# VRE and antibiotic use in German ICUs—an ecological analysis of 15 years of surveillance data

## TL;DR

This study examines 15 years of data to track vancomycin-resistant enterococci in German ICUs and links their rise to antibiotic use patterns.

## Contribution

The study identifies carbapenem use as a potential driver of vancomycin-resistant Enterococcus faecium, beyond known glycopeptide effects.

## Key findings

- Vancomycin-resistant Enterococcus faecium increased significantly in incidence and resistance over 15 years.
- Carbapenem use increased by 184.9%, suggesting a possible role in promoting vancomycin-resistant enterococci.
- Vancomycin-resistant Enterococcus faecalis remained rare throughout the study period.

## Abstract

This 15 years study reveals highlighting key differences in resistance trends and incidence of vancomycin-resistant Enterococcus faecium versus Enterococcus faecalis in German intensive care units (ICUs). By linking these patterns to antibiotic use, it uncovers crucial insights into the evolving battle against vancomycin-resistant enterococci (VRE) in critical care.

A retrospective ecological cohort study using data from the German SARI (Surveillance of Antimicrobial Use and Antimicrobial Resistance in German ICUs) system was conducted from January 2006 to December 2020. Data from 79 ICUs were analysed. Incidence densities (ID) and resistance rates (RR) for E. faecium and E. faecalis were calculated, alongside antibiotic use densities in defined daily doses per 100 patient days. Generalized linear models and generalized estimating equations assessed temporal trends and associations with antibiotic consumption.

A total of 42 701 Enterococcus isolates were analysed: 21 672 E. faecium and 21 029 E. faecalis. VRE was found in 17.0% of E. faecium and 0.2% of E. faecalis. VRE. faecium showed a significant increase in ID and RR, while vancomycin-sensitive E. faecium decreased. VRE. faecalis remained rare. Antibiotic use patterns showed a significant increase in carbapenem (184.9%), glycopeptides (131.7%), and vancomycin (93.9%).

This study highlights a sustained increase in the incidence and resistance of VRE. faecium. While glycopeptides are well-known contributors, carbapenem use may also play a role in VRE colonization, potentially through disruption of the microbiome. Further research is needed to clarify the complex relationship between antibiotic exposure, microbiome-related mechanisms, and resistance development.