Necrotizing Soft Tissue Infections Caused by Morganella morganii: A Case Report and Review of the Literature

<i>Morganella morganii</i> is an unusual opportunistic pathogen often isolated as a cause of nosocomial infections in adults, particularly in wound and urinary tract infections. Herein, we present a case of necrotizing soft tissue infections in the right lower leg to the foot caused by <i>Morganella morganii</i>. A 74-year-old Japanese male with a history of microscopic polyangiitis and chronic kidney disease was referred to our department with severe painful swelling, warmth, and purpura extending from the right lower leg to the foot. An exploratory incision revealed a discharge of a large amount of light yellowish pus, and the superficial fascia and overlying fat tissue were easily dissected using a swab. Surgical debridement was performed. Pus and two sets of blood cultures grew only <i>Morganella morganii</i>. Taken together, necrotizing soft tissue infections caused by <i>Morganella morganii</i> were diagnosed. Based on the results of the bacterial antibiotic susceptibility testing, antibiotic therapy was changed from intravenous meropenem to ciprofloxacin hydrochloride hydrate. Although skin necrosis did not spread after surgical debridement, the patient's general condition gradually deteriorated, and the patient died 14 days after hospitalization. This case is notable as the patient developed necrotizing soft tissue infections caused by <i>Morganella morganii</i>. We also reviewed eight reported cases of necrotizing soft tissue infections caused by <i>Morganella morganii</i>, including our case.