-
Journal of Environmental Sciences... Sep 2019The long-term persistence of antibiotic resistance in the environment, especially in drinking water, is a public health concern. Expression of an efflux pump, an...
The long-term persistence of antibiotic resistance in the environment, especially in drinking water, is a public health concern. Expression of an efflux pump, an important mechanism of resistance to antibiotics, usually confers a fitness cost in bacteria. In this study, we aimed to determine why antibiotic resistance conferred by overexpression of an efflux pump persisted in low-nutrient environments (TOC < 10 mg/L) such as drinking and source water in which antibiotic selective pressure might be very low or even absent. Competition experiments between wild-type Pseudomonas aeruginosa and ciprofloxacin-resistant mutants revealed that the fitness cost of ciprofloxacin resistance significantly decreased (p < 0.05) under low-nutrient (0.5 mg/L total organic carbon (TOC)) relative to high-nutrient (500 mg/L TOC) conditions. Mechanisms underlying this fitness cost were analyzed. The mexD gene expression in resistant bacteria (cip_3 strain) was significantly lower (p < 0.05) in low-nutrient conditions, with 10 mg/L TOC ((8.01 ± 0.82)-fold), than in high-nutrient conditions, with 500 mg/L TOC ((48.89 ± 4.16)-fold). Moreover, rpoS gene expression in resistant bacteria ((1.36 ± 0.13)-fold) was significantly lower (p < 0.05) than that in the wild-type strain ((2.78 ± 0.29)-fold) under low-nutrient conditions (10 mg/L TOC), suggesting a growth advantage. Furthermore, the difference in metabolic activity between the two competing strains was significantly smaller (p < 0.05) in low-nutrient conditions (5 and 0.5 mg/L TOC). These results suggest that nutrient levels are a key factor in determining the persistence of antibiotic resistance conferred by efflux pumps in the natural environment with trace amounts or no antibiotics.
Topics: Ciprofloxacin; Drinking Water; Drug Resistance, Microbial; Genetic Fitness; Pseudomonas aeruginosa; Water Pollutants
PubMed: 31221375
DOI: 10.1016/j.jes.2019.03.022 -
International Journal of Environmental... Dec 2013Water quality through the presence of pathogenic enteric microorganisms may affect human health. Coliform bacteria, Escherichia coli and coliphages are normally used as... (Review)
Review
Water quality through the presence of pathogenic enteric microorganisms may affect human health. Coliform bacteria, Escherichia coli and coliphages are normally used as indicators of water quality. However, the presence of above-mentioned indicators do not always suggest the presence of human enteric viruses. It is important to study human enteric viruses in water. Human enteric viruses can tolerate fluctuating environmental conditions and survive in the environment for long periods of time becoming causal agents of diarrhoeal diseases. Therefore, the potential of human pathogenic viruses as significant indicators of water quality is emerging. Human Adenoviruses and other viruses have been proposed as suitable indices for the effective identification of such organisms of human origin contaminating water systems. This article reports on the recent developments in the management of water quality specifically focusing on human enteric viruses as indicators.
Topics: Bacteria; Coliphages; Drinking Water; Environmental Monitoring; Humans; Viruses; Water Quality
PubMed: 23438312
DOI: 10.1080/09603123.2013.769201 -
Zhonghua Nan Ke Xue = National Journal... Dec 2022To explore the interactive effect of chemical fertilizer exposure and drinking untreated water during pregnancy on the risk of birth defects.
OBJECTIVE
To explore the interactive effect of chemical fertilizer exposure and drinking untreated water during pregnancy on the risk of birth defects.
METHODS
The data were collected from a population-based birth surveillance system in Pingding County, Shanxi Province, from 2007 to 2012. Totally, 157 cases of birth defects were followed up and 204 healthy newborns taken as controls. The additive model and relative excess risk of interaction (RERI) were used to evaluate the interactive effect of chemical fertilizer exposure and drinking untreated water during pregnancy on the risk of birth defects.
RESULTS
After adjusted for potential confounding factors, mothers living in villages with ≥ 65 ton/year chemical fertilizer application and drinking untreated water, as from deep underground, cellars, mountain spring, rivers, lakes or ponds, showed a higher risk of birth defects than those living in villages with <65 ton/year chemical fertilizer application and drinking tap or purified water (aOR = 2.12, 95% CI: 1.11-4.07). A strengthened interaction was observed between the annual application of chemical fertilizer at the village level and drinking untreated water (RERI = 2.08, 95% CI: 0.23-3.92, P < 0.05).
CONCLUSION
The pollution of drinking water may be an important pathway for chemical fertilizer exposure affecting birth outcomes.
Topics: Pregnancy; Female; Infant, Newborn; Humans; Drinking Water; Fertilizers
PubMed: 37846624
DOI: No ID Found -
Microbiome Jun 2019Residual disinfection is often used to suppress biological growth in drinking water distribution systems (DWDSs), but not without undesirable side effects. In this... (Comparative Study)
Comparative Study
BACKGROUND
Residual disinfection is often used to suppress biological growth in drinking water distribution systems (DWDSs), but not without undesirable side effects. In this study, water-main biofilms, drinking water, and bacteria under corrosion tubercles were analyzed from a chloraminated DWDS (USA) and a no-residual DWDS (Norway). Using quantitative real-time PCR, we quantified bacterial 16S rRNA genes and ammonia monooxygenase genes (amoA) of Nitrosomonas oligotropha and ammonia-oxidizing archaea-organisms that may contribute to chloramine loss. PCR-amplified 16S rRNA genes were sequenced to assess community taxa and diversity.
RESULTS
The chloraminated DWDS had lower biofilm biomass (P=1×10) but higher N. oligotropha-like amoA genes (P=2×10) than the no-residual DWDS (medians =4.7×10 and 1.1×10amoA copies cm, chloraminated and no residual, respectively); archaeal amoA genes were only detected in the no-residual DWDS (median =2.8×10 copies cm). Unlike the no-residual DWDS, biofilms in the chloraminated DWDS had lower within-sample diversity than the corresponding drinking water (P<1×10). Chloramine was also associated with biofilms dominated by the genera, Mycobacterium and Nitrosomonas (≤91.7% and ≤39.6% of sequences, respectively). Under-tubercle communities from both systems contained corrosion-associated taxa, especially Desulfovibrio spp. (≤98.4% of sequences).
CONCLUSIONS
Although residual chloramine appeared to decrease biofilm biomass and alpha diversity as intended, it selected for environmental mycobacteria and Nitrosomonas oligotropha-taxa that may pose water quality challenges. Drinking water contained common freshwater plankton and did not resemble corresponding biofilm communities in either DWDS; monitoring of tap water alone may therefore miss significant constituents of the DWDS microbiome. Corrosion-associated Desulfovibrio spp. were observed under tubercles in both systems but were particularly dominant in the chloraminated DWDS, possibly due to the addition of sulfate from the coagulant alum.
Topics: Bacteria; Biofilms; Chloramines; Disinfection; Drinking Water; Microbiota; RNA, Ribosomal, 16S; Water Microbiology; Water Purification; Water Supply
PubMed: 31174608
DOI: 10.1186/s40168-019-0707-5 -
Environmental Science and Pollution... Nov 2018Drinking water in the vast Arctic Canadian territory of Nunavut is sourced from surface water lakes or rivers and transferred to man-made or natural reservoirs. The raw...
Drinking water in the vast Arctic Canadian territory of Nunavut is sourced from surface water lakes or rivers and transferred to man-made or natural reservoirs. The raw water is at a minimum treated by chlorination and distributed to customers either by trucks delivering to a water storage tank inside buildings or through a piped distribution system. The objective of this study was to characterize the chemical and microbial drinking water quality from source to tap in three hamlets (Coral Harbour, Pond Inlet and Pangnirtung-each has a population of <2000) on trucked service, and in Iqaluit (population ~6700), which uses a combination of trucked and piped water conveyance. Generally, the source and drinking water was of satisfactory microbial quality, containing Escherichia coli levels of <1 MPN/100 mL with a few exceptions, and selected pathogenic bacteria and parasites were below detection limits using quantitative polymerase chain reaction (qPCR) methods. Tap water in households receiving trucked water contained less than the recommended 0.2 mg/L of free chlorine, while piped drinking water in Iqaluit complied with Health Canada guidelines for residual chlorine (i.e. >0.2 mg/L free chlorine). Some buildings in the four communities contained manganese (Mn), copper (Cu), iron (Fe) and/or lead (Pb) concentrations above Health Canada guideline values for the aesthetic (Mn, Cu and Fe) and health (Pb) objectives. Corrosion of components of the drinking water distribution system (household storage tanks, premise plumbing) could be contributing to Pb, Cu and Fe levels, as the source water in three of the four communities had low alkalinity. The results point to the need for robust disinfection, which may include secondary disinfection or point-of-use disinfection, to prevent microbial risks in drinking water tanks in buildings and ultimately at the tap.
Topics: Chlorine; Disinfection; Drinking Water; Escherichia coli; Family Characteristics; Fresh Water; Halogenation; Humans; Nunavut; Polymerase Chain Reaction; Water Microbiology; Water Purification; Water Quality; Water Supply
PubMed: 28612312
DOI: 10.1007/s11356-017-9423-5 -
Risk Analysis : An Official Publication... May 2014
Topics: Drinking Water; Environmental Exposure; Humans; Nitrosamines
PubMed: 24832762
DOI: 10.1111/risa.12205 -
Neurotoxicology Jan 2018Manganese is commonly found in water but potential neurotoxic effects from exposure through drinking water are poorly understood. We previously reported a...
BACKGROUND
Manganese is commonly found in water but potential neurotoxic effects from exposure through drinking water are poorly understood. We previously reported a cross-sectional study showing that drinking water Mn concentration was associated with lower IQ in children aged 6 to 13 years.
OBJECTIVE
For this follow-up study, we aimed to re-assess the relation between exposure to Mn from drinking water and IQ at adolescence. In addition, we aimed to examine whether changes in drinking water Mn concentration was associated with changes in IQ scores.
METHODS
From the 380 children enrolled in the baseline study, 287 participated to this follow-up study conducted in average 4.4 years after. Mn concentration was measured in home tap water and children's hair. The relationships between these Mn exposure indicators and IQ scores (Weschsler Abbreviated Scale of Intelligence) at follow-up were assessed with linear regression analysis, adjusting for potential confounders. Intra-individual differences in IQ scores between the two examinations were compared for children whose Mn concentration in water remained stable between examinations, increased or decreased.
RESULTS
The mean age at follow-up was 13.7 years (range, 10.5 to 18.0 years). Geometric mean of Mn concentration in water at follow-up was 14.5μg/L. Higher Mn concentration in water measured at follow-up was associated with lower Performance IQ in girls (β for a 10-fold increase=-2.8, 95% confidence intervals [CI] -4.8 to -0.8) and higher Performance IQ in boys (β=3.9, 95% CI 1.4 to 6.4). IQ scores were not significantly associated with Mn concentration in hair, although similar trends as for concentration in water were observed. For children whose Mn concentration in water increased between baseline and follow-up, Performance IQ scores decreased significantly (intra-individual difference, -2.4 points).
CONCLUSION
Higher levels of Mn in drinking water were associated with lower Performance IQ in girls, whereas the opposite was observed in boys. These findings suggest long-term exposure to Mn through drinking water is associated differently with cognition in boys and girls.
Topics: Adolescent; Child; Drinking Water; Environmental Exposure; Female; Humans; Intelligence; Male; Manganese; Sex Factors; Wechsler Scales
PubMed: 28870865
DOI: 10.1016/j.neuro.2017.08.015 -
Journal of Water and Health Aug 2020Sand dams can be an effective community-scale solution to increasing water supplies in some arid and semi-arid regions, but there are few studies that have investigated...
Sand dams can be an effective community-scale solution to increasing water supplies in some arid and semi-arid regions, but there are few studies that have investigated water quality at sand dams. This study investigated the levels of coliform bacteria and salt content as parameters of potential concern. Most water taken from sand dam sources had fecal coliforms present. Median fecal coliforms were in the range of 150-800 cfu/100 ml for unprotected sources (scoop holes, surface water or hand dug wells), levels which are considered high or very high health risk. Pump wells had less contamination, with fecal coliforms detected in one-third of samples in the dry season. Despite this contamination, user surveys indicated that 74% of communities generally view water as clean for drinking, and 72% reported that no or few people in their community treat their water. Salt content in the dry season was in the poor or unacceptable range (above 900 ppm as total dissolved solids) in 33% of water samples. Results suggest that fecal coliforms and salt content represent two types of challenges to water quality at sand dams: fecal coliforms are a health hazard, whereas high salt content potentially reduces the amount of usable water that is available.
Topics: Bacteria; Drinking Water; Feces; Kenya; Salinity; Sand; Water Microbiology; Water Supply
PubMed: 32833686
DOI: 10.2166/wh.2020.192 -
Journal of Water and Health Jun 2024It is well known that municipal drinking water may be the cause of gastrointestinal illness (GII) outbreaks, but it is still unclear to what extent drinking water...
It is well known that municipal drinking water may be the cause of gastrointestinal illness (GII) outbreaks, but it is still unclear to what extent drinking water contributes to endemic GII. To explore this, we conducted a prospective cohort study among 6,955 adults in five municipalities in Sweden, collecting monthly GII episodes and mean daily cold drinking water consumption through SMS (Short Message Service). When the association between drinking water consumption and GII (all symptoms) and acute gastrointestinal illness (AGI, vomiting and/or three loose stools during a 24-h period) were assessed, there were indications that the association departed from linearity, following a unimodal shape. Among consumers in surface water areas, the highest risk of GII and AGI was generally seen among the average consumers, while the opposite was seen among groundwater consumers. The association however also seemed to be affected by neighbouring communities. The results of the study indicate that there is indeed an association between drinking water consumption and endemic GII, but the nature of this association is complex and likely affected by multiple factors, for example, water source type in the home and degree of exposure to drinking water from additional sources.
Topics: Sweden; Humans; Drinking Water; Adult; Male; Gastrointestinal Diseases; Female; Prospective Studies; Middle Aged; Aged; Cohort Studies; Young Adult; Endemic Diseases; Water Supply
PubMed: 38935452
DOI: 10.2166/wh.2024.372 -
Journal of Hazardous Materials May 2022Reusable plastic sports bottles are used extensively worldwide, and little is known about the migration of chemicals from the bottles into drinking water. In this study,...
Reusable plastic sports bottles are used extensively worldwide, and little is known about the migration of chemicals from the bottles into drinking water. In this study, we investigated the chemical migration into drinking water stored for 24 h in new bottles, used bottles and bottles washed in the dishwasher. Non-target screening (NTS) by liquid-chromatography - high-resolution mass spectrometry (LC-HRMS) was performed to identify these compounds. We detected > 3500 dishwasher related compounds, with 430 showing migration even after subsequent flushing of the bottles. In addition, more than 400 plastic related compounds were detected, with high peaks for oligomers suspected to originate from the biodegradable polyester polycaprolactone, and aromatic amines, which may have been introduced as slip agents or antioxidants. These compounds have never been reported before in bottled water. Most of the identified compounds migrating out of the used bottles were plasticizers, antioxidants or photoinitiators. The presence of photoinitiators are of particular concern, due to possible endocrine disrupting effects. Furthermore, diethyltoluamide (DEET) was detected, which may have been formed from the plasticizer laurolactam. Typically, the dishwashing process enhanced the leaching of plastic related compounds, and even after additional water flushing, the average peak intensity of these compounds was only reduced by half.
Topics: Drinking Water; Plasticizers; Plastics
PubMed: 35091188
DOI: 10.1016/j.jhazmat.2022.128331