Coliforms and other microbial indicators occurrence in water and biofilm in full-scale distribution systems

2006 ◽  
Vol 54 (3) ◽  
pp. 41-48 ◽  
Author(s):  
M. Batté ◽  
C. Féliers ◽  
P. Servais ◽  
V. Gauthier ◽  
J.-C. Joret ◽  
...  

Biofilm and microbial water quality were studied in four middle size full-scale distribution systems (DS) in France serving 5,000–30,000 inhabitants (maximum residence time 23–160 h) through three sampling campaigns over 1 year. Three of these DSs were chosen because of a quite high occurrence of bacterial indicators (i.e. total coliforms), the last DS was considered as a reference. Biofilm was studied on cast iron coupons incubated for more than 1 month in devices continuously fed with water from the DS in conditions imitating those met in DS. The devices were located at different points (4–6) along each DS. The abundance of bacteria in biofilm was estimated by heterotrophic plate counts (HPC) after detachment of the biofilm from the support by sonication. Microbiological water quality was estimated in parallel; analysis of total coliforms, E. coli, enterococci and anaerobic sulphide-reducing bacteria spores (ASRB spores) was carried out in biofilm and water. Over the period of the study, 171 water samples and 57 biofilm samples were collected. Over these 171 waters, 19 (11%) were positive for at least one of the measured indicators while two biofilm samples were positive (3.5%). Significant differences were observed in the levels of contamination between the DSs. High residence time in the DS, low disinfectant residual and high temperature increased the risk of indicator occurrence in the water phase. Due to the low number of biofilm samples positive for bacterial indicators, the data collected in the present study did not allow observation of a direct association between biofilm and water contaminations, even if the occurrence of indicators in water appeared on DSs with the highest density of biofilm (HPC).

1995 ◽  
Vol 31 (5-6) ◽  
pp. 19-26 ◽  
Author(s):  
G. J. Medema ◽  
I. A. van Asperen ◽  
J. M. Klokman-Houweling ◽  
A. Nooitgedagt ◽  
M. J. W. van de Laar ◽  
...  

This pilot study was carried out to determine the relationship between microbiological water quality parameters and the occurrence of health complaints among triathletes. Data were collected at an Olympic distance triathlon (n=314) and a run-bike-run (n=81; controls for exposure to fresh water). At the time of the triathlon, the concentrations of Escherichia coli , thermotolerant coliforms, faecal streptococci, entero- and reoviruses, F-specific RNA phages, Salmonella, Campylobacter, Aeromonas, Plesiomonas shigelloides, Pseudomonas aeruginosa and Staphylococcus aureus were examined over the swimming course. Information on the occurrence of health complaints during the competition and in the week thereafter was collected through a written questionnaire. The results show that triathletes and run-bike-runners are comparable with respect to factors other than water exposure (age, sex, training history, physical stress, lower intestinal health complaints during the competition) that may influence the occurrence of health complaints in the week after the competition. Triathletes and run-bike-runners reported gastro-intestinal (7.7% vs 2.5%), respiratory (5.5% vs 3.7%), skin/mucosal (2.6% vs 1.2%), general (3.5% vs 1.2%) and total symptoms (14.8% vs 7.4%) in the week after the event. The health risks for triathletes for all symptom groups are not significantly higher than for run-bike-runners. The geometric mean concentration of faecal indicator bacteria is relatively low: E. coli 170/100 ml; faecal streptococci 13/100 ml, enteroviruses were present at concentrations of 0.1/l. The group of triathletes was homogeneusly and relatively intensely exposed to water; they all swam in the same body of water at the same time and 75% reported to have swallowed freshwater. It was concluded that this study design is suitable to study the relationship between health complaints and microbiological water quality. In the summers of 1993 and 1994, a study will be carried out concerning several run-bike-runs and triathlons in freshwaters of different quality.


Foods ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 206 ◽  
Author(s):  
Juliane Dao ◽  
Kathrin Stenchly ◽  
Oumar Traoré ◽  
Philip Amoah ◽  
Andreas Buerkert

Vegetable production in urban gardens of Ouagadougou contributes to food security, but water for irrigation is often of low quality. This is particularly acute if irrigation water is taken from wastewater polluted channels. This study aimed at (i) verifying to what degree irrigation water quality is correlated with contamination of lettuce with Escherichia coli, total coliforms, and Salmonella spp., and (ii) assessing effects of post-harvest handling on pathogen development during the trade chain. We tested pathogen removal efficiency on lettuce by applying post-harvest washing. Irrigation water of production areas in Ouagadougou (n = 10) showed a mean E. coli load of 2.1 × 105 CFU 100 mL−1. In 60% of the cases, irrigation water did not meet the standards of the World Health Organization (WHO) for safe irrigation water, and in 30% of the cases, irrigation water was contaminated with Salmonella spp. Loads of total coliforms on lettuce leaves ranged from 2.9 × 103 CFU g−1 to 1.3 × 106 CFU g−1, while E. coli averaged 1.1 × 102 CFU g−1. Results on post-harvest handling revealed that microbial loads increased along the trade chain. Overall, half of all lettuce samples (n = 60) were tested positively for Salmonella spp. The experiment showed that appropriate post-harvest handling could prevent the increase of total coliforms.


1986 ◽  
Vol 49 (12) ◽  
pp. 944-951 ◽  
Author(s):  
J. E. KENNEDY ◽  
C. I. WEI ◽  
J. L. OBLINGER

The distribution of coliphages in various foods and the relationship between the incidences of coliphages and bacterial indicators were investigated. A total of 120 food samples comprising twelve products and including fresh meats, shellfish, vegetables and processed meats, were analyzed for indigenous coliphages using Escherichia coli hosts C, C-3000 and B. Bacterial analyses included enumeration of E. coli, fecal coliforms and coliforms, as well as aerobic plate counts and Salmonella analyses. Coliphages were detected (≥10 PFU/100 g) in 56% of samples and eleven of twelve products. Coliphages, E. coli, fecal coliforms and coliforms were recovered at a level of at least 30 organisms per 100 g in 43, 43, 68 and 81% of samples, with overall mean recoveries of 13, 19, 93 and 4300 organisms/100 g, respectively. Highest and lowest recoveries of coliphages and E. coli were from fresh meats and vacuum-packaged processed meats, respectively. Significant nonparametric correlations between coliphages, E. coli, fecal coliforms and coliforms were found among all food samples.


2020 ◽  
Vol 8 (7) ◽  
pp. 1075 ◽  
Author(s):  
Domenico Cicciarella Modica ◽  
Massimo Maurici ◽  
Gian Loreto D’Alò ◽  
Cinzia Mozzetti ◽  
Alessandra Messina ◽  
...  

Mobile phones (MPs) are commonly used both in the personal and professional life. We assessed microbiological contamination of MPs from 108 students in healthcare professions (HPs), in relation to their demographic characteristics and MPs handling habits, collected by means of a questionnaire. Cultural and biochemical tests were performed, and statistical analyses were carried out. Staphylococci were present in 85% of MPs, Enterococci in 37%, Coliforms in 6.5%; E. coli was never detected. Staphylococcus epidermidis was the most frequently isolated staphylococcal species (72% of MPs), followed by S. capitis (14%), S. saprophyticus, S. warneri, S. xylosus (6%), and by S. aureus (4%). Heterotrophic Plate Counts (HPC) at 37 °C, ranged from 0 to 1.2 × 104 CFU/dm2 (mean = 362 CFU/dm2). In univariate analysis, the male gender only was significantly associated with higher HPCs and enterococcal contamination. Multiple linear regression models explained only 17% and 16% of the HPC 37 °C and staphylococcal load variability, respectively. Developing specific guidelines for a hygienic use of MPs in clinical settings, for preventing cross-infection risks, is advisable, as well as introducing specific training programs to HP students. MPs decontamination procedures could also be implemented in the community.


2011 ◽  
Vol 9 (4) ◽  
pp. 708-717 ◽  
Author(s):  
Andrew S. Ferguson ◽  
Brian J. Mailloux ◽  
Kazi M. Ahmed ◽  
Alexander van Geen ◽  
Larry D. McKay ◽  
...  

The retention and release of total coliforms and Escherichia coli was investigated in hand-pumps removed from tubewells tapping a faecally contaminated aquifer in Matlab, Bangladesh, and from a new hand-pump deliberately spiked with E. coli. All hand-pumps were connected to reservoirs of sterile water and flushed. Faecal coliforms were observed in the discharge from all three of the previously used hand-pumps, at concentrations comparable to levels measured in discharge when they were attached to the tubewells. During daily flushing of one of the previously used hand-pumps, the concentration of total coliforms in the discharge remained relatively constant (≈103 MPN/100 mL). Concentrations of E. coli in the pump discharge declined over time, but E. coli was still detectable up to 29 days after the start of flushing. In the deliberately spiked hand-pump, E. coli was observed in the discharge over 125 days (t50 = 8 days) and found to attach preferentially to elastomeric materials within the hand-pump. Attempts to disinfect both the village and new hand-pumps using shock chlorination were shown to be unsuccessful. These results demonstrate that hand-pumps can act as persistent reservoirs for microbial indicator bacteria. This could potentially influence drinking water quality and bias testing of water quality.


Engineering ◽  
2013 ◽  
Vol 05 (04) ◽  
pp. 449-457 ◽  
Author(s):  
Hossein Shamsaei ◽  
Othman Jaafar ◽  
Noor Ezlin Ahmad Basri

2006 ◽  
Vol 69 (7) ◽  
pp. 1514-1517 ◽  
Author(s):  
JAMES E. KENNEDY ◽  
SALLY K. WILLIAMS ◽  
TED BROWN ◽  
PHIL MINERICH

The objective of this study was to determine the prevalence of Escherichia coli O157:H7, other E. coli strains, total coliforms, and aerobic organisms on the surface of subprimal beef cuts prior to enhancement. Subprimal cuts were sampled during winter (January and February 2004) and summer (August through October 2004). During each collection period, six representative subprimal cuts (chuck tenders, 0.64-cm trimmed strips, bottom round flat, rough-trimmed brisket, cap-on top rounds, and cap-off insides) were sampled. A total of 600 samples in winter (100 samples per cut) and 599 samples in summer (100 chuck tenders, 100 0.64-cm trimmed strips, 100 bottom round flats, 100 cap-off insides, 97 rough-trimmed briskets, and 102 cap-on top rounds) were collected from five plants in the Midwest, southern Midwest, northern Midwest, and Southeast and swabbed using the sponge swab method. All sponges were analyzed for E. coli O157:H7. In addition, 400 subprimal cuts from four plants were analyzed for aerobic plate counts, total coliforms, and other E. coli strains during each collection period. E. coli O157:H7 was not detected on any of the 1,199 subprimal samples; thus, incidence of E. coli O157:H7 was <0.083%. Seasonal differences between aerobic plate counts and total coliform counts for each of the same cuts were 1.0 log CFU per cut or less. E. coli strains were not detected in 82, 52, 69, and 82% of the chuck tenders, 0.64-cm trimmed strips, bottom round flats, and cap-off insides, respectively.


2017 ◽  
Vol 6 (2) ◽  
pp. 411 ◽  
Author(s):  
Kirsten Ngaire Nicholson ◽  
Klaus Neumann ◽  
Carolyn Dowling ◽  
Subodh Sharma

During the 2016 pre-monsoon dry season, we undertook a systematic study of water quality, specifically fecal contamination of drinking water, in the Khumbu Valley, Sagarmatha National Park (SNP, Mt. Everest region) and SNP buffer zone, Nepal. Our goal was to quantify physical parameters (temperature, pH, conductivity and total dissolved solids), and the presence of fecal coliforms (E. coli and total coliforms) in drinking water and drinking water sources (predominately groundwater-fed springs). This data set will function as a baseline for access to potable water and further monitoring. Sample sites were selected based on primary use as a drinking water and/or drinking water source for each community. In general, there is little correlation between and physical parameters however, there are very weak correlations between total coliform data and increasing temperature, and decreasing elevation and pH. There does, however, appear to be a correlation between population (including tourist numbers) and both E. coli and total coliforms. Our study clearly indicates that the presence of bacterial indicators of fecal pollution during the dry season. Samples from the more populated, lower altitude areas had higher levels of E. coli and coliform bacteria. Importantly, drinking water that was stored in tanks or transported long distances had a much higher incidence of E. coli and total coliforms suggesting that a change in water handling practices might have an important impact on drinking water quality and population health. 


2007 ◽  
Vol 5 (3) ◽  
pp. 417-426 ◽  
Author(s):  
Jesús M. Ibarluzea ◽  
Belén Moreno ◽  
Elena Serrano ◽  
Karmele Larburu ◽  
María J. Maiztegi ◽  
...  

Monitoring the quality of the bathing waters of Gipuzkoa (the Basque Country, Spain) makes it possible to assess the suitability of its 15 beaches for bathing throughout each season. In 1998, the parameters E. coli, somatic coliphages (SOMCPH) and F-specific RNA bacteriophages (FRNAPH) were incorporated into the bathing water quality monitoring system. This enabled the study of the link between bacterial and viral indicators as well as the analysis of the ratios between both types of indicators in waters with different levels of pollution. Although bacterial indicators (total coliforms (TC) and faecal coliforms (FC)) and enterococci showed a strong correlation between them, the correlations between the viral indicators and between the viral and bacterial indicators were weaker, though significant in all cases. The ratio between SOMCPH and E. coli indicates that at low levels of bacterial pollution (E coli <100 MPN/100 ml) SOMCPH outnumber E coli. In contrast, at higher levels of pollution (E coli >100 MPN/100 ml), SOMCPH numbers are lower than those of E-coli. The data reveal the presence of viral indicators in waters classified as suitable for bathing by the European Directive and alert us to their suitability.


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