The influence of urbanization and water reclamation plants on fecal indicator bacteria and antibiotic resistance in the Los Angeles River watershed: A case study with complementary monitoring methods

Urban land use and water reclamation plants (WRPs) can impact fecal indicator bacteria (FIB) and antimicrobial resistance (AMR) in coastal watersheds. However, there is a lack of studies exploring these effects on the US West Coast. Additionally, there is limited research using a complementary appro...

Full description

Saved in:

Bibliographic Details
Published in:	The Science of the total environment Vol. 957; p. 177577
Main Authors:	Callejas, Ileana A., Kong, Yuwei, Osborn, Katie, Hung, Wei-Cheng, Cira, Marisol, Cason, Taylor, Sloane, Ashlyn, Shenkiryk, Alexis, Masikip, Aaron, Singh, Akshyae, Jones, Adriane, Steele, Joshua A., Jay, Jennifer A.
Format:	Journal Article
Language:	English
Published:	Elsevier B.V 20-12-2024
Subjects:	Antibiotic resistance Fecal indicator bacteria Human fecal markers Urbanization Water reclamation plants Urbanization Water reclamation plants Human fecal markers Antibiotic resistance Fecal indicator bacteria
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	Urban land use and water reclamation plants (WRPs) can impact fecal indicator bacteria (FIB) and antimicrobial resistance (AMR) in coastal watersheds. However, there is a lack of studies exploring these effects on the US West Coast. Additionally, there is limited research using a complementary approach across culture-, qPCR-, and metagenomics-based techniques for characterizing environmental AMR. In this study, sixteen locations were sampled in the Los Angeles River, encompassing both upstream and downstream of three WRPs discharging into the river. Culture-dependent methods quantified Enterococcus, total coliforms, E. coli, and extended spectrum beta-lactamase-producing E. coli as a low-cost screening tool for AMR, while qPCR measured selected antibiotic resistance genes (ARGs): sul1, ermF, tetW, blaSHV, along with intI1 and 16S rRNA genes. Bacteroides HF183 and crAssphage markers were quantified via ddPCR. All samples underwent shotgun sequencing to investigate gene abundance and mobility and an overall risk score for AMR. Results reveal downstream sites contain ARGs at least two orders of magnitude greater than upstream locations. Developed areas had the highest ARG sequence abundances and the most ARG classes as indicated by metagenomic analysis. WRP effluent exhibited elevated ARGs and co-location of ARGs, mobile genetic elements, and pathogens. A culture-based assessment of AR in E. coli and Pseudomonas aeruginosa revealed increased resistance ratios for most antibiotics from upstream to downstream a WRP discharge point. This study highlights the impacts of land use and WRPs on ARGs and FIB, offering a multi-pronged analysis of AMR. [Display omitted] •ARGs, fecal indicator bacteria, and human fecal markers increase in abundance through an urbanization gradient.•Water reclamation plants increase ARGs, reduce fecal indicator bacteria, and increase resistant E. coli and P. aeruginosa.•A low-cost culture based screening tool identified AR hotspots, confirmed by qPCR- and metagenomics-based techniques.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0048-9697 1879-1026 1879-1026
DOI:	10.1016/j.scitotenv.2024.177577