Health Significance and Occurrence of Injured Bacteria in Drinking Water

1986 ◽  
Vol 18 (10) ◽  
pp. 227-231 ◽  
Author(s):  
Gordon A. McFeters ◽  
Mark W. LeChevallier ◽  
Ajaib Singh ◽  
Joyce S. Kippin
Keyword(s):  
Drinking Water ◽  
Distribution Systems ◽  
Drinking Water Treatment ◽  
Indicator Bacteria ◽  
Enterotoxigenic Escherichia Coli ◽  
Coliform Bacteria ◽  
Physical Factors ◽  
Enteropathogenic Bacteria ◽  
Shigella Spp ◽  
Health Significance

Enteropathogenic and indicator bacteria become injured in drinking water with exposure to sublethal levels of various biological, chemical and physical factors. One manifestation of this injury is the inability to grow and form colonies on selective media containing surfactants. The resulting underestimation of indicator bacteria can lead to a false estimation of water potability. m-T7 medium was developed specifically for the recovery of injured coliforms (both “total” and fecal) in drinking water. The m-T7 method was used to survey operating drinking water treatment and distribution systems for the presence of injured coliforms that were undetected with currently used media. The mean recovery with m-Endo LES medium was less than 1/100 ml while it ranged between 6 and 68/100ml with m-T7 agar. The majority of samples giving positive results with m-T7 medium yielded no detectable coliforms with m-Endo LES agar. Over 95% of the coliform bacteria in these samples were injured. Laboratory experiments were also done to describe the virulence of injured waterborne pathogens. Enteropathogens including Salmonella tvphimurium, Yersinia enterocolitica and Shigella spp. required up to 20 times the chlorine levels to produce the same injury in enterotoxigenic Escherichia coli (ETEC) and nonpathogenic coliforms. Similar results were seen with Y. enterocolitica exposed to copper. The recovery of ETEC was followed by delayed enterotoxin production, both invitro and in the gut of experimental animals. This indicates that injured waterborne enteropathogenic bacteria can be virulent.

scholarly journals Occurrence of Antibiotic-Resistant Bacteria and Genes in Two Drinking Water Treatment and Distribution Systems in the North-West Province of South Africa

Antibiotics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 745
Author(s):  
Collins Njie Ateba ◽  
Naledi Mahalia Tabi ◽  
Justine Fri ◽  
Marie Ebob Agbortabot Bissong ◽  
Cornelius Carlos Bezuidenhout
Keyword(s):  
South Africa ◽  
Drinking Water ◽  
Water Treatment ◽  
Distribution Systems ◽  
Drinking Water Treatment ◽  
Coliform Bacteria ◽  
Resistant Bacteria ◽  
North West ◽  
The North ◽  
North West Province

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.

H2S papers as presumptive tests for Salmonella contamination in tropical drinking water

1996 ◽  
Vol 34 (7-8) ◽  
pp. 187-194 ◽  
Author(s):  
Tanya Gawthorne ◽  
Robyn A. Gibbs ◽  
Kuruvilla Mathew ◽  
Goen E. Ho
Keyword(s):  
Drinking Water ◽  
Hydrogen Sulphide ◽  
Incubation Temperature ◽  
Indicator Bacteria ◽  
Coliform Bacteria ◽  
Salmonella Spp ◽  
Faecal Contamination ◽  
Tropical Waters ◽  
Remote Areas ◽  
Traditional Indicator

Coliform bacteria may not be adequate as sole indicators of recent faecal contamination in tropical waters. Salmonella spp. in particular have been found in tropical waters in the absence of traditional indicator bacteria. Remote areas without access to a laboratory have no opportunity for salmonellae analysis as portable tests are currently not available. H2S papers indicate the presence of hydrogen sulphide producing bacteria, a characteristic shared by the majority of Salmonella spp.. The potential of H2S papers to act as a presumptive test for salmonellae in the absence of coliform bacteria was assessed. Salmonella spp. grew in the H2S medium, with an optimum incubation temperature of 37°C and a recommended length of incubation for a negative result of 48 hours. The presence of high numbers of the type of noncoliform bacteria commonly found in drinking water did not affect the performance of the H2S strips. H2S papers are recommended for use in conjunction with a coliform test as a presumptive test for the presence of Salmonella spp. in drinking water.

scholarly journals After the flood: an evaluation of in-home drinking water treatment with combined flocculent-disinfectant following Tropical Storm Jeanne — Gonaives, Haiti, 2004

2007 ◽  
Vol 5 (3) ◽  
pp. 367-374 ◽  
Author(s):  
Romulo E. Colindres ◽  
Seema Jain ◽  
Anna Bowen ◽  
Eric Mintz ◽  
Polyana Domond
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Drinking Water Treatment ◽  
Water Sources ◽  
Tropical Storm ◽  
Coliform Bacteria ◽  
Residual Chlorine ◽  
Household Water ◽  
Untreated Water ◽  
Local Leaders

Tropical Storm Jeanne struck Haiti in September 2004, causing widespread flooding which contaminated water sources, displaced thousands of families and killed approximately 2,800 people. Local leaders distributed PūR®, a flocculent-disinfectant product for household water treatment, to affected populations. We evaluated knowledge, attitudes, practices, and drinking water quality among a sample of PūR® recipients. We interviewed representatives of 100 households in three rural communities who received PūR® and PūR®-related education. Water sources were tested for fecal contamination and turbidity; stored household water was tested for residual chlorine. All households relied on untreated water sources (springs [66%], wells [15%], community taps [13%], and rivers [6%]). After distribution, PūR® was the most common in-home treatment method (58%) followed by chlorination (30%), plant-based flocculation (6%), boiling (5%), and filtration (1%). Seventy-eight percent of respondents correctly answered five questions about how to use PūR®; 81% reported PūR® easy to use; and 97% reported that PūR®-treated water appears, tastes, and smells better than untreated water. Although water sources tested appeared clear, fecal coliform bacteria were detected in all sources (range 1 – &gt;200 cfu/100 ml). Chlorine was present in 10 (45%) of 22 stored drinking water samples in households using PūR®. PūR® was well-accepted and properly used in remote communities where local leaders helped with distribution and education. This highly effective water purification method can help protect disaster-affected communities from waterborne disease.

Exploring the Role of Coliform Bacteria in Class 1 Integron Carriage and Biofilm Formation During Drinking Water Treatment

2016 ◽  
Vol 72 (4) ◽  
pp. 773-782 ◽  
Author(s):  
Anca Farkas ◽  
Cornelia Crăciunaş ◽  
Cecilia Chiriac ◽  
Edina Szekeres ◽  
Cristian Coman ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Biofilm Formation ◽  
Drinking Water Treatment ◽  
Coliform Bacteria ◽  
Class 1 Integron ◽  
Class 1

Chlorine sensitivity of environmental, distribution system and biofilm coliforms

1997 ◽  
Vol 35 (11-12) ◽  
pp. 289-292 ◽  
Author(s):  
D. P. Sartory ◽  
P. Holmes
Keyword(s):  
Drinking Water ◽  
River Water ◽  
Distribution System ◽  
Distribution Systems ◽  
Bulk Water ◽  
Coliform Bacteria ◽  
Environmental Distribution ◽  
River Waters ◽  
E Coli ◽  
Treated Drinking Water

Coliform bacteria, isolated from treated drinking water supplies, can be derived from a range of sources (e.g. infiltration, breakthrough at the treatment works or from the biofilm established within the pipework). The sensitivity of these bacteria to chlorine may be related to their source and metabolic status. Strains of coliforms were isolated from sewage works effluents, river and reservoir waters as well as from the bulk water and biofilms from distribution systems. These were assayed for sensitivity to free and total chlorine using two assay procedures. For E. coli, the isolates from the distribution system bulk water showed greater resistance to free chlorine than those from sewage effluents and equivalence to those from river waters. For non-E. coli coliforms (mainly strains of Klebsiella, Enterobacter and Citrobacter), those from distribution system biofilms showed the greatest sensitivity to free and total chlorine whilst those from river water had the greatest resistance.

scholarly journals Effect of increasing bromide concentration on toxicity in treated drinking water

2015 ◽  
Vol 14 (2) ◽  
pp. 183-191 ◽  
Author(s):  
Emma Sawade ◽  
Rolando Fabris ◽  
Andrew Humpage ◽  
Mary Drikas
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Water Treatment ◽  
Distribution Systems ◽  
Water Quality Management ◽  
Drinking Water Treatment ◽  
Sudden Onset ◽  
Toxic Species ◽  
Treated Drinking Water ◽  
The Impact

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.

The biological safety of distribution systems following UV disinfection in rural areas in Beijing, China

2013 ◽  
Vol 13 (3) ◽  
pp. 854-863 ◽  
Author(s):  
Wenjun Sun ◽  
Wenjun Liu ◽  
Lifeng Cui ◽  
Leibin Liu
Keyword(s):  
Drinking Water ◽  
Rural Areas ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution System ◽  
Drinking Water Treatment ◽  
Uv Disinfection ◽  
Biological Safety ◽  
Drinking Water Standard

In rural areas, UV disinfection has a great potential for drinking water treatment because of the ability to achieve target disinfection levels and the ease of operation and maintenance; however, UV disinfection provides no disinfection residual to the water distribution system. This study examines the biological safety of rural water distribution systems following UV disinfection. The results showed that in all the tested villages, heterotrophic plate counts (HPC) were below 500 colony-forming units (CFU)/mL and total bacterial counts (TBC) were below 100 CFU/mL. Both meet the drinking water standard in China. The HPC concentration was related to the water temperature, the assimilable organic carbon (AOC) and water distribution system conditions. Total coliforms were detectable at some water distribution system sampling points in two out of eight villages.

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