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The diversity and stability of Escherichia coli populations within the feces of individuals belonging to three mammalian host groups (humans, horses, and beef cattle) are investigated. The high genetic diversity of Escherichia coli populations, variations in diversity among hosts, and temporal variability all indicate complex population dynamics that impact the usefulness of Escherichia coli as a water indicator and its use in microbial source tracking studies.

PCR is used to screen DNA polymorphisms in strains from environmental or clinical sources, and genomic relationships were determined by repetitive extragenic palindromic DNA PCR (rep-PCR) typing. Significant (P

The validity of using indicator organisms was tested to predict the presence of absence of pathogens at six wastewater reclamation facilities. A major goal of wastewater reclamation facilities is to reduce pathogen loads in order to decrease public health risks associated with exposure.

Indicator organisms that reside in the gastrointestinal tracts of humans and animals are used worldwide to monitor water quality. The results have implications for the accuracy of microbial source tracking methods, modeling of microbial populations in water, and efficacy of regulatory standards for protection of water quality.

Research has been conducted on the coliform bacteria used as the fecal contamination indicator for the fresh and marine waters. The use of the Colilert-18 system in detecting both coliforms and E. coli in the filtered and cell-free marine and estuarine water samples is described.

Researchers isolated vancomycin-resistant strains of Enterococcus spp. from residential and hospital wastewater, sewage and chicken feces, but not from surface water or other animal feces. Vancomycin resistance was associated with the vanA and vanC genes.

Results discuss the application of antibiotic resistance analysis using discriminant analysis technique for differentiating animal and human fecal isolates from waters of Florida and to relate antibiotic resistance patterns to the bacterial source. Data show that the fecal streptococcus and fecal coliform formed groups of isolates from known sources with accuracy.

Extracellular copper-binding protein (CuBP) of Vibrio alginolyticus is required for the proliferation and survival of copper-sensitive and copper-resistant mutants. Copper-resistant mutants are constitutive producers of CuBP and copper-sensitive mutants induce physiological variations in the supernatant profile of CuBP, indicating the requirement of CuBP for induction of copper resistivity in V. alginolyticus.

The recovery of Vibrio alginolyticus from copper toxicity and the production of copper-binding proteins given a copper-stressed continuous culture is discussed. Experiments involved the assessment of the effect of copper on the growth of V. alginolyticus, the amount of copper-resistant cells and the production of extracellular protein producion in continuous culture. Itwas found that V. alginolyticus can recover from copper toxicity as extracellular copper-binding proteins were also produced.

Research was conducted to examine the isolation of fecal coliform bacteria from the diamondback terrapin, Malaclemys terrapin centrata. Fecal and total coliform bacteria were isolated from the feces and cloaca of the estuarine diamondback terrapin. Results revealed that Escherichia coli was the predominat fecal coliform species isolated. Salmonella species were also identified from the gastrointestinal tract of the terrapin.

Combination of hollow-fiber ultrafiltration (HFUF) and PCR are utilized to detect human-associated microbial source tracking marker genes in large volumes of fresh and estuarine Florida water. HFUF which facilitated the marker detection demonstrated the ability of HFUF to allow detection of diluted targets by PCR in a variety of water types.

The presence of all three classes of pathogens (viral, protozoan and bacterial) as well as indicator microbes at a non-point source recreational beach is assessed. The analysis of the various microbes under different targeted environmental conditions has included the evaluation of the sources of microbial contaminants and pathogens and the effectiveness of various analytical methods for microbe detection.

A TaqMan quantitative PCR (QPCR) assay is developed and optimized based on the conserved T antigen in order to quantify and detect two human polyomaviruses (HPyVs), JC virus and BK virus. The use of this quantitative assay in water quality research might help regulatory agencies in identifying sources of water pollution for improved remediation of contaminated waters and thus protecting humans from exposure to pathogens.

Real-time PCR assays developed for detecting and differentiating two 16S rRNA variants of Vibrio vulnificus in oysters and water is reported. These assays were found to be specific and sensitive in differentiating the strains of V. vulnificus in oysters without requiring its isolation and may be useful in quick detection of pathogens in shellfish and water.

The development, performance and validation of D source tracking (MST) methods are described.

A method developed to concentrate and extract human polyomaviruses (HPyVs) DNA, which are used as indicators of human fecal pollution, from environmental water samples and to amplify it by nested PCR is presented. The sensitivity, specificity and correlation with other human-associated markers have indicated that the HPyV assay can be a useful predictor of human fecal pollution in environmental waters and an important component of the microbial-source-tracking toolbox.

Escherichia coli is a promising subject for globally coordinated surveillance of antimicrobial resistance (AMR) in water environments due to its clinical relevance and widespread use as an indicator of fecal contamination. Cefotaxime-resistant E. coli was recently evaluated favorably for this purpose by the World Health Organization TriCycle Protocol, which specifies tryptone bile x-glucuronide (TBX) medium and incubation at 35°C. We assessed comparability with the U.S. Environmental Protection Agency-approved method for E. coli quantification, which uses membrane-thermotolerant E. coli (mTEC) agar and incubation at 44.5°C, in terms of recovery of E. coli and cefotaxime-resistant E. coli from wastewater influent and surface waters. Total E. coli concentrations in wastewater influent were 10 6 -10 8 CFU/100 mL, while cefotaxime-resistant E. coli were ~100-fold lower. Total E. coli in surface waters were ~10 2 CFU/100 mL, and cefotaxime-resistant isolates were near the limit of detection (0.4 CFU/100 mL). Total and putative cefotaxime-resistant E. coli concentrations did not differ significantly between media or by incubation method; however, colonies isolated on mTEC were more frequently confirmed to species (97.1%) compared to those from TBX (92.5%). Incubation in a water bath at 44.5°C significantly decreased non-specific background growth and improved confirmation frequency on both media (97.4%) compared to incubation at 35°C (92.3%). This study helps to advance globally coordinated AMR in water environments and suggests that the TriCycle Protocol is adaptable to other standard methods that may be required in different locales, while also offering a means to improve specificity by decreasing the frequency of false-positive identification of cefotaxime-resistant E. coli by modifying incubation conditions.IMPORTANCEAs antibiotic-resistant bacteria in water environments are increasingly recognized as contributors to the global antibiotic resistance crisis, the need for a monitoring subject that captures antibiotic resistance trends on a global scale increases. The World Health Organization TriCycle Protocol proposes the use of cefotaxime-resistant Escherichia coli isolated on tryptone bile x-glucuronide agar. The U.S. Environmental Protection Agency (USEPA) criteria for safe recreational waters also use E. coli as an indicator but specify the use of mTEC agar at a higher incubation temperature (44.5°C vs 35°C). We assessed the comparability of these methods for isolating total and cefotaxime-resistant E. coli , finding overall good agreement and performance, but significantly higher specificity toward E. coli selection with the use of the USEPA incubation protocol and mTEC agar. This study is the first to directly compare these methods and provides evidence that the methods may be used interchangeably for global surveillance of antibiotic resistance in the environment., Competing Interests: The authors declare no conflict of interest.