Microbiome Profiling Reveals Prognostic Heterogeneity in Staphylococcus aureus Pneumonia

A study examined 109 mechanically ventilated patients with culture-confirmed Staphylococcus aureus pneumonia. Using genetic sequencing and metagenomics, researchers found significant heterogeneity in bacterial abundance in the respiratory tract, with only 33% of patients showing high bacterial dominance (above 50%). Patients with high bacterial dominance had worse outcomes, with 50% survival compared to 80% in other patients. Bacterial dominance remained an independent predictor of mortality even after adjusting for age and other factors. Patients with high dominance showed elevated inflammatory markers and specific bacterial virulence factors. The research demonstrates that conventional diagnostic methods mask clinically meaningful differences in the course of this infection.