Pneumonia — CAP and HAP

A 68-year-old man with COPD (FEV₁ 35% predicted) presents with a 3-day history of cough, purulent sputum, and dyspnea. He was hospitalized 2 weeks ago for an acute exacerbation and discharged on oral corticosteroids. On examination: temperature 38.5°C, respiratory rate 28/min, SpO₂ 88% on room air. Chest X-ray shows a new infiltrate in the right lower lobe. Blood cultures are pending. Sputum Gram stain shows gram-negative rods. Which organism is most likely responsible, and what is the most appropriate empiric antibiotic regimen?

A 72-year-old woman with diabetes mellitus type 2 is admitted to the ICU on day 5 of mechanical ventilation following elective abdominal surgery. She develops fever (39.2°C), purulent endotracheal secretions, and a new infiltrate on chest X-ray in the right lower lobe. Blood cultures are negative. Sputum culture grows Acinetobacter baumannii resistant to all beta-lactams and fluoroquinolones. What is the most appropriate antimicrobial therapy?

A 72-year-old man on mechanical ventilation for 8 days develops hospital-acquired pneumonia (HAP). Sputum culture is pending. He has no recent antibiotic exposure. What is the most appropriate empirical antibiotic regimen?

A 68-year-old man with COPD presents with acute onset cough, fever (38.5°C), and dyspnea for 3 days. Chest X-ray shows a new left lower lobe consolidation. Sputum is purulent. Which investigation is most appropriate to guide initial antimicrobial therapy in community-acquired pneumonia?

A 55-year-old man on mechanical ventilation for 8 days post-abdominal surgery develops fever (39.2°C), purulent endotracheal secretions, and a new right lower lobe infiltrate on chest X-ray. Clinical suspicion for ventilator-associated pneumonia (VAP) is high. Which investigation is most specific for confirming the diagnosis and guiding antimicrobial therapy?