Acute bronchopneumonia with Bordetella bronchiseptica bacteremia in an immunocompromised patient with bronchiectasis: A case report and review of the literature.

Bordetella bronchiseptica rarely causes human disease, and bloodstream infection is exceptional. We describe a 69-year-old man with follicular lymphoma on lenalidomide-rituximab, complicated by hypogammaglobulinemia and bronchiectasis, who developed acute bronchopneumonia with B. bronchiseptica bacteremia. Despite pre-admission oral levofloxacin, he presented with fever and productive cough. Computed tomography of the chest revealed new ground-glass and consolidative opacities. Two aerobic blood-culture bottles yielded slender Gram-negative rods; direct matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) suggested B. bronchiseptica, concordant with subculture. The isolate showed high minimal inhibitory concentrations (MICs) to third-generation cephalosporins but low MICs to piperacillin, carbapenems, aminoglycosides, tetracyclines, and fluoroquinolones. Therapy was changed from ceftriaxone to piperacillin, followed by step-down to oral minocycline, with clinical resolution after a total of 14 days. There was no animal exposure. Because 16S rRNA sequencing alone cannot reliably distinguish classical Bordetella species, we reported the organism as most consistent with B. bronchiseptica based on composite evidence (phenotype, MALDI-TOF MS, 16S). A focused literature review identified few well-documented bacteremia cases, predominantly in immunocompromised hosts, most often with respiratory sources. This case underscores the need to consider B. bronchiseptica in immunocompromised patients with bronchiectasis, even in the absence of animal exposure, and highlights the limited activity of many β-lactams and macrolides, emphasizing the importance of susceptibility-guided therapy.