Fournier's Gangrene with Edwardsiella tarda: A Gas Production Case by Bacterial Synergism with Streptococcus anginosus

Edwardsiella tarda is an anaerobe associated with freshwater and marine life. Necrotizing soft tissue infection caused by E. tarda is rare, but its mortality rate is extremely high (61.1%). We experienced a survival case of Fournier’s gangrene with E. tarda. A key clinical feature for the diagnosis was gas production; however, there have been no previous reports of such a phenomenon in relation to E. tarda. A 64-year-old man was admitted with a 3-day history of a high fever. His medical history, which included paraplegia from the Th6 level down, made the focus of inflammation at the perineum difficult to notice. Whole-body CT revealed subcutaneous gas from the posterior scrotum around the entire circumference of the anus. During emergency surgery, an incision at the posterior scrotum revealed extensive fascia necrosis, and E. tarda and Streptococcus anginosus were identified. We speculated the gas production in this case to be the product of a mixed infection of aerobes and anaerobes, which acted synergistically to induce bacterial growth. Timely surgical debridement and antibiotic therapy led to the patient’s survival.