Presence and Persistence of ESKAPEE Bacteria before and after Hospital Wastewater Treatment

Abstract

The metagenomic surveillance of antimicrobial resistance in wastewater has been suggested as a methodological tool to characterize the distribution, status, and trends of antibiotic-resistant bacteria. In this study, a cross-sectional collection of samples of hospital-associated raw and treated wastewater were obtained from February to March 2020. Shotgun metagenomic sequencing and bioinformatic analysis were performed to characterize bacterial abundance and antimicrobial resistance gene analysis. The main bacterial phyla found in all the samples were as follows: <i>Proteobacteria</i>, <i>Bacteroides</i>, <i>Firmicutes</i>, and <i>Actinobacteria</i>. At the species level, <i>ESKAPEE</i> bacteria such as <i>E. coli</i> relative abundance decreased between raw and treated wastewater, but <i>S. aureus</i>, <i>A. baumannii</i>, and <i>P. aeruginosa</i> increased, as did the persistence of <i>K. pneumoniae</i> in both raw and treated wastewater. A total of 172 different ARGs were detected; <i>bla</i>_OXA, <i>bla</i>_VEB, <i>bla</i>_KPC, <i>bla</i>_GES, <i>mphE</i>, <i>mef</i>, <i>erm</i>, <i>msrE</i>, <i>AAC(6')</i>, <i>ant(3″)</i>, <i>aadS</i>, <i>lnu</i>, <i>PBP-2</i>, <i>dfrA</i>, <i>vanA-G</i>, <i>tet</i>, and <i>sul</i> were found at the highest abundance and persistence. This study demonstrates the ability of <i>ESKAPEE</i> bacteria to survive tertiary treatment processes of hospital wastewater, as well as the persistence of clinically important antimicrobial resistance genes that are spreading in the environment.