Evidence Of Fecal Contamination Research Articles

Optical Parameters for Using Visible-Wavelength Reflectance or Fluorescence Imaging to Detect Bird Excrements in Produce Fields

Consumption of produce contaminated with pathogens of fecal origin is the most common source of food borne illnesses. Current practice is to visually survey fields for evidence of fecal contamination, and to exclude problematic areas from harvest. Bird excrement is known to contain human pathogens, and is often not detectable in produce fields using current survey methods. The goal of this project was to identify parameters for optical detection of bird excrements to support development of instruments to be used to supplement existing visual surveys. Under daylight ambient conditions, results suggested that reflectance imaging at around 500–530 nm or 610–640 nm could be used to detect excrements from the three bird species tested. Images were acquired using ad hoc camera parameters; however, normalizing intensities for individual images at 525 nm and using a fixed detection threshold allowed detection of 100% of bird excrements with no false positives against the background that consisted of local soil and fresh romaine and spinach leaves. Similar results were obtained using fluorescence imaging. Fluorescent imaging was accomplished in a darkened room using 405-nm illumination. The largest consistent differences in intensity responses between excrements and the brightest non-excrement object in the background matrix occurred at around 550 nm. Results suggested that using reflectance or fluorescence imaging for detection of bird excrements could be a valuable tool for reducing risks of consuming contaminated produce. One possibility would be to incorporate appropriate reflectance imaging capabilities in drones under the control of the individuals currently conducting field surveys.

A highly specific Escherichia coli qPCR and its comparison with existing methods for environmental waters

The presence of Escherichia coli in environmental waters is considered as evidence of faecal contamination and is therefore commonly used as an indicator in both water quality and food safety analysis. The long period of time between sample collection and obtaining results from existing culture based methods means that contamination events may already impact public health by the time they are detected. The adoption of molecular based methods for E. coli could significantly reduce the time to detection. A new quantitative real-time PCR (qPCR) assay was developed to detect the ybbW gene sequence, which was found to be 100% exclusive and inclusive (specific and sensitive) for E. coli and directly compared for its ability to quantify E. coli in environmental waters against colony counts, quantitative real-time NASBA (qNASBA) targeting clpB and qPCR targeting uidA. Of the 87 E. coli strains tested, 100% were found to be ybbW positive, 94.2% were culture positive, 100% were clpB positive and 98.9% were uidA positive. The qPCR assays had a linear range of quantification over several orders of magnitude, and had high amplification efficiencies when using single isolates as a template. This compared favourably with qNASBA which showed poor linearity and amplification efficiency. When the assays were applied to environmental water samples, qNASBA was unable to reliably quantify E. coli while both qPCR assays were capable of predicting E. coli concentrations in environmental waters. This study highlights the inability of qNASBA targeting mRNA to quantify E. coli in environmental waters, and presents the first E. coli qPCR assay with 100% target exclusivity. The application of a highly exclusive and inclusive qPCR assay has the potential to allow water quality managers to reliably and rapidly detect and quantify E. coli and therefore take appropriate measures to reduce the risk to public health posed by faecal contamination.

Hydrogeochemistry and quality assessment of some ground water samples from Enugu and environs, south-eastern, Nigeria

This study was carried out to evaluate the groundwater quality and its suitability for drinking purposes in Enugu and environs, southeastern Nigeria. Water samples for this study were collected from ten different locations within the study area. Nine of the samples were subjected to physico-chemical analyses only, two out of the nine were subjected to both physico-chemical and microbiological analyses, while one (Egede borehole) was subjected to microbiological analyses only. The minimum and maximum values of pH (4.10–7.30 on scale), turbidity (0.17–218.60 NTU), colour (5.00–250.00 Hazen), electrical conductivity (14.00–550.00 iS/cm), total hardness (4.00–131.00 mg/l), total iron as Fe (0.12–8.60 mg/l), nitrate (0.01–3.50 mg/l), sulphate (0.50–43.00 mg/l), chloride (2.13–31.00 mg/l) and temperature (28–29 0C) were recorded in the groundwater samples from the study area Major ion concentrations were low and within the WHO guidelines for drinking water indicating chemical suitability of surface water. All the three groundwater samples tested positive to total bacterial count and E – coli. and this is evidence of faecal contamination and should be treated/disinfected before consumption. KEYWORDS : Hydro-geochemistry, Groundwater Quality Assessment, Enugu and Environs, Nigeria.

Chemical and microbiological assessment of surface water samples from Enugu area, south eastern, Nigeria

The importance of good quality water cannot be over emphasized. This is because it is only next to air as a critical sustainer of life therefore it is appropriate to evaluate its quality and quantity. A total number of thirteen water samples were investigated in this study: Nine samples from different surface water bodies, two samples from two effluent sources, one spring and one tap water sample were collected and used in the analyses. The objectives of the study are to assess, ascertain and evaluate the level, degree and type of pollution that characterize the surface water resources of Enugu area of southeastern Nigeria in terms of physico-chemical and bacterialogical constituents. Field measurements of physical parameters were preceded by chemical analyses of the samples for major ions concentrations and bacteriological content. Evaluation of the results showed that the waters are fresh and soft (Hardness ranges is 4.00 to 53.00mgl - l). The pH range is from 4.32 to 7.11 and these value fall within the acceptable limit of water for domestic use. Major ion concentrations were low and within the WHO guidelines for drinking water indicating chemical suitability of surface water. All the water samples tested positive to total bacterial count and E-coli. and this is evidence of faecal contamination and should be treated/disinfected before consumption. KEYWORDS : Freshwater, Chemical, Microbiological, Constituents, Enugu area, Nigeria

Water-related infrastructure in a region of post-earthquake Haiti: high levels of fecal contamination and need for ongoing monitoring.

We inventoried non-surface water sources in the Leogane and Gressier region of Haiti (approximately 270 km2) in 2012 and 2013 and screened water from 345 sites for fecal coliforms and Vibrio cholerae. An international organization/non-governmental organization responsible for construction could be identified for only 56% of water points evaluated. Sixteen percent of water points were non-functional at any given time; 37% had evidence of fecal contamination, with spatial clustering of contaminated sites. Among improved water sources (76% of sites), 24.6% had fecal coliforms versus 80.9% in unimproved sources. Fecal contamination levels increased significantly from 36% to 51% immediately after the passage of Tropical Storm Sandy in October of 2012, with a return to 34% contamination in March of 2013. Long-term sustainability of potable water delivery at a regional scale requires ongoing assessment of water quality, functionality, and development of community-based management schemes supported by a national plan for the management of potable water.

Identification of fecal contamination sources in water using host-associated markers

In British Columbia, Canada, drinking water is tested for total coliforms and Escherichia coli, but there is currently no routine follow-up testing to investigate fecal contamination sources in samples that test positive for indicator bacteria. Reliable microbial source tracking (MST) tools to rapidly test water samples for multiple fecal contamination markers simultaneously are currently lacking. The objectives of this study were (i) to develop a qualitative MST tool to identify fecal contamination from different host groups, and (ii) to evaluate the MST tool using water samples with evidence of fecal contamination. Singleplex and multiplex polymerase chain reaction (PCR) were used to test (i) water from polluted sites and (ii) raw and drinking water samples for presence of bacterial genetic markers associated with feces from humans, cattle, seagulls, pigs, chickens, and geese. The multiplex MST assay correctly identified suspected contamination sources in contaminated waterways, demonstrating that this test may have utility for heavily contaminated sites. Most raw and drinking water samples analyzed using singleplex PCR contained at least one host-associated marker. Singleplex PCR was capable of detecting host-associated markers in small sample volumes and is therefore a promising tool to further analyze water samples submitted for routine testing and provide information useful for water quality management.

Identifying the major influences on the microbial composition of roof harvested rainwater and the implications for water quality

Perceptions of the quality of roof harvested rainwater remain an impediment to widespread implementation of rainwater tanks on urban allotments. Previous literature reports on roof water quality have given little consideration to the relative significance of airborne environmental micro-organisms to roof catchment contamination and the issue of tank water quality. This paper outlines the findings of a recent study into the influence of weather on roof water contamination conducted at an urban housing development in Newcastle, on the east coast of Australia. Samples of direct roof run-off were collected during a number of separate rainfall events, and microbial counts were matched to climatic data corresponding to each of the monitored events. Roof run-off contamination was found to be under the strong influence of both wind speed and direction. The preliminary findings of an investigation currently under way into the microbial diversity of rainwater harvesting systems have also been presented. The results indicate that the composition of organisms present varied considerably from source to source and throughout the collection system. In all cases, evidence of faecal contamination was found to be negligible. The implications of these findings to the issues of tank water quality, health risk analysis and monitoring protocols have been discussed.

The microbiology of a pharmaceutical effluent and its public health implications

The effluent of a pharmaceutical company was examined microbiologically. Its bacterial count was 2.15 × 105 c.f.u./ml and there was evidence of faecal contamination with MPN of > 1800. The organisms encountered included Staphylococcus aureus, Escherichia coli, Proteus vulgaris, Serratia marcescens and Pseudomonas aeruginosa. The resistances of the 25 bacterial strains isolated from the effluent to the commonly used antibiotics were studied. About 80% of the isolates were resistant to Amoxycillin, 76% to Nitrofurantoin, 64% to Cotrimoxazole and Augmentin, 60% were resistant to Nalidixic acid, 52% were resistant to Tetracycline and Ofloxacin, while resistance of 12% was obtained for Gentamicin. Among the eight antibiotics tested, seven patterns of drug resistance were obtained and all of them were multiple-drug resistance with the number of antibiotics ranging from 2–8. All the strains of E. coli and S. aureus had high MIC values for Cloxacillin and Amoxycillin. In all, 13 strains of the bacterial isolates had evidence for the production of β-lactamases. The potential of the effluent in spreading drug resistance and the public health implications are discussed.

Hygiene in the home: relating bugs and behaviour

Much infectious intestinal disease (IID) arises in the home environment. If programmes to prevent infection are to be effective it is essential to both identify the particular practices that risk disease transmission, and to understand the reasons for these practices. An in-depth, multidisciplinary study of carer and child hygiene in the domestic environment in the Wirral, UK, employed structured observation, surface swabbing for polio vaccine virus and enteric marker organisms, semi-structured interviews, projective interviews and focus group discussions. Observations revealed that child carers washed hands with soap after changing a dirty nappy on 42% of occasions, and that one in five toilet users did not wash hands with soap afterwards. Microbiological samples were taken from household surfaces at sites thought likely to be involved in the transfer of faecal material. 15% of bathroom samples showed contamination with polio vaccine virus. Nappy changing took place mainly in living rooms. Contact with living room surfaces and objects during nappy changing was frequent and evidence of faecal contamination was found in 12% of living room samples. Evidence of faecal contamination was also found in kitchens, again on surfaces thought likely to be involved in the transmission of faeces (taps and soap dispensers). Key factors motivating hygiene were the desire to give a good impression to others, protection of the child and aesthetics. In this setting, the particular risk practices to be addressed included washing hands with soap after stool and nappy contact and preventing the transfer of pathogenic organisms to the kitchen. The occasion of the birth of a child may be a privileged moment for the promotion of safer home hygiene practices. Using polio vaccine virus as an indicator of faecal contamination produces results that could be used in large-scale studies of household disease transmission. A better understanding of the household transmission of the agents of IID using multidisciplinary methods is needed if effective hygiene promotion programmes are to be designed.

Current knowledge on groundwater microbial pathogens and their control

Those who drink groundwater that has not been disinfected are at increased risk of infection and disease from pathogenic microorganisms. Recent stud- ies have shown that up to half of all US drinking- water wells tested had evidence of fecal contamination. A significant fraction of all waterborne disease outbreaks is associated with groundwater. An estimated 750,000 to 5.9 million illnesses per year result from contaminated groundwaters in the US. Mortality from these illnesses may be 1400-9400 deaths per year. Control of these pathogens starts with source-water protection activities to prevent fecal contamination of aquifers and wells. These include assessment of wellhead vulnerability to fecal contami- nation and correction of identified deficiencies. Cor- rection may include control of sources or rehabilitation of the well itself. Disinfection can serve as a useful barrier and is recommended as a prudent public-health policy for all groundwater systems.

Enhanced Chemiluminescence Cannot Predict the Presence of Cryptosporidium parvum When Applied to Water-Quality Monitoring in an Agricultural Environment

Adaptation of the enhanced chemiluminescent reaction (ECLOX test) to water-quality monitoring revealed that pollutants in industrial and domestic effluent and farmyard and dairy washings may suppress or completely inhibit enhanced chemiluminescent light emission. Inhibition or changes in the kinetics of light emission occur in the presence of a wide range of extraneous substances. Interaction of such substances with ECLOX reaction components or reaction intermediates can produce changes in light emission, allowing detection of a broad range of chemical pollutants. This work examined the suitability of the ECLOX test to differentiate between water quality at various points along a rural stream. In addition, the study was used to measure whether changes in water quality detected by the ECLOX test were consistent with measured levels of the protozoan parasite Cryptosporidium parvum. Seven locations along a stream and a farmyard drainage ditch were sampled on the basis of position, continuity of flow, permanence, and evidence of fecal contamination. The stream frequently contained C. parvum (75% of occasions tested), although according to the ECLOX test and other standard parameters (suspended solids and pH), it seemed relatively uncontaminated. The ECLOX test did, however, distinguish among a range of water qualities. The ECLOX test can be considered as a useful qualitative indicator of differing water qualities, but C. parvum can be present in water of any quality; therefore, ECLOX is not an appropriate method for detecting the presence of this parasite.

Considerations on contamination of groundwater by waste disposal systems in Nigeria

Abstract The interdependence of water quality parameters with distance from polluting sources and depth of twenty four native wells in Abeokuta, Nigeria is examined in this study. In gross features, the bacteriological quality as monitored by coliform counts showed significant negative correlation of 0.74 and 0.60 with distance from polluting source and depth of well respectively. Most of the wells examined had construction defects and there was evidence of faecal contamination. The results highlight possible environmental impacts of lapses in construction and obvious contamination of this popular water systems. The study probably highlights the much needed awareness on the part of local residents and environmental health authorities to curb dangers inherent in poor sanitation and consumption of contaminated groundwater. The results could serve as a basis for planning and policy formulation on environmental sanitation, drainage systems, native well siting, construction, finishing and maintenance.

The Correlation of the Voges-Proskauer and Methyl-Red Reactions in the Colonaerogenes Group of Bacteria

Bacillus coli was firs.t isolated by Escherich, from the feces of a cholera patient in 1884. It was soon recognized as a normal inhabitant of the intestinal tract of man and other animals, and for the past two decades the colon-aerogenes group of bacteria has attracted considerable attention from bacteriologists; particularly those interested in sanitation. Numerous attempts have been made to differentiate colonlike bacteria from different sources by their cultural characteristics, by agglutination reactions, complement-fixation tests, pathogenicity, etc., but until very recently the results were so uniformly negative that the entire group of lactose-fermenting bacteria is held, by some, to be characteristically of intestinal origin. In routine water and milk analyses the presence of colon-like organisms is regarded, by many, as an index of pollution. There is considerable evidence accumulating, however, to show that the animal intestine is not the sole and exclusive habitat of colon-like bacteria. Prescott,1 in this country, and Papasotiriu,2 in Germany, report the presence of colon-like organisms on grains of various kinds. Prescott regards those from grain and feces as identical. He believes that multiplication actually takes place on the grain and that their presence cannot be explained by contamination from the air and dust. Rogers and his co-workers3 of the U. S. Department of Agriculture have recently isolated 166 specimens of colon-like bacteria from 33 samples of dry grain (corn, barley, wheat, and oats). They also obtained 14 cultures from 2 samples of green oats, which had been opened aseptically, and are therefore inclined to believe that these were growing in the milk of the immature grain. In view of the fact that organisms which are apparently B. coli are not uncommon on grains, their presence in water and milk cannot be regarded as prima facia evidence of fecal contamination. Some