Adult severe community-acquired pneumonia with bloodstream infection caused by ψUSA 300: A case report.

We report the first case of fatal community-acquired pneumonia with concomitant bloodstream infection caused by the ψUSA300 strain of methicillin-resistant Staphylococcus aureus (MRSA). The isolate was positive for Panton-Valentine leukocidin (PVL) gene, with a unique 12-base pair deletion in the ccrB2 gene, differentiating it from the canonical USA300 strain. Despite aggressive therapeutic interventions, the patient developed multiple complications, including septic shock, which ultimately proved fatal. Genetic sequencing confirmed the presence of the ψUSA300 strain.