Risk factors and outcome associated with the acquisition of MDR linezolid-resistant Enterococcus faecium: a report from tertiary care centre

The aim of the study was to determine the resistance profile of linezolid-resistant Enterococcus faecium (LREfm) and to investigate risk factors and outcomes associated with LREfm infections.

A prospective case-control study was undertaken (2019 to 2022) and included 202 patients with LREfm infections (cases) and 200 controls with LSEfm infections. Clinical data was prospectively collected and analysed for risk factors and outcomes. Antimicrobial susceptibility was performed, and resistance profile was studied using WHOnet.

Risk factors associated with LREfm infection were site of infection UTI (OR 5.87, 95% CI 2.59–13.29, p ≤ 0.001), prior use of carbapenem (OR 2.85 95% CI 1.62–5.02, p ≤ 0.001) and linezolid (OR 10.13, 95% CI 4.13–24.82, p ≤ 0.001), use of central line (OR 5.54, 95% CI 2.35–13.09, p ≤ 0.001), urinary catheter (OR 0.29, 95% CI 0.12–0.70, p ≤ 0.001) and ventilation (OR 14.87, 95% CI 7.86–28.11, p ≤ 0.007). The hospital stay 8–14 days (< 0.001) prior to infection and the mortality rate (p = 0.003) were also significantly high among patients with LREfm infections. Linezolid and vancomycin resistance coexisted; further, MDR, XDR and PDR phenotypes were significantly higher among LREfm.

This study provided insight into epidemiology of MDR LREfm in a setting where linezolid use is high. The main drivers of infections with LREfm are multiple, including use of carbapenems and linezolid. Invasive procedures and increased hospital stay facilitate spread through breach in infection control practises. As therapeutic options are limited, ongoing surveillance of LREfm and VRE is critical to guide appropriate use of linezolid and infection control policies.