Case Report: Bacteremic respiratory tularemia causing refractory ARDS requiring VV-ECMO

BackgroundRespiratory tularemia is a rare but potentially serious manifestation of Francisella tularensis infection. We report a rare case of bacteremic respiratory tularemia complicated by refractory acute respiratory distress syndrome (ARDS) requiring veno-venous extracorporeal membrane oxygenation (VV-ECMO), highlighting the diagnostic challenges and therapeutic implications of this uncommon presentation.Case presentationA 78-year-old man developed severe pneumonia following river water aspiration after a bicycle accident. After transient initial improvement, he experienced progressive respiratory deterioration despite broad-spectrum antimicrobial treatment, ultimately developing refractory ARDS requiring invasive mechanical ventilation, prone positioning and VV-ECMO. Three consecutive sets of blood cultures revealed the presence of Francisella tularensis, whereas bronchoalveolar lavage (BAL) cultures remained negative. No extrapulmonary manifestations of tularemia were identified. Targeted antimicrobial therapy with ciprofloxacin and gentamicin was initiated but failed to prevent a fatal outcome.ConclusionRespiratory tularemia should be considered in patients with severe pneumonia following environmental exposure, particularly when respiratory status deteriorates despite broad-spectrum β-lactam therapy. Repeated blood cultures may establish the diagnosis despite negative BAL cultures. Early recognition and prompt initiation of effective antimicrobial therapy are essential, as β-lactam antibiotics are clinically ineffective against F. tularensis. This case also illustrates the potential severity of respiratory tularemia, which may progress to refractory ARDS requiring VV-ECMO.