Genomic epidemiology and phylodynamics of Acinetobacter baumannii bloodstream isolates in China.

Summary

Analyzing 1,506 bloodstream A. baumannii isolates from 76 hospitals (2011–2021), the study shows IC2 dominance and a shift toward ST208, which displays higher virulence, resistance, and desiccation tolerance compared with ST191/195. The findings indicate rapid evolutionary dynamics with implications for infection control and empirical therapy.

Key Findings

• IC2 accounted for 81.74% of 1,506 bloodstream isolates across 76 hospitals (2011–2021).
• Shift in prevalent STs: ST208 increased while ST191 and ST195 declined, mirroring global trends.
• ST208 showed higher virulence, greater antibiotic resistance, enhanced desiccation tolerance, and complex transmission patterns.
• High-resolution Oxford MLST revealed greater population diversity and genetic drivers of ST208’s rise.

Clinical Implications

Hospitals should strengthen surveillance of A. baumannii, particularly ST208, refine infection control, and consider local clone dynamics when selecting empiric therapy for severe sepsis. Enhanced environmental decontamination may be required due to desiccation tolerance.

Limitations

• Findings derive from one country; generalizability may vary by region
• Limited linkage to patient-level clinical outcomes; causality cannot be inferred

Future Directions

Integrate genomic surveillance with patient outcomes and antimicrobial use to model transmission and guide targeted interventions; assess ST208-specific virulence mechanisms as therapeutic targets.