Validation of Bacteroidales-based microbial source tracking markers for pig fecal pollution and their application in two rivers of North China

In China,pig feces is the predominant source of excrement produced b y animal husbandry.Improper use or direct discharge of pig feces can result in contamination of natural water systems.Microbial source tracking(MST)technology can identify the sources of fecal pollution in environmental water,and contribute to the management of pig fecal pollution by local environmental protection agencies.However,the accuracy of such assays can be context-dependent,and they have not been comprehensively evaluated under Chinese conditions.We aimed to compare the performance of five previously reported nig-specific MST assays(PF,Pig-Bac 1 STBR,Pig-Bac2 SYBR,Pig-1-Bac TaqMan,and Pig-2-Bac TaqMan,which are based on Bacteroidales 16S rRNA gene markers)and apply them in two rivers of North China.We collected a total of 173 fecal samples from pigs,cows,goats,chickens,humans,and horses across China.The PF assay optimized in this study showed outstanding qualitative performance and achieved 100%specificity and sensitivity.However,the two SYBR green qPCR assays(Pig-Bac1 SYBR and Pig-Bac2 SYBR)cross-reacted with most non-pig fecal samples.In contrast,both the Pig-l-Bac TaqMan and Pig-2-Bacr TaqMan assays gave 100%specificity and sensitivity.Of these,the Pig-2-Bac TaqMan assay showed higher reproducibility.Our results regarding the specificity of these pig-specific MST assays differ from those reported in Thailand,Japan,and America.Using the PF and Pig-2-Bac TaqMan assays,a field test comparing the levels of pig fecal pollution in rivers near a pig farm before and after comprehensive environmental pollution governance indicated that pig fecal pollution was effectively controlled at this location.

Microbial Quality of Wastewater Used in Urban Truck Farming and Health Risks Issues in Developing Countries:Case Study of Ouagadougou in Burkina Faso

Urban truck farming in developing countries appears of great importance to overcome unemployment and poverty. However, the quality of wastewater used for such activity could expose populations to waterborne diseases. The microbial quality of wastewaters used for truck farming in Ouagadougou city, was examined for the presence of bacterial and parasitological fecal indicators during the dry-hot season (May) and the wet season (July) in 2012. The wastewaters of three water reservoirs and two canals intensively used for truck farming were analyzed throughout the study. These indicators were also monitored in waste stabilization ponds during wastewater treatment in 3 plants of the city. For all the selected sampling sites, the concentrations of microbial indicators in water were significantly higher in the dry-hot season compared to the wet one (p - 53,800 CFU/100ml for Escherichia coli, 8200 - 108,400 CFU/100ml for fecal coliforms, 650 - 45,000 CFU/100ml) for fecal streptococcus, and 0 - 2.4 eggs/l for helminthes during the study periods. For wastewater under treatment in waste stabilization ponds, significant microbial concentration drops (p 0.0001) in the range of 82% - 100%, 78% - 98%, 60% - 100% and 82% - 88%, respectively were recorded between the anaerobic and the maturation ponds. The later results highlighted that improving the refining performances of the waste stabilization ponds technology could help decreasing health risks related to wastewater reuse in urban agriculture for a sustainable development of cities in developing countries.

Development of a sensor for the detection of Escherichia coli in brackish waters

Monitoring of bacterial pathogens is important for marine environmental protection,because the presence of these microorganisms can be a serious risk for human health.For this reason,a portable sensor implemented as an electronic embedded system featuring disposable measurement cells was used to evaluate the ability and sensitivity of detection of Escherichia coli(E.coli)as an indicator of fecal pollution in transitional environments and a water sample added with E.coli(10^(2) CFU/mL)was assayed.The first result obtained from the laboratory experiment seems promising for the determination of E.coli in environmental samples,though further improvements will be needed for the field application of this sensor in marine and brackish waters.