Pulmonary Campylobacter concisus infection in an immunocompromised patient with underlying mucormycosis.

Campylobacter concisus is a rarely encountered agent of human infection. The first isolation of C. concisus from a pulmonary abscess in an immunocompromised patient who underwent allogeneic stem cell transplantation is reported here. This unusual case demonstrates the pathogenic potential of this bacterium and outlines species-immanent difficulties in gaining a reliable diagnosis. Molecular methods were a cornerstone for definite identification of the organism grown on anaerobic culture from surgically excised tissue. Antimicrobial susceptibility testing revealed unusual quinolone and macrolide resistance, and therefore antimicrobial therapy was based on β-lactam antibiotics.