Transmission of clones of carbapenem-resistant Escherichia coli between a hospital and an urban wastewater treatment plant

Di Wang; Björn Berglund; Qi Li; Xiaorong Shangguan; Jingjing Li; Feng Liu; Fanghui Yao; Xuewen Li

doi:10.1016/j.envpol.2023.122455

Transmission of clones of carbapenem-resistant Escherichia coli between a hospital and an urban wastewater treatment plant

Environ Pollut. 2023 Nov 1:336:122455. doi: 10.1016/j.envpol.2023.122455. Epub 2023 Aug 24.

Authors

Di Wang¹, Björn Berglund², Qi Li¹, Xiaorong Shangguan¹, Jingjing Li¹, Feng Liu¹, Fanghui Yao¹, Xuewen Li³

Affiliations

¹ Department of Environment and Health, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China.
² Department of Cell and Molecular Biology, Uppsala University, 751 24, Uppsala, Sweden.
³ Department of Environment and Health, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China. Electronic address: lxw@sdu.edu.cn.

PMID: 37633440
DOI: 10.1016/j.envpol.2023.122455

Abstract

Carbapenem-resistant Enterobacterales (CRE) constitute an urgent threat to worldwide public health. The spread of CRE is facilitated by transmission via the environment. Wastewater treatment plants (WWTPs) are considered to be important sources of antibiotic resistance and hot spots of antibiotic-resistant bacteria (ARB) which can facilitate dissemination of antibiotic resistance genes. In this study, water samples were collected over one year from a WWTP in Jinan, Shandong province, China, from different functional sites in the wastewater treatment process. Carbapenem-resistant Escherichia coli (CREC) were isolated by selective cultivation and whole-genome sequenced to investigate the occurrence and characteristics of CREC in the WWTP. A total of 77 CREC isolates were included in the study and the detection rate of CREC in the WWTP water inlet was found to be 85%. An additional 10 CREC were isolated from a nearby teaching hospital during the sampling period and included for comparison to the environmental isolates. Susceptibility testing showed that all CREC were multidrug-resistant. 6 different carbapenem resistance genes (CRGs) were detected, including bla_NDM-5 (n = 75), bla_NDM-1 (n = 6), bla_NDM-4 (n = 3), bla_NDM-6 (n = 1), bla_NDM-9 (n = 1), and bla_KPC-2 (n = 4). 42 CREC isolates were whole-genome sequenced with Illumina short-read sequencing. 11 of these were also sequenced with Nanopore long-read sequencing. Plasmids carrying CRGs were found to belong to IncX3 (n = 35), IncFII (n = 12), IncFIA (n = 5), IncFIB (n = 2), IncC (n = 1), and IncP6 (n = 1). Clonal dissemination of CREC belonging to ST167, ST448, and ST746 was observed between different parts of the WWTP. Furthermore, isolates from the WWTP, including an isolate belonging to the high-risk ST167 strain, were found to be clonally related to CREC isolated at the hospital. The spread of CRGs is of considerable concern and strategies to prevent environmental dissemination of this contaminant urgently needs to be implemented.

Keywords: Carbapenem-resistant enterobacterales; Carbapenemases; Escherichia coli; Plasmid; Wastewater treatment plant; Water-based epidemiology.