Ouf SA, Yehia RS, Ouf AS, Abdul-Rahim RF. Bacterial contamination and health risks of drinking water from the municipal non-government managed water treatment plants. Environmental monitoring and assessment. 2018 Oct 29;190(11):685. doi: 10.1007/s10661-018-7054-z.
Water quality and bacterial contamination from 18 drinking water municipal plants in three locations at Giza governorate were investigated. The average total count of bacteria detected after four stages of treatments in the investigated plants was 32 CFU/1 mL compared to 2330 cfu/mL for raw water, with a reduction percentage of 98.6. Although there is a relatively high removal percent of bacterial contamination from the water sources, however, several bacterial pathogens were identified in the produced water prepared for drinking including Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, and Shigella spp. After 3 days of water incubation at 30 °C, the amount of bacterial endotoxins ranged from 77 to 137 ng/mL in the water produced from the municipal plants compared to 621-1260 ng/mL for untreated water. The main diseases reported from patients attending different clinics and hospitals during summer 2014 at the surveyed locations and assuredly due to drinking water from these plants indicated that diarrheas and gastroenteritis due to E. coli and Campylobacter jejuni constituted 65.7% of the total patients followed by bacillary dysentery or shigellosis due to Shigella spp. (7.9%) and cholera due to Vibrio cholera (7.2%). There was an increase in serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) as well as urea and creatinine values of guinea pigs consuming water produced from the non-governmental plants for 6 months indicating remarkable liver and kidney damages. Histological sections of liver and kidney from the tested animal revealed liver having ballooning degeneration of hepatocytes and distortion and fragmentation of the nuclei, while the section of the kidney showed irregularly distributed wrinkled cells, degenerated Bowman’s capsule, congested blood vessels, and inflammatory cells.
Chen Z, Yu D, He S, Ye H, Zhang L, Wen Y, Zhang W, Shu L, Chen S. Prevalence of Antibiotic-Resistant Escherichia coli in Drinking Water Sources in Hangzhou City. Front Microbiol. 2017 Jun 16;8:1133. doi: 10.3389/fmicb.2017.01133. eCollection 2017.
This study investigated the distribution of antibiotic resistant Escherichia coli (E. coli) and examined the possible relationship between water quality parameters and antibiotic resistance from two different drinking water sources (the Qiantang River and the Dongtiao Stream) in Hangzhou city of China. E. coli isolates were tested for their susceptibility to 18 antibiotics. Most of the isolates were resistant to tetracycline (TE), followed by ampicillin (AM), piperacillin (PIP), trimethoprim/sulfamethoxazole (SXT), and chloramphenicol (C). The antibiotic resistance rate of E. coli isolates from two water sources was similar; For E. coli isolates from the Qiantang River, their antibiotic resistance rates decreased from up- to downstream. Seasonally, the dry and wet season had little impact on antibiotic resistance. Spearman’s rank correlation revealed significant correlation between resistance to TE and phenicols or ciprofloxacin (CIP), as well as quinolones (ciprofloxacin and levofloxacin) and cephalosporins or gentamicin (GM). Pearson’s chi-square tests found certain water parameters such as nutrient concentration were strongly associated with resistance to some of the antibiotics. In addition, tet genes were detected from all 82 TE-resistant E. coli isolates, and most of the isolates (81.87%) contained multiple tet genes, which displayed 14 different combinations. Collectively, this study provided baseline data on antibiotic resistance of drinking water sources in Hangzhou city, which indicates drinking water sources could be the reservoir of antibiotic resistance, potentially presenting a public health risk.
Ercumen A, Arnold BF, Naser AM, Unicomb L, Colford JM Jr. Potential sources of bias in the use of Escherichia coli to measure waterborne diarrhea risk in low-income settings. Trop Med Int Health. 2016 Oct 31. doi: 10.1111/tmi.12803
OBJECTIVES: Escherichia coli is the standard water quality indicator for diarrhea risk. Yet the association between E. coli and diarrhea is inconsistent across studies without a systematic assessment of methodological differences behind this variation. Most studies measure water quality cross-sectionally with diarrhea, risking exposure misclassification and reverse causation. Studies use different recall windows for self-reported diarrhea; longer periods increase potential outcome misclassification through misrecall. Control of confounding is inconsistent across studies. Additionally, diarrhea measured in unblinded intervention trials can present courtesy bias. We utilized measurements from a randomized trial of water interventions in Bangladesh to assess how these factors affect the E. coli-diarrhea association.
METHODS: We compared cross-sectional versus prospective measurements of water quality and diarrhea, two- versus seven-day symptom recall periods, estimates with and without controlling for confounding and using measurements from control versus intervention arms of the trial.
RESULTS: In the control arm, two-day diarrhea prevalence, measured prospectively one month after water quality, significantly increased with log10 E. coli (PR=1.50, 1.02-2.20). This association weakened when we used seven-day recall (PR=1.18, 0.88-1.57), cross-sectional measurements of E. coli and diarrhea (PR=1.11, 0.79-1.56) or did not control for confounding (PR=1.20, 0.88-1.62). Including data from intervention arms led to less interpretable associations, potentially due to courtesy bias, effect modification and/or reverse causation.
CONCLUSIONS: By systematically addressing potential sources of bias, our analysis demonstrates a clear relationship between E. coli in drinking water and diarrhea, suggesting that the continued use of E. coli as an indicator of waterborne diarrhea risk is justified.
F Nabeela, A Azizullah, U Roqaia, M Syeda, W Murad, S Shakir, W Ullah, M Qasim, D-P Häder. Microbial contamination of drinking water in Pakistan-a review. Environmental Science & Pollution Research; Dec2014, Vol. 21 Issue 24, p13929-13942
Water pollution with pathogenic microorganisms is one of the serious threats to human health, particularly in developing countries. The main objective of this article is to highlight microbial contamination of drinking water, the major factors responsible for microbial contamination, and the resulting health problems in Pakistan. Furthermore, this study will be helpful for researchers and administrative agencies to initiate relevant studies and develop new policies to protect further deterioration of water supply with pathogenic microbes and ensure clean and safe drinking water to the public in Pakistan. In Pakistan, water at the source, in the distribution network, and at the consumer tap is heavily polluted with coliforms and fecal coliforms all over the country. An overview of more than 7,000 water samples reviewed here reveals that an average of over 71 and 58 % samples in the country was contaminated with total coliforms and fecal coliforms, respectively. Drinking water contamination accounts for 20 to 40 % of all diseases in the country, which causes national income losses of Rs 25-58 billion annually (US$0.25-0.58 billion, approximately 0.6-1.44 % of the country’s GDP). Improper disposal of industrial and municipal wastes is the most important factor responsible for water pollution in the country followed by cross-contamination due to old and leaking pipes and lack of water filtration and disinfection facilities. There is an urgent need for emergency steps to stop further deterioration of water quality and improve the existing water quality so as to protect the public from widespread waterborne diseases.
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Seman M, Gaálová B, Cíchová M, Prokšová M, Haviarová D, Fľaková R. The occurrence of coliform bacteria in the cave waters of Slovak Karst, Slovakia. Folia microbiologica 2014 Nov 23.
The diversity and abundance of coliform bacteria (taxonomically enterobacterias), an important quality water indicator, were determined for four representative caves in Slovak Karst: Domica Cave, Gombasecká Cave, Milada Cave and Krásnohorská Cave. Three hundred and fifty-two enterobacterial isolates were successfully identified by biochemical testing (commercial ENTEROtest 24) and selected isolates confirmed by molecular techniques (PCR, 16S rDNA sequence analysis). A total of 39 enterobacterial species were isolated from cave waters, with predominance of Escherichia coli, Serratia spp. and Enterobacter spp. PCR amplification of lacZ gene is not specific enough to provide a reliable detection of coliform bacteria isolated from the environment. Sequence analysis of 16S rDNA confirmed that all of the selected isolates belong to the family Enterobacteriaceae. In general, physical and chemical parameters of cave waters in Slovak Karst corresponded to national drinking water quality standards.