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Antimicrobial Resistance Linked to Septic System Contamination in the Indiana Lake Michigan Watershed

Extended-spectrum β-lactamases confer resistance to a variety of β-lactam antimicrobials, and the genes for these enzymes are often found on plasmids that include additional antimicrobial resistance genes (ARG). We surveyed aquatic environments in the Indiana Lake Michigan watershed in proximity to...

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Autores principales: Sidhu, Angad S., Mikolajczyk, Faith N., Fisher, Jenny C.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10044017/
https://www.ncbi.nlm.nih.gov/pubmed/36978436
http://dx.doi.org/10.3390/antibiotics12030569
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author Sidhu, Angad S.
Mikolajczyk, Faith N.
Fisher, Jenny C.
author_facet Sidhu, Angad S.
Mikolajczyk, Faith N.
Fisher, Jenny C.
author_sort Sidhu, Angad S.
collection PubMed
description Extended-spectrum β-lactamases confer resistance to a variety of β-lactam antimicrobials, and the genes for these enzymes are often found on plasmids that include additional antimicrobial resistance genes (ARG). We surveyed aquatic environments in the Indiana Lake Michigan watershed in proximity to areas with high densities of residential septic systems to determine if human fecal contamination from septic effluent correlated with the presence of antimicrobial resistance genes and phenotypically resistant bacteria. Of the 269 E. coli isolated from environmental samples and one septic source, 97 isolates were resistant to cefotaxime, a third-generation cephalosporin. A subset of those isolates showed phenotypic resistance to other β-lactams, fluoroquinolones, sulfonamides, and tetracyclines. Quantitative PCR was used to quantify human-associated Bacteroides dorei gene copies (Human Bacteroides) from water samples and to identify the presence of ARG harbored on plasmids from E. coli isolates or in environmental DNA. We found a strong correlation between the presence of ARG and human fecal concentrations, which supports our hypothesis that septic effluent is a source of ARG and resistant organisms. The observed plasmid-based resistance adds an additional level of risk, as human-associated bacteria from septic systems may expand the environmental resistome by acting as a reservoir of transmissible resistance genes.
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spelling pubmed-100440172023-03-29 Antimicrobial Resistance Linked to Septic System Contamination in the Indiana Lake Michigan Watershed Sidhu, Angad S. Mikolajczyk, Faith N. Fisher, Jenny C. Antibiotics (Basel) Article Extended-spectrum β-lactamases confer resistance to a variety of β-lactam antimicrobials, and the genes for these enzymes are often found on plasmids that include additional antimicrobial resistance genes (ARG). We surveyed aquatic environments in the Indiana Lake Michigan watershed in proximity to areas with high densities of residential septic systems to determine if human fecal contamination from septic effluent correlated with the presence of antimicrobial resistance genes and phenotypically resistant bacteria. Of the 269 E. coli isolated from environmental samples and one septic source, 97 isolates were resistant to cefotaxime, a third-generation cephalosporin. A subset of those isolates showed phenotypic resistance to other β-lactams, fluoroquinolones, sulfonamides, and tetracyclines. Quantitative PCR was used to quantify human-associated Bacteroides dorei gene copies (Human Bacteroides) from water samples and to identify the presence of ARG harbored on plasmids from E. coli isolates or in environmental DNA. We found a strong correlation between the presence of ARG and human fecal concentrations, which supports our hypothesis that septic effluent is a source of ARG and resistant organisms. The observed plasmid-based resistance adds an additional level of risk, as human-associated bacteria from septic systems may expand the environmental resistome by acting as a reservoir of transmissible resistance genes. MDPI 2023-03-14 /pmc/articles/PMC10044017/ /pubmed/36978436 http://dx.doi.org/10.3390/antibiotics12030569 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Sidhu, Angad S.
Mikolajczyk, Faith N.
Fisher, Jenny C.
Antimicrobial Resistance Linked to Septic System Contamination in the Indiana Lake Michigan Watershed
title Antimicrobial Resistance Linked to Septic System Contamination in the Indiana Lake Michigan Watershed
title_full Antimicrobial Resistance Linked to Septic System Contamination in the Indiana Lake Michigan Watershed
title_fullStr Antimicrobial Resistance Linked to Septic System Contamination in the Indiana Lake Michigan Watershed
title_full_unstemmed Antimicrobial Resistance Linked to Septic System Contamination in the Indiana Lake Michigan Watershed
title_short Antimicrobial Resistance Linked to Septic System Contamination in the Indiana Lake Michigan Watershed
title_sort antimicrobial resistance linked to septic system contamination in the indiana lake michigan watershed
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10044017/
https://www.ncbi.nlm.nih.gov/pubmed/36978436
http://dx.doi.org/10.3390/antibiotics12030569
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