most commonly found in marine environments. It is an emerging human pathogen, most often associated with hepatobiliary and skin and soft tissue infections (SSTI) following water exposure. Known risk factors for infection include those participating in recreational water activities, flood victims, and those with underlying liver disease, immunosuppression, or IV drug use. This case involves a 70-year-old male who was involved in a motor vehicle accident in 2008 leading to multiple orthopedic surgeries complicated by recurrent prosthesis infections who presented with concern for sepsis. Case Description: Patient is a 70-year-old male with a past medical history of chronic atrial fibrillation, nonischemic cardiomyopathy, type 2 diabetes mellitus, and multiple left hip surgeries with recurrent prosthesis infections who presented to the hospital with left hip pain, fevers, and fatigue. About 3 weeks prior to admission, the patient had a fall resulting in a periprosthetic fracture of his proximal femur requiring I&D and subsequent left hip disarticulation due to extensive scar tissue. At that time, he was discharged to subacute rehab on a 6-week course of IV cefazolin due to rare Staphylococcus capitis isolated from his left hip synovial fluid. In the ED the patient was hypotensive, tachycardic, and febrile. Labs were remarkable for leukocytosis (33.9) and anemia (9.6). CT abdomen and pelvis showed a 6.4 x 6.4 x 5.8 cm complex fluid collection in the left hip. The patient was evaluated by the medical ICU but didn’t require admission as his blood pressure was fluid responsive and did not require vasopressor support. He was admitted to the medicine service and started on IV vancomycin and piperacillin-tazobactam. Orthopedic surgery was consulted and the patient underwent a left hip I&D on hospital day #2. Intra-operative wound cultures grew rare Shewanella algae and few Enterobacter cloacae complex, while hip fluid cultures grew only Shewanella algae. Blood cultures collected in the ED remained negative. Infectious disease was consulted and transitioned the patient to IV meropenem based on the intra-operative culture results. His hemoglobin slowly down-trended, initially thought to be related to hemodilution from aggressive fluid resuscitation as well as his recent surgery – he ultimately required 1 unit of pRBC on hospital day #5. He had a wound vac placed on hospital day #12 due to ongoing serosanguinous drainage from his stump. His hospitalization was further complicated by a COVID-19 infection. Overall, the patient responded well to IV antibiotics and was ultimately discharged to inpatient rehabilitation. Based on ID recommendations, the patient completed a 6-week course of IV meropenem, starting from the date of his surgery. Discussion: This case presents a unique scenario given the patient’s lack of exposure to an aquatic environment and typical risk factors. This highlights the need for consideration of Shewanella algae as a potential pathogen in patients with prosthetic devices and significant comorbidities, even in those without marine exposure. It reinforces the importance of prompt and thorough diagnostic evaluation, appropriate antimicrobial adjustments, and a multidisciplinary approach in managing rare and complex infections.

Comments

American College of Physicians Michigan Chapter and Society of Hospital Medicine Michigan Chapter Resident and Medical Student Day, May 2, 2025, Troy, MI

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