Abstract Introduction Pseudomonas stutzeri is a non-fluorescent, oxidase-positive, gram-negative bacillus commonly found in soil and water. Unlike Pseudomonas aeruginosa, it is regarded as a low-virulence organism and uncommonly associated with human infection. Reported cases have been linked to healthcare exposure, prosthetic devices, or immunosuppression. However, recent evidence indicates its role in causing severe community-acquired infections in the absence of typical nosocomial risk factors. We present a case of P. stutzeri septic shock in an elderly woman with no recent healthcare exposure, highlighting its potential as an under-recognized community-acquired pathogen. Case Presentation An 80-year-old woman with chronic obstructive pulmonary disease, heart failure with preserved ejection fraction, and chronic steroid use presented with progressive respiratory distress. Her spouse reported three days of malaise, poor oral intake, and inability to ambulate following a minor fall with superficial knee abrasions. On arrival, she was tachycardic, tachypneic, and hypotensive with a lactate of 3.6 mmol/L. Urinalysis revealed blood and bacteria, but subsequent urine cultures were sterile. CT chest showed moderate emphysema, an atypical left major fissure hydropneumothorax, and a spiculated lung lesion suspicious for bronchogenic carcinoma. She was managed in the ICU for septic shock and acute hypoxemic respiratory failure with noninvasive ventilatory support, pressors, hydrocortisone, and vancomycin plus piperacillin-tazobactam. Despite appropriate antimicrobial coverage and hemodynamic support, she developed recurrent supraventricular tachycardia and died on hospital day 2. Blood cultures later finalized as Pseudomonas stutzeri susceptible to piperacillin-tazobactam. Discussion Pseudomonas stutzeri is a non-fluorescent, denitrifying organism historically regarded as an opportunistic environmental bacterium. These occur most often in elderly patients with chronic comorbidities, even without hospitalization or instrumentation. Because of its low intrinsic virulence, positive cultures may be dismissed as contaminants. Nonetheless, severe infections can develop, particularly in those with chronic lung disease or immune dysfunction. Most isolates remain highly susceptible to antipseudomonal agents, and outcomes depend more on host factors and illness severity than resistance. In Pseudomonas stutzeri, resistance is mainly driven by altered permeability and efflux, with profiles varying by strain and environment. It generally shows lower intrinsic resistance than P. aeruginosa and less frequent β-lactamase production. Horcajada et al. (2024) reported P. stutzeri bacteremia as predominantly community-onset, with high mortality among those with respiratory sources without observed resistance. Conclusion Clinicians should recognize Pseudomonas stutzeri as a potential cause of community-acquired sepsis requiring timely identification and targeted management. This abstract is funded by: None
Kaiwan et al. (Fri,) studied this question.