Occurrence and removal of antibiotic resistant Escherichia coli and antibiotic resistance genes in an urban wastewater treatment plant
Although domestic wastewater is a reservoir of antibiotic resistance factors including antibiotic resistant bacteria, genes, and many other pollutants including antimicrobial compounds, most of the current treatment processes in the wastewater treatment plant (WWTP) are not designed to specifically...
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Published in | International journal of environmental science and technology (Tehran) Vol. 20; no. 12; pp. 13739 - 13752 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Berlin/Heidelberg
Springer Berlin Heidelberg
01.12.2023
|
Subjects | |
Online Access | Get full text |
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Summary: | Although domestic wastewater is a reservoir of antibiotic resistance factors including antibiotic resistant bacteria, genes, and many other pollutants including antimicrobial compounds, most of the current treatment processes in the wastewater treatment plant (WWTP) are not designed to specifically remove these emerging contaminants. In this study, the occurrences and removal efficiency of antibiotic resistant
Escherichia coli
and genes in a WWTP were examined, and explored any potential correlations between these antibiotic resistance factors and physicochemical parameters, nutrients, and heavy metal levels in wastewater. Wastewater samples were collected at five sampling sites after different treatment processes in a WWTP in Ho Chi Minh City, Vietnam. The concentrations of
E. coli
resistant to amoxicillin/clavulanic acid, amikacin, cefixime, ciprofloxacin, and sulfamethoxazole/trimethoprim were determined using Tryptone Bile X-glucuronide agar supplemented with target antibiotics and then confirmed with indole test. The levels of the total bacterial 16S rDNA, integron integrase genes (
intI1
,
intI2
, and
intI3
), efflux pump (
OqxB
), and antibiotic resistance genes (
sul1
,
sul2
,
dfrA
,
aac(6)-Ib-cr
,
qnrA
,
qnrB
,
bla
TEM
, and
bla
CTX
) were quantified using qPCR assay. As the results, the concentrations of
E. coli
resistant to the five tested antibiotics in wastewater influent were ranging from 32.7 to 1.8 × 10
4
CFU/mL, and resistance rates to AMC, CEF, SXT, CIP, and AMK were 78.9, 43.0, 25.0, 24.0, and 0.1%, respectively. Among tested genes, the
sul1
,
sul2
,
intI1
, and
aac(6)-Ib-cr
were highly detected in the influent wastewaters with the average concentrations ranging from 1.29 × 10
6
to 1.09 × 10
8
GCN/mL, followed by
qnrA, OxqB, intI3, dfrA,
and
bla
TEM
with the average concentrations ranging from 6.32 × 10
4
to 1.26 × 10
5
GCN/mL, and
qnrB
,
intI2
, and
bla
CTX
detected at the low levels ranging from 1.43 × 10
3
to 1.61 × 10
4
GCN/mL. Although overall removal efficiencies of antibiotic resistant
E. coli
and genes for the final effluent were up to 99.9%, the detectable levels of ARB and ARGs in the final effluent were still of concern as these emerging contaminants can be discharged into the environments. |
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ISSN: | 1735-1472 1735-2630 |
DOI: | 10.1007/s13762-023-04907-8 |