Reduction of nutrients, microbes, and personal care products in domestic wastewater by a benchtop electrocoagulation unit.

To preserve environmental and human health, improved treatment processes are needed to reduce nutrients, microbes, and emerging chemical contaminants from domestic wastewater prior to discharge into the environment. Electrocoagulation (EC) treatment is increasingly used to treat industrial wastewater; however, this technology has not yet been thoroughly assessed for its potential to reduce concentrations of nutrients, a variety of microbial surrogates, and personal care products found in domestic wastewater. This investigation's objective was to determine the efficiency of a benchtop EC unit with aluminum sacrificial electrodes to reduce concentrations of the aforementioned biological and chemical pollutants from raw and tertiary-treated domestic wastewater. EC treatment resulted in significant reductions (p < 0.05, α = 0.05) in phosphate, all microbial surrogates, and several personal care products from raw and tertiary-treated domestic wastewater. When wastewater was augmented with microbial surrogates representing bacterial, viral, and protozoan pathogens to measure the extent of reduction, EC treatment resulted in up to 7-log10 reduction of microbial surrogates. Future pilot and full-scale investigations are needed to optimize EC treatment for the following: reducing nitrogen species, personal care products, and energy consumption; elucidating the mechanisms behind microbial reductions; and performing life cycle analyses to determine the appropriateness of implementation.

Morphologic, genetic, and biochemical characterization of Helicobacter magdeburgensis, a novel species isolated from the intestine of laboratory mice.

BACKGROUND: The presence of enterohepatic Helicobacter species (EHS) is commonly noted in mouse colonies. These infections often remain unrecognized but can cause severe health complications or more subtle host immune perturbations and therefore can confound the results of animal experiments. The aim of this study was to isolate and characterize a putative novel EHS that has previously been detected by PCR screening of specific-pathogen-free mice. MATERIALS AND METHODS: Biochemical analysis of enzyme activities (API campy), morphologic investigation (Gram-staining and electron microscopy) and genetic analyses (16SrRNA and 23SrRNA analyses, DNA fingerprinting, restriction fragment polymorphisms, and pulsed-field gel electrophoresis) were used to characterize isolated EHS. Genomic DNA fragments were sequenced to develop a species-specific PCR detection assay. RESULTS: Scanning electron microscopy revealed the presence of spiral-shaped EHS, which varied in length (2.5-6 µm) and contained single monopolar or single bipolar sheathed flagella. The bacteria were grown under anaerobic conditions, preferably on agar plates containing serum or blood. The 16SrRNA, genetic, and biochemical analyses indicated the identification of a novel EHS species, named Helicobacter magdeburgensis. We also examined the genome content using pulsed-field gel electrophoresis. Based on the pattern produced by two restriction enzymes, BamIII and KspI, the genome size was determined to be about 1.7-1.8 Mbp. CONCLUSION: We isolated and characterized a novel EHS species, H. magdeburgensis, morphologically, biochemically, and genetically. These results are important for future studies on the prevalence and pathophysiologic relevance of such infections. Our PCR assay can be used to detect and discriminate H. magdeburgensis from other Helicobacter species.

Clostridium difficile-associated diarrhoea, a frequent complication in patients with acute myeloid leukaemia.

Diarrhoea occurs frequently in neutropenic patients with acute leukaemia receiving chemotherapy and may be caused by either infection- or drug-induced cytotoxicity. Since Clostridium difficile is the most common cause of nosocomial infectious diarrhoea in non-haematologic patients, we were interested in its incidence in patients with acute myeloid leukaemia (AML). In this retrospective study, we analysed 134 patients with AML receiving a total of 301 chemotherapy courses. Diarrhoea occurred during 33% of all courses in 58 patients. C. difficile-associated diarrhoea (CDAD) occurred in 18% of all patients and 9% of all treatment courses. Almost one third of diarrhoea episodes were caused by C. difficile. CDAD was associated with older age (58 vs. 50 years), number of antibiotics administered (2 vs. 1), duration of antibiotic therapy (7 vs. 4 days), ceftazidime as the antibiotic of choice (75% vs. 54%) and duration of neutropenia (12 vs. 7 days) prior to onset of diarrhoea. An increased risk for CDAD was seen for prolonged neutropenia. CDAD responded well to oral metronidazole and/or vancomycin and no patient died of this complication. In conclusion, CDAD is common in patients with AML receiving chemotherapy. C. difficile enterotoxin testing of stool specimens should be included in all symptomatic patients.

Eradication of H. pylori Infection: the Challenge is on if Standard Therapy Fails.

The recommended standard triple therapy for Helicobacter pylori infection, consisting of a proton pump inhibitor, clarithromycin and amoxicillin or metronidazole, can reach eradication rates in over 90%. However, in recent years resistance to antibiotics has increased and eradication rates have declined. Approximately one in five patients need a second-line therapy because eradication therapy fails. Second-line treatment with a bismuth-based quadruple therapy leads to satisfactory eradication rates, but bismuth is not available in many countries. Modern second- and third-line treatments can only be successful if they are adapted to the current resistance situation and they need to evolve continuously. Moreover, pharmacodynamic effects due to polymorphisms of the cytochrome P450 system are important. Because therapy adherence is significantly associated with therapy success, modern regimens if possible should be easy to take and well tolerated. In recent years, various novel salvage-therapy regimens have been investigated that significantly improve treatment options.

Inflammatory bowel diseases: multiple benefits from therapy with dipeptidyl- and alanyl-aminopeptidase inhibitors.

Inflammatory bowel diseases (IBD) are driven by imbalances in innate and acquired immune response. In IBD two dysregulated T cell subsets are in the focus of interest: activated effector T cells and regulatory T cells. These T cell subsets are characterized by a strong expression of the ectopeptidases dipeptidyl peptidase IV (DPIV /CD26) and aminopeptidase N (APN/CD13), which are thought to a role in the control of immune activation and in regulating cellular communication by hydrolyzing bioactive polypeptides. Since inhibitors of both enzymes were shown to be effective in limiting immune activation processes in vitro as well as in vivo, they emerged as new drug candidates for the treatment of diseases associated with an imbalanced T cell response, such as IBD. In this review we intent to throw light on the putative role of DPIV, APN and related enzymes in the regulation of immune and non-immune processes in inflammatory bowel diseases, on possible benefits from peptidase inhibitor therapy in these diseases as well on the gaps of knowledge in this field.

Extragastric manifestations of Helicobacter pylori infection -- other Helicobacters.

Today there is evidence that Helicobacter pylori has a critical role in different extragastric diseases. The discovery of a number of other novel Helicobacter species has stimulated the research in different extragastric diseases, in which an infectious hypothesis is plausible. Enterohepatic Helicobacter species have been hypothesized to play a role in different disorders, including hepatocellular carcinoma, gallstones formation and cholangiocellular carcinoma, as well as enteric diseases and inflammatory bowel diseases. Concerning the extragastric manifestations of H. pylori infection, idiopathic thrombocytopenic purpura, and sideropenic anemia represent, based on the current data, the diseases in which the pathogenic link appears to be strongest. There is also an increasing evidence for a possible association of H. pylori with cardiovascular disease.

Identification of enterohepatic Helicobacter species in patients suffering from inflammatory bowel disease.

Using a group-specific PCR assay, we investigated the presence of enterohepatic Helicobacter species in gut specimens from patients with inflammatory bowel disease. Enterohepatic Helicobacter species were detected in 12% (3 of 25) of the patients with Crohn's disease, in 17% (3 of 18) of the ulcerative colitis samples, and in 4% (1 of 23) of the controls.

Molecular confirmation of Enterococcus faecalis and E. faecium from clinical, faecal and environmental sources.

AIMS: The genus Enterococcus includes opportunistic pathogens such as E. faecalis and E. faecium, and is also used to assess water quality. Speciation of enterococci in environmental studies can be particularly problematic, therefore protocols for unambiguous, DNA-based analysis could receive wide use in applications ranging from water quality monitoring to microbial source tracking. The goal of this work was to investigate the usefulness of PCR for speciation of putative, biochemically identified E. faecalis and E. faecium isolated from water, faeces and sewage. METHODS AND RESULTS: Putative enterococci (n = 139) were isolated on mEI agar from dog, human, gull and cow faeces, and from sewage, freshwaters and marine waters. A total of 128 isolates passed standard physiological tests for the genus, and were speciated by the API 20 Strep (APIStrep) biochemical test system. 42.2% were identified as E. faecalis, and all were confirmed by PCR. 19.5% were biochemically identified as E. faecium, but only seven were PCR-positive. CONCLUSIONS: The 16S rDNA of PCR-positive and PCR-negative E. faecium, including isolates that were inconclusively identified by APIStrep, was sequenced. All formed a monophyletic clade with E. faecium sequences in Genbank. SIGNIFICANCE AND IMPACT OF THE STUDY: Biochemical identification of E. faecalis agreed 100% with PCR assays, therefore a simple protocol of isolation on mEI followed by PCR should be useful for environmental studies. Discrepancies among biochemical identification, PCR confirmation and DNA sequencing were noted for E. faecium, indicating that routine isolation/identification of E. faecium from environmental samples is a much more difficult task.

Detection of a putative novel Wolinella species in patients with squamous cell carcinoma of the esophagus.

BACKGROUND: Certain regions of South Africa exhibit an extraordinarily high incidence of esophageal carcinoma that develops via an esophagitis-dysplasia-carcinoma sequence. Bacteria belonging to the family Helicobacteraceae are candidates for involvement in the initiation of the esophagitis. We investigated patients with esophageal carcinoma for the occurrence of Helicobacter-related species. METHODS: Biopsies from tumor and nonlesional tissue of the esophagus from nine patients with squamous cell carcinoma were investigated for Helicobacteraceae using a PCR-based method targeting the 16S rRNA gene. RESULTS: Four out of nine patients tested negative, while samples from the other five patients revealed an infection by different Helicobacter species. Sequence analysis of the PCR fragments led to the identification of a hitherto unknown bacterium in three of these patients. Phylogenetically, this bacterium was assigned to the genus Wolinella within the family of Helicobacteraceae. Helicobacter pylori was identified in three patients, and one revealed a coinfection with the novel Wolinella species. CONCLUSIONS: Helicobacteraceae were detected in approximately 50% of South African patients with esophageal carcinoma. Furthermore, a novel bacterium was identified that might be linked to the enhanced incidence of esophagitis and subsequent malignant disease in South Africa.

A group-specific PCR assay for the detection of Helicobacteraceae in human gut.

BACKGROUND: Enterohepatic Helicobacter species are emerging pathogens, which are increasingly isolated from humans with enteric diseases. Nevertheless, current methods to detect Helicobacteraceae in the human gut have significant limitations. METHODS: Based on 16S-rRNA gene alignments and computer aided primer analysis a set of group-specific PCR primers was designed. The evaluation of the PCR assay was performed using 36 ATCC reference strains and intestinal biopsies from 10 patients with defined gastric Helicobacter pylori status. The amplification products derived from clinical samples were cloned and subsequently analyzed by DNA sequencing. Sensitivity of the PCR-assay was determined by spiking previously negative tested samples with decreasing amounts of Helicobacter DNA. RESULTS: The analysis of the ATCC reference strains revealed amplification products in all 14 Helicobacter strains and Wolinella succinogenes, 21 other microorganisms representing negative controls did not produce PCR fragments. Four out of the 10 patient-derived samples were positive. Three of them represented H. pylori-derived DNA confirming the gastric H. pylori infection in these patients. In the fourth patient, who was suffering from Crohn's disease, H. pullorum was identified. The sensitivity of the PCR assay was 0.1 pg of Helicobacter-derived DNA representing about 40 bacteria. CONCLUSION: The novel PCR assay described here is an important new tool in rapid and sensitive assessment for the presence of Helicobacteraceae in human gut.

Determinants of power-frequency magnetic fields in residences located away from overhead power lines.

The Wertheimer-Leeper wire code, originally developed as a surrogate for magnetic-field exposure, has been associated with childhood leukemia in several epidemiologic investigations. However, these and other studies indicate that most between-residence variability in measured magnetic fields remains unexplained by wire codes. To better understand this remaining variability, engineering and demographic data were examined for 333 underground (UG) and very-low current configuration (VLCC) single-family or duplex residences, selected from a database of nearly 1000 residences specifically because their magnetic fields are most likely affected negligibly by overhead power lines. Using linear regression techniques, four factors predictive of the log-transformed residential field were identified: the square-root of the 24-h average net service drop current (this current is equivalent to the current in the grounding system), the log of the number of service drops on the same secondary serving the residence, residence age (four categories), and area type (rural, suburban, or urban). Complete data on ground current and service drops, the two factors with the strongest individual relationships to measured fields, were available for only half of the residences in the sample. However, these data were determined to be "missing at random" according to established statistical criteria. The full-sample or "composite" models thus relied on a method similar to regression imputation, accounting for missing data with binary dummy variables. When applied to the samples from which they were derived, these models accounted for 25% of the variance of the log-spot-measured magnetic field values in the full sample, while models that considered only those residences with complete data (n = 167) explained about 35%. The model validated well against a sample of 201 ordinary low current configuration (OLCC) homes selected from the same database.

Temporal characteristics of transmission-line loadings in the Swedish childhood cancer study.

A recent study conducted in Sweden reported that 1) leukemia risk in children who lived near 220 or 400 kV electric-power transmission lines was associated with calculated historical magnetic field levels; 2) children living within a distance of 50 m of transmission lines had an elevated risk of leukemia; and 3) there was no association between leukemia and residential magnetic fields measured many years after diagnosis. Subsequently, these investigators found through logistic regression analysis that disease was more strongly associated with calculated historical fields than with distance. Since the calculated historical fields in that study depended predominantly on distance and transmission-line load current, the logistic regression results suggest that historical load current plays an important role in the epidemiological results. Thus, we studied hourly 1974 load-current data for six transmission lines, and we examined 1958-1985 annual load-current data for 112 transmission lines. Most lines exhibited marked diurnal load-current rhythms during 1974, and all six showed systematic weekday-weekend differences. During 1958-1985, average loadings of Swedish 220 and 400 kV lines increased by about 1.3% year. Predictive-value and kappa-statistic analyses indicated that Swedish transmission-line load currents were not stable over long periods, so that contemporaneous load current (or a contemporary magnetic field measurement) was not a good surrogate for historical load current (or historical magnetic fields). The results provide a potential explanation of the failure of the Swedish Study to find an association between leukemia and contemporaneous magnetic field levels measured many years after the etiologic period, and suggest that the inclusion of load-current data could significantly improve the quality of historical field calculations.