scholarly journals Critical Review: Propensity of Premise Plumbing Pipe Materials to Enhance or Diminish Growth of Legionella and Other Opportunistic Pathogens

Pathogens ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 957
Author(s):  
Abraham C. Cullom ◽  
Rebekah L. Martin ◽  
Yang Song ◽  
Krista Williams ◽  
Amanda Williams ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Chemistry ◽  
Legionella Pneumophila ◽  
High Surface ◽  
Metallic Copper ◽  
Health Concern ◽  
Future Research ◽  
Opportunistic Pathogens ◽  
Premise Plumbing ◽  
Pipe Materials

Growth of Legionella pneumophila and other opportunistic pathogens (OPs) in drinking water premise plumbing poses an increasing public health concern. Premise plumbing is constructed of a variety of materials, creating complex environments that vary chemically, microbiologically, spatially, and temporally in a manner likely to influence survival and growth of OPs. Here we systematically review the literature to critically examine the varied effects of common metallic (copper, iron) and plastic (PVC, cross-linked polyethylene (PEX)) pipe materials on factors influencing OP growth in drinking water, including nutrient availability, disinfectant levels, and the composition of the broader microbiome. Plastic pipes can leach organic carbon, but demonstrate a lower disinfectant demand and fewer water chemistry interactions. Iron pipes may provide OPs with nutrients directly or indirectly, exhibiting a high disinfectant demand and potential to form scales with high surface areas suitable for biofilm colonization. While copper pipes are known for their antimicrobial properties, evidence of their efficacy for OP control is inconsistent. Under some circumstances, copper’s interactions with premise plumbing water chemistry and resident microbes can encourage growth of OPs. Plumbing design, configuration, and operation can be manipulated to control such interactions and health outcomes. Influences of pipe materials on OP physiology should also be considered, including the possibility of influencing virulence and antibiotic resistance. In conclusion, all known pipe materials have a potential to either stimulate or inhibit OP growth, depending on the circumstances. This review delineates some of these circumstances and informs future research and guidance towards effective deployment of pipe materials for control of OPs.

scholarly journals Nontuberculous Mycobacteria, Fungi, and Opportunistic Pathogens in Unchlorinated Drinking Water in the Netherlands

2012 ◽  
Vol 79 (3) ◽  
pp. 825-834 ◽  
Author(s):  
Paul W. J. J. van der Wielen ◽  
Dick van der Kooij
Keyword(s):  
Drinking Water ◽  
Organic Carbon ◽  
The Netherlands ◽  
Legionella Pneumophila ◽  
Water Samples ◽  
Distribution System ◽  
Nontuberculous Mycobacteria ◽  
Opportunistic Pathogens ◽  
Content Type ◽  
Premise Plumbing

ABSTRACTThe multiplication of opportunistic pathogens in drinking water supplies might pose a threat to public health. In this study, distributed unchlorinated drinking water from eight treatment plants in the Netherlands was sampled and analyzed for fungi, nontuberculous mycobacteria (NTM), and several opportunistic pathogens by using selective quantitative PCR methods. Fungi and NTM were detected in all drinking water samples, whereasLegionella pneumophila,Pseudomonas aeruginosa,Stenotrophomonas maltophilia, andAspergillus fumigatuswere sporadically observed.Mycobacterium aviumcomplex andAcanthamoebaspp. were not detected. Season had no influence on the occurrence of these organisms, except for NTM andS. maltophilia, which were present in higher numbers in the summer. Opportunistic pathogens were more often observed in premise plumbing water samples than in samples from the distribution system. The lowest number of these organisms was observed in the finished water at the plant. Thus, fungi, NTM, and some of the studied opportunistic pathogens can multiply in the distribution and premise plumbing systems. Assimilable organic carbon (AOC) and/or total organic carbon (TOC) had no clear effects on fungal and NTM numbers or onP. aeruginosa- andS. maltophilia-positive samples. However,L. pneumophilawas detected more often in water with AOC concentrations above 10 μg C liter−1than in water with AOC levels below 5 μg C liter−1. Finally, samples that containedL. pneumophila,P. aeruginosa, orS. maltophiliawere more frequently positive for a second opportunistic pathogen, which shows that certain drinking water types and/or sampling locations promote the growth of multiple opportunistic pathogens.

scholarly journals Flushing of stagnant premise water systems after the COVID-19 shutdown can reduce infection risk by Legionella and Mycobacterium spp.

2020 ◽  
Author(s):  
Raymond M Hozalski ◽  
Timothy M LaPara ◽  
Xiaotian Zhao ◽  
Taegyu Kim ◽  
Michael B Waak ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Water Levels ◽  
Hot Water ◽  
Quantitative Microbial Risk Assessment ◽  
Opportunistic Pathogens ◽  
Bacterial Gene ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Commercial Cultivation ◽  
Premise Plumbing

The unprecedented widespread closing of buildings due to the COVID-19 pandemic has allowed water to stagnate in premise plumbing systems, creating conditions that may facilitate the growth of opportunistic pathogens. In this study, we flushed and collected samples from showers in buildings that had been unoccupied for approximately two months and quantified Legionella pneumophila using a commercial cultivation-based assay. In addition, all bacteria, Legionella spp., L. pneumophila, L. pneumophila serogroup 1, non-tuberculous mycobacteria (NTM), and Mycobacterium avium complex (MAC) were analyzed using quantitative PCR (qPCR). Despite low or negligible total chlorine in the stagnant pre-flush water samples, L. pneumophila were not detected by either method; Legionella spp., NTM, and MAC, however, were widespread. Using quantitative microbial risk assessment (QMRA), estimated risks of clinical illness from exposure to legionella and MAC via showering were generally low, but the risk of subclinical infection via Legionella spp. could exceed a 10-7 daily risk threshold if just a small fraction (≥0.1 %) of those legionellae detected by qPCR are highly infectious. Flushing cold and hot water lines rapidly restored a total chlorine (as chloramine) residual and decreased all bacterial gene targets to building inlet water levels within 30 min. Following flushing, the chlorine residual rapidly dissipated and bacterial gene targets rebounded, approaching pre-flush concentrations after 6 to 7 days of stagnation. These results suggest that stagnant water in premise plumbing may contain elevated levels of opportunistic pathogens; flushing, however, can rapidly improve water quality and reduce the health risk but the improvement will be short-lived if building disuse persists.

scholarly journals Nitrification in Premise Plumbing: A Review

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 830 ◽  
Author(s):  
Tyler C. Bradley ◽  
Charles N. Haas ◽  
Christopher M. Sales
Keyword(s):  
Drinking Water ◽  
Water Conservation ◽  
High Surface ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
High Water ◽  
Free Ammonia ◽  
Water Age ◽  
Premise Plumbing ◽  
Plumbing Systems

Nitrification is a major issue that utilities must address if they utilize chloramines as a secondary disinfectant. Nitrification is the oxidation of free ammonia to nitrite which is then further oxidized to nitrate. Free ammonia is found in drinking water systems as a result of overfeeding at the water treatment plant (WTP) or as a result of the decomposition of monochloramine. Premise plumbing systems (i.e., the plumbing systems within buildings and homes) are characterized by irregular usage patterns, high water age, high temperature, and high surface-to-volume ratios. These characteristics create ideal conditions for increased chloramine decay, bacterial growth, and nitrification. This review discusses factors within premise plumbing that are likely to influence nitrification, and vice versa. Factors influencing, or influenced by, nitrification include the rate at which chloramine residual decays, microbial regrowth, corrosion of pipe materials, and water conservation practices. From a regulatory standpoint, the greatest impact of nitrification within premise plumbing is likely to be a result of increased lead levels during Lead and Copper Rule (LCR) sampling. Other drinking water regulations related to nitrifying parameters are monitored in a manner to reduce premise plumbing impacts. One way to potentially control nitrification in premise plumbing systems is through the development of building management plans.

Minerals in drinking water: impacts on taste and importance to consumer health

2007 ◽  
Vol 55 (5) ◽  
pp. 283-291 ◽  
Author(s):  
A.J. Whelton ◽  
A.M. Dietrich ◽  
G.A. Burlingame ◽  
M. Schechs ◽  
S.E. Duncan
Keyword(s):  
Drinking Water ◽  
Water Chemistry ◽  
Consumer Preference ◽  
Future Research ◽  
Research Needs ◽  
Consumer Health ◽  
Safe Drinking Water ◽  
Water Taste ◽  
Human Sense

More than 100 years of research has focused on removing acute and chronic health threats to produce safe drinking water, but limited research has focused the consequences of removing minerals that affect drinking water taste and health. This paper covers the human sense of taste, typical variations in drinking water taste, comparisons of global taste standards, the role of water chemistry and future research needs for understanding consumer preference. Results of several consumer tap and bottled water acceptability investigations conducted by the authors are presented.

scholarly journals Chlorine disinfection against Legionella pneumophila biofilms

2020 ◽  
Vol 10 (4) ◽  
pp. 885-893
Author(s):  
Abdelwahid Assaidi ◽  
Mostafa Ellouali ◽  
Hassan Latrache ◽  
Hafida Zahir ◽  
Abdelaziz Karoumi ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Bacterial Resistance ◽  
Galvanized Steel ◽  
Opportunistic Pathogens ◽  
New Approach ◽  
Force Microscopy ◽  
Chlorine Disinfection ◽  
Atomic Force ◽  
Premise Plumbing ◽  
Planktonic Form

Abstract Premise plumbing promotes the regrowth and survival of opportunistic pathogens, such as Legionella pneumophila (L. pneumophila), especially within biofilms. The purpose of this study was to investigate the effectiveness of chlorine disinfection against L. pneumophila serogroup 1 and serogroup 2–15 planktonic form and biofilms. Planktonic cells were able to survive during the study period in the presence of chlorine at recommended free chlorine levels (0.2–0.5 mg/L). Biofilms were developed on galvanized steel and polyvinyl chloride (PVC) for 18 and 30 days and exposed to 50, 100, 150, and 200 mg/L for 2 hours. No colony appeared immediately after chlorination; however, persistent cells were able to tolerate treatment and continue to grow on subsequent days. The biofilm formation was evaluated by atomic force microscopy. This study demonstrates that the biofilm formed on the surfaces of plumbing materials increases bacterial resistance against high levels of chlorination. A new approach towards monitoring and eradicating L. pneumophila from water systems is required.

Differences in Suicidal Thoughts and Behaviors Among Three Racial Groups

Crisis ◽  
2020 ◽  
Vol 41 (3) ◽  
pp. 172-178
Author(s):  
Brooke A. Ammerman ◽  
Martha K. Fahlgren ◽  
Kristen M. Sorgi ◽  
Michael S. McCloskey
Keyword(s):  
Suicide Attempts ◽  
Health Concern ◽  
Future Research ◽  
Racial Groups ◽  
Contributing Factors ◽  
Suicidal Thoughts ◽  
Final Sample ◽  
And Behaviors ◽  
Assessment Procedures ◽  
Suicidal Thoughts And Behaviors

Abstract. Background: Despite being a major public health concern, it is unclear how suicidal thoughts and behaviors differentially impact separate racial groups. Aims: The aim of the current study was to examine the occurrence of nonlethal suicide events, in addition to suicide attempt characteristics and factors contributing to suicide attempts. Method: A final sample of 7,094 undergraduates from a large northeastern university, identifying as members of three racial groups (White [67.30%], Black [17.30%], and Asian [15.40%]), completed online questionnaires. Results: White participants reported increased likelihood of endorsing lifetime suicidal ideation and plan, whereas Black participants reported decreased likelihood of these events; no differences were found in rates of lifetime suicide attempts. Black participants' suicidal behavior may involve greater ambivalence of intent. A higher proportion of Asian participants endorsed interpersonal factors as contributing to their suicide attempts, whereas a greater percentage of White participants reported internal contributing factors. Limitations: Findings are limited by the sample size and assessment of lifetime suicidal thoughts and behaviors. Conclusion: The findings present a more nuanced look at attitudes and actions related to suicidal thoughts and behaviors that may inform future research and risk assessment procedures.

Removal of microcystin-LR from drinking water with TiO2-coated activated carbon

2004 ◽  
Vol 4 (5-6) ◽  
pp. 21-28
Author(s):  
S.-C. Kim ◽  
D.-K. Lee
Keyword(s):  
Drinking Water ◽  
Activated Carbon ◽  
Synergistic Effect ◽  
Fluidized Bed ◽  
Continuous Flow ◽  
High Surface ◽  
High Surface Area ◽  
Fluidized Bed Reactor ◽  
Exterior Surface ◽  
Tio2 Particles

TiO2-coated granular activated carbon was employed for the removal of toxic microcystin-LR from water. High surface area of the activated carbon provided sites for the adsorption of microcystin-LR, and the adsorbed microcystin-LR migrated continuously onto the surface of TiO2 particles which located mainly at the exterior surface in the vicinity of the entrances of the macropores of the activated carbon. The migrated microcystin-LR was finally degraded into nontoxic products and CO2 very quickly. These combined roles of the activated carbon and TiO2 showed a synergistic effect on the efficient degradation of toxic microcystin-LR. A continuous flow fluidized bed reactor with the TiO2-coated activated carbon could successfully be employed for the efficient photocatalytic of microcystin-LR.

Stem Cell-Based Therapies: A New Ray of Hope for Diabetic Patients

2019 ◽  
Vol 14 (2) ◽  
pp. 146-151 ◽  
Author(s):  
Junaid Khan ◽  
Amit Alexander ◽  
Mukta Agrawal ◽  
Ajazuddin ◽  
Sunil Kumar Dubey ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Drug Therapy ◽  
Type I Diabetes ◽  
Embryonic Stem ◽  
Health Concern ◽  
Future Research ◽  
Diabetic Patients ◽  
Successful Implementation ◽  
Type I

Diabetes and its complications are a significant health concern throughout the globe. There are physiological differences in the mechanism of type-I and type-II diabetes and the conventional drug therapy as well as insulin administration seem to be insufficient to address the problem at large successfully. Hypoglycemic swings, frequent dose adjustments and resistance to the drug are major problems associated with drug therapy. Cellular approaches through stem cell based therapeutic interventions offer a promising solution to the problem. The need for pancreatic transplants in case of Type- I diabetes can also be by-passed/reduced due to the formation of insulin producing β cells via stem cells. Embryonic Stem Cells (ESCs) and induced Pluripotent Stem Cells (iPSCs), successfully used for generating insulin producing β cells. Although many experiments have shown promising results with stem cells in vitro, their clinical testing still needs more exploration. The review attempts to bring into light the clinical studies favoring the transplantation of stem cells in diabetic patients with an objective of improving insulin secretion and improving degeneration of different tissues in response to diabetes. It also focuses on the problems associated with successful implementation of the technique and possible directions for future research.

scholarly journals Water Quality and Hydrogeochemical Characteristics of Some Karst Water Sources in Apuseni Mountains, Romania

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 857
Author(s):  
Maria-Alexandra Hoaghia ◽  
Ana Moldovan ◽  
Eniko Kovacs ◽  
Ionut Cornel Mirea ◽  
Marius Kenesz ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Chemistry ◽  
Major Ions ◽  
Anthropogenic Activities ◽  
Water Sources ◽  
Main Process ◽  
Karst Water ◽  
Rock Interaction ◽  
Apuseni Mountains ◽  
Karst Waters

Human activities and natural factors determine the hydrogeochemical characteristics of karst groundwaters and their use as drinking water. This study assesses the hydrogeochemical characteristics of 14 karst water sources in the Apuseni Mountains (NW Romania) and their potential use as drinking water sources. As shown by the Durov and by the Piper diagrams, the chemical composition of the waters is typical of karst waters as it is dominated by HCO3− and Ca2+, having a circumneutral to alkaline pH and total dissolved solids ranging between 131 and 1092 mg L−1. The relation between the major ions revealed that dissolution is the main process contributing to the water chemistry. Limestone and dolostone are the main Ca and Mg sources, while halite is the main Na and Cl source. The Gibbs diagram confirmed the rock dominance of the water chemistry. The groundwater quality index (GWQI) showed that the waters are of excellent quality, except for two waters that displayed medium and good quality status. The quality of the studied karst waters is influenced by the geological characteristics, mainly by the water–rock interaction and, to a more limited extent, by anthropogenic activities. The investigated karst waters could be exploited as drinking water resources in the study area. The results of the present study highlight the importance of karst waters in the context of good-quality water shortage but also the vulnerability of this resource to anthropogenic influences.

scholarly journals Occurrence of carcinogenic illudane glycosides in drinking water wells

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Natasa Skrbic ◽  
Vaidotas Kisielius ◽  
Ann-Katrin Pedersen ◽  
Sarah C. B. Christensen ◽  
Mathilde J. Hedegaard ◽  
...  
Keyword(s):  
Drinking Water ◽  
Health Concern ◽  
Liquid Chromatography Mass Spectrometry ◽  
Deep Groundwater ◽  
Hydrolysis Products ◽  
First Finding ◽  
Water Wells ◽  
Shallow Wells ◽  
Great Health ◽  
Groundwater Wells

Abstract Background Ptaquiloside (PTA), caudatoside (CAU) and ptesculentoside (PTE) are carcinogenic illudane glycosides found in bracken ferns (Pteridium spp.) world-wide. The environmentally mobile PTA entails both acute and chronic toxicity. A comparable risk might be associated with the structurally similar CAU and PTE. It is of great health concern if these compounds are present in drinking water, however, it is currently unknown if these compounds can detected in wells in bracken-dominated regions. This study investigates the presence of PTA, CAU, PTE, and their corresponding hydrolysis products pterosins B (PtB), A (PtA) and G (PtG) in water wells in Denmark, Sweden and Spain. Water samples from a total of 77 deep groundwater wells (40–100 m) and shallow water wells (8–40 m) were collected and preserved in the field, pre-concentrated in the laboratory and analysed by liquid chromatography–mass spectrometry (LC–MS). Results Deep groundwater wells contained neither illudane glycosides nor their pterosins. However, seven private shallow wells contained at least one of the illudane glycosides and/or pterosins at concentrations up to 0.27 µg L−1 (PTA), 0.75 µg L−1 (CAU), 0.05 µg L−1 (PtB), 0.03 µg L−1 (PtA) and 0.28 µg L−1 (PtG). This is the first finding of illudane glycosides and pterosins in drinking water wells. Conclusions Detected concentrations of illudane glycosides in some of investigated wells exceeded the suggested maximum tolerable concentrations of PTA, although they were used for drinking water purpose. Contaminated wells were shallow with neutral pH and lower electric conductivity compared to deep groundwater wells with no illudane glycosides nor pterosins.

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