Severe Shewanella Cellulitis Following Saltwater Exposure in an Elderly Patient

Shewanella algae is an opportunistic Gram-negative bacillus primarily found in marine environments. It can cause a range of infections in humans, from superficial soft tissue infections to more severe conditions like bacteremia, otitis, and hepatobiliary infections. While infections are rare, they can be significant, leading to complications such as sepsis and tissue necrosis. We present the case of severe cellulitis caused by Shewanella in an 88-year-old patient with multiple comorbidities. Following a blue crab pinch and consequent saltwater exposure, the patient developed severe cellulitis, sepsis, delirium, and atrial fibrillation. Despite these complications and the patient's age, a prompt diagnosis and a combination of antibiotic treatments led to a successful recovery. This case is notable for its illustration of the potential severity and diverse clinical presentation of Shewanella infections. It highlights the importance of considering Shewanella as a possible pathogen in cases of saltwater exposure and teaches management in elderly, multi-morbid patients.