Analysis of the biological stability of tap water on the basis of risk analysis and parameters limiting the secondary growth of microorganisms in water distribution systems

2018 ◽  
Vol 117 ◽  
pp. 1-8 ◽  
Author(s):  
Dorota Papciak ◽  
Barbara Tchórzewska-Cieslak ◽  
Katarzyna Pietrucha-Urbanik ◽  
Andzelika Pietrzyk
2013 ◽  
Vol 185 (9) ◽  
pp. 7675-7691 ◽  
Author(s):  
Jin Lee ◽  
Eun-Sook Kim ◽  
Bang-Sik Roh ◽  
Seog-Won Eom ◽  
Kyung-Duk Zoh

2011 ◽  
Vol 9 (4) ◽  
pp. 799-812 ◽  
Author(s):  
Elisabetta Lambertini ◽  
Susan K. Spencer ◽  
Burney A. Kieke ◽  
Frank J. Loge ◽  
Mark A. Borchardt

We tested the association of common events in drinking water distribution systems with contamination of household tap water with human enteric viruses. Viruses were enumerated by qPCR in the tap water of 14 municipal systems that use non-disinfected groundwater. Ultraviolet disinfection was installed at all active wellheads to reduce virus contributions from groundwater to the distribution systems. As no residual disinfectant was added to the water, any increase in virus levels measured downstream at household taps would be indicative of distribution system intrusions. Utility operators reported events through written questionnaires. Virus outcome measures were related to distribution system events using binomial and gamma regression. Virus concentrations were elevated in the wells, reduced or eliminated by ultraviolet disinfection, and elevated again in distribution systems, showing that viruses were, indeed, directly entering the systems. Pipe installation was significantly associated with higher virus levels, whereas hydrant flushing was significantly associated with lower virus levels. Weak positive associations were observed for water tower maintenance, valve exercising, and cutting open a water main. Coliform bacteria detections from routine monitoring were not associated with viruses. Understanding when distribution systems are most vulnerable to virus contamination, and taking precautionary measures, will ensure delivery of safe drinking water.


2009 ◽  
Vol 75 (17) ◽  
pp. 5714-5718 ◽  
Author(s):  
Chuanwu Xi ◽  
Yongli Zhang ◽  
Carl F. Marrs ◽  
Wen Ye ◽  
Carl Simon ◽  
...  

ABSTRACT The occurrence and spread of antibiotic-resistant bacteria (ARB) are pressing public health problems worldwide, and aquatic ecosystems are a recognized reservoir for ARB. We used culture-dependent methods and quantitative molecular techniques to detect and quantify ARB and antibiotic resistance genes (ARGs) in source waters, drinking water treatment plants, and tap water from several cities in Michigan and Ohio. We found ARGs and heterotrophic ARB in all finished water and tap water tested, although the amounts were small. The quantities of most ARGs were greater in tap water than in finished water and source water. In general, the levels of bacteria were higher in source water than in tap water, and the levels of ARB were higher in tap water than in finished water, indicating that there was regrowth of bacteria in drinking water distribution systems. Elevated resistance to some antibiotics was observed during water treatment and in tap water. Water treatment might increase the antibiotic resistance of surviving bacteria, and water distribution systems may serve as an important reservoir for the spread of antibiotic resistance to opportunistic pathogens.


2016 ◽  
Vol 82 (21) ◽  
pp. 6483-6489 ◽  
Author(s):  
Véronique Edel-Hermann ◽  
Marc Sautour ◽  
Nadine Gautheron ◽  
Julie Laurent ◽  
Serge Aho ◽  
...  

ABSTRACTFusarium oxysporumis typically a soilborne fungus but can also be found in aquatic environments. In hospitals, water distribution systems may be reservoirs for the fungi responsible for nosocomial infections.F. oxysporumwas previously detected in the water distribution systems of five French hospitals. Sixty-eight isolates from water representative of all hospital units that were previously sampled and characterized by translation elongation factor 1α sequence typing were subjected to microsatellite analysis and full-length ribosomal intergenic spacer (IGS) sequence typing. All but three isolates shared common microsatellite loci and a common two-locus sequence type (ST). This ST has an international geographical distribution in both the water networks of hospitals and among clinical isolates. The ST dominant in water was not detected among 300 isolates ofF. oxysporumthat originated from surrounding soils. Further characterization of 15 isolates by vegetative compatibility testing allowed us to conclude that a clonal lineage ofF. oxysporumcirculates in the tap water of the different hospitals.IMPORTANCEWe demonstrated that a clonal lineage ofFusarium oxysporuminhabits the water distribution systems of several French hospitals. This clonal lineage, which appears to be particularly adapted to water networks, represents a potential risk for human infection and raises questions about its worldwide distribution.


2021 ◽  
Author(s):  
Luo Xu ◽  
cong li ◽  
Guozijian Wei ◽  
Jie Ji ◽  
Eric Lichtfouse ◽  
...  

Abstract Sulfamethoxazole (SMX) is a veterinary drugs and feed additives, which has been frequently detected in surface waters in recent years. This paper investigated the kinetics, evolution of toxicity and antibiotic resistance genes (ARGs) of SMX in reactions with free chlorine (FC) to evaluate the fate of SMX in batch reactors and water distribution systems (WDS). In the range of investigated pH (6.3 – 9.0), the SMX degradation had the fastest rate at close to neutral pH. The chlorination of SMX could be described by the first-order kinetics, with specific second-order rate constants in batch reactors of (2.23 ± 0.07) × 102 M− s and (5.04 ± 0.30) × 101 M− s− for HClO and ClO−, respectively. And in WDS of (1.76 ± 0.07) × 102 M− s− and (4.06 ± 0.62) × 101 M− s−, respectively. The SMX degradation rate was also affected by pipe material, and the rate followed the order: stainless-steel pipe (SS) > ductile iron pipe (DI) > polyethylene pipe (PE). The flow rate from 0.7 to 1.5 m/s led to an increase of SMX degradation rate in DI, but the increase was limited. In addition, SMX could increase the toxicity of water initially, yet the toxicity reduced to the level of tap water after 2 hours chlorination. The relative abundance of ARGs (sul1 and sul2) of tap water samples was significantly increased under different conditions including only use SMX, chlorination products of SMX, or pretreatment with SMX followed by chlorination.


Chemotherapy ◽  
2016 ◽  
Vol 62 (1) ◽  
pp. 34-42 ◽  
Author(s):  
Ayodele T. Adesoji ◽  
Adeniyi A. Ogunjobi ◽  
Isaac O. Olatoye

Background: The emergence of antibiotic resistance among pathogenic bacteria in clinical and environmental settings is a global problem. Many antibiotic resistance genes are located on mobile genetic elements such as plasmids and integrons, enabling their transfer among a variety of bacterial species. Water distribution systems may be reservoirs for the spread of antibiotic resistance. Materials and Methods: Bacteria isolated from raw, treated, and municipal tap water samples from selected water distribution systems in south-western Nigeria were investigated using the point inoculation method with seeded antibiotics, PCR amplification, and sequencing for the determination of bacterial resistance profiles and class 1/2 integrase genes and gene cassettes, respectively. Results:sul1,sul2, and sul3 were detected in 21.6, 27.8, and 0% of the isolates, respectively (n = 162). Class 1 and class 2 integrons were detected in 21.42 and 3.6% of the isolates, respectively (n = 168). Genes encoding resistance to aminoglycosides (aadA2, aadA1, and aadB), trimethoprim (dfrA15, dfr7, and dfrA1), and sulfonamide (sul1) were detected among bacteria with class 1 integrons, while genes that encodes resistance to strepthothricin (sat2) and trimethoprim (dfrA15) were detected among bacteria with class 2 integrons. Conclusions: Bacteria from these water samples are a potential reservoir of multidrug-resistant traits including sul genes and mobile resistance elements, i.e. the integrase gene.


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