Continuous increase of vancomycin resistance in enterococci causing nosocomial infections in Germany-10 years of surveillance

Background: Enterococci are frequent pathogens causing nosocomial infections in Germany. Infections due to strains with vancomycin resistance are high when compared with other European states. Therefore, the study aimed to describe the recent progression of nosocomial infections due to vancomycin-resistant enterococci (VRE) in Germany. Methods: We analyzed data from two components of the German national nosocomial infection surveillance system for the period 2007-2016. For primary bloodstream infections (BSIs) and urinary tract infections (UTIs) we used data from intensive care units and for surgical site infections (SSIs) data from surgical departments. In a sensitivity analysis, we considered only data from participants that participated continuously from 2007 to 2016 (core group). We calculated proportions of VRE among all nosocomial enterococcal infections with 95% confidence intervals (95% CIs) and trends over time. A multivariable logistic regression was used to compare occurrence of VRE proportions among German federal states. Results: Enterococcal infections from 857 ICUs and 1119 surgical departments were analyzed. On ICUs, the proportion of vancomycin resistance in enterococci causing nosocomial infections significantly increased for BSIs from 5.9 to 16.7% and for UTIs from 2.9 to 9.9%; for surgical site infections, the proportion of VRE increased from 0.9 to 52% (P < 0.001 for all). In the core group, the increase of VRE was more pronounced in ICUs (BSIs: 5.5 to 21.6%; UTIs: 2 to 11.2%) but was not seen in surgical departments (SSIs: 1.5 to 2.8%). Compared with the most populous German federal state North Rhine Westphalia, enterococcal infections in Hesse (Odds Ratio (OR) 2.3, 95% CI 1.7-3.1), Saxony (OR 2.5, 95% CI 1.8-3.5) and Thuringia (OR 1.9, 95% CI 1.4-2.6) were more likely to be caused by vancomycin-resistant strains. Conclusion: In Germany, the proportion of VRE in nosocomial infection due to enterococci is still increasing. It remains unclear, why a large variation in the proportion of VRE exists between German federal states.