Prevalence and occurrence of zoonotic bacterial pathogens in surface waters determined by quantitative PCR

The prevalence and concentrations of Campylobacter jejuni, Salmonella spp. and enterohaemorrhagic E. coli (EHEC) were investigated in surface waters in Brisbane, Australia using quantitative PCR (qPCR) based methodologies. Water samples were collected from Brisbane City Botanic Gardens (CBG) Pond, and two urban tidal creeks (i.e., Oxley Creek and Blunder Creek). Of the 32 water samples collected, 8 (25%), 1 (3%), 9 (28%), 14 (44%), and 15 (47%) were positive for C. jejuni mapA, Salmonella invA, EHEC O157 LPS, EHEC VT1, and EHEC VT2 genes, respectively. The presence/absence of the potential pathogens did not correlate with either E. coli or enterococci concentrations as determined by binary logistic regression. In conclusion, the high prevalence, and concentrations of potential zoonotic pathogens along with the concentrations of one or more fecal indicators in surface water samples indicate a poor level of microbial quality of surface water, and could represent a significant health risk to users. The results from the current study would provide valuable information to the water quality managers in terms of minimizing the risk from pathogens in surface waters

Faecal Pollution Along the Southeastern Coast of Florida and Insight into the Use of Pepper Mild Mottle Virus as an Indicator

Aims To identify faecal pollution along the southeastern Florida coast and determine the performance of a reverse transcription‐quantitative polymerase chain reaction (RT‐qPCR) method for pepper mild mottle virus (PMMoV). Methods and Results In 2014, bimonthly surface water samples were collected from inlets, exposed to runoff and septic seepage, and coastal sites, exposed to ocean outfalls. Analysis of culturable enterococci and a suite of microbial source tracking (MST) markers (BacHum, CowM2, DogBact, HF183, HPyV, PMMoV) revealed faecal pollution, primarily of human origin, at all sites. Since PMMoV was detected more frequently than other MST markers, the process limits of quantification (undiluted to 10−2 dilution) and detection (10−2 dilution) for the RT‐qPCR method were determined by seeding untreated wastewater into the coastal waters. Simulated quantitative microbial risk assessment, employing human norovirus as a reference pathogen, calculated a 0·286 median risk of gastrointestinal illness associated with the PMMoV limit of detection. Conclusions All sites met the U.S. EPA recreational water criteria, despite detection of domestic wastewater‐associated MST markers. PMMoV correlated only with human‐associated MST markers. Significance and Impact of the Study This study demonstrated that PMMoV is an important domestic wastewater‐associated marker that should be included in the MST toolbox; therefore, future studies should thoroughly investigate the health risks associated with its detection and quantification in environmental waters

Reduction of Nutrients, Microbes, and Personal Care Products in Domestic Wastewater by a Benchtop Electrocoagulation Unit

To preserve environmental and human health, improved treatment processes are needed to reduce nutrients, microbes, and emerging chemical contaminants from domestic wastewater prior to discharge into the environment. Electrocoagulation (EC) treatment is increasingly used to treat industrial wastewater; however, this technology has not yet been thoroughly assessed for its potential to reduce concentrations of nutrients, a variety of microbial surrogates, and personal care products found in domestic wastewater. This investigation\u27s objective was to determine the efficiency of a benchtop EC unit with aluminum sacrificial electrodes to reduce concentrations of the aforementioned biological and chemical pollutants from raw and tertiary-treated domestic wastewater. EC treatment resulted in significant reductions (p \u3c 0.05, α = 0.05) in phosphate, all microbial surrogates, and several personal care products from raw and tertiary-treated domestic wastewater. When wastewater was augmented with microbial surrogates representing bacterial, viral, and protozoan pathogens to measure the extent of reduction, EC treatment resulted in up to 7-log10 reduction of microbial surrogates. Future pilot and full-scale investigations are needed to optimize EC treatment for the following: reducing nitrogen species, personal care products, and energy consumption; elucidating the mechanisms behind microbial reductions; and performing life cycle analyses to determine the appropriateness of implementation

Reduction of Nutrients, Microbes, and Personal Care Products in Domestic Wastewater by a Benchtop Electrocoagulation Unit

To preserve environmental and human health, improved treatment processes are needed to reduce nutrients, microbes, and emerging chemical contaminants from domestic wastewater prior to discharge into the environment. Electrocoagulation (EC) treatment is increasingly used to treat industrial wastewater; however, this technology has not yet been thoroughly assessed for its potential to reduce concentrations of nutrients, a variety of microbial surrogates, and personal care products found in domestic wastewater. This investigation\u27s objective was to determine the efficiency of a benchtop EC unit with aluminum sacrificial electrodes to reduce concentrations of the aforementioned biological and chemical pollutants from raw and tertiary-treated domestic wastewater. EC treatment resulted in significant reductions (p \u3c 0.05, α = 0.05) in phosphate, all microbial surrogates, and several personal care products from raw and tertiary-treated domestic wastewater. When wastewater was augmented with microbial surrogates representing bacterial, viral, and protozoan pathogens to measure the extent of reduction, EC treatment resulted in up to 7-log10 reduction of microbial surrogates. Future pilot and full-scale investigations are needed to optimize EC treatment for the following: reducing nitrogen species, personal care products, and energy consumption; elucidating the mechanisms behind microbial reductions; and performing life cycle analyses to determine the appropriateness of implementation

Microbial Source Tracking in Shellfish Harvesting Waters in the Gulf of Nicoya, Costa Rica

Current microbial water quality monitoring is generally limited to culture-based measurements of fecal indicator bacteria (FIB). Given the many possible sources of fecal pollution within a watershed and extra-intestinal FIB reservoirs, it is important to determine source(s) of fecal pollution as a means to improve water quality and protect public health. The principal objective of this investigation was to characterize the microbial water quality of shellfish harvesting areas in the Gulf of Nicoya, Costa Rica during 2015. In order to achieve this objective, the specificity and sensitivity of 11 existing microbial source tracking (MST) PCR assays, associated with cows (BacCow), dogs (BacCan, DogBac), domestic wastewater (PMMoV), general avian (GFD), gulls (Gull2), horses (HorseBac, HoF), humans (HF183, HPyV), and pigs (PF), were evaluated using domestic wastewater and animal fecal samples collected from the region. The sensitivity of animal-associated assays ranged from 13 to 100%, while assay specificity ranged from 38 to 100%. The specificity of pepper mild mottle virus (PMMoV) and human polyomavirus (HPyV) was 100% for domestic wastewater, as compared to 94% specificity of the HF183 Bacteroidales marker. PMMoV was identified as a useful domestic wastewater-associated marker, with concentrations as high as 1.1 × 105 copies/ml and 100% sensitivity and specificity. Monthly surface water samples collected from four shellfish harvesting areas were analyzed using culture-based methods for Escherichia coli as well as molecular methods for FIB and a suite of MST markers, which were selected for their specificity in the region. While culturable E. coli results suggested possible fecal pollution during the monitoring period, the absence of human/domestic wastewater-associated markers and low FIB concentrations determined using molecular methods indicated sufficient microbial water quality for shellfish harvesting. This is the first study to our knowledge to test the performance of MST markers in Costa Rica as well as in Central America. Given the lack of wastewater treatment and the presence of secondary sources of FIB, this study highlights the importance of an MST toolbox approach to characterize water quality in tropical regions. Furthermore, it confirms and extends the geographic range of PMMoV as an effective tool for monitoring domestic wastewater pollution