Multiple Pulmonary Nodules Caused by Pasteurella multocida Pneumonia in an Immunocompetent Young Woman: A Case Report

Background Pasteurella multocida typically causes soft-tissue infections following animal bites or scratches, with respiratory infections being exceptionally rare. These predominantly occur in immunocompromised hosts and manifest radiographically as consolidation. Case Presentation: A 31-year-old immunocompetent woman with prolonged close contact with a cat (including sleeping nearby and inhaling its scent) presented with an 11-day history of nocturnal productive cough. Chest computed tomography (CT) revealed multiple bilateral pulmonary nodules—an atypical finding. Initial empirical treatment with levofloxacin resulted in partial improvement. Bronchoscopy with bronchoalveolar lavage (BAL) showed purulent secretions and 98% neutrophils. Cultures isolated P. multocida, confirmed by microbial mass spectrometry identification. Due to the patient's penicillin allergy, levofloxacin (500 mg daily for 14 days) was continued, leading to complete symptom resolution. Conclusion This case highlights: (1) the diagnostic imperative of BAL for zoonotic pathogens in nodular lung disease, (2) the critical role of animal exposure history in pulmonary nodule evaluation, and (3) fluoroquinolone efficacy as alternative therapy for penicillin-allergic patients.