Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2021 Oct 11:12:717809.
doi: 10.3389/fmicb.2021.717809. eCollection 2021.

A Review on Occurrence and Spread of Antibiotic Resistance in Wastewaters and in Wastewater Treatment Plants: Mechanisms and Perspectives

Cansu Uluseker  1 , Krista Michelle Kaster  1 , Kristian Thorsen  2 , Daniel Basiry  1 , Sutha Shobana  3 , Monika Jain  4 , Gopalakrishnan Kumar  1 , Roald Kommedal  1 , Ilke Pala-Ozkok  1
Affiliations
Review

A Review on Occurrence and Spread of Antibiotic Resistance in Wastewaters and in Wastewater Treatment Plants: Mechanisms and Perspectives

Cansu Uluseker et al. Front Microbiol. .

Abstract

This paper reviews current knowledge on sources, spread and removal mechanisms of antibiotic resistance genes (ARGs) in microbial communities of wastewaters, treatment plants and downstream recipients. Antibiotic is the most important tool to cure bacterial infections in humans and animals. The over- and misuse of antibiotics have played a major role in the development, spread, and prevalence of antibiotic resistance (AR) in the microbiomes of humans and animals, and microbial ecosystems worldwide. AR can be transferred and spread amongst bacteria via intra- and interspecies horizontal gene transfer (HGT). Wastewater treatment plants (WWTPs) receive wastewater containing an enormous variety of pollutants, including antibiotics, and chemicals from different sources. They contain large and diverse communities of microorganisms and provide a favorable environment for the spread and reproduction of AR. Existing WWTPs are not designed to remove micropollutants, antibiotic resistant bacteria (ARB) and ARGs, which therefore remain present in the effluent. Studies have shown that raw and treated wastewaters carry a higher amount of ARB in comparison to surface water, and such reports have led to further studies on more advanced treatment processes. This review summarizes what is known about AR removal efficiencies of different wastewater treatment methods, and it shows the variations among different methods. Results vary, but the trend is that conventional activated sludge treatment, with aerobic and/or anaerobic reactors alone or in series, followed by advanced post treatment methods like UV, ozonation, and oxidation removes considerably more ARGs and ARB than activated sludge treatment alone. In addition to AR levels in treated wastewater, it examines AR levels in biosolids, settled by-product from wastewater treatment, and discusses AR removal efficiency of different biosolids treatment procedures. Finally, it puts forward key-points and suggestions for dealing with and preventing further increase of AR in WWTPs and other aquatic environments, together with a discussion on the use of mathematical models to quantify and simulate the spread of ARGs in WWTPs. Mathematical models already play a role in the analysis and development of WWTPs, but they do not consider AR and challenges remain before models can be used to reliably study the dynamics and reduction of AR in such systems.

Keywords: antibiotic resistance genes; antibiotic resistant bacteria; antibiotics; spread mechanisms; wastewater treatment plants.

PubMed Disclaimer

Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

FIGURE 1
FIGURE 1
Antibiotic action and resistance mechanisms (adapted from Wright, 2010).
FIGURE 2
FIGURE 2
Antibiotic resistance transport mechanisms (adapted from von Wintersdorff et al., 2016).
See this image and copyright information in PMC

References

    1. Alexander J., Bollmann A., Seitz W., Schwartz T. (2015). Microbiological characterization of aquatic microbiomes targeting taxonomical marker genes and antibiotic resistance genes of opportunistic bacteria. Sci. Total Environ. 512–513 316–325. 10.1016/j.scitotenv.2015.01.046 - DOI - PubMed
    1. Alexander J., Knopp G., Dötsch A., Wieland A., Schwartz T. (2016). Ozone treatment of conditioned wastewater selects antibiotic resistance genes, opportunistic bacteria, and induce strong population shifts. Sci. Total Environ. 559 103–112. 10.1016/j.scitotenv.2016.03.154 - DOI - PubMed
    1. Amador P. P., Fernandes R. M., Prudêncio M. C., Barreto M. P., Duarte I. M. (2015). Antibiotic resistance in wastewater: occcurrence and fate of Enterobacteriaceae producers of class A and class C β-lactamases. J. Environ. Sci. Heal. - Part A Toxic/Hazardous Subst. Environ. Eng. 50 26–39. 10.1080/10934529.2015.964602 - DOI - PubMed
    1. Andersson D. I., Hughes D. (2014). Microbiological effects of sublethal levels of antibiotics. Nat. Rev. Microbiol. 12 465–478. 10.1038/nrmicro3270 - DOI - PubMed
    1. Ardern E., Lockett W. T. (1914). Experiments on the oxidation of sewage without the aid of filters. J. Soc. Chem. Ind. 33 523–539. 10.1002/jctb.5000331005 - DOI