Ulcere delle gambe a tipo ectima gangrenoso da Morganella morganii, inquinante biotico dell’ambiente

Morganella morganii (Mm) is a Gram-negative bacillus which belongs to the Enterobacteriaceae family. It is found in the environment (water and soil) and in the bowel of humans, mammals, and reptiles as part of the normal flora. Despite its wide distribution, Mm is an uncommon cause of infections in humans. The lesions are mainly located in the skin, soft tissues, and urinary tract, but severe septicemias are possible especially in immunosuppressed subjects. Post-traumatic skin lesions are mostly seen in immunocompetent subjects, whereas multiple in immunosuppressed subjects; in this case there is often concomitant septicemia. In addition to abscess-type skin lesions, Mm can cause ecthyma gangrenosum-like eruption. An immunocompetent 69-year-old woman affected by multiple ecthyma gangrenosum-like ulcers of the legs is reported. Histopathologically there were epidermic necrosis and dermal inflammatory infiltrate with neutrophils, eosinophils, and histiocytes; there was no evidence of bacilli in dermal vessels. Anamnestic, clinical, haematochemical and structural findings concurred to diagnose ecthyma gangrenosum-like eruption caused by Mm. Skin lesions quickly healed whit combined antibiotic therapy (ceftriaxone and ciprofloxacin). No relapses at 5 months follow up were observed.