Fecal Origin Research Articles

Detection and prevalence of protozoan parasites in ready-to-eat packaged salads on sale in Italy

To investigate the prevalence of protozoan contamination by Giardia duodenalis, Cryptosporidium spp., Toxoplasma gondii and Cyclospora cayetanensis, in ‘ready to eat’ (RTE) salads on sale in Italy, 648 packages were purchased from industrial and local brands. Nine individual packages from each brand were collected per month, pooled and subjected to microscopy and molecular analyses. Microscopic examination of 864 slides detected Cryptosporidium spp. but also Blastocystis hominis and Dientamoeba fragilis. Molecular tools identified G. duodenalis assemblage A, Cryptosporidium parvum and Cryptosporidium ubiquitum, T. gondii Type I and C. cayetanensis. B. hominis and D. fragilis were also molecularly confirmed. The overall prevalence of each protozoan species was 0.6% for G. duodenalis, 0.8% for T. gondii, 0.9% for Cryptosporidium spp., and 1.3% for C. cayetanensis, while prevalence for B. hominis was 0.5% and for D. fragilis 0.2%. Microscopy and/or molecular tools revealed that 4.2% of the samples were contaminated by at least one protozoan species, and 0.6% of samples presented contamination by two protozoan species, with a number of oocysts ranging from 62 to 554 per g of vegetable matter for T. gondii, and 46 to 1.580 for C. cayetanensis. This is Europe's first large-scale study on the presence of protozoans in packaged salads, and shows that RTE sanitation processes do not guarantee a product free from protozoans of fecal origin.

Épidémiologie moléculaire et cinétique des infections urinaires précoces à Escherichia coli chez les sujets transplantés d’un rein

BackgroundEscherichia coli strains causing Urinary Tract Infections (UTI) have a fecal origin. MethodsA fecal sample was collected before Kidney Transplantation (KT) and concomitantly with urine at each of the 15 E. coli UTIs which occurred in 11 KT recipients. Unique E. coli strains were identified among 25 isolates per feces and 5 isolates per urinary sample by random amplification of polymorphic DNA. Phylogenetic group (which is correlated to virulence in the E. coli species) was determined for each E. coli strain by a PCR based method. ResultsForty-three unique fecal strains and 14 unique urinary strains were identified among 650 fecal isolates and 75 urinary isolates. Urinary strains frequently (55% of the cases) belonged to a phylogroup usually not linked to virulence. They were detected in the feces collected concomitantly in 60% of the cases. Urinary strains belonging to a phylogroup usually linked to virulence were more frequently dominant in the feces (100%) than urinary strains belonging to a non-pathogenic phylogroup (42%; P<0.05). Vesical catheter was a facilitating factor only for urinary strains belonging to non-pathogenic phylogroups. Thirty-three percent of the fecal strains were persisting in two consecutive fecal samples and 62% were detected for the first time at the UTI. Numerous pathway lead to UTIs: from a unique, virulent and persisting strain to a non-virulent recently acquired strain facilitated by a vesical catheter. ConclusionOur work shows the diversity of host-microbial interactions which precede extra-intestinal virulence.

Potential tracers for tracking septic tank effluent discharges in watercourses

Septic tank effluent (STE) contributes to catchment nutrient and pollutant loads. To assess the role of STE discharges in impairment of surface water, it is essential to identify the sources of pollution by tracing contaminants in watercourses. We examined tracers that were present in STE to establish their potential for identifying STE contamination in two stream systems (low and high dilution levels) against the background of upstream sources. The studied tracers were microbial, organic matter fluorescence, caffeine, artificial sweeteners and effluent chemical concentrations. The results revealed that tracer concentration ratios Cl/EC, Cl/NH4-N, Cl/TN, Cl/TSS, Cl/turbidity, Cl/total coliforms, Cl/sucralose, Cl/saccharin and Cl/Zn had potential as tracers in the stream with low dilution level (P < 0.05). Fluorescence spectroscopy could detect STE inputs through the presence of the tryptophan-like peak, but was limited to water courses with low level of dilution and was positively correlated with stream Escherichia coli (E. coli) and soluble reactive phosphorus (SRP). The results also suggested that caffeine and artificial sweeteners can be suitable tracers for effluent discharge in streams with low and high level of dilution. Caffeine and saccharin were positively correlated with faecal coliforms, E. coli, total P and SRP, indicating their potential to trace discharge of a faecal origin and to be a marker for effluent P. Caffeine and SRP had similar attenuation behaviour in the receiving stream waters suggesting caffeine's potential role as a surrogate indicator for the behaviour of P downstream of effluent inputs. Taken together, results suggest that a single tracer alone was not sufficient to evaluate STE contamination of watercourses, but rather a combination of multiple chemical and physical tracing approaches should be employed. A multiple tracing approach would help to identify individual and cumulative STE inputs that pose risks to stream waters in order to prioritise and target effective mitigation measures.

Norwegian study on microbial source tracking for water quality control and pollution removal in constructed wetland treating catchment run-off.

This study describes the first Norwegian microbial source tracking (MST) approach for water quality control and pollution removal from catchment run-off in a nature-based treatment system (NBTS) with a constructed wetland. The applied MST tools combined microbial analyses and molecular tests to detect and define the source(s) and dominant origin(s) of faecal water contamination. Faecal indicator bacteria Escherichia coli and host-specific Bacteroidales 16 s rRNA gene markers have been employed. The study revealed that the newly developed contribution profiling of faecal origin derived from the Bacteroidales DNA could quantitatively distinguish between human and non-human pollution origins. Further, the outcomes of the MST test have been compared with the results of both physicochemical analyses and tests of pharmaceutical and personal care products (PPCPs). A strong positive correlation was discovered between the human marker and PPCPs. Gabapentin was the most frequently detected compound and it showed the uppermost positive correlation with the human marker. The study demonstrated that the NBTS performs satisfactorily with the removal of E. coli but not PPCPs. Interestingly, the presence of PPCPs in the water samples was not correlated with high concentrations of E. coli. Neither has the latter an apparent correlation with the human marker.

Hydrological modeling of Fecal Indicator Bacteria in a tropical mountain catchment

The occurrence of pathogen bacteria in surface waters is a threat to public health worldwide. In particular, inadequate sanitation resulting in high contamination of surface water with pathogens of fecal origin is a serious issue in developing countries such as Lao P.D.R. Despite the health implications of the consumption of contaminated surface water, the environmental fate and transport of pathogens of fecal origin and their indicators (Fecal Indicator Bacteria or FIB) are still poorly known in tropical areas. In this study, we used measurements of flow rates, suspended sediments and of the FIB Escherichia coli (E. coli) in a 60-ha catchment in Northern Laos to explore the ability of the Soil and Water Assessment Tool (SWAT) to simulate watershed-scale FIB fate and transport. We assessed the influences of 3 in-stream processes, namely bacteria deposition and resuspension, bacterial regrowth, and hyporheic exchange (i.e. transient storage) on predicted FIB numbers. We showed that the SWAT model in its original version does not correctly simulate small E. coli numbers during the dry season. We showed that model's performance could be improved when considering the release of E. coli together with sediment resuspension. We demonstrated that the hyporheic exchange of bacteria across the Sediment-Water Interface (SWI) should be considered when simulating FIB concentration not only during wet weather, but also during the dry season, or baseflow period. In contrast, the implementation of the regrowth process did not improve the model during the dry season without inducing an overestimation during the wet season. This work thus underlines the importance of taking into account in-stream processes, such as deposition and resuspension, regrowth and hyporheic exchange, when using SWAT to simulate FIB dynamics in surface waters.

Thermotolerant coliform loadings to coastal areas of Santa Catarina (Brazil) evidence the effect of growing urbanisation and insufficient provision of sewerage infrastructure.

Thermotolerant coliform (TC) loadings were quantified for 49 catchments draining into the North and South Bays of Santa Catarina (SC, southeastern Brazil), an area known for its tourism and aquaculture. TC loadings were calculated based on flow measurements taken in 26 rivers. TC concentrations ere quantified based on surface water samples collected at 49 catchment outlets in 2012 and 2013. Median TC loads ranged from 3.7×103 to 6.8×108 MPNs-1. TC loadings in the catchments increased in proportion to increases in resident human population, population density and percentage of urbanised area. Catchments with more than 60% of area covered by wastewater collection and treatment systems had higher TC loads per person than catchments with less than 25%. Based on the study catchments, these results indicate that current sewerage infrastructure is ineffective in reducing contamination of faecal origin to surface waters. These findings have important implications for the management of microbiological health hazards in bathing, recreational and shellfish aquaculture waters in the North and South Bays of Santa Catarina Island.

Next generation sequencing reveals distinct fecal pollution signatures in aquatic sediments across gradients of anthropogenic influence

&lt;p&gt;Aquatic sediments are the repository of a variety of anthropogenic pollutants, including bacteria of fecal origin, that reach the aquatic environment from a variety of sources. Although fecal bacteria can survive for long periods of time in aquatic sediments, the microbiological quality of sediments is almost entirely neglected when performing quality assessments of aquatic ecosystems. Here we investigated the relative abundance, patterns and diversity of fecal bacterial populations in two coastal areas in the Northern Adriatic Sea (Italy): the Po river prodelta (PRP, an estuarine area receiving significant contaminant discharge from one of the largest European rivers) and the Lagoon of Venice (LV, a transitional environment impacted by a multitude of anthropogenic stressors). From both areas, several indicators of fecal and sewage contamination were determined in the sediments using Next Generation Sequencing (NGS) of 16S rDNA amplicons. At both areas, fecal contamination was high, with fecal bacteria accounting for up to 3.96% and 1.12% of the sediment bacterial assemblages in PRP and LV, respectively. The magnitude of the fecal signature was highest in the PRP site, highlighting the major role of the Po river in spreading microbial contaminants into the adjacent coastal area. In the LV site, fecal pollution was highest in the urban area, and almost disappeared when moving to the open sea. Our analysis revealed a large number of fecal Operational Taxonomic Units (OTU, 960 and 181 in PRP and LV, respectively) and showed a different fecal signature in the two areas, suggesting a diverse contribution of human and non-human sources of contamination. These results highlight the potential of NGS techniques to gain insights into the origin and fate of different fecal bacteria populations in aquatic sediments.&lt;/p&gt;

Source tracking of Enterococcus moraviensis and E. haemoperoxidus.

Enterococci were detected occasionally in 100 L samples of water abstracted from a shallow aquifer in a natural dune infiltration area for drinking water production. Enterococcus moraviensis was the species most frequently identified in these samples. Because there are no existing reports of faecal sources of E. moraviensis and the closely related E. hemoperoxidus, this study aimed to find such sources of these two species in the dunes. Faecal samples from various animal species living in the vicinity of abstraction wells, were analysed for enterococci on Slanetz and Bartley Agar. From these samples, enterococci isolates (1,386 in total) were subsequently identified using matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. E. moraviensis was found in the faeces of geese, foxes and rabbits. Also, E. haemoperoxidus was isolated from goose faeces. Using hierarchical clustering, the species composition of Enterococcus spp. isolated from abstracted water formed one cluster with the species composition found in geese droppings. A sanitary survey supported the indication that feral geese may provide a substantial faecal load in particular parts of this dune infiltration area, close to the water abstraction system. This study confirms the faecal origin of E. moraviensis and E. haemoperoxidus from specific animals, which strengthens their significance as faecal indicators.

Biogeochemical and hydrological drivers of the dynamics of Vibrio species in two Patagonian estuaries.

The ecology of the most relevant Vibrio species for human health and their relation to water quality and biogeochemistry were studied in two estuaries in Argentinian Patagonia. Vibrio cholerae and Vibrio parahaemolyticus were reported in >29% of cases at the Río Colorado and Río Negro estuaries. Neither the pandemic serogroups of Vibrio cholerae O1, Vibrio cholerae O139 nor the cholera toxin gene were detected in this study. However, several strains of V. cholerae (not O1 or O139) are able to cause human disease or acquire pathogenic genes by horizontal transfer. Vibrio vulnificus was detected only in three instances in the microplankton fraction of the Río Negro estuary. The higher salinity in the Río Colorado estuary and in marine stations at both estuaries favours an abundance of culturable Vibrio. The extreme peaks for ammonium, heterotrophic bacteria and faecal coliforms in the Río Negro estuary supported a marked impact on sewage discharge. Generally, the more pathogenic strains of Vibrio have a faecal origin. Salinity, pH, ammonium, chlorophyll a, silicate and carbon/nitrogen ratio of suspended organic particulates were the primary factors explaining the distribution of culturable bacteria after distance-based linear models. Several effects of dissolved organic carbon on bacterial distribution are inferred. Global change is expected to increase the trophic state and the salinisation of Patagonian estuaries. Consequently, the distribution and abundance of Vibrio species is projected to increase under future changing baselines. Adaptation strategies should contribute to sustaining good water quality to buffer climate- and anthropogenic- driven impacts.

Water Quality Changes Shortly After Low‐Head Dam Removal Examined With Cultural and Microbial Source Tracking Methods

AbstractShort‐term effects of low head dam removal on water quality of urbanized stream were evaluated, focusing on fecal pollution indicators. Composite river samples were analyzed for Escherichia coli concentrations, nitrates, phosphates, turbidity and human‐specific marker (HF183) and antibiotic resistance marker (tetQ) before and after dam removal during dry weather conditions. The sampled Olentangy River water in summer before the dam removal showed poor water quality with mean E. coli concentration of 439 colony forming unit (CFU)/100 mL, mean turbidity of 10 NTU and mean nutrient concentrations of 0.61 and 0.41 mg/L for nitrate and phosphate, respectively. Surprisingly, even one month after the dam removal, E. coli numbers doubled and nitrate concentration tripled compared to pre‐removal concentrations. Although the detected HF183 concentrations were below the quantifiable levels, they did not correlate with E. coli concentrations, suggesting E. coli from other than human fecal origin. The correlation between turbidity and E. coli during dry weather further suggests E. coli accumulation in impoundment sediments and release once dam was removed. These short‐term effects of dam removal on water quality should be further evaluated, especially if recreation and other beneficial uses of water in the area are expected. Copyright © 2016 John Wiley &amp; Sons, Ltd.

Environmental quality and hygienic safety of the Alimini Lakes (Puglia, Italy): 20 years of monitoring (1995–2014)

The Alimini Lakes are two water bodies located in the south-eastern part of the Salento Peninsula. They are part of a complex hydrogeological system that includes various intercommunicating water bodies particularly sensitive to point and diffuse pollution. In consideration of the environmental and hygiene-health risks, from 1995 to 2014 the University of Salento and various public authorities, responsible for environmental quality in the Apulia region, conducted a series of monitoring activities to analyse the microbiological, toxicological and ecological quality of the waters throughout the hydrogeological system. The studies made it possible to: quantify the input of fresh water and nutrients to the lakes, revealing a greater environmental risk for Fontanelle as a result of the reduced exchange of waters; identify diffuse contamination of faecal origin linked to the anthropization of the surrounding area, which may have affected the stretch of sea near the mouth of the seaward channel and the underlying aquifer; highlight chemical and toxic risk factors arising from agricultural activities; and identify potential consequences for human health linked to the use of the waters (for domestic purposes, agriculture, recreation, etc.). However, the results of the investigations conducted revealed the gradual improvement of the quality of the waters in the two lakes and the hydrological networks that feed them.

A survey of heterotrophic bacteria and coliforms in the water of old and new distribution networks

Controlling the microbiological quality of water is important for its uses. Microbiological requirements of drinking water ensure the absence of coliforms, but may indicate the potential presence of other potentially pathogenic microorganisms and viruses of fecal origin. A total of 36 water samples, representing the drinking water of the whole city of Aradan, Semnan, Iran, were randomly collected from the old and new distribution systems of Aradan from December 2014 to June 2015.The hetroterophic plate count (HPC), coliform, residual chlorine, and pH of the samples were measured. Heterotrophic bacteria were measure using R2A and nutrients agar culture media, and the spread plate count method was used to determine HPC. Average concentration of total coliform in the old distribution network ( 13⁄84 100 ml ) was more than the new distribution network ( 9⁄42 100 ml ). The results of studying microbial load in the old and new distribution network showed that there is a significant difference between total coliforms in the two networks (P = 0.002). Moreover, the average concentration of heterotrophic bacteria in the old distribution network (1917.33 number/100 ml) was more than that in the new distribution network (14.57 number/100 ml). There was a significant difference between the average concentration of heterotrophic bacteria in the old and new distribution networks (P = 0.003). The effects of seasons and the age of the water network on coliform bacteria and heterotrophic bacteria were also studied. The concentrations of heterotrophic bacteria, total coliform, and fecal coliforms were higher in the old distribution network in comparison to that in the new distribution network.

Mode of Delivery to the Brave New (Microbial) World: A Defining Moment for the Respiratory Microbiome?

Mode of Delivery to the Brave New (Microbial) World: A Defining Moment for the Respiratory Microbiome?

Bacterial community composition and structure in an Urban River impacted by different pollutant sources

Microbial communities in terrestrial fresh water are diverse and dynamic in composition due to different environmental factors. The goal of this study was to undertake a comprehensive analysis of bacterial composition along different rivers and creeks and correlate these to land-use practices and pollutant sources. Here we used 454 pyrosequencing to determine the total bacterial community composition, and bacterial communities that are potentially of fecal origin, and of relevance to water quality assessment. The results were analyzed using UniFrac coupled with principal coordinate analysis (PCoA) to compare diversity, abundance, and community composition. Detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA) were used to correlate bacterial composition in streams and creeks to different environmental parameters impacting bacterial communities in the sediment and surface water within the watershed. Bacteria were dominated by the phyla Proteobacteria, Bacteroidetes, Acidobacteria, and Actinobacteria, with Bacteroidetes significantly (P<0.001) higher in all water samples than sediment, where as Acidobacteria and Actinobacteria where significantly higher (P<0.05) in all the sediment samples than surface water. Overall results, using the β diversity measures, coupled with PCoA and DCA showed that bacterial composition in sediment and surface water was significantly different (P<0.001). Also, there were differences in bacterial community composition between agricultural runoff and urban runoff based on parsimony tests using 454 pyrosequencing data. Fecal indicator bacteria in surface water along different creeks and channels were significantly correlated with pH (P<0.01), NO2 (P<0.03), and NH4N (P<0.005); and in the sediment with NO3 (P<0.015). Our results suggest that microbial community compositions were influenced by several environmental factors, and pH, NO2, and NH4 were the major environmental factors driving FIB in surface water based on CCA analysis, while NO3 was the only factor in sediment.

Restructuring of the Aquatic Bacterial Community by Hydric Dynamics Associated with Superstorm Sandy.

Bacterial community composition and longitudinal fluctuations were monitored in a riverine system during and after Superstorm Sandy to better characterize inter- and intracommunity responses associated with the disturbance associated with a 100-year storm event. High-throughput sequencing of the 16S rRNA gene was used to assess microbial community structure within water samples from Muddy Creek Run, a second-order stream in Huntingdon, PA, at 12 different time points during the storm event (29 October to 3 November 2012) and under seasonally matched baseline conditions. High-throughput sequencing of the 16S rRNA gene was used to track changes in bacterial community structure and divergence during and after Superstorm Sandy. Bacterial community dynamics were correlated to measured physicochemical parameters and fecal indicator bacteria (FIB) concentrations. Bioinformatics analyses of 2.1 million 16S rRNA gene sequences revealed a significant increase in bacterial diversity in samples taken during peak discharge of the storm. Beta-diversity analyses revealed longitudinal shifts in the bacterial community structure. Successional changes were observed, in which Betaproteobacteria and Gammaproteobacteria decreased in 16S rRNA gene relative abundance, while the relative abundance of members of the Firmicutes increased. Furthermore, 16S rRNA gene sequences matching pathogenic bacteria, including strains of Legionella, Campylobacter, Arcobacter, and Helicobacter, as well as bacteria of fecal origin (e.g., Bacteroides), exhibited an increase in abundance after peak discharge of the storm. This study revealed a significant restructuring of in-stream bacterial community structure associated with hydric dynamics of a storm event. In order to better understand the microbial risks associated with freshwater environments during a storm event, a more comprehensive understanding of the variations in aquatic bacterial diversity is warranted. This study investigated the bacterial communities during and after Superstorm Sandy to provide fine time point resolution of dynamic changes in bacterial composition. This study adds to the current literature by revealing the variation in bacterial community structure during the course of a storm. This study employed high-throughput DNA sequencing, which generated a deep analysis of inter- and intracommunity responses during a significant storm event. This study has highlighted the utility of applying high-throughput sequencing for water quality monitoring purposes, as this approach enabled a more comprehensive investigation of the bacterial community structure. Altogether, these data suggest a drastic restructuring of the stream bacterial community during a storm event and highlight the potential of high-throughput sequencing approaches for assessing the microbiological quality of our environment.

A Meta-analysis of Bacterial Diversity in the Feces of Cattle

In this study, we conducted a meta-analysis on 16S rRNA gene sequences of bovine fecal origin that are publicly available in the RDP database. A total of 13,663 sequences including 603 isolate sequences were identified in the RDP database (Release 11, Update 1), where 13,447 sequences were assigned to 10 phyla, 17 classes, 28 orders, 59 families, and 110 genera, while the remaining 216 sequences could not be assigned to a known phylum. Firmicutes and Bacteroidetes were the first and the second predominant phyla, respectively. About 41% of the total sequences could not be assigned to a known genus. The total sequences were assigned to 1252 OTUs at 97% sequence similarity. A small number of OTUs shared among datasets indicate that fecal bacterial communities of cattle are greatly affected by various factors, specifically diet. This study may guide future studies to further analyze fecal bacterial communities of cattle.

Petrography, lithofacies and depositional environment of carbonate-clastic strata in part of the north-western Douala Basin, Cameroon

The lithofacies, petrofacies and sedimentary environments of carbonate-siliciclastic strata of the Tertiary Nkapa Formation have been examined. This paper provides new data on the carbonates whose location and composite thicknesses of outcrop lithologies represent an important segment of the broader West-Central African Platform. The main carbonate outcropping belt is along the Bongoue River and its tributaries. Field and petrographic investigations reveal that carbonates in the study area consist of a number of lithologically distinct facies. These facies are non-skeletal to skeletal in composition including olithic, perlithic, bioclastic and marly limestones which occur in alternation with sandstones and shales. The studied limestones were mostly grain-supported exhibiting textures that range from grainstone, packstone to wackestone. Non-skeletal bioclasts are mainly made up of superficial and composite ooids, and peloids showing grainstone and packstone texture, respectively. The ooids have grain diameter varying from 0.1 to 1.5 mm. The pellets are of faecal origin. The bioclastic limestones are characterised with a packstone to wackestone texture (fifty–fifty), typically associated with nodules and abundant skeletal fragments suggesting deposition in shallow marine barrier reef settings. This interpretation is further supported by the presence of worm tubes in the limestones. Micritic and sparry calcite cement and opaque grains (FeS2) make up the matrix and infill within skeletal fragments. The limestones range from abundant biosparites to minor biomicrites.The marly limestones are characterised with a wacke-to-packstone texture, mainly made up of abundant lithoclasts and minor bioclasts indicating their deposition in areas closer to the continent with large influx of terrigenous clastic material. Sandstones are mostly sublitharenites (>75 %) with minor litharenites (≤25 %). The different lithofacies (carbonates, sandstones, shales) investigated demonstrate that these sediments were deposited in a wide range of environments that varies from continental shelve zones, shallow marine (reef related) to relatively deep marine environments.

Application of host-specific genetic markers for microbial source tracking of faecal water contamination in an agricultural catchment

Elevated nutrient concentrations in streams in the Norwegian agricultural landscape may occur due to faecal contamination. Escherichia coli (E. coli) has been used conventionally as an indicator of this contamination; however, it does not indicate the source of faecal origin. This work describes a study undertaken for the first time in Norway on an application of specific host-associated markers for faecal source tracking of water contamination. Real-time quantitative polymerase chain reaction (qPCR) on Bacteroidales host-specific markers was employed for microbial source tracking (MST) to determine the origin(s) of faecal water contamination. Four genetic markers were used: the universal AllBac (Bacteroidales) and the individual specific markers BacH (humans), BacR (ruminants) and Hor-Bac (horses). In addition, a pathogenicity test was carried out to detect the top seven Shiga toxin-producing E. coli (STEC) serogroups. The ratio between each individual marker and the universal one was used to: (1) normalise the markers to the level of AllBac in faeces, (2) determine the relative abundance of each specific marker, (3) develop a contribution profile for faecal water contamination and (4) elucidate the sources of contamination by highlighting the dominant origin(s). The results of the qPCR MST analyses indicated the actual contributions of humans and animals to faecal water contamination. The pathogenicity test revealed that water samples were STEC positive at a low level, which was in proportion to the concentration of the ruminant marker. The outcomes were verified statistically by coupling the findings of major contamination sources with observations in the field regarding local land use (residential or agricultural). Furthermore, clear correlations between the human marker and E. coli counts as well as the ruminant marker and STEC quantity in faecally contaminated water were observed. The results of this study have the potential to help identify sources of pollution for targeted mitigation of nutrient losses.

Qualitative analysis of drinking water through the most probable number (MPN) method

Water borne disease outbreaks associated with the drinking of unsafe water, containing pathogenic bacteria of fecal origin, is common in densely populated countries like Bangladesh. Present study was attempted to detect indicator bacteria from drinking water samples for the presumptive occurrence of fecal contaminations that are responsible for health associated problems. Therefore, a laboratory scale qualitative analysis through most probable number (MPN) method was employed. The indicator bacterium Escherichia coli were detected in 24 water samples out of 75 samples as revealed consequently by the presumptive, confirmed and completed tests of MPN method. Other Gram negative bacteria found in the samples included Alcaligenes faecalis, Pseudomonas spp., Klebsiella spp. and Proteus spp. Almost all of the identified bacteria showed resistance against commonly used antibiotics which is of significant health concern. DOI: http://dx.doi.org/10.3329/sjm.v3i1.22745 Stamford Journal of Microbiology, Vol.3(1) 2013: 9-16

A method to evaluate relative ovicidal effects of soil microfungi on thick-shelled eggs of animal-parasitic nematodes

Thick-shelled eggs of animal-parasitic ascarid nematodes can survive and remain infective in the environment for years. The present study evaluated a simple in vitro method and evaluation scheme to assess the relative effect of two species of soil microfungi, Pochonia chlamydosporia Biotype 10 and Purpureocillium lilacinum Strain 251 (Ascomycota: Hypocreales), on the development and survival of eggs of faecal origin of three ascarid species, Ascaridia galli (chicken roundworm), Toxocara canis (canine roundworm) and Ascaris suum (pig roundworm). Ascarid eggs were embryonated on water agar with or without a fungus, and the resulting viability of the eggs was evaluated on days 7, 14, 21, 28, 35 and 42 post exposure (pe) by observing eggs in situ. On days 7–42 pe, P. chlamydosporia had reduced the viability of A. galli and T. canis eggs by 64–86% and 26–67%. Corresponding reductions for P. lilacinum Strain 251 were only 15–29% and 4–28%. In contrast, A. suum eggs were extremely resistant to both fungi (2–4% reduction). The differences in results are likely due to different morphologies and chemistry of the egg shell of the three ascarid species. The current in vitro method and evaluation criteria allow for a simple, repeatable and non-invasive evaluation of the ovicidal effects of microfungi. This study demonstrates that P. chlamydosporia Biotype 10 may be utilised as a biocontrol agent to reduce A. galli and T. canis egg contamination of the environment.