Invasive enterococcal infections in Poland: the current epidemiological situation.

Area of Science:

• Clinical Microbiology
• Infectious Diseases
• Molecular Epidemiology

Background:

• Enterococci are significant causes of hospital-acquired infections.
• Prospective surveillance is crucial for monitoring antimicrobial resistance trends.

Purpose of the Study:

• To investigate the characteristics of human invasive enterococcal isolates in Poland.
• To identify antimicrobial resistance patterns and molecular epidemiology of Enterococcus faecium.

Main Methods:

• Prospective surveillance in 30 Polish hospitals (May 2010-June 2011).
• Species identification, antimicrobial susceptibility testing.
• Molecular typing including MLVA, MLST, and PCR for specific markers (IS16, esp(Efm), intA, GDRs).

Main Results:

• 259 isolates: Enterococcus faecalis (54.1%) and Enterococcus faecium (43.2%).
• 18.1% 14-day mortality rate.
• All isolates susceptible to linezolid and daptomycin.
• High-level aminoglycoside resistance (>50%).
• Vancomycin resistance (vanA/vanB) in 7.1% of E. faecium.
• 71.4% of isolates were multidrug resistant.
• E. faecium dominated by hospital-associated meroclone markers and lineages 78 (52.7%) and 17/18 (46.4%).
• Lineage 78 strains showed enrichment in genomic difference regions (GDRs).

Conclusions:

• Enterococcus faecium, particularly lineage 78, is increasingly prevalent in invasive hospital infections in Poland.
• Molecular markers and MLST are essential for tracking the spread of resistant strains.
• Effective treatment options like linezolid and daptomycin remain available, but high-level aminoglycoside resistance is common.