Abstract
Pseudomonas aeruginosa (P. aeruginosa), traditionally regarded as a nosocomial pathogen, has emerged as an increasingly recognized etiologic agent in community-acquired pneumonia (CAP). Cavitary lung lesions-a severe complication of CAP characterized by parenchymal necrosis and cavity formation-are exceptionally rare in P. aeruginosa-associated CAP. We report a 64-year-old male with CAP complicated by P. aeruginosa infection (OXA-positive genotype carrying the virulence factors exoU and lasA), which rapidly progressed to cavitary lesions in the right upper lobe. This case highlights the aggressive clinical trajectory and antimicrobial resistance challenges inherent to community-acquired P. aeruginosa infections. Furthermore, it underscores the imperative for serial radiographic monitoring to detect cavitary evolution and the critical role of comprehensive antimicrobial susceptibility testing in guiding precision therapy.