Contaminated Stream Water as Source for Escherichia coli O157 Illness in Children

Two-year Monitoring of Microbiological Water Quality in Small Water Supply Systems: Implications for Microbial Risk Management

Small water supply systems (SWSSs) are often more vulnerable to waterborne disease outbreaks. In Japan, many SWSSs operate without regulation under the Waterworks Law, yet there is limited investigation into microbial contamination and the associated health risks. In this study, the microbiological water quality of four SWSSs that utilize mountain streams as water sources and do not install water treatment facilities were monitored for over 2 years. In investigated SWSSs, the mean heterotrophic plate counts were below 350 CFU/mL, and the total bacterial loads (16S rDNA concentration) ranged from 4.71 to 5.35 log10 copies/mL. The results also showed the consistent presence of fecal indicator bacteria (FIB), i.e., Escherichia coli and Clostridium perfringens, suggesting the potential of fecal pollution. E. coli was then utilized as an indicator to assess the health risk posed by E. coli O157:H7 and Campylobacter jejuni. The results indicated that the estimated mean annual risk of infection and disability-adjusted life years (DALYs) exceeded acceptable levels in all SWSSs for the two reference pathogens. To ensure microbial water safety, implementing appropriate water treatment facilities with an estimated mean required reduction of 5-6 log10 was necessary. This study highlighted the potential microbial contamination and health risk level in SWSSs that utilize mountain streams as water sources, even though the water sources were almost not affected by human activities. Furthermore, this study would also be helpful in supporting risk-based water management to ensure a safe water supply in SWSSs.

Prevalence and Implications of Shiga Toxin-Producing E. coli in Farm and Wild Ruminants

Shiga-toxin-producing Escherichia coli (STEC) is a food-borne pathogen that causes human gastrointestinal infections across the globe, leading to kidney failure or even death in severe cases. E. coli are commensal members of humans and animals' (cattle, bison, and pigs) guts, however, may acquire Shiga-toxin-encoded phages. This acquisition or colonization by STEC may lead to dysbiosis in the intestinal microbial community of the host. Wildlife and livestock animals can be asymptomatically colonized by STEC, leading to pathogen shedding and transmission. Furthermore, there has been a steady uptick in new STEC variants representing various serotypes. These, along with hybrids of other pathogenic E. coli (UPEC and ExPEC), are of serious concern, especially when they possess enhanced antimicrobial resistance, biofilm formation, etc. Recent studies have reported these in the livestock and food industry with minimal focus on wildlife. Disturbed natural habitats and changing climates are increasingly creating wildlife reservoirs of these pathogens, leading to a rise in zoonotic infections. Therefore, this review comprehensively surveyed studies on STEC prevalence in livestock and wildlife hosts. We further present important microbial and environmental factors contributing to STEC spread as well as infections. Finally, we delve into potential strategies for limiting STEC shedding and transmission.

Detangling Seasonal Relationships of Fecal Contamination Sources and Correlates with Indicators in Michigan Watersheds

Despite the widely acknowledged public health impacts of surface water fecal contamination, there is limited understanding of seasonal effects on (i) fate and transport processes and (ii) the mechanisms by which they contribute to water quality impairment. Quantifying relationships between land use, chemical parameters, and fecal bacterial concentrations in watersheds can help guide the monitoring and control of microbial water quality and explain seasonal differences. The goals of this study were to (i) identify seasonal differences in Escherichia coli and Bacteroides thetaiotaomicron concentrations, (ii) evaluate environmental drivers influencing microbial contamination during baseflow, snowmelt, and summer rain seasons, and (iii) relate seasonal changes in B. thetaiotaomicron to anticipated gastrointestinal infection risks. Water chemistry data collected during three hydroclimatic seasons from 64 Michigan watersheds were analyzed using seasonal linear regression models with candidate variables including crop and land use proportions, prior precipitation, chemical parameters, and variables related to both wastewater treatment and septic usage. Adaptive least absolute shrinkage and selection operator (LASSO) linear regression with bootstrapping was used to select explanatory variables and estimate coefficients. Regardless of season, wastewater treatment plant and septic system usage were consistently selected in all primary models for B. thetaiotaomicron and E. coli. Chemistry and precipitation-related variable selection depended upon season and organism. These results suggest a link between human pollution (e.g., septic systems) and microbial water quality that is dependent on flow regime.

IMPORTANCE In this study, a data set of 64 Michigan watersheds was utilized to gain insights into fecal contamination sources, drivers, and chemical correlates across seasons for general E. coli and human-specific fecal indicators. Results reaffirmed a link between human-specific sources (e.g., septic systems) and microbial water quality. While the importance of human sources of fecal contamination and fate and transport variables (e.g., precipitation) remain important across seasons, this study provides evidence that fate and transport mechanisms vary with seasonal hydrologic condition and microorganism source. This study contributes to a body of research that informs prioritization of fecal contamination source control and surveillance strategy development to reduce the public health burden of surface water fecal contamination.

The Persistence of Bacterial Pathogens in Surface Water and Its Impact on Global Food Safety

Water is vital to agriculture. It is essential that the water used for the production of fresh produce commodities be safe. Microbial pathogens are able to survive for extended periods of time in water. It is critical to understand their biology and ecology in this ecosystem in order to develop better mitigation strategies for farmers who grow these food crops. In this review the prevalence, persistence and ecology of four major foodborne pathogens, Shiga toxin-producing Escherichia coli (STEC), Salmonella, Campylobacter and closely related Arcobacter, and Listeria monocytogenes, in water are discussed. These pathogens have been linked to fresh produce outbreaks, some with devastating consequences, where, in a few cases, the contamination event has been traced to water used for crop production or post-harvest activities. In addition, antimicrobial resistance, methods improvements, including the role of genomics in aiding in the understanding of these pathogens, are discussed. Finally, global initiatives to improve our knowledge base of these pathogens around the world are touched upon.

Review: Trends in point-of-care diagnosis for Escherichia coli O157:H7 in food and water

Escherichia coli O157:H7, a Shiga-producing E. coli is a major pathogenic E. coli strain which since the early 1980s has become a crucial food and water-borne pathogen. Several management strategies can be applied to control the spread of infection; however early diagnosis represents the optimum preventive strategy to minimize the infection. Therefore, it is crucial to detect this pathogen in a fast and efficient manner in order to reduce the morbidity and mortality. Currently used gold standard tests rely on culture and pre-enrichment of E. coli O157:H7 from the contaminated source; they are time consuming and laborious. Molecular methods such as polymerase chain reaction are sensitive; however, they require expensive instrumentation. Therefore, there is a requirement for Accurate, Sensitive, Specific, User friendly, Rapid, Equipment free and Deliverable (ASSURED) detection methods for use in the laboratory and in the field. Emerging technologies such as isothermal amplification methods, biosensors, surface enhanced Raman Spectroscopy, paper-based diagnostics and smartphone-based digital methods are recognized as new approaches in the field of E. coli O157:H7 diagnostics and are discussed in this review. Mobile PCR and CRISPR-Cas diagnostic platforms have been identified as new tools in E. coli O157:H7 POC diagnostics with the potential for implementation by industry. This review describes advances and progress in the field of E. coli O157:H7 diagnosis in the context of food and water industry. The focus is on emerging high throughput point-of-care (POC) E. coli O157:H7 diagnostics and the requirement for the transformation to service routine diagnostics in the food and water industry.

Characterization of a non-glycosylated fraction from honey proteins of Melipona beecheii with antimicrobial activity against Escherichia coli O157:H7

AIMS

To analyse the non-glycosylated protein fraction from Melipona beecheii honey for antimicrobial activity against Escherichia coli O157:H7.

METHODS AND RESULTS

The proteins from M. beecheii honey were separated according to their degree of glycosylation using Concanavalin A-affinity chromatography. The total protein extract and its fractions were analysed by 1D and 2D electrophoresis. We also determined the antimicrobial and antihaemolytic activities of the total protein extract and the non-glycosylated fraction. Furthermore, we evaluated the effect of this non-glycosylated fraction for the expression of the Stx1, Stx2, EAE and HlyA pathogen genes. Melipona beecheii honey contained at least 24 proteins with molecular weights ranging between 7·6 and 95 kDa and isoelectric points between 3 and 10, three proteins from the 24 are non-glycosylated. The non-glycosylated fraction had an MIC₉₀ of 1·128 µg ml^-1 , and this fraction inhibited the haemolytic activity of the pathogen, as well as reduced the expression of Stx1, Stx2 and HlyA. The MbF1-2 protein from the non-glycosylated fraction was sequenced and identified as a homologue of the royal jelly-like protein of Melipona quadrifasciata.

CONCLUSIONS

The non-glycosylated protein fraction from M. beecheii honey greatly contributes to antibacterial activity and it is composed of at least three proteins, of which MbF1-2 provided over 50% of the antimicrobial activity.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study showed significant antimicrobial activity from several proteins present in the honey of M. beecheii. Interestingly, the non-glycosylated protein fraction demonstrated antihaemolytic activity and adversely affected the expression of virulence genes in Escherichia coli O157:H7; these proteins have the potential to be used in developing therapeutic agents against this bacterium.

Dissemination of antibiotic resistance genes (ARGs) via integrons in Escherichia coli: A risk to human health

With the induction of various emerging environmental contaminants such as antibiotic resistance genes (ARGs), environment is considered as a key indicator for the spread of antimicrobial resistance (AMR). As such, the ARGs mediated environmental pollution raises a significant public health concern worldwide. Among various genetic mechanisms that are involved in the dissemination of ARGs, integrons play a vital role in the dissemination of ARGs. Integrons are mobile genetic elements that can capture and spread ARGs among environmental settings via transmissible plasmids and transposons. Most of the ARGs are found in Gram-negative bacteria and are primarily studied for their potential role in antibiotic resistance in clinical settings. As one of the most common microorganisms, Escherichia coli (E. coli) is widely studied as an indicator carrying drug-resistant genes, so this article aims to provide an in-depth study on the spread of ARGs via integrons associated with E. coli outside clinical settings and highlight their potential role as environmental contaminants. It also focuses on multiple but related aspects that do facilitate environmental pollution, i.e. ARGs from animal sources, water treatment plants situated at or near animal farms, agriculture fields, wild birds and animals. We believe that this updated study with summarized text, will facilitate the readers to understand the primary mechanisms as well as a variety of factors involved in the transmission and spread of ARGs among animals, humans, and the environment.

Combining physicochemical properties and microbiome data to evaluate the water quality of South African drinking water production plants

Anthropogenic activities in catchments used for drinking water production largely contaminates source waters, and this may impact the quality of the final drinking water product. These contaminants may also affect taxonomic and functional profiles of the bacterial communities in the drinking water. Here, we report an integrated insight into the microbiome and water quality of four water treatment plants (NWC, NWE, WCA and NWG) that supply portable water to communities in South Africa. A new scoring system based on combined significant changes of physicochemical parameters and microbial abundance from raw to treated water was used to evaluate the effectiveness of the treatment plants at water purification. Physicochemical parameters which include total soluble solids, turbidity, pH, nitrites and phosphorus among others, were measured in source, treated, and distributed water. There were general statistically significant (P ≤ 0.05) differences between raw and treated water, demonstrating the effectiveness of the purification process. Illumina sequencing of the 16S rRNA gene was used for taxonomic profiling of the microbial communities and this data was used to infer functional attributes of the communities. Structure and composition of the bacterial communities differed significantly (P < 0.05) among the treatment plants, only NWE and NWG showed no significant differences (P > 0.05), this correlated with the predicted functional profile of the microbial communities obtained from Phylogenetic Investigation of Communities by Reconstruction of Observed States (PICRUSt), as well as the likely pollutants of source water. Bacteroidetes, Chlorobi and Fibrobacteres significantly differed (P < 0.05) between raw and distributed water. PICRUSt inferred a number of pathways involved in the degradation of xenobiotics such as Dichlorodiphenyltrichloroethane, atrazine and polycyclic aromatic hydrocarbons. More worryingly, was the presence of pathways involved in beta-lactam resistance, potential pathogenic Escherichia coli infection, Vibrio cholerae infection, and Shigellosis. Also present in drinking and treated water were OTUs associated with a number of opportunistic pathogens.

Response of soil native microbial community to Eschericia coli O157:H7 invasion

The presence of Eschericia coli O157:H7 in the natural environment is a serious threat to human health. The native microbial community in soil plays an important role in resisting E. coli O157:H7 invasion. This study examined the responses of soil microbial community to E. coli O157:H7 invasion during a 32-day incubation. The E. coli O157:H7 persisted longer in γ-irradiated soil than non-irradiated soil while glucose addition decreased its persistence in the irradiated soil which was associated with an increasing recovery of the native community. The invasion of E. coli O157:H7 increased soil organic carbon mineralization, an indicator of microbial activity, in both non-irradiated and irradiated soils, while glucose addition significantly promoted the carbon mineralization process. The 16S rRNA sequencing data showed the gradual recovery of the native bacterial population including specific taxa such as proteobacteria and actinobacteria following irradiation. It is concluded that soil microbial function and structure can affect persistence of E. coli O157:H7 and that lower biodiversity of the native community favors its persistence.

Metagenomics as a Public Health Risk Assessment Tool in a Study of Natural Creek Sediments Influenced by Agricultural and Livestock Runoff: Potential and Limitations

Little is known about the public health risks associated with natural creek sediments that are affected by runoff and fecal pollution from agricultural and livestock practices. For instance, the persistence of foodborne pathogens such as Shiga toxin-producing Escherichia coli (STEC) originating from these practices remains poorly quantified. Towards closing these knowledge gaps, the water-sediment interface of two creeks in the Salinas River Valley of California was sampled over a 9-month period using metagenomics and traditional culture-based tests for STEC. Our results revealed that these sediment communities are extremely diverse and have functional and taxonomic diversity comparable to that observed in soils. With our sequencing effort (∼4 Gbp per library), we were unable to detect any pathogenic E. coli in the metagenomes of 11 samples that had tested positive using culture-based methods, apparently due to relatively low abundance. Furthermore, there were no significant differences in the abundance of human- or cow-specific gut microbiome sequences in the downstream impacted sites compared to that in upstream more pristine (control) sites, indicating natural dilution of anthropogenic inputs. Notably, the high number of metagenomic reads carrying antibiotic resistance genes (ARGs) found in all samples was significantly higher than ARG reads in other available freshwater and soil metagenomes, suggesting that these communities may be natural reservoirs of ARGs. The work presented here should serve as a guide for sampling volumes, amount of sequencing to apply, and what bioinformatics analyses to perform when using metagenomics for public health risk studies of environmental samples such as sediments.IMPORTANCE Current agricultural and livestock practices contribute to fecal contamination in the environment and the spread of food- and waterborne disease and antibiotic resistance genes (ARGs). Traditionally, the level of pollution and risk to public health are assessed by culture-based tests for the intestinal bacterium Escherichia coli However, the accuracy of these traditional methods (e.g., low accuracy in quantification, and false-positive signal when PCR based) and their suitability for sediments remain unclear. We collected sediments for a time series metagenomics study from one of the most highly productive agricultural regions in the United States in order to assess how agricultural runoff affects the native microbial communities and if the presence of Shiga toxin-producing Escherichia coli (STEC) in sediment samples can be detected directly by sequencing. Our study provided important information on the potential for using metagenomics as a tool for assessment of public health risk in natural environments.

Prediction, Diversity, and Genomic Analysis of Temperate Phages Induced From Shiga Toxin-Producing Escherichia coli Strains

Shiga toxin-producing Escherichia coli (STEC) is a notorious foodborne pathogen containing stx genes located in the sequence region of Shiga toxin (Stx) prophages. Stx prophages, as one of the mobile elements, are involved in the transfer of virulence genes to other strains. However, little is known about the diversity of prophages among STEC strains. The objectives of this study were to predict various prophages from different STEC genomes and to evaluate the effect of different stress factors on Stx prophage induction. Forty bacterial whole-genome sequences of STEC strains obtained from National Center for Biotechnology Information (NCBI) were used for the prophage prediction using PHASTER webserver. Eight of the STEC strains from different serotypes were subsequently selected to quantify the induction of Stx prophages by various treatments, including antibiotics, temperature, irradiation, and antimicrobial agents. After induction, Stx1-converting phage Lys8385Vzw and Stx2-converting phage Lys12581Vzw were isolated and further confirmed for the presence of stx genes using conventional PCR. Phage morphology was observed by transmission electron microscopy. The prediction results showed an average of 8–22 prophages, with one or more encoding stx, were predicted from each STEC genome obtained in this study. Additionally, the phylogenetic analysis revealed high genetic diversity of Stx prophages among the 40 STEC genomes. However, the sequences of Stx prophages in the genomes of STEC O45, O111, and O121 strains, in general, shared higher genetic homology than those in other serotypes. Interestingly, most STEC strains with two or more stx genes carried at least one each of Stx1 and Stx2 prophages. The induction results indicated EDTA and UV were the most effective inducers of Stx1 and Stx2 prophages of the 8 selected STECs, respectively. Additionally, both Stx-converting phages could infect non-pathogenic E. coli (WG5, DH5α, and MG1655) and form new lysogens. The findings of this study confirm that Stx prophages can be induced by environmental stress, such as exposure to solar radiation, and lysogenize other commensal E. coli strains.

Molecular characteristics and genotypic diversity of enterohaemorrhagic Escherichia coli O157:H7 isolates in Gauteng region, South Africa

Enterohaemorrhagic Escherichia coli (EHEC) O157:H7 is one of the major foodborne and waterborne pathogens causing severe diseases and outbreaks worldwide. There is scarcity of EHEC O157:H7 data in South Africa. This study was carried out to determine the molecular characteristics and genotypic diversity of EHEC O157:H7 isolates in the Gauteng region, South Africa. Samples were cultured on selective chromogenic media. Antibiotic susceptibility profile of isolates was determined using the VITEK®-2 automated system. Isolates were characterised using multiplex PCR assays and the genetic diversity was determined using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). A total of 520 samples of which 270 environmental water samples and 250 stool specimens were collected and analysed. Overall, EHEC O157:H7 was recovered from 2.3% (12/520) of samples collected. Environmental water samples and clinical stool specimens showed a prevalence of 4.07% (11/270) and 0.4% (1/250) respectively. Antibiotic susceptibility profile varied from isolates with full susceptibility to isolates with resistance to multiple antibiotics. Most resistance was detected to the penicillins, specifically ampicillin (7/12), amoxicillin (3/12) and piperacillin/Tazobactam (3/12) followed by one of the folate inhibitors, trimethoprim (3/12) and the carbapenems, imipenem and meropenem (2/12) each. Three isolates harboured a combination of Shiga-toxins (Stx)-2, intimin (eae) and enterohaemolysin (hlyA) genes, while two isolates harboured the Stx-1, Stx-2 and hlyA genes. The PFGE performed showed that EHEC O157:H7 isolates were genetically diverse, with two minor pulsotypes and eight singletons. The MLST analysis identified three sequence types (STs) (ST10, ST11 and ST1204) that have been previously reported associated with outbreaks. The STs identified in this study pose a potential public health risk to consumers of untreated environmental water and closed human contacts. There is necessity to enhance surveillance in reducing the propagation of this bacterium which is a public health problem.

Shiga toxin-producing Escherichia coli O26:H11 associated with a cluster of haemolytic uraemic syndrome cases in South Africa, 2017

INTRODUCTION

Shiga toxin-producing Escherichia coli (STEC) are foodborne pathogens that may cause diarrhoeal outbreaks and occasionally are associated with haemolytic-uraemic syndrome (HUS). We report on STEC O26:H11 associated with a cluster of four HUS cases in South Africa in 2017.

METHODOLOGY

All case-patients were female and aged 5 years and under. Standard microbiological tests were performed for culture and identification of STEC from specimens (human stool and food samples). Further analysis of genomic DNA extracted from bacterial cultures and specimens included PCR for specific virulence genes, whole-genome sequencing and shotgun metagenomic sequencing.

RESULTS

For 2/4 cases, stool specimens revealed STEC O26:H11 containing eae, stx2a and stx2b virulence genes. All food samples were found to be negative for STEC. No epidemiological links could be established between the HUS cases. Dried meat products were the leading food item suspected to be the vehicle of transmission for these cases, as 3/4 case-patients reported they had eaten this. However, testing of dried meat products could not confirm this.

CONCLUSION

Since STEC infection does not always lead to severe symptoms, it is possible that many more cases were associated with this cluster and largely went unrecognized.

First Insights Into Bacterial Gastrointestinal Tract Communities of the Eurasian Beaver (Castor fiber)

The Eurasian or European beaver (Castor fiber) is the second-largest living rodent after the capybara. It is a semi-aquatic animal known for building dams and lodges. They strictly feed on lignocellulose-rich plants and correspondingly harbor cellulolytic microbial communities in their digestive tract. In this study, the bacterial community composition, diversity, and functional profile of different gut compartments ranging from stomach to colon have been explored. A total of 277 bacterial operational taxonomic units (OTUs) at species level were obtained from the gut systems of two males (juvenile and subadult) and one subadult female beaver. In general, cecum and colon are dominated by Firmicutes and Actinobacteria. High abundance of Bacteroidetes was observed only in male juvenile beaver cecum and colon, suggesting that the bacterial composition changes with age. Within the cecum and colon, members of known cellulase-producing bacterial taxa including the families Ruminococcaceae, Lachnospiraceae, and Clostridiaceae 1 were detected. The presence of putative genes encoding cellulolytic and carbohydrate-degrading enzymes indicated also the degradation of recalcitrant plant material in both gut compartments. The bacterial community in the gut systems of the Eurasian beaver differed from that of the North American beaver. Higher abundance of Actinobacteria and lower abundances of Bacteroidetes were recorded in the Eurasian beaver. Similar differences were obtained to bacterial communities of termites and herbivorous animals such as bovine. The data presented in this study provides the first insight into bacterial communities in the gut system of the Eurasian beaver.

Fecal pollution: new trends and challenges in microbial source tracking using next-generation sequencing

In this minireview, we expand upon traditional microbial source tracking (MST) methods by discussing two recently developed, next-generation-sequencing (NGS)-based MST approaches to identify sources of fecal pollution in recreational waters. One method defines operational taxonomic units (OTUs) that are specific to a fecal source, e.g., humans and animals or shared among multiple fecal sources to determine the magnitude and likely source association of fecal pollution. The other method uses SourceTracker, a program using a Bayesian algorithm, to determine which OTUs have contributed to an environmental community based on the composition of microbial communities in multiple fecal sources. Contemporary NGS-based MST tools offer a promising avenue to rapidly characterize fecal source contributions for water monitoring and remediation efforts at a broader and more efficient scale than previous molecular MST methods. However, both NGS methods require optimized sequence processing methodologies (e.g. quality filtering and clustering algorithms) and are influenced by primer selection for amplicon sequencing. Therefore, care must be taken when extrapolating data or combining datasets. Furthermore, traditional limitations of library-dependent MST methods, including differential decay of source material in environmental waters and spatiotemporal variation in source communities, remain to be fully understood. Nevertheless, increasing use of these methods, as well as expanding fecal taxon libraries representative of source communities, will help improve the accuracy of these methods and provide promising tools for future MST investigations.

Illnesses Associated with Freshwater Recreation During International Travel

PURPOSE OF REVIEW

International travel, adventure travel, and eco-tourism are increasing over the past few decades. This review aims to summarize the spectrum of infections associated with recreational freshwater activities and international travel.

RECENT FINDINGS

Recreational water activities can be associated with a wide range of infections. Acute febrile illnesses due to leptospirosis and schistosomiasis are not uncommon in travelers following extensive freshwater exposure. Aeromonas and other water-associated pathogens are important to consider in a traveler presenting with a skin and soft tissue infection. Recreational water activities are often associated with diarrheal illnesses, especially in children, and the range of enteric pathogens includes bacterial pathogens such as Escherichia coli O157:H7 and Shigella species and the protozoan parasites Cryptosporidium and Giardia duodenalis. Infections due to free-living amebas though rare can lead to fulminant central nervous system infections. A diverse range of infections may be associated with freshwater exposure, and it is important that these entities are considered in a returning traveler presenting with an acute illness.

Prevalence and characterization of Escherichia coli isolated from the Upper Oconee Watershed in Northeast Georgia

Surface waters are important sources of water for drinking, industrial, agricultural, and recreational uses; hence, contamination of water by fecal, pathogenic, or antimicrobial resistant (AR) bacteria is a major environmental and public health concern. However, very little data is available on prevalence of these bacteria in surface water throughout a watershed. This study aimed to characterize Escherichia coli present in the Upper Oconee Watershed, a mixed-use watershed in Athens, GA, USA for potential pathogenicity and AR. E. coli were enumerated by colony counts, cultured by enrichment and direct plating, and characterized by phylo-groups, diarrheagenic pathotypes, and antimicrobial susceptibility. From the analysis, 99.3% (455/458) of the total samples were positive for E. coli resulting in 496 isolates. E. coli counts were as high as 1.2×10⁴ CFU/100 ml, which is above the United States Environmental Protection Agency (U.S. EPA) threshold for recreational water (235 CFU/100 ml based on a one-time measurement). Phylo-groups B2 (31.7%; 157/496) and B1 (30.8%; 153/496) were the most prevalent among the isolates. Enteropathogenic E. coli (EPEC) (19/496) and Shiga toxin-producing E. coli (STEC) (1/496) were the only diarrheagenic pathotypes detected. AR was observed in 6.9% (34/496) of the isolates, 15 of which were multidrug resistant (MDR; resistance to two or more classes of antimicrobials). Tetracycline resistance was most often detected (76.5%; 26/34), followed by ampicillin (32.4%; 11/34), streptomycin (23.5%; 8/34), sulfisoxazole (23.5%; 8/34), and nalidixic acid (14.7%; 5/34). Results from this study showed that E. coli is prevalent in high levels in the Upper Oconee Watershed, suggesting possible widespread fecal contamination. The presence of pathogenic, AR E. coli in the watershed indicates that environmental water can serve as a reservoir of resistant bacteria that may be transferred to humans through drinking and recreational activities.