Trends in vancomycin-resistant Enterococcus faecium and methicillin-resistant Staphylococcus aureus and their association with vancomycin / linezolid consumption in a tertiary hospital in China

Antimicrobial resistance is a major global public health challenge. Vancomycin-resistant Enterococcus faecium (VR-Efm) is a significant cause of healthcare-associated infections. To investigate the incidence density of VR-Efm and methicillin-resistant Staphylococcus aureus (MRSA), and to analyze their correlation with vancomycin and linezolid antimicrobial consumption (defined daily doses per 1,000 patient-days), thereby providing evidence for developing effective infection prevention and antimicrobial stewardship strategies. A retrospective analysis was conducted to investigate the epidemiology of VR-Efm and MRSA from 2019 to the first and second quarters of 2025 (2025 Q1-Q2) in a tertiary care hospital in China. Correlation analyses were performed to assess the relationships between VR-Efm and MRSA incidence density and the consumption of vancomycin and linezolid, respectively. The vancomycin resistance rate among Enterococcus faecium isolates showed an upward trend, increasing from 1.6% in 2019 to 23.1% in 2025 Q1-Q2. Linezolid resistance was first identified during 2025 Q1–Q2, with a resistance rate of 1.9%. A significant positive correlation was observed between linezolid consumption and the incidence density of VR-Efm (ρ = 0.779, n = 7, p = 0.039). However, no significant association was found between vancomycin consumption and VR-Efm incidence density (ρ = -0.022, n = 7, p = 0.963). No significant correlation was found between MRSA incidence density and the consumption of vancomycin (ρ = -0.490, n = 7, p = 0.265) or linezolid (ρ = -0.190, n = 7, p = 0.683). The increasing vancomycin resistance rate of Enterococcus faecium, along with the emergence of linezolid-resistant strains, warrants heightened attention and strategic action. Strengthened hospital infection control measures targeting VR-Efm are urgently needed, along with the rational use of linezolid as a key strategy to mitigate antimicrobial selection pressure.