Assessment of Antibacterial Activity of Solanum surrattense Against Waterborne Pathogens Isolated from Surface Drinking Water of the Potohar Region in Pakistan

People dwelling in different cities of the Potohar region, Pakistan, are mostly dependent on surface water for drinking and domestic use. In an attempt to make available potable, safe water, filtration plants were constructed along with dams in the Potohar region. Water samples from these filtration plants were collected and analyzed for total and faecal coliform bacteria as well as for total viable count. Results showed that bacterial indicators of faecal contamination were numerous and significantly greater than World Health Organization recommended guidelines. Accordingly, antibacterial activity of methanolic and aqueous extracts of different parts of Solanum surrattense were assessed in vitro against waterborne pathogens. Fruits exhibited more antibacterial activities at incubation at 37°C than shoots and roots, which showed lowest Minimum Inhibitory Concentration (MIC) and zones of inhibition. These results suggest that plants offer a great potential for purification of drinking water that needs to be explored further because fruit extract of the aforementioned plant can be of practical use against waterborne pathogens.     

Microbial Exposure Assessment of Waterborne Pathogens

The large number of waterborne illnesses in Ireland and worldwide has highlighted the need to enhance strategies that minimize human exposure to pathogens in drinking water supplies. Waterborne pathogens of public concern together with relevant national and international legislation are reviewed in this study. Cryptosporidium species and pathogenic Escherichia coli are among pathogens of primary concern. The organisms originate from the gastrointestinal tract of animals and humans. They may be associated with persistent contamination of water sources, survive for long periods in the environment, and, in particular in the case of Cryptosporidium species, may survive in chlorinated water supplies. Prevention of waterborne infection should emphasize source protection in addition to water treatment. Risk assessment models can play an important role in protecting natural water systems from contamination with these pathogens. Qualitative approaches can provide an effective means of assessing risks with minimum resources and limited data; however, they lack the precision and predictive ability of fully quantitative approaches. Thirteen quantitative simulation models that could potentially be used for modeling bacterial pollutants in agricultural watersheds have been assessed in this study. No one model suits all modeling criteria. Pathogen predictions have proved variable and no model was capable of accounting for all geological and hydrological factors in addition to modeling the physical transport of bacteria in surface runoff. This assessment summarizes commonly used models and their capacity to model water pollution while also providing a good reference point for the microbial risk assessment of waterborne pathogens.     

A Probabilistic Assessment of Household Exposures to MTBE from Drinking Water

The oxygenate methyl tertiary butyl ether (MTBE) has been added to reformulated gasoline in the U.S. to meet national ambient air quality standards. Although MTBE has provided significant health benefits in terms of reduced criteria and toxic air pollutants, detections of MTBE in some groundwater and drinking water sources have raised concerns about potential environmental contamination and human exposures. In this paper, we examine the frequency and concentration of MTBE detections in drinking water sources in California from 1995 to 1999, and provide a preliminary analysis of the distribution of household exposures to MTBE from water-related activities. Using published data on the toxicity and possible cancer hazard posed by MTBE, we estimate the likely cancer and non-cancer risks for the general population in California from past and potential future MTBE exposures. More highly exposed subgroups were also addressed. Our findings indicate that less than 2% of all sampled drinking water sources in California had detectable levels of MTBE in 1999, with average MTBE drinking water concentrations ranging from 0.09 to 4.9?ppb for this year. Both the detection rate for MTBE and average MTBE concentrations have remained relatively stable since 1995, despite increased sampling of drinking water sources in California. The probabilistic exposure analysis suggests that drinking water exposures to MTBE are unlikely to pose a significant health risk for the general population or more highly exposed individuals in California.     

Arsenic and Heavy Metal Concentrations in Drinking Water in Pakistan and Risk Assessment: A Case Study

The present study was performed to assess drinking water quality and potential health risk in the Nowshera District, Khyber Pakhtunkhwa, Pakistan. For this purpose drinking water samples were collected from local available sources and analyzed for physico-chemical characteristics, arsenic (As) and heavy metals. Results revealed high levels of toxic heavy metals such as chromium (Cr), nickel (Ni), lead (Pb), cadmium (Cd), and As contaminations in the drinking water. Results were evaluated for chronic risk including average daily intake (ADI) and hazard quotient (HQ). Among heavy metals the HQ values were highest for Cd (5.80) and As (2.00). Therefore, populations in the study area may be at a low level of chronic toxicity and carcinogenic risk. Statistical analyses showed that contribution of different drinking water sources to the mean contaminant levels in the study area was insignificant (p =.53). Correlation analysis further revealed that anthropogenic activities were the main sources of contamination, rather than geogenic. This study strongly recommends the treatment of urban and industrial wastewater in the vicinity of the study area and provision of safe drinking water.     

黄花夹竹桃内生真菌抗病原细菌的初步研究

从植物黄花夹竹桃 (Thevetiaperuviana)的根、茎、叶、果实中分离出内生真菌 10 1株。以鼠伤寒沙门氏菌 (Salmonellatyphimurium)、肺炎链球菌 (Streptococcuspneumoniae)、乙型溶血链球菌 (Streptococcushemolyticus)、金黄色葡萄球菌 (Staphyllococcusaureus) 4种人类病原菌为指示菌 ,对其进行抑菌活性筛选 ,结果有 17株内生真菌对 1株或 1株以上人类病原菌有抑菌活性 ,其中平板抑菌圈直径大于 2 0mm的菌株有9株。具有抗菌活性的内生真菌分别来自木霉属 (Trichoderma)、曲霉属 (Aspergillus)等 9个属。     

Prevalence of Zoonotic Pathogens from Feral Pigs in Major Public Drinking Water Catchments in Western Australia

Australia has the largest number of wild pigs in the world. Their pronounced impacts on agriculture and biodiversity make the estimated 23 million feral pigs one of Australia’s most important vertebrate pest species. The foraging and wallowing behavior of pigs can markedly increase the turbidity of water supplies, but more importantly, they can transmit and excrete a number of infectious waterborne organisms pathogenic to humans. Their persistence in drinking water catchments also makes them potentially significant reservoirs for zoonotic pathogens. In this study, important protozoan parasite pathogens, such as Giardia, Cryptosporidium, Balantidium, and Entamoeba, were detected from the feces of feral pigs caught in metropolitan drinking water catchment areas. All are potentially important waterborne human pathogens that pose a major threat to drinking water quality. Fortunately, the overall prevalence in feral pigs appears to be relatively low, with ≤13% of pigs detected with parasites. In this study, we combined the findings from the parasitological analysis with the use of 14 highly informative DNA markers to define a series of highly structured populations that indicated very little movement of feral pigs between the populations. The implication of this pattern is that any public health risk may spread very slowly between populations, but may be much higher within watercourses. This study represents an innovative and important new approach to drinking water source protection in Australia.     

In vitro Antagonism of Rhizobacteria Isolated from Coffea arabica L. against Emerging Fungal Coffee Pathogens

In vitro antagonistic effects of rhizobacteria associated with Coffea arabica L. against some fungal coffee pathogens were studied. The aims were to screen indigenous coffee‐associated isolates for their inherent antagonistic potential against major coffee wilt diseases induced by Fusarium spp. Antagonistic effects, siderophore, HCN and lytic enzyme production were determined on standard solid media. Chemical methods were employed to categorize the major types of siderophores. From a total of 212 rhizobacterial isolates tested, over 10 % (all Pseudomonas and Bacillus spp.) exhibited remarkable inhibition against Fusarium spp. One isolate AUPB24 (P. chlororaphis) showed maximum inhibition of mycelial growth against all fungal pathogens tested, whereas other isolates were mostly inhibitory to F. stilboides and F. oxysporum. The isolate AUBB20 (B. subtilis) was most antagonistic to F. xylarioides. Of the rhizobacterial isolates tested, 67 % produced siderophores and 35 % produced HCN. Many strains (all Pseudomonas spp.) produced siderophores of the hydroxamate type and only a small proportion produced those of the catecholate type. Few antagonists showed chitinase activity. The production of siderophores and HCN by Pseudomonas spp., lipase and protease by all antagonists and β‐1,3‐glucanase by several Bacillus spp. could be considered the major mechanisms involved in the inhibition of fungal growth. The in vitro results provide the first evidence of an antagonistic effect of coffee‐associated rhizobacteria against the emerging fungal coffee pathogens F. stilboides and F. xylarioides and indicate the potential of both bacterial groups for biological control of coffee wilt diseases.     

Organophosphate Pesticide Residues in Drinking Water from Artesian Wells and Health Risk Assessment of Agricultural Communities,Thailand

Organophosphate pesticide (OPPs) concentrations in artesian wells located in Thai agricultural and non-agricultural communities were studied during both wet and dry seasons. A total of 100 water samples were collected and subjects were asked to complete a survey. Gas chromatography flame photometric detector was used for OPP analysis. The average OPP concentration in the agricultural communities (0.085 and 0.418 μg/l in dry and wet season) was higher than in the non-agricultural communities (0.004 μg/l in both seasons). Ingestion of OPPs in contaminated water in the agricultural communities were estimated to be 0.187 and 0.919 μg/day during the dry and wet seasons, respectively, and 0.008 μg/day during both seasons in the non-agricultural communities. Agricultural communities were exposed to pesticide residues under the oral chronic reference dose. This study suggests that people in agricultural communities may be exposed to significantly greater levels of pesticides than non-agricultural populations during the dry and wet seasons (p < .001, .001).     

Fungicidal Activity of Volatiles from Selected Cruciferous Plants against Resting Propagules of Soil-borne Fungal Pathogens

The efficacy of volatiles evolved from tissues of nine cruciferous plants against resting propagules of Fusarium oxysporum var radicis f. sp. lycopersici, Sclerotium cepivorum, and Sclerotinia sclerotiorum was tested. The cruciferous plants released biocidal compounds, mainly isothiocyanates, produced during the enzymatic degradation of glucosinolates present in the plant cells. Among the plants investigated, the highest fungicidal activity and also the highest concentration of isothiocyanates were found in Brassica juncea. The resting propagules of tested fungi differed significantly in their sensitivity towards volatiles released from plant tissues.     

桶装纯净水中三种有害元素对人体的健康风险评价

本文根据2001～2004年对桶装纯净水的监测结果,将健康风险评价的方法应用于纯净水的卫生质量评价中,根据相应的数学模型分别计算了桶装纯净水中化学致癌物As和非致癌污染物Pb、Cu通过饮用途径对人体健康的年风险。桶装纯净水中的3种有害元素由饮水途径对人体所致的健康危害程度依次是As>Pb>Cu。其中As是主要的污染,占个人年风险的99.98%。而在非致癌污染物中,Pb又是主要污染,占非致癌污染物个人年风险的82.9%。     

Antibacterial activity and mechanism of essential oils in combination with medium-chain fatty acids against predominant bovine mastitis pathogens

Bovine mastitis has become a significant economic importance for the dairy industry. Concerns regarding poor milk quality and emergence of bacterial resistance have necessitated to develop an alternative therapeutic approach to antibiotics for the treatment of mastitis. Saturated medium-chain fatty acids (MCFAs) and essential oils (EOs) are known natural antimicrobials, but their combined effect has not been investigated extensively. The objective of the present investigation was to examine the bactericidal effect of various combined treatments of eight EOs and three saturated MCFAs to inactivate predominant mastitis pathogens, including Staphylococcus aureus ATCC 29213; Escherichia coli ATCC 25922; Klebsiella pneumoniae ATCC 27736 and Streptococcus agalactiae ATCC 27956. The minimum inhibitory concentration (MIC) values confirmed that all the tested pathogens were variably susceptible to both EOs and saturated MCFAs. Among essential oils, carvacrol (CAR), trans-cinnamaldehyde (TC) and thymol (TM) showed the highest inhibitory activity at concentration 0·38–1·32 mg/mL. Carvacrol exhibited effective additive antibacterial activity in combined treatment with octanoic acid (OA) in terms of its fractional inhibitory index (0·63–0·88) and time-kill effect in reducing about 6 log CFU/mL bacterial cells in less than 5 min. The effort was also made to elucidate the mechanism of antibacterial action of CAR and OA against selected mastitis pathogens by observing changes in cell microstructure, permeability and integrity of cell membrane and their membrane potential. After adding CAR and OA at MIC level, there were obvious changes in cell morphology, leakage of small electrolytes and macromolecules at the initial few hours of treatment i.e. within 1–2 h were observed. Our results indicated that CAR and OA could be evaluated as alternatives or adjuncts to antibiotics as intramammary infusion or topical application to treat bovine mastitis, significantly improving the microbiological safety of milk.     

A Waterborne Outbreak and Detection of Cryptosporidium Oocysts in Drinking Water of an Older High-Rise Apartment Complex in Seoul

From May to June 2012, a waterborne outbreak of 124 cases of cryptosporidiosis occurred in the plumbing systems of an older high-rise apartment complex in Seoul, Republic of Korea. The residents of this apartment complex had symptoms of watery diarrhea and vomiting. Tap water samples in the apartment complex and its adjacent buildings were collected and tested for 57 parameters under the Korean Drinking Water Standards and for additional 11 microbiological parameters. The microbiological parameters included total colony counts, Clostridium perfringens, Enterococcus, fecal streptococcus, Salmonella, Shigella, Pseudomonas aeruginosa, Cryptosporidium oocysts, Giardia cysts, total culturable viruses, and Norovirus. While the tap water samples of the adjacent buildings complied with the Korean Drinking Water Standards for all parameters, fecal bacteria and Cryptosporidium oocysts were detected in the tap water samples of the outbreak apartment complex. It turned out that the agent of the disease was Cryptosporidium parvum. The drinking water was polluted with sewage from a septic tank in the apartment complex. To remove C. parvum oocysts, we conducted physical processes of cleaning the water storage tanks, flushing the indoor pipes, and replacing old pipes with new ones. Finally we restored the clean drinking water to the apartment complex after identification of no oocysts.     

The Use of Probabilistic Risk Assessment in Establishing Drinking Water Quality Objectives

There has been a trend in recent years toward the use of probabilistic methods for the analysis of uncertainty and variability in risk assessment. By developing a plausible distribution of risk, it is possible to obtain a more complete characterization of risk than is provided by either best estimates or upper limits. We describe in this paper a general framework for evaluating uncertainty and variability in risk estimation and outline how this framework can be used in the establishment of drinking water quality objectives. In addition to characterizing uncertainty and variability in risk, this framework also facilitates the identification of specific factors that contribute most to uncertainty and variability. The application of these probabilistic risk assessment methods is illustrated using tetrachloroethylene and trihalomethanes as examples.     

Promiscuity in populations of the cushion plant Saxifraga oppositifolia in the Swiss Alps as inferred from random amplified polymorphic DNA (RAPD)

Overviews on patterns of genetic variation within and among plant populations show that widespread, outcrossing species should have a high proportion of the total genetic variation within populations and a low proportion among populations, which results in little population differentiation. However, in Alpine areas, large–scale distribution barriers as well as small-scale habitat heterogeneity could lead to geographical and temporal isolation, respectively. We investigated the genetic variation of Saxifraga oppositifolia from 10 populations of the Alps in southeastern Switzerland using random amplified polymorphic DNA (RAPD). Based on the banding patterns of four RAPD primers, 84 polymorphic markers identified all 189 sampled individuals as being genetically different. The genetic variation was mainly found within populations (95%), whereas less than 5% was found among populations and among regions. Analyses of molecular variance ( AMOVA ) suggested that population differentiation was highly significant. However, grouping populations differently into regions did not appear to result in a clear correspondence of genetic and geographical relatedness. Genetic variation did not significantly differ between populations of two elevational levels. This coincides with results of former pollination experiments that revealed a breeding system of S. oppositifolia which remains the same irrespective of the elevation. We assume that the high outcrossing rate, rare clonal reproduction, and some long-distance dispersal even among topographically separated populations are the crucial determinants for the pattern of genetic variation found in the investigated area.     

Assessing Risk of Inorganic Arsenic in Drinking Water in the United States

Limitations of the current EPA risk assessment for inorganic arsenic in drinking water in the U.S. are discussed. An empirical approach is suggested that would sample survey the populations in regions with the highest arsenic levels in drinking water for signs of arsenicism, which has been much more prevalent and appeared much earlier in exposed populations than cancer (e.g., of the skin). Biomarkers of exposure, such as arsenic content in urine, nails, hair, and skin scales, may provide even earlier indications of subpopulations with excessive arsenic exposure and identify individuals at risk. Further study is needed to evaluate fully the potential for use of biomarkers, focusing on the accuracy and reliability of analytical methods, the utility of biomarkers as indicators of short-term and long-term exposure and as precursors to clinical signs of arsenicism, and the use of “normal” ranges of biomarkers for interpretation of field observations.     

从滑桃树种壳中分离到具抗细菌活性的新木脂素(英文)

Five neolignans including four new ones were obtained from the seed endotheliums of Trewia nudiflora L. Their structures were determined to be 9‘-methyl americanol A(1), 9‘-methyl isoamericanol A(2), 9‘-ethyl americanol A(3), 9‘-butyl americanol A(4), and americanin (5). Two acetylated products 3,4-diacetyl americanin (5a) and 3,4,9-triacetyl americanin (5b) had been prepared from compound 5. All of these compounds were investigated on antibacterial assays when carbenicillin sodium, streptomycin sulfate and rifampicin were used as positive controls. Compounds 4 and 5 exhibited antibacterial activities against gram-positive bacterium Staphylococcus aureus and gram-negative bacterium Mycobacterium tuberculosis at the minimum inhibitory concentrations (MIC) of 50μg/mL and 100μg/mE respectively, but 5a and 5b did not exhibit antibacterial activity at 200μg/disk.     

Sensitivity Analysis of U.S. EPA's Estimates of Skin Cancer Risk from Inorganic Arsenic in Drinking Water

The current U.S. Environmental Protection Agency's (USEPA's) risk analysis on the Integrated Risk Information System (IRIS) for arsenic in drinking water is based on an epidemiological study of skin cancer in Taiwan. Assumptions used in the USEPA application of the multistage-Weibull model for risk estimation were varied to assess the effect on predicted risk of skin cancer to the U.S. population at arsenic concentrations of 1 to 50?µg/L in drinking water. Among the assumptions tested, the only notable change in risk estimates was a reduction when the arsenic concentration used as representative for Taiwan villages in the low range (<300?µg/L) was increased to the 75th percentile (245?µg/L) in place of the mean used in the USEPA analysis (170?µg/L), but the representative value for Taiwan villages in the high range (≥600?µg/L) was not increased simultaneously to the 75th percentile. Additionally, a simulation study was conducted using records of arsenic measurements in wells from the same period and region of Taiwan as the original study. The exposure-response curve estimated from 60 villages (60 data points) differed only marginally from the outcome when data were summarized into four data points (as in the USEPA skin cancer analysis). Briefly discussed are differences between the study area of Taiwan and the U.S. in nutritional status and consumption of inorganic arsenic in food that might bias predicted U.S. skin cancer risks.     

Optimizing the Production of Antioxidant and Antibacterial Alkaloids from Macleaya cordata by Subcritical Water Extraction Technology

In this work, the subcritical water extraction technology was used to extract alkaloids from Macleaya cordata, and the effects of extraction temperature and time on its yield were investigated to find the best extraction conditions. Moreover, the antioxidant capacity and antibacterial activity of Macleaya cordata extract were studied. Furthermore, through the single-factor method, it was found that properly increasing the extraction temperature and prolonging the extraction time was conducive to increasing alkaloid yield. Still, a considerable amount of alkaloids might be decomposed by heat, resulting in a decrease in their yield. The results showed that the optimal extraction temperature of alkaloids from Macleaya cordata with subcritical water is 190 °C, the time is 45 min, and the corresponding maximum yield is 35.19±0.12 mg/g (sanguinarine equivalent in raw materials). In addition, the antioxidation and bacteriostasis abilities of subcritical water extract are better than those of traditional hot water extract, indicating that it is a feasible method to extract alkaloids from Macleaya cordata with subcritical water.     

Assessing the Effects of Climate Change on Waterborne Microorganisms: Implications for EU and U.S. Water Policy

Despite advances in water treatment, outbreaks of waterborne diseases still occur in developed regions including the United States and Europe Union (EU). Water quality impairments attributable to elevated concentrations of fecal indicator bacteria, and associated with health risk, are also very common. Research suggests that the impact of such microorganisms on public health may be intensified by the effects of climate change. At present, the major regulatory frameworks in these regions (i.e., the US Clean Water Act [CWA] and the EU Water Framework Directive [WFD]), do not explicitly address risks posed by climate change. This article reviews existing U.S. and EU water quality regulatory legislation for robustness to climate change and suggests watershed modeling approaches to inform additional pollution control measures given the likely impacts on microbial fate and transport. Comprehensive analysis of future climate and water quality scenarios may only be achievable through the use of watershed-scale models. Unless adaptation measures are generated and incorporated into water policy, the potential threat posed to humans from exposure to waterborne pathogens may be amplified. Such adaptation measures will assist in achieving the aims of the EU WFD and US CWA and minimize impacts of climate change on microbial water quality.     

Evaluating the Risk of Infection from the Presence of Giardia and Cryptosporidium in Drinking Water

Monte-Carlo simulations were performed in order to quantify the microbiological risk arising from the presence of Giardia and Cryptosporidium in drinking water. A two-year survey of 45 utilities located on a portion of the St. Lawrence River (Quebec, Canada) allowed us to collect the information required for this assessment: parasite occurrence data, treatment performances and daily unboiled water consumption. For a conventional treatment, the mean annual risk of infection with Cryptosporidium was found to be approximately eight times higher than with Giardia. The Monte-Carlo simulations confirm that the clarification process plays an important role in the reduction of the health risk associated with protozoan parasites. In fact, in the case of Cryptosporidium, the impact of chemical disinfectants (O₃ or Cl₂) appears to be minimal in the cold water treatment conditions prevailing in Quebec. According to the Monte-Carlo simulations, 45% (for conventional treatment+O₃) and 51% (for conventional treatment) of individuals are exposed to a risk of infection with Cryptosporidium higher than the proposed USEPA guideline (1 infection per 10[emsp4 ]000 individuals per year).