SHEWANELLA ALGAE: A RARE CAUSE OF SEPTICEMIA

Abstract

SESSION TITLE: Medical Student/Resident Critical Care Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Shewanella algae, a motile gram-negative bacillus, is one of the four species of Shewanella genus known to cause human infections (1). Shewanella, with its broad spectrum of clinical presentations, is becoming an emerging cause of opportunistic infections. We present a first case of death in an immunocompromised patient with Shewanella algae septicemia in the United States (US) with no known exposure to marine environments or recent seafood consumption. CASE PRESENTATION: This is a 65-year-old male with past medical history of AIDS with CD4 count of 30 cells/mm3, multiple serositis-ascites, chronic bilateral pleural effusion and recurrent pericardial effusion, liver cirrhosis, penile intraepithelial neoplasia, and chronic hepatitis C infection who presented with a three-day history of generalized malaise, fever, and productive cough with yellow sputum. He was afebrile, hypotensive and dyspneic, with decreased bilateral breath sounds which quickly decompensated into acute hypoxic respiratory failure, needing intubation. Labs notable for elevated lactate, white count and creatinine. He was admitted to the critical care unit for management of septic shock, started on vasopressors and vancomycin, piperacillin-tazobactam, and trimethoprim-sulfamethoxazole. Chest x-ray was suspicious for heart failure, with later echocardiogram confirming left ventricular systolic heart dysfunction with markedly decreased ejection fraction 10-15% and diffuse hypokinetic wall motion. Patient developed hyponatremia, worsening lactic acidosis, generalized anasarca, and oliguria, prompting start of Continuous Veno-Venous Hemofiltration. Blood cultures grew Shewanella Algae and piperacillin-tazobactam was switched to meropenem. Repeat blood cultures 10 days later turned negative. Unfortunately, patient's condition worsened, with bradycardia and hypotension despite multiple vasopressors progressed into pulseless electrical activity and death. DISCUSSION: Shewanella algae primarily causes opportunistic infection in people with exposed skin ulcers who have been exposed to marine environment and patients with hepatobiliary disorders who ingest raw seafood. Literature review shows that this virulent pathogen has also been implicated in invasive infections like bacteremia, infective arthritis and osteomyelitis especially in the elderly and immunocompromised patients (2). Most cases of invasive infections have been reported outside the US, with only about a total of less than 10 cases reported in mainland US. CONCLUSIONS: Given the possible grave consequence of Shewanella infections, it is important to include it in the differential diagnosis of invasive infections with or without skin ulceration, not only following reported exposure to marine environments, but also in all immunocompromised patients. Reference #1: 1.Holt HM, Gahrn-Hansen B, Bruun B. Shewanella algae and Shewanella putrefaciens: clinical and microbiological characteristics. Clinical Microbiology and Infection. 2005;11(5):347–52. Reference #2: 2.Torri A, Bertini S, Schiavone P, et al. Shewanella algae infection in Italy: report of 3 years' evaluation along the coast of the northern Adriatic Sea. New Microbes New Infect. 2018;23:39–43. DISCLOSURES: No relevant relationships by Giovanna Bettoli, source=Web Response No relevant relationships by Abidemi Idowu, source=Web Response No relevant relationships by MARIA MARITATO, source=Web Response No relevant relationships by Alice Yau, source=Web Response