Multiple approaches to microbial source tracking in tropical northern Australia (original) (raw)

Comparative microbial source tracking methods for identification of fecal contamination sources at Sunnyside Beach in the Toronto region area of concern

Journal of Water and Health

Several beaches within the Toronto region area of concern have persistent issues with fecal contamination, causing a beach beneficial use impairment (BUI). In this study, Escherichia coli, including ampicillin-resistant strains, were enumerated via culturable and quantitative polymerase chain reaction (qPCR) methods. Microbial source tracking (MST) markers (for general Bacteroidales, human, ruminant/cow, gull, and dog) were detected and enumerated via PCR and qPCR to identify sources of fecal contamination at Sunnyside Beach and in the Humber River. Human, cow, and dog markers had good host-specificity, while gull markers sometimes amplified a few other bird species. The ruminant endpoint PCR marker amplified a variety of other animal species rendering it less useful. Both human and gull fecal contamination were prevalent in the Humber River, while Sunnyside Beach was predominantly impacted by gull fecal contamination. Human sewage impacts were more prevalent in the lower Humber Riv...

Spatial and rainfall related patterns of bacterial contamination in Sydney Harbour estuary

Journal of Water and Health, 2005

Water quality in recreational areas in Sydney Harbour, Australia, was analysed first to identify spatial patterns in faecal coliform and enterococci densities, and then to determine the relationship between bacterial densities and catchment rainfall. Non-metric multidimensional scaling separated sites closest to the mouth of the harbour from those further up the harbour's west and north-west arms. Sites closest to the harbour mouth generally had lower frequencies of high bacterial densities that exceeded median water quality guideline values. We attribute this to greater tidal flushing at sites closer to the harbour mouth. Eight site groups were identified within the harbour. Within each group, multiple regression analyses indicated rainfall accounted for between 15 and 66% of the variability in the bacterial densities. Variation in bacterial densities explained by rainfall was lower for sites closer to the harbour mouth where tidal flushing is greatest. Thus, our findings indic...

Quantitative detection of human- and canine-associated Bacteroides genetic markers from an urban coastal lagoon

Water Science and Technology

The contamination of water catchments by nonpoint source faecal pollution is a major issue affecting the microbial quality of receiving waters and is associated with the occurrence of a range of enteric illnesses in humans. The potential sources of faecal pollution in surface waters are diverse, including urban sewage leaks, surface runoff and wildlife contamination originating from a range of hosts. The major contributing hosts require identification to allow targeted management of this public health concern. In this study, two high-performing Microbial Source Tracking (MST) assays, HF183/Bac242 and BacCan-UCDmodif, were used for their ability to detect host-specific Bacteroides 16Sr RNA markers for faecal pollution in a 12-month study on an urban coastal lagoon in Sydney, Australia. The lagoon was found to contain year-round high numbers of human and canine faecal markers, as well as faecal indicator bacteria counts, suggesting considerable human and animal faecal pollution. The h...

Occurrence and predictive correlations of Escherichia coli and Enterococci at Sandpoint beach (Lake St Clair), Windsor, Ontario and Holiday beach (Lake Erie), Amherstburg, Ontario

Water Quality Research Journal of Canada, 2013

Point and nonpoint sources contribute to fecal contamination of surface waters by human pathogens that exist at low concentrations and are difficult, expensive, and/or impossible to easily detect. Therefore, fecal indicator bacteria (FIB) are used as surrogates in identification of fecal contamination, including Escherichia coli (EC) and Enterococcus spp. (ENT), at recreational beaches to protect from adverse health effects from exposure to water-borne pathogens. The objective of the current study was to conduct a preliminary investigation of the environmental processes contributing to the nature and significance of FIB (EC and ENT) over 30 d at Sandpoint beach (Windsor, Ontario) and Holiday beach (Amherstburg, Ontario). Daily, three 100 mL samples were collected for EC and ENT for analysis by Colilert® and Entrolert®, respectively. Additionally, physicochemical and hydrometerological data were measured or taken from data archives. Both EC and ENT populations were dynamic and well c...