Community-acquired, hospital-acquired, and healthcare-associated pneumonia caused by Pseudomonas aeruginosa

We describe three types of Pseudomonas aeruginosa pneumonia. Case 1. P. aeruginosa was isolated from the blood and sputum of a 29-year-old male non-smoker who developed severe community-acquired pneumonia (CAP). Piperacillin was initially effective, but fever and lobular pneumonia with cavities developed seven days after discharge. Intravenous piperacillin/tazobactam and tobramycin were administered for four weeks, followed by oral ciprofloxacin for two weeks. He finally recovered, but developed recurrent CAP due to P. aeruginosa despite appropriate antibiotic therapy and immunocompetent status. Case 2. P. aeruginosa was isolated from the blood and sputum of a 57-year-old woman with renal cancer who developed hospital-acquired pneumonia (HAP) after surgical treatment. She recovered after meropenem administration for four weeks. Case 3. A 67-year-old woman with systemic sclerosis and malignant lymphoma who was followed up on an outpatient basis underwent immunosuppressive therapy. Thereafter, she developed pneumonia and was admitted to our institution where P aeruginosa was isolated from blood and sputum samples. Healthcare-associated pneumonia (HCAP) was diagnosed and effectively treated with tobramycin and ciprofloxacin. P. aeruginosa is not only a causative pathogen of HAP and HCAP, but possibly also of CAP.