Flow cytometry and adenosine tri-phosphate analysis: Alternative possibilities to evaluate major bacteriological changes in drinking water treatment and distribution systems

2012 ◽  
Vol 46 (15) ◽  
pp. 4665-4676 ◽  
Author(s):  
Marius Vital ◽  
Marco Dignum ◽  
Aleksandra Magic-Knezev ◽  
Petra Ross ◽  
Luuk Rietveld ◽  
...  
2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Michael D. Besmer ◽  
Jannis Epting ◽  
Rebecca M. Page ◽  
Jürg A. Sigrist ◽  
Peter Huggenberger ◽  
...  

Antibiotics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 745
Author(s):  
Collins Njie Ateba ◽  
Naledi Mahalia Tabi ◽  
Justine Fri ◽  
Marie Ebob Agbortabot Bissong ◽  
Cornelius Carlos Bezuidenhout

With the increasing spread of antimicrobial resistance, there is growing attention to the contribution made by drinking water systems. The potential health impact of two drinking water treatment and distribution systems (A and B) in the North-West Province of South Africa was determined by investigating the water quality and occurrence of antimicrobial-resistant heterotrophic bacteria and genes in the raw and treated water over four seasons. Most of the physicochemical parameters except for electrical conductivity were within permissible limits. Coliform bacteria reduced from raw to potable water except for counts higher than the threshold recorded in Summer and Winter. A total of 203 heterotrophic bacterial isolates were recovered on chromogenic R2A medium and subjected to susceptibility testing to twelve antibiotics. Most of the isolates were resistant to β-lactam antibiotics and Trimethoprim, whereas they were susceptible to Ciprofloxacin, Erythromycin, and Neomycin. The proportions of Cephalothin and Kanamycin-resistant isolates were significantly higher (p < 0.05) after treatment for site A, compared to significantly lower β-lactam, Oxytetracycline, and Trimethoprim-resistant isolates for B. Over 50% of isolates were of high risk, indicating their origin from high antibiotic-use sources. Seventy-one (35%) isolates were multidrug-resistant, out of which the majority (53.5%, n = 38) possessed the strA gene, followed by strB 21 (29.6%), dfrB 13 (18.3%), aadA 11 (15.5%), blaCTX-M 5 (7.0%), and tetA 3 (4.2%). The 16S rRNA gene sequences of the isolates revealed strains belonging to eight bacterial families, some of which are clinically important.


2015 ◽  
Vol 14 (2) ◽  
pp. 183-191 ◽  
Author(s):  
Emma Sawade ◽  
Rolando Fabris ◽  
Andrew Humpage ◽  
Mary Drikas

Research is increasingly indicating the potential chronic health effects of brominated disinfection by-products (DBPs). This is likely to increase with elevated bromide concentrations resulting from the impacts of climate change, projected to include extended periods of drought and the sudden onset of water quality changes. This will demand more rigorous monitoring throughout distribution systems and improved water quality management at water treatment plants (WTPs). In this work the impact of increased bromide concentration on formation of DBPs following conventional treatment and chlorination was assessed for two water sources. Bioanalytical tests were utilised to determine cytotoxicity of the water post disinfection. Coagulation was shown to significantly reduce the cytotoxicity of the water, indicating that removal of natural organic matter DBP precursors continues to be an important factor in drinking water treatment. Most toxic species appear to form within the first half hour following disinfectant addition. Increasing bromide concentration across the two waters was shown to increase the formation of trihalomethanes and shifted the haloacetic acid species distribution from chlorinated to those with greater bromine substitution. This correlated with increasing cytotoxicity. This work demonstrates the challenges faced by WTPs and the possible effects increasing levels of bromide in source waters could have on public health.


2014 ◽  
Vol 14 (5) ◽  
pp. 850-856 ◽  
Author(s):  
K. Helmi ◽  
A. Watt ◽  
P. Jacob ◽  
I. Ben-Hadj-Salah ◽  
A. Henry ◽  
...  

A 4-month sampling campaign has been conducted for the monitoring of three drinking water treatment plants using flow cytometry and culture-based methods to provide information related to changes in bacterial concentration according to treatments. Flow cytometry is a fast and user-friendly technique enabling bacteria quantification and viability assessment in less than 1 hour. Specific profiles regarding log-reduction of total bacteria were obtained for each treatment plant. Chlorination appeared to be the most effective by causing metabolism inactivation and nucleic acid damages. Ozonation showed a significant impact on cell activity in contrast with ultraviolet treatment which strongly affected bacterial DNA. In addition, the results showed that active bacteria quantified by flow cytometry were significantly correlated with culturable bacteria. This alternative approach appeared as gainful compared to culture methods as it greatly facilitates the diagnosis of treatment plant process for drinking water production monitoring.


2010 ◽  
pp. 69-73
Author(s):  
Franclin S. Foping

Drinking contaminated water can be harmful to our health. According to the World Health Organization, about 1.8 million people die every year across the world from water-borne diseases mainly caused by polluted drinking water. Furthermore, the cryptosporidium outbreak that happened in Galway in 2007 indicates the urgency to provide appropriate solutions in order to counteract this ominous situation in the country. Water treatment plants (WTP) are basic components of modern water supply and distribution systems. These are engineering systems that purify raw water to specific safety levels. The raw water passes through a series of treatment phases wherein it is processed and purified according to existing safety protocols regulating drinking water. After undergoing a purification step, the drinking water is distributed to the consumers through a network of pipes, pumps and reservoirs. The research presented in this report is focused on the safety of these critical infrastructures. In particular, the ...


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.


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