Mixed infection of the lower limb caused by rare bacterial and fungal pathogens in a patient with multiple traumatic injuries

Abstract Objectives: Enterobacter amnigenus and Leclercia adecarboxylata are gram-negative aerobic bacilli of the family Enterobacteriaceae that have been isolated from water and, rarely, from various clinical specimens. Absidia is a filamentous fungus of the class Zygomycetes that is ubiquitous in nature and can cause infection, primarily in compromised hosts. Here we describe a case of mixed infection of the left lower limb caused by E.amnigenus and L.adecarboxylata and subsequent superinfection by Absidia in a patient with severe traumatic injury. Methods: Multiple surgical samples of the wound were collected for microbiological cultures. The identification of bacteria was carried out by standard techniques: isolation on blood agar plates, subsequent biochemical identification and susceptibility testing by an automated method (Vitek 2, bioMérieux, France). The identification of the fungus was carried out after inoculation onto Sabouraud dextrose agar for culture and direct microscopic examination. Case report: A 37-year-old male with multiple traumatic injuries (open fractures of the left distal femur and tibia with bone loss, multiple fractures of the left foot with soft-tissue involvement) following motorcycle accident was admitted to our emergency department after first aid on the road. He was treated with irrigation and debridément, open reduction and internal fixation of the tibia and foot fractures, and external fixation of the femur fracture. Intravenous antibiotics (tobramycin, teicoplanin, metronidazole) were empirically initiated on the basis of a hospital protocol. After 14 days, a below-knee amputation was performed as there was no possibility for limb salvage. Following isolation of two isolates of E.amnigenus and L.adecarboxylata, piperacillin/tazobactam was substituted for tobramycin. After seven days, a novel amputation on a more proximal level was needed for control of stump infection. Following isolation of a strain of the genus Absidia, a 15-day course of liposomal amphotericin B was started, and control of stump infection was finally achieved. At five months from final surgery, no signs of infection are present. Conclusion: E.amnigenus and L.adecarboxylata are multi-susceptible environmental Enterobacteriaceae and Absidia an ubiquitous zygomycete, and all of them are rare agents of infection. Nevertheless, they can cause severe life-threatening infections that require complex and sometimes devastating treatments.