Quantification and Multidrug Resistance Profiles of Vancomycin-Resistant Enterococci Isolated from Two Wastewater Treatment Plants in the Same Municipality

Abstract

Wastewater treatment plants (WWTPs) are points of control for the environmental dissemination of antimicrobial resistant bacteria. Vancomycin-resistant enterococci (VRE) were used as indicators of antimicrobial resistance (AMR) in two WWTPs (biologically aerated filter (BAF) and conventional activated sludge (CAS)) in the same municipality. The removal and abundance of enterococci and VRE as well as the species and antimicrobial resistance profiles of VRE were assessed. Enterococci and VRE from the primary and final effluents were enumerated. Results were assessed from an ecological context. VRE was not selected for by either WWTP but the BAF system outperformed the CAS system for the removal of enterococci/VRE. Enterococcus faecalis (n = 151), E. faecium (n = 94) and E. casseliflavus/E. gallinarum (n = 59) were the dominant VRE species isolated. A decrease in levofloxacin resistance in enterococci was observed in the BAF WWTP. An increase in nitrofurantoin resistant (p < 0.001) and a decrease in quinupristin/dalfopristin (p = 0.003) and streptomycin (p = 0.022) resistant enterococci were observed in the CAS WWTP, corresponding to a shift of VRE from E. faecalis to E. faecium. Wastewater treatment processes can be managed to limit the dissemination of antimicrobial resistance determinants into the surrounding environment.

Enterococci, Van Gene-Carrying Enterococci, and Vancomycin Concentrations in the Influent of a Wastewater Treatment Plant in Southeast Germany

“…In consequence, screening on VRESelect agar probably covers all vancomycin-resistant enterococci occurring in the wastewater of the sampled plant. This also applies to strains having low-level vancomycin resistance [ 44 ], which were detected in a previous environmental study [ 45 ] but could not be found among the tested isolates in this report.…”

Antimicrobial Resistance Gene Detection and Plasmid Typing Among Multidrug Resistant Enterococci Isolated from Freshwater Environment

“…However, studies reporting enterococci and their AR from the environment are scarce since enterococci are generally not considered important pathogens outside of hospitals and healthcare settings. A limited number of studies on environmental enterococci are mostly focused on water environments polluted by human inputs, such as wastewater, on species that are associated with human infections, such as E. faecalis and E. faecium, and on certain antimicrobial drugs, such as vancomycin [4][5][6][7]. Data concerning the presence of resistant enterococci in the aquatic environment is limited and still fewer data exists on the genetic content of waterborne antimicrobial resistant enterococci.…”

Diversity of Multidrug-Resistant Bacteria in an Urbanized River: A Case Study of the Potential Risks from Combined Sewage Overflows

“…The strongest association among the resistance profiles was for vancomycin and ampicillin. Sanderson et al [60] and Martins da Costa et al [61] also observed a link between resistance to these two antibiotics, but further research is necessary to ascertain the mechanism of the relationship. We also observed a strong association of the resistance profiles for cefotaxime and amoxicillin clavulanate.…”