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Lau M, Monis PT, King BJ. The efficacy of current treatment processes to remove, inactivate, or reduce environmental bloom-forming Escherichia coli. Microbiol Spectr 2024; 12:e0085624. [PMID: 38980016 PMCID: PMC11302305 DOI: 10.1128/spectrum.00856-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Accepted: 06/06/2024] [Indexed: 07/10/2024] Open
Abstract
Escherichia coli is excreted in high numbers from the intestinal tract of humans, other mammals, and birds. Traditionally, it had been thought that E. coli could grow only within human or animal hosts and would perish in the environment. Therefore, the presence of E. coli in water has become universally accepted as a key water quality indicator of fecal pollution. However, recent research challenges the assumption that the presence of E. coli in water is always an indicator of fecal contamination, with some types of E. coli having evolved to survive and grow in aquatic environments. These strains can form blooms in water storages, resulting in high E. coli counts even without fecal contamination. Although these bloom-forming strains lack virulence genes and pose little threat to public health, their presence in treated water triggers the same response as fecal-derived E. coli. Yet, little is known about the effectiveness of treatment processes in removing or inactivating them. This study evaluated the effectiveness of current treatment processes to remove bloom-forming strains, in comparison to fecal-derived strains, with conventional coagulation-flocculation-sedimentation and filtration investigated. Second, the effectiveness of current disinfection processes-chlorination, chloramination, and ultraviolet (UV) light to disinfect bloom-forming strains in comparison to fecal-derived strains-was assessed. These experiments showed that the responses of bloom isolates were not significantly different from those of fecal E. coli strains. Therefore, commonly used water treatment and disinfection processes are effective to remove bloom-forming E. coli strains from water.IMPORTANCEThe presence of Escherichia coli in water has long been used globally as a key indicator of fecal pollution and for quantifying water safety. Traditionally, it was believed that E. coli could only thrive within hosts and would perish outside, making its presence in water indicative of fecal contamination. However, recent research has unveiled strains of E. coli capable of surviving and proliferating in aquatic environments, forming blooms even in the absence of fecal contamination. While these bloom-forming strains lack the genes to be pathogenic, their detection in source or drinking water triggers the same response as fecal-derived E. coli. Yet, little is known about the efficacy of treatment processes in removing them. This study evaluated the effectiveness of conventional treatment and disinfection processes in removing bloom-forming strains compared to fecal-derived strains. Results indicate that these commonly used processes are equally effective against both types of E. coli, reassuring that bloom-forming E. coli strains can be eliminated from water.
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Affiliation(s)
- Melody Lau
- South Australian Water Corporation, Adelaide, South Australia, Australia
| | - Paul T. Monis
- South Australian Water Corporation, Adelaide, South Australia, Australia
| | - Brendon J. King
- South Australian Water Corporation, Adelaide, South Australia, Australia
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2
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Yu D, Andersson-Li M, Maes S, Andersson-Li L, Neumann NF, Odlare M, Jonsson A. Development of a logic regression-based approach for the discovery of host- and niche-informative biomarkers in Escherichia coli and their application for microbial source tracking. Appl Environ Microbiol 2024; 90:e0022724. [PMID: 38940567 PMCID: PMC11267920 DOI: 10.1128/aem.00227-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 06/07/2024] [Indexed: 06/29/2024] Open
Abstract
Microbial source tracking leverages a wide range of approaches designed to trace the origins of fecal contamination in aquatic environments. Although source tracking methods are typically employed within the laboratory setting, computational techniques can be leveraged to advance microbial source tracking methodology. Herein, we present a logic regression-based supervised learning approach for the discovery of source-informative genetic markers within intergenic regions across the Escherichia coli genome that can be used for source tracking. With just single intergenic loci, logic regression was able to identify highly source-specific (i.e., exceeding 97.00%) biomarkers for a wide range of host and niche sources, with sensitivities reaching as high as 30.00%-50.00% for certain source categories, including pig, sheep, mouse, and wastewater, depending on the specific intergenic locus analyzed. Restricting the source range to reflect the most prominent zoonotic sources of E. coli transmission (i.e., bovine, chicken, human, and pig) allowed for the generation of informative biomarkers for all host categories, with specificities of at least 90.00% and sensitivities between 12.50% and 70.00%, using the sequence data from key intergenic regions, including emrKY-evgAS, ibsB-(mdtABCD-baeSR), ompC-rcsDB, and yedS-yedR, that appear to be involved in antibiotic resistance. Remarkably, we were able to use this approach to classify 48 out of 113 river water E. coli isolates collected in Northwestern Sweden as either beaver, human, or reindeer in origin with a high degree of consensus-thus highlighting the potential of logic regression modeling as a novel approach for augmenting current source tracking efforts.IMPORTANCEThe presence of microbial contaminants, particularly from fecal sources, within water poses a serious risk to public health. The health and economic burden of waterborne pathogens can be substantial-as such, the ability to detect and identify the sources of fecal contamination in environmental waters is crucial for the control of waterborne diseases. This can be accomplished through microbial source tracking, which involves the use of various laboratory techniques to trace the origins of microbial pollution in the environment. Building on current source tracking methodology, we describe a novel workflow that uses logic regression, a supervised machine learning method, to discover genetic markers in Escherichia coli, a common fecal indicator bacterium, that can be used for source tracking efforts. Importantly, our research provides an example of how the rise in prominence of machine learning algorithms can be applied to improve upon current microbial source tracking methodology.
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Affiliation(s)
- Daniel Yu
- School of Public Health, University of Alberta, Edmonton, Alberta, Canada
| | | | - Sharon Maes
- Department of Natural Sciences, Design and Sustainable Development, Mid Sweden University, Östersund, Sweden
| | - Lili Andersson-Li
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - Norman F. Neumann
- School of Public Health, University of Alberta, Edmonton, Alberta, Canada
| | - Monica Odlare
- Department of Natural Sciences, Design and Sustainable Development, Mid Sweden University, Östersund, Sweden
| | - Anders Jonsson
- Department of Natural Sciences, Design and Sustainable Development, Mid Sweden University, Östersund, Sweden
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3
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Yu D, Stothard P, Neumann NF. Emergence of potentially disinfection-resistant, naturalized Escherichia coli populations across food- and water-associated engineered environments. Sci Rep 2024; 14:13478. [PMID: 38866876 PMCID: PMC11169474 DOI: 10.1038/s41598-024-64241-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 06/06/2024] [Indexed: 06/14/2024] Open
Abstract
The Escherichia coli species is comprised of several 'ecotypes' inhabiting a wide range of host and natural environmental niches. Recent studies have suggested that novel naturalized ecotypes have emerged across wastewater treatment plants and meat processing facilities. Phylogenetic and multilocus sequence typing analyses clustered naturalized wastewater and meat plant E. coli strains into two main monophyletic clusters corresponding to the ST635 and ST399 sequence types, with several serotypes identified by serotyping, potentially representing distinct lineages that have naturalized across wastewater treatment plants and meat processing facilities. This evidence, taken alongside ecotype prediction analyses that distinguished the naturalized strains from their host-associated counterparts, suggests these strains may collectively represent a novel ecotype that has recently emerged across food- and water-associated engineered environments. Interestingly, pan-genomic analyses revealed that the naturalized strains exhibited an abundance of biofilm formation, defense, and disinfection-related stress resistance genes, but lacked various virulence and colonization genes, indicating that their naturalization has come at the cost of fitness in the original host environment.
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Affiliation(s)
- Daniel Yu
- School of Public Health, University of Alberta, Edmonton, AB, Canada.
- Antimicrobial Resistance-One Health Consortium, Calgary, AB, Canada.
| | - Paul Stothard
- Department of Agriculture, Food and Nutritional Sciences, University of Alberta, Edmonton, AB, Canada
| | - Norman F Neumann
- School of Public Health, University of Alberta, Edmonton, AB, Canada
- Antimicrobial Resistance-One Health Consortium, Calgary, AB, Canada
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4
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Bong CW, Low KY, Chai LC, Lee CW. Prevalence and Diversity of Antibiotic Resistant Escherichia coli From Anthropogenic-Impacted Larut River. Front Public Health 2022; 10:794513. [PMID: 35356018 PMCID: PMC8960044 DOI: 10.3389/fpubh.2022.794513] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 01/20/2022] [Indexed: 11/13/2022] Open
Abstract
Aquatic environments, under frequent anthropogenic pressure, could serve as reservoirs that provide an ideal condition for the acquisition and dissemination of antibiotic resistance genetic determinants. We investigated the prevalence and diversity of antibiotic-resistant Escherichia coli by focusing on their genetic diversity, virulence, and resistance genes in anthropogenic-impacted Larut River. The abundance of E. coli ranged from (estimated count) Est 1 to 4.7 × 105 (colony-forming units per 100 ml) CFU 100 ml−1 to Est 1 to 4.1 × 105 CFU 100 ml−1 with phylogenetic group B1 (46.72%), and A (34.39%) being the most predominant. The prevalence of multiple antibiotic resistance phenotypes of E. coli, with the presence of tet and sul resistance genes, was higher in wastewater effluents than in the river waters. These findings suggested that E. coli could be an important carrier of the resistance genes in freshwater river environments. The phylogenetic composition of E. coli and resistance genes was associated with physicochemical properties and antibiotic residues. These findings indicated that the anthropogenic inputs exerted an effect on the E. coli phylogroup composition, diversification of multiple antibiotic resistance phenotypes, and the distribution of resistance genes in the Larut River.
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Affiliation(s)
- Chui Wei Bong
- Institute of Biological Sciences, Universiti Malaya, Kuala Lumpur, Malaysia
- Institute of Ocean and Earth Sciences (IOES), Universiti Malaya, Kuala Lumpur, Malaysia
- *Correspondence: Chui Wei Bong ;
| | - Kyle Young Low
- Institute of Ocean and Earth Sciences (IOES), Universiti Malaya, Kuala Lumpur, Malaysia
- Institute for Advanced Studies, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Lay Ching Chai
- Institute of Biological Sciences, Universiti Malaya, Kuala Lumpur, Malaysia
- Institute of Ocean and Earth Sciences (IOES), Universiti Malaya, Kuala Lumpur, Malaysia
| | - Choon Weng Lee
- Institute of Biological Sciences, Universiti Malaya, Kuala Lumpur, Malaysia
- Institute of Ocean and Earth Sciences (IOES), Universiti Malaya, Kuala Lumpur, Malaysia
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5
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Sun J, Lin Z, Ning D, Wang H, Zhang Z, He Z, Zhou J. Functional microbial community structures and chemical properties indicated mechanisms and potential risks of urban river eco-remediation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 803:149868. [PMID: 34481163 DOI: 10.1016/j.scitotenv.2021.149868] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 08/17/2021] [Accepted: 08/19/2021] [Indexed: 06/13/2023]
Abstract
To investigate the mechanisms and potential risks of river eco-remediation, river water, sediment, and biofilms in remediation facilities were sampled from a 2-year full scale eco-remediation site in an urban river in southeastern China. The samples from both remediated and adjacent control areas were analyzed for chemical properties and functional microbial community structures. The eco-remediation significantly changed the community structures in the river and introduced much more diverse functional microorganisms in facility biofilms. Corresponding to effective reduction of organics and ammonium in river water, some labile-organics-degrading and ammonia-oxidizing gene families showed higher abundances in river water of remediated area than control area, and were obviously more abundant in facility biofilms than in river water and sediment. The eco-remediation facilities showed obvious absorption of N, P, and heavy metals (Mn, CrVI, Fe, Al, As, Co), contributing to nutrients and metals removal from river water. The eco-remediation also increased transparency and sedimentation of some heavy metals (Cu, Pb, Zn), which probably associated with colloids breakdown. Various metal-resistance microorganisms showed different abundances between facility biofilms and sediment, in accordance with relative metals. Most detected pathogens were not significantly affected by eco-remediation. However, our measurements in sediment and facilities showed heavy metals accumulation and development of some pathogens and several antibiotic-resistance pathogens, alerting us to investigate and control these potential risks to ecosystem and human health.
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Affiliation(s)
- Jiao Sun
- State Key Joint Laboratory on Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China
| | - Ziyu Lin
- State Key Joint Laboratory on Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China
| | - Daliang Ning
- State Key Joint Laboratory on Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China; Institute for Environmental Genomics, Department of Microbiology and Plant Biology, School of Civil Engineering and Environmental Science, University of Oklahoma, Norman, OK, USA.
| | - Hui Wang
- State Key Joint Laboratory on Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China.
| | - Zuotao Zhang
- State Key Joint Laboratory on Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China
| | - Zhili He
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, School of Civil Engineering and Environmental Science, University of Oklahoma, Norman, OK, USA
| | - Jizhong Zhou
- State Key Joint Laboratory on Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China; Institute for Environmental Genomics, Department of Microbiology and Plant Biology, School of Civil Engineering and Environmental Science, University of Oklahoma, Norman, OK, USA; Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
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6
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Yu D, Banting G, Neumann NF. A review of the taxonomy, genetics, and biology of the genus Escherichia and the type species Escherichia coli. Can J Microbiol 2021; 67:553-571. [PMID: 33789061 DOI: 10.1139/cjm-2020-0508] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Historically, bacteriologists have relied heavily on biochemical and structural phenotypes for bacterial taxonomic classification. However, advances in comparative genomics have led to greater insights into the remarkable genetic diversity within the microbial world, and even within well-accepted species such as Escherichia coli. The extraordinary genetic diversity in E. coli recapitulates the evolutionary radiation of this species in exploiting a wide range of niches (i.e., ecotypes), including the gastrointestinal system of diverse vertebrate hosts as well as non-host natural environments (soil, natural waters, wastewater), which drives the adaptation, natural selection, and evolution of intragenotypic conspecific specialism as a strategy for survival. Over the last few years, there has been increasing evidence that many E. coli strains are very host (or niche)-specific. While biochemical and phylogenetic evidence support the classification of E. coli as a distinct species, the vast genomic (diverse pan-genome and intragenotypic variability), phenotypic (e.g., metabolic pathways), and ecotypic (host-/niche-specificity) diversity, comparable to the diversity observed in known species complexes, suggest that E. coli is better represented as a complex. Herein we review the taxonomic classification of the genus Escherichia and discuss how phenotype, genotype, and ecotype recapitulate our understanding of the biology of this remarkable bacterium.
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Affiliation(s)
- Daniel Yu
- School of Public Health, University of Alberta, Edmonton, AB T6G IC9, Canada.,School of Public Health, University of Alberta, Edmonton, AB T6G IC9, Canada
| | - Graham Banting
- School of Public Health, University of Alberta, Edmonton, AB T6G IC9, Canada.,School of Public Health, University of Alberta, Edmonton, AB T6G IC9, Canada
| | - Norman F Neumann
- School of Public Health, University of Alberta, Edmonton, AB T6G IC9, Canada.,School of Public Health, University of Alberta, Edmonton, AB T6G IC9, Canada
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7
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Di DYW, Shin H, Han D, Unno T, Hur HG. High genetic diversity of Vibrio parahaemolyticus isolated from tidal water and mud of southern coast of South Korea. FEMS Microbiol Ecol 2020; 95:5308828. [PMID: 30753635 DOI: 10.1093/femsec/fiz022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 02/06/2019] [Indexed: 12/30/2022] Open
Abstract
A horizontal, fluorophore-enhanced, repetitive extragenic palindromic-polymerase chain reaction (rep-PCR) DNA fingerprinting technique was adapted to examine the genotypic richness and source differentiation of Vibrio parahaemolyticus (n = 1749) isolated from tidal water and mud of southern coast of South Korea. The number of unique genotypes observed from June (163, 51.9%), September (307, 63.9%), December (205, 73.8%) and February (136, 74.7%), indicating a high degree of genetic diversity. Contrary, lower genetic diversity was detected in April (99, 46.8%), including predominant genotypes comprised >30 V. parahaemolyticus isolates. Jackknife analysis indicated that 65.1% tidal water isolates and 87.1% mud isolates were correctly assigned to their source groups. Sixty-nine isolates of pathogenic V. parahaemolyticus were clustered into two groups, separated by sampling month, source of isolation and serogroups. Serotypes O1, O4, O5, O10/O12 and O11 were the dominant serovariants, while serotypes O3/O13 were highly detected in April where there were no pathogenic V. parahaemolyticus isolates. Most of the V. parahaemolyticus isolates were resistant to ampicillin, ceftazidime and sulfamethoxazole. Interestingly, four V. parahaemolyticus isolates resistant to carbepenem did not contain the known carbapenemase-encoding gene, but possess an extended-spectrum β-lactamase blaTEM.
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Affiliation(s)
- Doris Y W Di
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Oryong-dong, Buk-gu, 61005 Gwangju, South Korea
| | - Hansub Shin
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Oryong-dong, Buk-gu, 61005 Gwangju, South Korea
| | - Dukki Han
- Faculty of Biotechnology, College of Applied Life Science, SARI, Jeju National University, 102 Jejudaehakno, Jeju-si, 690-756 Jeju, South Korea
| | - Tatsuya Unno
- Faculty of Biotechnology, College of Applied Life Science, SARI, Jeju National University, 102 Jejudaehakno, Jeju-si, 690-756 Jeju, South Korea
| | - Hor-Gil Hur
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Oryong-dong, Buk-gu, 61005 Gwangju, South Korea
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8
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Suzuki Y, Hashimoto R, Xie H, Nishimura E, Nishiyama M, Nukazawa K, Ishii S. Growth and antibiotic resistance acquisition of Escherichia coli in a river that receives treated sewage effluent. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 690:696-704. [PMID: 31301509 DOI: 10.1016/j.scitotenv.2019.07.050] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 06/14/2019] [Accepted: 07/03/2019] [Indexed: 05/13/2023]
Abstract
Wastewater treatment plants could discharge Escherichia coli and antibiotic resistant bacteria to the environment adjacent to, or downstream of their discharge point. However, their discharge also contains nutrients which could promote growth of E. coli in water environments. This study was done to clarify the potential of growth and antibiotic resistance acquisition of E. coli in a river environment. Levels of E. coli were monitored in a river that receives treated sewage effluent for over four years. River water, periphyton and sediment samples were collected at sites upstream and downstream of treated sewage inflow. Concentrations of E. coli increased in river water and periphyton at the sites downstream of the treated sewage inflow, although levels of E. coli were very low or below detection limit in the treated sewage samples. Concentrations of Chlorophyll a increased at the downstream sites, likely due to nutrient input from the treated sewage. Based on pulsed field gel electrophoresis, identical genotype occurred at multiple sites both upstream and downstream of the treated sewage inflow. However, strains resistant to antibiotics such as ampicillin, cefazolin, ciprofloxacin, and chloramphenicol were more frequently obtained from the downstream sites than the upstream sites. Multidrug resistant E. coli strains were detected in periphyton and sediment samples collected at the downstream sites. Non-resistant strains with PDGE genotype identical to the multi-drug strains were also detected, indicating that E. coli might have become resistant to antibiotics by acquiring resistance genes via horizontal gene transfer. Laboratory incubation experiment showed the growth of E. coli in periphyton or sediment-fed river water samples. These results suggest that the wastewater treatment inflow did not directly provide E. coli to the river water, but could promote the growth of periphyton, which could lead to the elevated levels of E. coli and the emergence of antibiotic resistant E. coli.
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Affiliation(s)
- Yoshihiro Suzuki
- Department of Civil and Environmental Engineering, Faculty of Engineering, University of Miyazaki, Gakuen Kibanadai-Nishi 1-1, Miyazaki 889-2192, Japan.
| | - Reina Hashimoto
- Department of Civil and Environmental Engineering, Faculty of Engineering, University of Miyazaki, Gakuen Kibanadai-Nishi 1-1, Miyazaki 889-2192, Japan
| | - Hui Xie
- Department of Civil and Environmental Engineering, Faculty of Engineering, University of Miyazaki, Gakuen Kibanadai-Nishi 1-1, Miyazaki 889-2192, Japan
| | - Emi Nishimura
- Department of Civil and Environmental Engineering, Faculty of Engineering, University of Miyazaki, Gakuen Kibanadai-Nishi 1-1, Miyazaki 889-2192, Japan
| | - Masateru Nishiyama
- Department of Food, Life and Environmetal Science, Faculty of Agriculture, Yamagata University, Wakaba-machi 1-23, Tsuruoka, Yamagata 977-8222, Japan
| | - Kei Nukazawa
- Department of Civil and Environmental Engineering, Faculty of Engineering, University of Miyazaki, Gakuen Kibanadai-Nishi 1-1, Miyazaki 889-2192, Japan
| | - Satoshi Ishii
- Department of Soil, Water, and Climate, University of Minnesota, MN 55108-6028, USA; BioTechnology Institute, University of Minnesota, MN 55108-1095, USA
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9
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Jang J, Hur HG, Sadowsky MJ, Byappanahalli MN, Yan T, Ishii S. Environmental Escherichia coli: ecology and public health implications-a review. J Appl Microbiol 2017; 123:570-581. [PMID: 28383815 DOI: 10.1111/jam.13468] [Citation(s) in RCA: 334] [Impact Index Per Article: 47.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 03/29/2017] [Accepted: 03/31/2017] [Indexed: 12/19/2022]
Abstract
Escherichia coli is classified as a rod-shaped, Gram-negative bacterium in the family Enterobacteriaceae. The bacterium mainly inhabits the lower intestinal tract of warm-blooded animals, including humans, and is often discharged into the environment through faeces or wastewater effluent. The presence of E. coli in environmental waters has long been considered as an indicator of recent faecal pollution. However, numerous recent studies have reported that some specific strains of E. coli can survive for long periods of time, and potentially reproduce, in extraintestinal environments. This indicates that E. coli can be integrated into indigenous microbial communities in the environment. This naturalization phenomenon calls into question the reliability of E. coli as a faecal indicator bacterium (FIB). Recently, many studies reported that E. coli populations in the environment are affected by ambient environmental conditions affecting their long-term survival. Large-scale studies of population genetics revealed the diversity and complexity of E. coli strains in various environments, which are affected by multiple environmental factors. This review examines the current knowledge on the ecology of E. coli strains in various environments with regard to its role as a FIB and as a naturalized member of indigenous microbial communities. Special emphasis is given on the growth of pathogenic E. coli in the environment, and the population genetics of environmental members of the genus Escherichia. The impact of environmental E. coli on water quality and public health is also discussed.
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Affiliation(s)
- J Jang
- BioTechnology Institute, University of Minnesota, St. Paul, MN, USA
| | - H-G Hur
- School of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, Korea
| | - M J Sadowsky
- BioTechnology Institute, University of Minnesota, St. Paul, MN, USA.,Department of Soil, Water, and Climate, University of Minnesota, St. Paul, MN, USA
| | - M N Byappanahalli
- Lake Michigan Ecological Research Station, Great Lakes Science Center, U.S. Geological Survey, Chesterton, IN, USA
| | - T Yan
- Department of Civil and Environmental Engineering, University of Hawai'i at Manoa, Honolulu, HI, USA
| | - S Ishii
- BioTechnology Institute, University of Minnesota, St. Paul, MN, USA.,Department of Soil, Water, and Climate, University of Minnesota, St. Paul, MN, USA
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10
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Huang WC, Hsu BM, Kao PM, Tao CW, Ho YN, Kuo CW, Huang YL. Seasonal distribution and prevalence of diarrheagenic Escherichia coli in different aquatic environments in Taiwan. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2016; 124:37-41. [PMID: 26454073 DOI: 10.1016/j.ecoenv.2015.09.040] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 09/25/2015] [Accepted: 09/27/2015] [Indexed: 06/05/2023]
Abstract
Diarrheagenic Escherichia coli (DEC) are the most common agents of diarrhea. Waterborne DEC could pose a potential health risk to human through agricultural, household, recreational, and industrial use. There are few published reports on the detection of DEC and its seasonal distribution in aquatic environments. The presence of DEC in different types of aquatic environments was investigated in this study. Water samples were collected from major rivers, water reservoirs, and recreational hot springs throughout Taiwan. Moreover, an intensive water sampling plan was carried out along Puzih River. The detection of DEC target genes was used to determine the presence of enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC), and Shiga toxin-producing E. coli (STEC). Among the 383 water samples analyzed, DEC was found in 122 (31.8%) samples. The detection rate varied by genotype, raging from 3.6% for STEC to 17.2% for EPEC. The DEC detection rate was higher from river waters than reservoirs and hot springs. In addition, DEC was detected at a higher rate in spring and summer. The presence of EPEC was significantly associated with total coliform levels among hot spring samples. Moreover, the presence of ETEC in river water samples was associated with heterotrophic plate counts. Water with EPEC differed significantly in pH from Puzih River samples. These results suggest that seasonal characteristics may affect the presence of DEC in different aquatic environments, and water quality indicators may be indicative of the presence of DEC.
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Affiliation(s)
- Wen-Chien Huang
- Department of Medicine, Mackay Medicine College, Taipei, Taiwan, ROC; Department of Thoracic Surgery, Mackay Memorial Hospital, Taipei, Taiwan, ROC; Institute of Traditional Medicine, School of Medicine, National Yang Ming University, Taipei, Taiwan, ROC
| | - Bing-Mu Hsu
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC.
| | - Po-Min Kao
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC
| | - Chi-Wei Tao
- Section of Respiratory Therapy, Cheng Hsin General Hospital, Taipei, Taiwan, ROC
| | - Ying-Ning Ho
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC
| | - Chun-Wei Kuo
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC
| | - Yu-Li Huang
- Department of Safety Health and Environmental Engineering, National Kaohsiung First University of Science and Technology, Kaohsiung, Taiwan, ROC
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11
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Jang J, Di DYW, Han D, Unno T, Lee JH, Sadowsky MJ, Hur HG. Dynamic changes in the population structure ofEscherichia coliin the Yeongsan River basin of South Korea. FEMS Microbiol Ecol 2015; 91:fiv127. [DOI: 10.1093/femsec/fiv127] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/18/2015] [Indexed: 11/14/2022] Open
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12
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Pathogenic potential, genetic diversity, and population structure of Escherichia coli strains isolated from a forest-dominated watershed (Comox Lake) in British Columbia, Canada. Appl Environ Microbiol 2014; 81:1788-98. [PMID: 25548059 DOI: 10.1128/aem.03738-14] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Escherichia coli isolates (n = 658) obtained from drinking water intakes of Comox Lake (2011 to 2013) were screened for the following virulence genes (VGs): stx1 and stx2 (Shiga toxin-producing E. coli [STEC]), eae and the adherence factor (EAF) gene (enteropathogenic E. coli [EPEC]), heat-stable (ST) enterotoxin (variants STh and STp) and heat-labile enterotoxin (LT) genes (enterotoxigenic E. coli [ETEC]), and ipaH (enteroinvasive E. coli [EIEC]). The only genes detected were eae and stx2, which were carried by 37.69% (n = 248) of the isolates. Only eae was harbored by 26.74% (n = 176) of the isolates, representing potential atypical EPEC strains, while only stx2 was detected in 10.33% (n = 68) of the isolates, indicating potential STEC strains. Moreover, four isolates were positive for both the stx2 and eae genes, representing potential EHEC strains. The prevalence of VGs (eae or stx2) was significantly (P < 0.0001) higher in the fall season, and multiple genes (eae plus stx2) were detected only in fall. Repetitive element palindromic PCR (rep-PCR) fingerprint analysis of 658 E. coli isolates identified 335 unique fingerprints, with an overall Shannon diversity (H') index of 3.653. Diversity varied among seasons over the years, with relatively higher diversity during fall. Multivariate analysis of variance (MANOVA) revealed that the majority of the fingerprints showed a tendency to cluster according to year, season, and month. Taken together, the results indicated that the diversity and population structure of E. coli fluctuate on a temporal scale, reflecting the presence of diverse host sources and their behavior over time in the watershed. Furthermore, the occurrence of potentially pathogenic E. coli strains in the drinking water intakes highlights the risk to human health associated with direct and indirect consumption of untreated surface water.
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Jang J, Di DYW, Lee A, Unno T, Sadowsky MJ, Hur HG. Seasonal and genotypic changes in escherichia coli phylogenetic groups in the Yeongsan River basin of South Korea. PLoS One 2014; 9:e100585. [PMID: 24999864 PMCID: PMC4085056 DOI: 10.1371/journal.pone.0100585] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 05/28/2014] [Indexed: 11/19/2022] Open
Abstract
With 3,480 E. coli strains isolated from the Yeongsan River basin, South Korea, correlations between phylogenetic groups and horizontal fluorophore enhanced rep-PCR (HFERP) genotypes were examined, and environmental factors affecting E. coli phylogenetic groups in the river water were determined. Interestingly, multidimentional scaling (MDS) analyses based on HFERP DNA fingerprint data indicated that E. coli in phylogenetic groups A and B1 were uniquely clustered. Results of self-organized maps (SOMs) analyses also indicated that E. coli phylogenetic groups were seasonally affected by water temperature, with greater occurrences of phylogenetic groups A and B1 in low and high temperature seasons, respectively. The presence of E. coli in phylogenetic groups A and B1 were inversely related. Furthermore, redundancy analysis (RDA) revealed that phylogenetic group B1 correlated positively with temperature, strain diversity, and biochemical oxygen demand (BOD) but negatively with phylogenetic group A. Results of this study indicated that while E. coli strains could be clustered based on their genotypes and environment conditions, their phylogenetic groups did not change in relation to the same conditions. The distributional differences of phylogenetic groups among E. coli populations in different environments may be caused by different genomic adaptability and plasticity of E. coli strains belonging to each phylogenetic group. Although several previous studies have reported different E. coli ecological structures depending on their origins, this study is a first description of the specific environmental factors affecting E. coli phylogenetic groups in river water.
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Affiliation(s)
- Jeonghwan Jang
- School of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Doris Y. W. Di
- School of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Anna Lee
- School of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Tatsuya Unno
- College of Molecular Life Sciences, Jeju National University, Jeju, Republic of Korea
| | - Michael J. Sadowsky
- Department of Soil, Water and Climate, University of Minnesota, St. Paul, Minnesota, United States of America
- BioTechnology Institute, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Hor-Gil Hur
- School of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
- International Environmental Analysis and Education Center, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
- * E-mail:
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Prevalence of Escherichia coli in surface waters of Southeast Asian cities. World J Microbiol Biotechnol 2013; 29:2115-24. [DOI: 10.1007/s11274-013-1376-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 05/10/2013] [Indexed: 12/21/2022]
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Jang J, Suh YS, Di DYW, Unno T, Sadowsky MJ, Hur HG. Pathogenic Escherichia coli strains producing extended-spectrum β-lactamases in the Yeongsan River basin of South Korea. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:1128-1136. [PMID: 23256438 DOI: 10.1021/es303577u] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A total of 3564 E. coli isolates obtained from Yeongsan River basin of South Korea were investigated for their production of extended-spectrum β-lactamases (ESBLs) and potential pathogenicity to better understand the linkage between antibiotic-resistant pathogens in the environment and their public health risks. Interestingly, 60% (53 of 89) of the screen-positive ESBL producers were determined to be potentially one or both of the diarrheagenic and extraintestinal pathogenic (ExPEC) pathotypes, suggesting that trade-off between resistance and virulence of E. coli may not apply to this study. In addition, 67% (60 of 89) of the screen-positive ESBL producers possessed more than one β-lactamase gene, and most (59 of 63) of the ESBL producers had the CTX-M-14 enzyme, which is the most dominant ESBL and seems to be related to urban anthropogenic activities. About 68% (36 of 53) of the potential pathogenic strains were resistant to more than 2 non-β-lactam antibiotics. Results from this study indicate that the Yeongsan River basin has been contaminated with antibiotic-resistant and potential pathogenic E. coli strains. While few studies have examined pathogenecity of ESBL-producing bacteria, this study reports the possible public health risk which could be caused by the fecal indicator bacterium itself containing both ESBL genes and virulence factors. This will likely impact the dissemination of potential pathogenic E. coli producing ESBLs in the environment and suggests the need for further investigations of antibiotic-resistant pathogens to prevent public health impacts in the Yeongsan River basin.
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Affiliation(s)
- Jeonghwan Jang
- School of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
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