Epidemiological and Molecular Investigation of Multidrug-Resistant Enterococcus spp. Strains Isolated from Hospitalized Patients Using a One-Health Approach

Aims: The surveillance and investigation of antimicrobial resistance and virulence factor genes in nosocomial pathogens such as Enterococcus spp. have not been adequately prioritized within health institutions, especially in the context of COVID-19. The objective of this work was to conduct an epidemiological and molecular study in multidrug-resistant Enterococcus spp. strains isolated from hospitalized patients using a "One Health" approach in the middle of the COVID-19 pandemic.

Study Design: An observational, prospective, cross-sectional study was designed. All strains were isolated from hospitalized patients in a public hospital in La Plata, Buenos Aires, Argentina from September 2019 to August 2021; coincidental with the COVID-19 pandemic.

Methodology: In this study, we used N=17 Enterococcus spp. detected by biochemical testing and BD Phoenix™ M50: E. faecalis (n=6) and E. faecium (n=11). Antimicrobial susceptibility was determined according to standard guidelines (disk diffusion and MIC). AR and VF genes were detected by PCR assays.

Results: 10/11 (90.9%) vancomycin-resistant E. faecium strains were confirmed by molecular test. The highest detection of vanA-VREFM resulted after the pandemic cohort (2021). Resistance to glycopeptides was associated with resistance to ß-lactams and high-level resistance to aminoglycosides. The gen aac(6′)-Ie-aph(2″)-Ia was detected in E. faecium (n=7) and E. faecalis (n=1). The esp gene (52.9%) was the most frequent virulence factor, followed by gelE 7 (41.2%) and cylA 1 (5.9%) among E. faecalis and E. faecium isolates.

Conclusions: Nosocomial pathogens and commensal bacteria such as Enterococcus have an essential role in spreading AR and VF using genome plasticity to transfer genes located in MGE. The epidemiological and molecular investigation of multidrug-resistant strains allows adjusting biosafety protocols to prevent their spread.