Pathogen removal in farm-scale psychrophilic anaerobic digesters processing swine manure.

This study assessed the efficiency of commercial-scale psychrophilic anaerobic digestion in sequencing batch reactors (PADSBRs) for pathogen removal from pig manure. The impact of treatment cycle length and of hydraulic flow regimes on pathogen removal efficiency was investigated. Two conventionally operated SBRs (BR1 and BR2) and two SBRs simultaneously fed during the draw step (BR3 and BR4) were monitored over a two-year period.

Fate of the antiretroviral drug tenofovir in agricultural soil.

Tenofovir (9-(R)-(2-phosphonylmethoxypropyl)-adenine) is an antiretroviral drug widely used for the treatment of human immunodeficiency virus (HIV-1) and Hepatitis B virus (HBV) infections. Tenofovir is extensively and rapidly excreted unchanged in the urine. In the expectation that tenofovir could potentially reach agricultural lands through the application of municipal biosolids or wastewater, and in the absence of any environmental fate data, we evaluated its persistence in selected agricultural soils.

Dynamics of antimicrobial resistance and virulence genes in Enterococcus faecalis during swine manure storage.

In this study we used 2 experimental approaches to evaluate the stability of antimicrobial resistance (AMR) phenotypes, selected AMR genes, and selected virulence genes in Enterococcus faecalis during manure storage on a commercial swine farm. Isolates of E. faecalis were obtained directly from fresh fecal material (n = 120) and from the manure storage facility (n = 85) and compared.

Enumeration and strain characterization of fecal Escherichia coli associated with feeding triticale dried distillers grain with solubles in beef cattle diets.

Triticale dried distillers grain with solubles (TDDGS), a major by-product of the bioethanol industry, has potential for utilization in animal feed. This study investigated the changes in generic fecal Escherichia coli strains associated with inclusion of TDDGS in cattle diets. Within this study, a longitudinal experiment (112 days) examined the effect of step-up increasing TDDGS inclusion from control to a final diet containing 30% TDDGS among cattle (n = 4), and a short-term experiment (28 days) compared animals (n = 16) fed control, 20%, 25%, or 30% TDDGS diets.

Impacts of climate change on indirect human exposure to pathogens and chemicals from agriculture.

Climate change is likely to affect the nature of pathogens/ chemicals in the environment and their fate and transport. We assess the implications of climate change for changes in human exposures to pathogens/chemicals in agricultural systems in the UK and discuss the effects on health impacts, using expert input and literature on climate change; health effects from exposure to pathogens/chemicals arising from agriculture; inputs of chemicals/pathogens to agricultural systems; and human exposure pathways for pathogens/chemicals in agricultural systems. We established the evidence base for health effects of chemicals/pathogens in the agricultural environment; determined the potential implications of climate change on chemical/pathogen inputs in agricultural systems; and explored the effects of climate change on environmental transport and fate of various contaminants.

Practical considerations optically sensing rhodamine WT in water impacted by municipal biosolids.

Rhodamine WT (RWT) is an adsorptive flourescent dye tracer that is used in hydrological and hydrogeological studies. Municipal biosolids (sewage) are rich in organic matter and have a variety of chemical constituents that can interact to confound optical sensing of RWT florescence in water (e.g.

Spatial distribution of some microbial trophic groups in a plug-flow-type anaerobic bioreactor treating swine manure.

Anaerobic digestion of swine manure is carried out by a consortium of microbial species, including volatile fatty acid (VFA) producers, VFA-degraders and methanogens. The distribution of five phylogenetic groups within a plug-flow-type anaerobic bioreactor consisting of eight serially-connected tanks was examined through the sequential digestion of swine manure. Quantification was carried out using reverse transcription real-time PCR (RT-Q-PCR) assays targeting the 16S rRNA of Clostridium (cluster XIVa), Peptostreptococcus, Syntrophomonas, Methanosaeta, and Methanosarcina spp.

Adhesive/Dentin interface: the weak link in the composite restoration.

Results from clinical studies suggest that more than half of the 166 million dental restorations that were placed in the United States in 2005 were replacements for failed restorations. This emphasis on replacement therapy is expected to grow as dentists use composite as opposed to dental amalgam to restore moderate to large posterior lesions. Composite restorations have higher failure rates, more recurrent caries, and increased frequency of replacement as compared to amalgam.

The occurrence and sources of Campylobacter spp., Salmonella enterica and Escherichia coli O157:H7 in the Salmon River, British Columbia, Canada.

In this study, we wished to assess the prevalence and determine the sources of three zoonotic bacterial pathogens (Salmonella, Campylobacter, and Escherichia coli O157:H7) in the Salmon River watershed in southwestern British Columbia. Surface water, sewage, and animal faecal samples were collected from the watershed. Selective bacterial culture and PCR techniques were used to isolate these three pathogens and indicator bacteria from these samples and characterize them.

Presence of zoonotic pathogens in physico-chemically characterized manures from hog finishing houses using different production systems.

Hog production has been intensified in Eastern Canada, by 50% over the last 20years. Wastes are now managed with conventional production systems (slatted floor), litter systems or source separation systems. We studied the presence of total and fecal coliforms, Campylobacter, Clostridium perfringens, Enterococcus, Escherichia coli, Salmonella, Yersinia enterocolitica, Giardia and Cryptosporidium in the manure of all of these production systems.

Optimization and validation of rep-PCR genotypic libraries for microbial source tracking of environmental Escherichia coli isolates.

Escherichia coli can be used to help identify sources of fecal contamination in the environment. Escherichia coli genotypic fecal libraries and pattern-matching algorithms were assessed for their effectiveness in correctly identifying sources. Fecal samples (n = 172) were collected from various sources from three agricultural landscapes in Canada.

Distribution and diversity of Escherichia coli populations in the South Nation River drainage basin, eastern Ontario, Canada.

We investigated the prevalence and diversity of Escherichia coli strains isolated from surface waters from multiple watersheds within the South Nation River basin in eastern Ontario, Canada. The basin is composed of mixed but primarily agricultural land uses. From March 2004 to November 2007, a total of 2,004 surface water samples were collected from 24 sampling sites.

Prolonged survival of Campylobacter species in bovine manure compost.

The persistence of naturally occurring campylobacteria in aerobic compost constructed of manure from beef cattle that were administered chlortetracycline and sulfamethazine (AS700) or from cattle not administered antibiotics (control) was examined. Although there were no differences in population sizes of heterotrophic bacteria, the temperature of AS700 compost was more variable and did not become as high as that of control compost. There were significant differences in water content, total carbon (C), total nitrogen (N), and electrical conductivity but not in the C/N ratio or pH between the two compost treatments.

Polybrominated diphenyl ethers, perfluorinated alkylated substances, and metals in tile drainage and groundwater following applications of municipal biosolids to agricultural fields.

Polybrominated diphenyl ethers (PBDEs), perfluorinated alkylated substances (PFAS), and metals were monitored in tile drainage and groundwater following liquid (LMB) and dewatered municipal biosolid (DMB) applications to silty-clay loam agricultural field plots. LMB was applied (93,500 L ha(-1)) in late fall 2005 via surface spreading on un-tilled soil (SS(LMB)), and a one-pass aerator-based pre-tillage prior to surface spreading (AerWay SSD) (A). The DMB was applied (8 Mg d wha(-1)) in early summer 2006 on the same plots by injecting DMB beneath the soil surface (DI), and surface spreading on un-tilled soil (SS(DMB)).

Farm-to-fork characterization of Escherichia coli associated with feedlot cattle with a known history of antimicrobial use.

This study investigated antimicrobial-resistant (AR) Escherichia coli isolated from "farm-to-fork" production of cattle fed diets containing the antimicrobial growth promoter (AGP) chlortetracycline plus sulfamethazine (44ppm each, AS700) or no AGP (control). For each treatment, samples included: feces just prior to euthanization; hides after euthanization; intestinal digesta from the lower digestive tract; carcasses immediately after evisceration and after 24h in the chiller; and ground beef stored at 5 degrees C for 1 and 8days. Samples were also collected from the abattoir environment and from air during hide removal.

Environmental risk assessment of human pharmaceuticals in the European Union: A case study with the β-blocker atenolol.

β-Adrenergic receptor blockers (β-blockers) are applied to treat high blood pressure, ischemic heart disease, and heart rhythm disturbances. Due to their widespread use and limited human metabolism, β-blockers are widely detected in sewage effluents and surface waters. β-Adrenergic receptors have been characterized in fish and other aquatic animals, so it can be expected that physiological processes regulated by these receptors in wild animals may be affected by the presence of β-blockers.

Effect of photoinitiator system and water content on dynamic mechanical properties of a light-cured bisGMA/HEMA dental resin.

The selection of an appropriate photoinitiator system is critical for efficient polymerization of dental resins with satisfactory mechanical and physical properties. The purpose of this study was to evaluate the influence of adding an iodonium salt to two-component photoinitiator systems. Four photoinitiator systems were included in a model bisGMA/HEMA resin and used to prepare samples at different water contents; the dynamic mechanical properties and the final degree of conversion of the samples were then characterized.

A methods comparison for the isolation and detection of thermophilic Campylobacter in agricultural watersheds.

Campylobacter species contribute to an enormous burden of enteric illnesses around the world. This study compared two different methods for detecting Campylobacter species in surface water samples from agricultural watersheds across Canada. One method was based on membrane filtration (MF) of 500 ml water samples followed by selective microaerophilic enrichment at 42 degrees C in Bolton broth, isolation of Campylobacter on CCDA, and subsequent identification confirmation by a PCR assay.

Longitudinal characterization of resistant Escherichia coli in fecal deposits from cattle fed subtherapeutic levels of antimicrobials.

Model fecal deposits from cattle fed or not fed antimicrobial growth promoters were examined over 175 days in the field for growth and persistence of total Escherichia coli and numbers and proportions of ampicillin-resistant (Amp(r)) and tetracycline-resistant (Tet(r)) E. coli. In addition, genotypic diversity and the frequency of genetic determinants encoded by Amp(r) and Tet(r) E.

Characterization of tetracycline- and ampicillin-resistant Escherichia coli isolated from the feces of feedlot cattle over the feeding period.

The objective of this study was to investigate tetracycline and ampicillin resistance in Escherichia coli isolated from the feces of 50 crossbred steers housed in 5 feedlot pens. The steers were not administered antibiotics over a 246-day feeding period. A total of 216 isolates were selected for further characterization.

Pathotype and antibiotic resistance gene distributions of Escherichia coli isolates from broiler chickens raised on antimicrobial-supplemented diets.

The impact of feed supplementation with bambermycin, monensin, narasin, virginiamycin, chlortetracycline, penicillin, salinomycin, and bacitracin on the distribution of Escherichia coli pathotypes in broiler chickens was investigated using an E. coli virulence DNA microarray. Among 256 E.

Immune response to controlled release of immunomodulating peptides in a murine experimental autoimmune encephalomyelitis (EAE) model.

The effects of controlled release on immune response to an immunomodulating peptide were evaluated in a murine experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis (MS). The peptide, Ac-PLP-BPI-NH(2)-2 (Ac-HSLGKWLGHPDKF-(AcpGAcpGAcp)(2)-ITDGEATDSG-NH(2); Ac = acetyl, Acp = epsilon aminocaproic acid) was designed to suppress T-cell activation in response to PLP(139-151), an antigenic peptide in MS. Poly-lactide-co-glycolide (PLGA) microparticles containing Ac-PLP-BPI-NH(2)-2 (8+/-4 microm, 1.

Impact of biosolids on the persistence and dissipation pathways of triclosan and triclocarban in an agricultural soil.

The broad spectrum antimicrobial agents triclosan (TCS) and triclocarban (TCC) are widely used in many personal care products. Knowledge concerning the fate of these two compounds in different environmental matrices is scarce. In this study, the fate of TCS and TCC in soil following direct addition, or when residues were applied via either liquid municipal biosolids (LMB) or dewatered municipal biosolids (DMB) was investigated in laboratory dissipation experiments and under outdoor conditions using radioisotope methods.

Water sorption and dynamic mechanical properties of dentin adhesives with a urethane-based multifunctional methacrylate monomer.

Objectives: Our previous study showed the synthesis and characterization of a novel urethane-linked trimethacrylate monomer for use as a co-monomer in dentin adhesives. The objective of this work was to further investigate the performance of dentin adhesives containing a new monomer, with particular emphasis on the water sorption and viscoelastic behavior of the crosslinked networks.

Materials And Methods: Dentin adhesives contained 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) phenyl]-propane (BisGMA), 2-hydroxyethyl methacrylate (HEMA), and a new multifunctional methacrylate with urethane-linked groups-1,1,1-tri-[4-(methacryloxyethylaminocarbonyloxy)-phenyl]ethane (MPE) and were photo-polymerized in the presence or absence of water.

Multivariate statistical analyses of rDNA and rRNA fingerprint data to differentiate microbial communities in swine manure.

Fingerprint data from swine manure microbial community rRNAs and rRNA genes were treated by multivariate statistical and diversity analyses to differentiate swine manures. Microbial communities from finishing pig manure and from a mixture of manure slurries from maternity confinement and finishing pigs were characterized using a combination of amplicon length heterogeneity PCR (LH-PCR) and terminal restriction fragment length polymorphism (T-RFLP), using PCR primers targeting Bacteria and Archaea, respectively. Unweighted pair group method with arithmetic mean clustering, principal components analysis (PCA), indicator species analysis (ISA), and diversity analyses showed that rRNA-based fingerprinting methods [reverse transcription (RT)-LH-PCR and RT-T-RFLP] were more effective than rDNA-based fingerprinting methods for distinguishing the manure samples.