Antibacterial and antiviral effectiveness of two household water treatment devices that use monobrominated hydantoinylated polystyrene.

Many different household water treatment (HWT) methods have been researched and promoted to mitigate the serious burden of diarrheal disease in developing countries. However, HWT methods using bromine have not been extensively evaluated. Two gravity-fed HWT devices (AquaSure™ and Waterbird™) were used to test the antimicrobial effectiveness of HaloPure® Br beads (monobrominated hydantoinylated polystyrene) that deliver bromine. As water flows over the beads, reactive bromine species are eluted, which inactivate microorganisms. To assess log10 reduction values (LRVs) for Vibrio cholerae, Salmonella enterica Typhimurium, bacteriophage MS2, human adenovirus 2 (HAdV2), and murine norovirus (MN), these organisms were added to potable water and sewage-contaminated water. These organisms were quantified before and after water treatment by the HWT devices. On average, 6 LRVs against Vibrio were attained, as well as 5 LRVs against Salmonella, 4 LRVs against MS2, 5 LRVs against HAdV2, and 3 LRVs against MN. Disinfection was similar regardless of whether sewage was present. Polymer beads delivering bromine to drinking water are a potentially effective and useful component of HWT methods in developing countries.

Hemodialysis and water quality.

Over 383,900 individuals in the U.S. undergo maintenance hemodialysis that exposes them to water, primarily in the form of dialysate. The quality of water and associated dialysis solutions have been implicated in adverse patient outcomes and is therefore critical. The Association for the Advancement of Medical Instrumentation has published both standards and recommended practices that address both water and the dialyzing solutions. Some of these recommendations have been adopted into Federal Regulations by the Centers for Medicare and Medicaid Services as part of the Conditions for Coverage, which includes limits on specific contaminants within water used for dialysis, dialysate, and substitution fluids. Chemical, bacterial, and endotoxin contaminants are health threats to dialysis patients, as shown by the continued episodic nature of outbreaks since the 1960s causing at least 592 cases and 16 deaths in the U.S. The importance of the dialysis water distribution system, current standards and recommendations, acceptable monitoring methods, a review of chemical, bacterial, and endotoxin outbreaks, and infection control programs are discussed.

Impacts of rainfall on the water quality of the Newport River Estuary (Eastern North Carolina, USA).

The Newport River Estuary (NPRE), an important North Carolina (NC) shellfish harvesting area, has been experiencing alterations to the land-water interface due to increasing population and coastal development. Water quality degradation in the estuary over the last decade has led to an increase of shellfish harvesting area closures, and has been postulated to be due to non-point source contamination in the form of stormwater. Water samples were taken in the NPRE (n =179) over a range of weather conditions and all seasons from August 2004 to September 2006. Fecal coliform (FC), as estimated by E. coli (EC), and Enterococcus (ENT) concentrations (MPN per 100 ml) were examined in relation to rainfall levels and distance from land. The relationships among the fecal indicator bacteria (FIB) and environmental parameters were also examined. The data revealed a significant increase in FC concentrations after measured rainfall amounts of 2.54 cm (general threshold) and 3.81 cm (management action threshold). However, higher than expected FIB concentrations existed during conditions of negligible rainfall (<0.25 cm), indicating a possible reservoir population in the sediment. Overall, stormwater runoff appears to be adversely impacting water quality in the NPRE.

Cryptosporidium parvum: treatment effects and the rate of decline in oocyst infectivity.

Cryptosporidium parvum has become the focus of numerous studies on waterborne disease and transmission in response to outbreaks endangering populations worldwide. The Foci Detection Method-Most Probable Number Assay (FDM-MPN) is an in vitro cell culture method that has been developed and used to determine the quantity of infectious C. parvum oocysts. This research evaluated 2 vendor's producing oocysts, Sterling Parasitology Laboratory (SPL) and Pleasant Hill Farms (PHF) (now known as Bunch Grass Farms as of 12/03), classified as young (<30 days) and aged (>165 days), for comparison of treatments (bleach, antibiotic, no treatment) before cell culture, as well as an age study, to determine any lot-to-lot differences and vendor differences regarding the rate of decline in infectivity. Bleach treatment (0.525%) appeared to be the optimum method for the FDM-MPN with regards to maximum infectivity, efficient disinfection, with no visible antagonistic affects on the C. parvum oocysts. The age study revealed that lot-to-lot variability within each vendor stayed within 1 log10 difference, while the rates of decline in infectivity measured until 107 and 120 days of age when stored at 4 C for SPL and PHF were -0.016 and -0.014 log10 infectious oocysts/day, respectively. These results provide insight regarding C. parvum oocyst viability in a fecal population, as well as useful knowledge for further methods development.

Draft Genome Sequence of Mycobacterium wolinskyi, a Rapid-Growing Species of Nontuberculous Mycobacteria.

Mycobacterium wolinskyi is a nonpigmented, rapidly growing nontuberculous mycobacterium species that is associated with bacteremia, peritonitis, infections associated with implants/prostheses, and skin and soft tissue infections often following surgical procedures in humans. Here, we report the first functionally annotated draft genome sequence of M. wolinskyi CDC_01.

Risk reduction assessment of waterborne Salmonella and Vibrio by a chlorine contact disinfectant point-of-use device.

Unsafe drinking water continues to burden developing countries despite improvements in clean water delivery and sanitation, in response to Millennium Development Goal 7. Salmonella serotype Typhi and Vibrio cholerae bacteria can contaminate drinking water, causing waterborne typhoid fever and cholera, respectively. Household water treatment (HWT) systems are widely promoted to consumers in developing countries but it is difficult to establish their benefits to the population for specific disease reduction. This research uses a laboratory assessment of halogenated chlorine beads treating contaminated water to inform a quantitative microbial risk assessment (QMRA) of S. Typhi and V. cholerae disease in a developing country community of 1000 people. Laboratory challenges using seeded well water resulted in log10 reductions of 5.44 (± 0.98 standard error (SE)) and 6.07 (± 0.09 SE) for Salmonella serotype Typhimurium and V. cholerae, respectively. In well water with 10% sewage and seeded bacteria, the log10 reductions were 6.06 (± 0.62 SE) and 7.78 (± 0.11 SE) for S. Typhimurium and V. cholerae, respectively. When one infected individual was contributing to the water contamination through fecal material leaking into the water source, the risk of disease associated with drinking untreated water was high according to a Monte Carlo analysis: a median of 0.20 (interquartile range [IQR] 0.017-0.54) for typhoid fever and a median of 0.11 (IQR 0.039-0.20) for cholera. If water was treated, risk greatly decreased, to a median of 4.1 × 10(-7) (IQR 1.6 × 10(-8) to 1.1 × 10(-5)) for typhoid fever and a median of 3.5 × 10(-9) (IQR 8.0 × 10(-10) to 1.3 × 10(-8)) for cholera. Insights on risk management policies and strategies for public health workers were gained using a simple QMRA scenario informed by laboratory assessment of HWT.

Evaluation of a new disinfection approach: efficacy of chlorine and bromine halogenated contact disinfection for reduction of viruses and microcystin toxin.

Contaminated drinking water is responsible for causing diarrheal diseases that kill millions of people a year. Additionally, toxin-producing blue-green algae associated with diarrhea and neurologic effects continues to be an issue for many drinking water supplies. Disinfection has been used to reduce these risks. A novel gravity-fed household drinking water system with canisters containing N-halamine bromine or chlorine media was challenged with MS2 bacteriophage and microcystin. Chlorine and bromine systems were effective against this virus, with an mean +/- SE reduction of 2.98 +/- 0.26 log(10) and 5.02 +/- 0.19 log(10), respectively. Microcystin toxin was reduced by 27.5% and 88.5% to overall mean +/- SE concentrations of 1,600 +/- 98 ng/L and 259 +/- 50 ng/L for the chlorine and bromine canisters, respectively. Only the bromine units consistently produced microcystin effluent < 1,000 ng/L (the World Health Organization recommended level) when challenged with 2,500 ng/L and consistently surpassed the U.S. Environmental Protection Agency virus reduction goal of 99.99%.

Space/time analysis of fecal pollution and rainfall in an eastern North Carolina estuary.

The Newport River Estuary (NPRE) is a high-priority shellfish harvesting area in eastern North Carolina that is impaired due to fecal contamination, specifically exceeding recommended levels for fecal coliforms. A hydrologic-driven mean trend model was developed, as a function of antecedent rainfall, in the NPRE to predict levels of Escherichia coli (EC, measured as a proxyforfecal coliforms). This mean trend model was integrated in a Bayesian Maximum Entropy (BME) framework to produce informative space/time (S/T) maps depicting fecal contamination across the NPRE during winter and summer months. These maps showed that during dry winter months, corretponding to the oyster harvesting season in North Carolina (October 1-March 30), predicted EC concentrations were below the shellfish harvesting standard (14 MPN/100 mL). However, after substantial rainfall of 3.81 cm (1.5 in.), the NPRE did not appear to mee this requirement. Warmer months resulted in the predicted EC concentrations exceeding the threshold for the NPRE. Predicted ENT concentrations were generally below the recreational water quality threshold (104 MPN/100 mL), except for warmer months after substantial rainfall. Once established, this combined approach produces near real-time visual information on which to base water quality management decisions.