Case Presentation: We present the case of a 46-year-old male from Guyana with a history of type-2 diabetes mellitus who presented with cellulitis of his left foot.  He is a rice farmer working in brakish water environments and had sustained a laceration on the left medial surface of his foot. Five days prior to admission, he noticed some erythema and swelling of the medial aspect of his left first metatarsal that progressively spread up his left leg.  He experienced fever and chills, and presented after noticing purulent drainage from his wound. On admission, he was afebrile. Laboratory testing was notable for a white blood cell count of 26.8K/uL, creatinine of 2.13mg/dL, and lactate of 4.6mmoL/L. An X-ray of the left foot showed soft tissue edema and subcutaneous gas on the dorsal and lateral soft tissues. He was empirically treated with vancomycin and piperacillin/tazobactam, and subsequently underwent surgical debridement for acute necrotizing inflammation. Intraoperative cultures grew numerous Edwardsiella tarda and Staphylococcus aureus however his blood cultures remained negative. This Edwardsiella tardaisolate was sensitive to all antibiotics tested and the patient was treated with an intravenous course of ceftriaxone for 14 days with rapid improvement. He had an uncomplicated postoperative course.

Discussion: Edwardsiella tarda is an uncommon enteric pathogen that is usually found in fresh or brackish water environments, and occasionally in human feces.  It is a member of the Enterobacteriaceae family, and commonly spread by contact with marine life or by eating raw shrimp or fish. Recent reports of extraintestinal disease have broadened our understanding of this conundrum. Gastroenteritis with Edwarsiella tarda isolated in stool cultures is the most common manifestation (>80% of cases), followed by wound infection, osteomyelitis, endocarditis, and intra-abdominal infection. Edwardsiella tarda has been associated with two types of wound infections, those involving an abscess formation, and those associated with penetrating injuries to exposed epithelial surfaces. Interestingly, abscess formation has been associated with liver disease (i.e. alcoholic cirrhosis, hepatosplenomegaly) in many case reports. Predisposing factors include diabetes mellitus and C1 esterase deficiency. Open wound infections are often polymicrobial, and infection severity ranges from mild cellulitis to limb myonecrosis. Edwardsiella tarda wound infection may lead to septicemia, which has a high mortality rate of 50%. Most isolates are susceptible to common antibiotics targeted at gram-negative bacteria such as aminoglycosides, cephalosporins, beta-lactams and fluoroquinolones. Necrotizing soft tissue infection requires early surgical debridement to limit the proximal spread of the disease.

Conclusions: Human infection with Edwardsiella tarda is uncommon and can manifest as an acute necrotizing wound infection, which, if left untreated, can be fatal. Thus, early diagnostic and therapeutic measures are important.