1
|
Yi J, Huang K, Nitin N. Modeling bioaffinity-based targeted delivery of antimicrobials to Escherichia coli biofilms using yeast microparticles. Part II: Parameter evaluation and validation. Biotechnol Bioeng 2021; 119:247-256. [PMID: 34693998 DOI: 10.1002/bit.27969] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 10/08/2021] [Accepted: 10/21/2021] [Indexed: 12/19/2022]
Abstract
The design of bioaffinity-based targeted delivery systems for biofilm inactivation may require a comprehensive understanding of physicochemical and biochemical properties of biobased antimicrobial particles and their interactions with biofilm. In this study, Escherichia coli biofilm inactivation by chlorine-charged yeast microparticles was numerically simulated, and the roles of chemical stability, binding affinity, and controlled release of this targeted delivery system were assessed using this numerical simulation. The simulation results were experimentally validated using two different types of yeast microparticles. The results of this study illustrate that chorine stability achieved by yeast microparticles was a key factor for improved biofilm inactivation in an organic-rich environment (>6 additional log reduction in 20 min compared to the free chlorine treatment). Moreover, the binding affinity of yeast microparticles to E. coli biofilms was another key factor for an enhanced inactivation of biofilm, as a 10-fold increase in binding rate resulted in a 4.2-fold faster inactivation. Overall, the mechanistic modeling framework developed in this study could guide the design and development of biobased particles for targeted inactivation of biofilms.
Collapse
Affiliation(s)
- Jiyoon Yi
- Department of Food Science and Technology, University of California-Davis, Davis, California, USA
| | - Kang Huang
- School of Chemical Sciences, The University of Auckland, Auckland, New Zealand
| | - Nitin Nitin
- Department of Food Science and Technology, University of California-Davis, Davis, California, USA.,Department of Biological and Agricultural Engineering, University of California-Davis, Davis, California, USA
| |
Collapse
|
2
|
Chen GQ, Wu YH, Wang YH, Chen Z, Tong X, Bai Y, Luo LW, Xu C, Hu HY. Effects of microbial inactivation approaches on quantity and properties of extracellular polymeric substances in the process of wastewater treatment and reclamation: A review. JOURNAL OF HAZARDOUS MATERIALS 2021; 413:125283. [PMID: 33582467 DOI: 10.1016/j.jhazmat.2021.125283] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 01/25/2021] [Accepted: 01/29/2021] [Indexed: 06/12/2023]
Abstract
Microbial extracellular polymeric substances (EPS) have a profound role in various wastewater treatment and reclamation processes, in which a variety of technologies are used for disinfection and microbial growth inhibition. These treatment processes can induce significant changes in the quantity and properties of EPS, and altered EPS could further adversely affect the wastewater treatment and reclamation system, including membrane filtration, disinfection, and water distribution. To clarify the effects of microbial inactivation approaches on EPS, these effects were classified into four categories: (1) chemical reactions, (2) cell lysis, (3) changing EPS-producing metabolic processes, and (4) altering microbial community. Across these different effects, treatments with free chlorine, methylisothiazolone, TiO2, and UV irradiation typically enhance EPS production. Among the residual microorganisms in EPS matrices after various microbial inactivation treatments, one of the most prominent is Mycobacterium. With respect to EPS properties, proteins and humic acids in EPS are usually more susceptible to treatment processes than polysaccharides. The affected EPS properties include changes in molecular weight, hydrophobicity, and adhesion ability. All of these changes can undermine wastewater treatment and reclamation processes. Therefore, effects on EPS quantity and properties should be considered during the application of microbial inactivation and growth inhibition techniques.
Collapse
Affiliation(s)
- Gen-Qiang Chen
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, PR China
| | - Yin-Hu Wu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, PR China.
| | - Yun-Hong Wang
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, PR China
| | - Zhuo Chen
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, PR China
| | - Xing Tong
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, PR China
| | - Yuan Bai
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, PR China
| | - Li-Wei Luo
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, PR China
| | - Chuang Xu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, PR China
| | - Hong-Ying Hu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, PR China; Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, PR China
| |
Collapse
|
3
|
Szabo J, Rodgers M, Mistry J, Steenbock J, Hall J. The effectiveness of disinfection and flushing procedures to prevent coliform persistence in aircraft water systems. WATER SCIENCE & TECHNOLOGY, WATER SUPPLY 2019; 19:1339-1346. [PMID: 31031576 PMCID: PMC6483101 DOI: 10.2166/ws.2018.195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A full-scale reproduction of an aircraft drinking water system was conditioned using municipal tap water with a mixture of free chlorine and chloramines, and subsequently contaminated with coliforms. Disinfection was undertaken using chlorine dioxide, ozone and a mixed oxidant solution followed by flushing until no disinfectant residual remained. Results showed that coliforms were not persistent on the aircraft plumbing surfaces, and coliforms were not detected after disinfection and flushing with any disinfectant. The one exception was the aerator installed in the lavatory faucet, which was coliform positive after disinfection with ozone and mixed oxidants. These data suggest that the faucet aerators could be a source of coliform contamination that may result in coliform positive samples. Further experiments conducted on disinfection of aerators with glycolic acid and quaternary ammonia (both commonly used by the airlines) showed no detectable coliforms on coliform contaminated aerators after 30 minutes of soaking in the disinfectants.
Collapse
Affiliation(s)
- Jeffrey Szabo
- US Environmental Protection Agency, National Homeland Security Research Center, 26 W. Martin Luther King Dr. (MS NG-16), Cincinnati, OH 45268, USA
| | - Mark Rodgers
- US Environmental Protection Agency, National Risk Management Research Laboratory, 26 W. Martin Luther King Dr. (MS NG-16), Cincinnati, OH 45268, USA
| | - Jatin Mistry
- US Environmental Protection Agency, Region 6, 1445 Ross Avenue, Dallas, Texas 75202, USA
| | - Joshua Steenbock
- Wheeling Jesuit University-US Environmental Protection Agency, 316 Washington Avenue, Wheeling, WV 26003, USA
| | - John Hall
- US Environmental Protection Agency, National Homeland Security Research Center, 26 W. Martin Luther King Dr. (MS NG-16), Cincinnati, OH 45268, USA
| |
Collapse
|
4
|
Bio-enzymes for inhibition and elimination of Escherichia coli O157:H7 biofilm and their synergistic effect with sodium hypochlorite. Sci Rep 2019; 9:9920. [PMID: 31289312 PMCID: PMC6616338 DOI: 10.1038/s41598-019-46363-w] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 06/21/2019] [Indexed: 12/17/2022] Open
Abstract
Escherichia coli O157:H7 is one of the most important pathogens worldwide. In this study, three different kinds of enzymes, DNase I, proteinase K and cellulase were evaluated for inhibitory or degrading activity against E. coli O157:H7 biofilm by targeting extracellular DNA, proteins, and cellulose, respectively. The cell number of biofilms formed under proteinase K resulted in a 2.43 log CFU/cm2 reduction with an additional synergistic 3.72 log CFU/cm2 reduction after NaClO post-treatment, while no significant reduction occurred with NaClO treatment alone. It suggests that protein degradation could be a good way to control the biofilm effectively. In preformed biofilms, all enzymes showed a significant reduction of 16.4–36.7% in biofilm matrix in 10-fold diluted media (p < 0.05). The sequential treatment with proteinase K, cellulase, and NaClO showed a significantly higher synergistic inactivation of 2.83 log CFU/cm2 compared to 1.58 log CFU/cm2 in the sequence of cellulase, proteinase K, and NaClO (p < 0.05). It suggests that the sequence of multiple enzymes can make a significant difference in the susceptibility of biofilms to NaClO. This study indicates that the combination of extracellular polymeric substance-degrading enzymes with NaClO could be useful for the efficient control of E. coli O157:H7 biofilms.
Collapse
|
5
|
Perrin Y, Bouchon D, Héchard Y, Moulin L. Spatio-temporal survey of opportunistic premise plumbing pathogens in the Paris drinking water distribution system. Int J Hyg Environ Health 2019; 222:687-694. [PMID: 31085113 DOI: 10.1016/j.ijheh.2019.04.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 04/07/2019] [Accepted: 04/19/2019] [Indexed: 11/26/2022]
Abstract
Opportunistic premise plumbing pathogens present in drinking water are linked to a significant number of infections for health compromised patients. However, their monitoring is not required in current water potability standards and they have been poorly studied in a full-scale network. In this study, we quantified, by qPCR, three opportunistic pathogens, Mycobacterium spp., Legionella pneumophila, Pseudomonas aeruginosa throughout the Paris drinking water network over a one-year sampling campaign. While Mycobacteria spp. seemed ubiquitous whatever the distribution system and the time of the year, the occurrence of L. pneumophila and P. aeruginosa showed seasonal variations. Unlike L. pneumophila and P. aeruginosa, the concentration (copies number/L) of Mycobacterium spp. varied between sampling sites. The variation in microbial numbers did not demonstrate any correlations with temperature, pH, chlorine, conductivity, orthophosphate or nitrate levels. In conclusion, Mycobacterium spp. are common inhabitants of the Paris network while L. pneumophila and P. aeruginosa presence fluctuate over space and time. Such qPCR approach would help to better understand the behaviour of opportunistic premise plumbing pathogens.
Collapse
Affiliation(s)
- Yoann Perrin
- Laboratoire Ecologie et Biologie des Interactions, Equipes « Microbiologie de l'Eau » et « Ecologie, Evolution, Symbiose », Université de Poitiers, UMR CNRS 7267, F8 86073, Poitiers, France; Eau de Paris, Direction de la Recherche et du Développement pour la Qualité de l'Eau, R&D Biologie, 33, Avenue Jean Jaurès, F-94200, Ivry sur Seine, France
| | - Didier Bouchon
- Laboratoire Ecologie et Biologie des Interactions, Equipes « Microbiologie de l'Eau » et « Ecologie, Evolution, Symbiose », Université de Poitiers, UMR CNRS 7267, F8 86073, Poitiers, France
| | - Yann Héchard
- Laboratoire Ecologie et Biologie des Interactions, Equipes « Microbiologie de l'Eau » et « Ecologie, Evolution, Symbiose », Université de Poitiers, UMR CNRS 7267, F8 86073, Poitiers, France.
| | - Laurent Moulin
- Eau de Paris, Direction de la Recherche et du Développement pour la Qualité de l'Eau, R&D Biologie, 33, Avenue Jean Jaurès, F-94200, Ivry sur Seine, France.
| |
Collapse
|
6
|
Microbiological and Cellular Evaluation of a Fluorine-Phosphorus-Doped Titanium Alloy, a Novel Antibacterial and Osteostimulatory Biomaterial with Potential Applications in Orthopedic Surgery. Appl Environ Microbiol 2019; 85:AEM.02271-18. [PMID: 30367003 DOI: 10.1128/aem.02271-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 10/09/2018] [Indexed: 02/08/2023] Open
Abstract
Joint prosthesis failure is mainly related to aseptic loosening and prosthetic joint infections, both of which are associated with high morbidity and substantial costs for patients and health systems. The development of a biomaterial that is capable of stimulating bone growth while minimizing bacterial adhesion would reduce the incidence of prosthetic failure. We report antibacterial and osteostimulatory effects in a novel fluorine-phosphorus (F-P)-doped TiO2 oxide film grown on Ti-6Al-4V alloy with a nanostructure of bottle-shaped nanotubes (bNT) using five bacterial species (Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia) and MCT3T3-E1 osteoblastic cells. The interaction between the bacteria and bNT Ti-6Al-4V was complex, as the adhesion of four bacterial species decreased (two staphylococcus species, E. coli, and S. maltophilia), and the viability of staphylococci and S. maltophilia also decreased because of the aluminum (Al) released by bNT Ti-6Al-4V. This released Al can be recruited by the bacteria through siderophores and was retained only by the Gram-negative bacteria tested. P. aeruginosa showed higher adhesion on bNT Ti-6Al-4V than on chemically polished (CP) samples of Ti-6Al-4V alloy and an ability to mobilize Al from bNT Ti-6Al-4V. The cell adhesion and proliferation of MCT3T3-E1 osteoblastic cells significantly increased at 48 and 168 h, as did the matrix mineralization of these cells and the gene expression levels of three of the most important markers related to bone differentiation. According to our results, the bNT Ti-6Al-4V alloy could have clinical application, preventing infection and stimulating bone growth and thus preventing the two main causes of joint prosthesis failure.IMPORTANCE This work evaluates F-P-doped bNT Ti-6Al-4V from microbiological and cellular approaches. The bacterial results highlight that the antibacterial ability of bNT Ti-6Al-4V is the result of a combination of antiadhesive and bactericidal effects exerted by Al released from the alloy. The cell results highlight that F-P bNT Ti-6Al-4V alloy increases osseointegration due to modification of the chemical composition of the alloy resulting from P incorporation and not due to the nanostructure, as reported previously. A key finding was the detection of Al release from inside the bNT Ti-6Al-4V nanostructures, a result of the nanostructure growth during the anodizing process that is in part responsible for its bactericidal effect.
Collapse
|
7
|
Fish KE, Boxall JB. Biofilm Microbiome (Re)Growth Dynamics in Drinking Water Distribution Systems Are Impacted by Chlorine Concentration. Front Microbiol 2018; 9:2519. [PMID: 30459730 PMCID: PMC6232884 DOI: 10.3389/fmicb.2018.02519] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 10/03/2018] [Indexed: 12/21/2022] Open
Abstract
Biofilms are the dominant form of microbial loading (and organic material) within drinking water distribution systems (DWDS), yet our understanding of DWDS microbiomes is focused on the more easily accessible bulk-water. Disinfectant residuals are commonly provided to manage planktonic microbial activity in DWDS to safeguard water quality and public health, yet the impacts on the biofilm microbiome are largely unknown. We report results from a full-scale DWDS facility used to develop biofilms naturally, under one of three chlorine concentrations: Low, Medium, or High. Increasing the chlorine concentration reduced the bacterial concentration within the biofilms but quantities of fungi were unaffected. The chlorine regime was influential in shaping the community structure and composition of both taxa. There were microbial members common to all biofilms but the abundance of these varied such that at the end of the Growth phase the communities from each regime were distinct. Alpha-, Beta-, and Gamma-proteobacteria were the most abundant bacterial classes; Sordariomycetes, Leotiomycetes, and Microbotryomycetes were the most abundant classes of fungi. Mechanical cleaning was shown to immediately reduce the bacterial and fungal concentrations, followed by a lag effect on the microbiome with continued decreases in quantity and ecological indices after cleaning. However, an established community remained, which recovered such that the microbial compositions at the end of the Re-growth and initial Growth phases were similar. Interestingly, the High-chlorine biofilms showed a significant elevation in bacterial concentrations at the end of the Re-growth (after cleaning) compared the initial Growth, unlike the other regimes. This suggests adaptation to a form a resilient biofilm with potentially equal or greater risks to water quality as the other regimes. Overall, this study provides critical insights into the interaction between chlorine and the microbiome of DWDS biofilms representative of real networks, implications are made for the operation and maintenance of DWDS disinfectant and cleaning strategies.
Collapse
Affiliation(s)
- Katherine E Fish
- Pennine Water Group, Department of Civil and Structural Engineering, The University of Sheffield, Sheffield, United Kingdom.,NERC Biomolecular Analysis Facility, Department of Animal and Plant Sciences, The University of Sheffield, Sheffield, United Kingdom
| | - Joby B Boxall
- Pennine Water Group, Department of Civil and Structural Engineering, The University of Sheffield, Sheffield, United Kingdom
| |
Collapse
|
8
|
Elfadaly HA, Hassanain NA, Hassanain MA, Barakat AM, Shaapan RM. Evaluation of primitive ground water supplies as a risk factor for the development of major waterborne zoonosis in Egyptian children living in rural areas. J Infect Public Health 2018; 11:203-208. [DOI: 10.1016/j.jiph.2017.07.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 04/30/2017] [Accepted: 07/09/2017] [Indexed: 11/24/2022] Open
|
9
|
O'Flaherty E, Borrego CM, Balcázar JL, Cummins E. Human exposure assessment to antibiotic-resistant Escherichia coli through drinking water. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 616-617:1356-1364. [PMID: 29126642 DOI: 10.1016/j.scitotenv.2017.10.180] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 10/17/2017] [Accepted: 10/17/2017] [Indexed: 06/07/2023]
Abstract
Antibiotic-resistant bacteria (ARB) are a potential threat to human health through drinking water with strong evidence of ARB presence in post treated tap water around the world. This study examines potential human exposure to antibiotic-resistant (AR) Escherichia coli (E. coli) through drinking water, the effect of different drinking water treatments on AR E. coli and the concentration of AR E. coli required in the source water for the EU Drinking Water Directive (DWD) (Council Directive 98/83/EC, 0CFU/100ml of E. coli in drinking water) to be exceeded. A number of scenarios were evaluated to examine different water treatment combinations and to reflect site specific conditions at a study site in Europe. A literature search was carried out to collate data on the effect of environmental conditions on AR E. coli, the effect of different water treatments on AR E. coli and typical human consumption levels of tap water. A human exposure assessment model was developed with probability distributions used to characterise uncertainty and variability in the input data. Overall results show the mean adult human exposure to AR E. coli from tap water consumption ranged between 3.44×10-7 and 2.95×10-1cfu/day for the scenarios tested and varied depending on the water treatments used. The level of AR E. coli required in the source water pre-treatment to exceed the DWD varied between 1 and 5logcfu/ml, depending on the water treatments used. This can be used to set possible monitoring criteria in pre-treated water for potential ARB exposure in drinking water.
Collapse
Affiliation(s)
- E O'Flaherty
- University College Dublin, School of Biosystems and Food Engineering, Belfield, Dublin 4, Ireland.
| | - C M Borrego
- Catalan Institute for Water Research (ICRA), Scientific and Technological Park of the University of Girona, Girona, Spain; Group of Molecular Microbial Ecology, Institute of Aquatic Ecology, University of Girona, Girona, Spain
| | - J L Balcázar
- Catalan Institute for Water Research (ICRA), Scientific and Technological Park of the University of Girona, Girona, Spain
| | - E Cummins
- University College Dublin, School of Biosystems and Food Engineering, Belfield, Dublin 4, Ireland
| |
Collapse
|
10
|
Knowledge to Predict Pathogens: Legionella pneumophila Lifecycle Critical Review Part I Uptake into Host Cells. WATER 2018. [DOI: 10.3390/w10020132] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
11
|
Li J, Liu L, Yang D, Liu WL, Shen ZQ, Qu HM, Qiu ZG, Hou AM, Wang DN, Ding CS, Li JW, Guo JH, Jin M. Culture-dependent enumeration methods failed to simultaneously detect disinfectant-injured and genetically modified Escherichia coli in drinking water. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2017; 19:720-726. [PMID: 28406501 DOI: 10.1039/c6em00625f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Underestimation of Escherichia coli in drinking water, an indicator microorganism of sanitary risk, may result in potential risks of waterborne diseases. However, the detection of disinfectant-injured or genetically modified (GM) E. coli has been largely overlooked so far. To evaluate the accuracy of culture-dependent enumeration with regard to disinfectant-injured and GM E. coli, chlorine- or ozone-injured wild-type (WT) and GM E. coli were prepared and characterized. Then, water samples contaminated with these E. coli strains were assayed by four widely used methods, including lactose tryptose broth-based multiple-tube fermentation (MTF), m-endo-based membrane filtration method (MFM), an enzyme substrate test (EST) known as Colilert, and Petrifilm-based testing slip method (TSM). It was found that MTF was the most effective method to detect disinfectant-injured WT E. coli (with 76.9% trials detecting all these bacteria), while this method could not effectively detect GM E. coli (with uninjured bacteria undetectable and a maximal detection rate of 21.5% for the injured). The EST was the only method which enabled considerable enumeration of uninjured GM E. coli, with a detection rate of over 93%. However, the detection rate declined to lower than 45.4% once the GM E. coli was injured by disinfectants. The MFM was invalid for both disinfectant-injured and GM E. coli. This is the first study to report the failure of these commonly used enumeration methods to simultaneously detect disinfectant-injured and GM E. coli. Thus, it highlights the urgent requirement for the development of a more accurate and versatile enumeration method which allows the detection of disinfectant-injured and GM E. coli on the assessment of microbial quality of drinking water.
Collapse
Affiliation(s)
- Jing Li
- Department of Environment and Health, Tianjin Institute of Health and Environmental Medicine, Key Laboratory of Risk Assessment and Control for Environment & Food Safety, Tianjin 300050, China.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Zhang J, Zhu C, Guan R, Xiong Z, Zhang W, Shi J, Sheng Y, Zhu B, Tu J, Ge Q, Chen T, Lu Z. Microbial profiles of a drinking water resource based on different 16S rRNA V regions during a heavy cyanobacterial bloom in Lake Taihu, China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:12796-12808. [PMID: 28364202 PMCID: PMC5418304 DOI: 10.1007/s11356-017-8693-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Accepted: 02/23/2017] [Indexed: 05/31/2023]
Abstract
Understanding of the bacterial community structure in drinking water resources helps to enhance the security of municipal water supplies. In this study, bacterial communities were surveyed in water and sediment during a heavy cyanobacterial bloom in a drinking water resource of Lake Taihu, China. A total of 325,317 high-quality sequences were obtained from different 16S ribosomal RNA (rRNA) regions (V3, V4, and V6) using the Miseq sequencing platform. A notable difference was shown between the water and sediment samples, as predominated by Cyanobacteria, Proteobacteria, and Actinobacteria in the water and Proteobacteria, Chloroflexi, and Verrucomicrobia in the sediment, respectively. The LD12 family dominated the water surface and was tightly associated with related indicators of cyanobacterial propagation, indicating involvement in the massive proliferation of cyanobacterial blooms. Alternatively, the genus Nitrospira dominated the sediment samples, which indicates that nitrite oxidation was very active in the sediment. Although pathogenic bacteria were not detected in a large amount, some genera such as Mycobacterium, Acinetobacter, and Legionella were still identified but in very low abundance. In addition, the effects of different V regions on bacterial diversity survey were evaluated. Overall, V4 and V3 were proven to be more promising V regions for bacterial diversity survey in water and sediment samples during heavy water blooms in Lake Taihu, respectively. As longer, cheaper, and faster DNA sequencing technologies become more accessible, we expect that bacterial community structures based on 16S rRNA amplicons as an indicator could be used alongside with physical and chemical indicators, to conduct comprehensive assessments for drinking water resource management.
Collapse
Affiliation(s)
- Junyi Zhang
- State Key Lab for Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
- Wuxi Environmental Monitoring Centre, Wuxi, China
| | - Congming Zhu
- MOE Key Lab of Bioinformatics, Bioinformatics Division/Center for Synthetic and Systems Biology, TNLIST and Department of Automation, Tsinghua University, Beijing, China
| | - Rui Guan
- State Key Lab for Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Zhipeng Xiong
- Wuxi Metagene Science & Technology Co., Ltd, Lake Taihu Cyanobacterial Blooms Research Institute, Wuxi, China
| | - Wen Zhang
- China Environmental Protection Foundation, Beijing, China
| | - Junzhe Shi
- Wuxi Environmental Monitoring Centre, Wuxi, China
| | - Yi Sheng
- Wuxi Environmental Monitoring Centre, Wuxi, China
| | | | - Jing Tu
- State Key Lab for Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Qinyu Ge
- State Key Lab for Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Ting Chen
- MOE Key Lab of Bioinformatics, Bioinformatics Division/Center for Synthetic and Systems Biology, TNLIST and Department of Automation, Tsinghua University, Beijing, China
| | - Zuhong Lu
- State Key Lab for Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China.
| |
Collapse
|
13
|
Abberton CL, Bereschenko L, van der Wielen PWJJ, Smith CJ. Survival, Biofilm Formation, and Growth Potential of Environmental and Enteric Escherichia coli Strains in Drinking Water Microcosms. Appl Environ Microbiol 2016; 82:5320-31. [PMID: 27342552 PMCID: PMC4988207 DOI: 10.1128/aem.01569-16] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Accepted: 06/16/2016] [Indexed: 12/22/2022] Open
Abstract
UNLABELLED Escherichia coli is the most commonly used indicator for fecal contamination in drinking water distribution systems (WDS). The assumption is that E. coli bacteria are of enteric origin and cannot persist for long outside their host and therefore act as indicators of recent contamination events. This study investigates the fate of E. coli in drinking water, specifically addressing survival, biofilm formation under shear stress, and regrowth in a series of laboratory-controlled experiments. We show the extended persistence of three E. coli strains (two enteric isolates and one soil isolate) in sterile and nonsterile drinking water microcosms at 8 and 17°C, with T90 (time taken for a reduction in cell number of 1 log10 unit) values ranging from 17.4 ± 1.8 to 149 ± 67.7 days, using standard plate counts and a series of (reverse transcription-)quantitative PCR [(RT-)Q-PCR] assays targeting 16S rRNA, tuf, uidA, and rodA genes and transcripts. Furthermore, each strain was capable of attaching to a surface and replicating to form biofilm in the presence of nutrients under a range of shear stress values (0.6, 2.0, and 4.4 dynes [dyn] cm(-2); BioFlux system; Fluxion); however, cell numbers did not increase when drinking water flowed over the biofilm (P > 0.05 by t test). Finally, E. coli regrowth within drinking water microcosms containing polyethylene PE-100 pipe wall material was not observed in the biofilm or water phase using a combination of culturing and Q-PCR methods for E. coli The results of this work highlight that when E. coli enters drinking water it has the potential to survive and attach to surfaces but that regrowth within drinking water or biofilm is unlikely. IMPORTANCE The provision of clean, safe drinking water is fundamental to society. WDS deliver water to consumers via a vast network of pipes. E. coli is used as an indicator organism for recent contamination events based on the premise that it cannot survive for long outside its host. A key public health concern therefore arises around the fate of E. coli on entering a WDS; its survival, ability to form a biofilm, and potential for regrowth. In particular, if E. coli bacteria have the ability to incorporate and regrow within the pipe wall biofilm of a WDS, they could reinoculate the water at a later stage. This study sheds light on the fate of environmental and enteric strains of E. coli in drinking water showing extended survival, the potential for biofilm formation under shear stress, and importantly, that regrowth in the presence of an indigenous microbial community is unlikely.
Collapse
Affiliation(s)
- Cathy L Abberton
- Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | | | | | - Cindy J Smith
- Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
| |
Collapse
|
14
|
Botsaris G, Kanetis L, Slaný M, Parpouna C, Makris KC. Microbial quality and molecular identification of cultivable microorganisms isolated from an urban drinking water distribution system (Limassol, Cyprus). ENVIRONMENTAL MONITORING AND ASSESSMENT 2015; 187:739. [PMID: 26559553 DOI: 10.1007/s10661-015-4957-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 11/02/2015] [Indexed: 06/05/2023]
Abstract
Microorganisms can survive and multiply in aged urban drinking water distribution systems, leading to potential health risks. The objective of this work was to investigate the microbial quality of tap water and molecularly identify its predominant cultivable microorganisms. Tap water samples collected from 24 different households scattered in the urban area of Limassol, Cyprus, were microbiologically tested following standard protocols for coliforms, E. coli, Pseudomonas spp., Enterococcus spp., and total viable count at 22 and 37 °C. Molecular identification was performed on isolated predominant single colonies using 16SrRNA sequencing. Approximately 85% of the household water samples were contaminated with one or more microorganisms belonging to the genera of Pseudomonas, Corynebacterium, Agrobacterium, Staphylococcus, Bacillus, Delftia, Acinetobacter, Enterococcus, Enterobacter, and Aeromonas. However, all samples tested were free from E. coli. This is the first report in Cyprus molecularly confirming specific genera of relevant microbial communities in tap water.
Collapse
Affiliation(s)
- George Botsaris
- Department of Agricultural Sciences, Biotechnology and Food Science, Cyprus University of Technology, 3603, Limassol, Cyprus.
| | - Loukas Kanetis
- Department of Agricultural Sciences, Biotechnology and Food Science, Cyprus University of Technology, 3603, Limassol, Cyprus
| | - Michal Slaný
- Veterinary Research Institute, Hudcova 70, 621 00, Brno, Czech Republic
| | - Christiana Parpouna
- Department of Agricultural Sciences, Biotechnology and Food Science, Cyprus University of Technology, 3603, Limassol, Cyprus
| | - Konstantinos C Makris
- Water and Health Laboratory, Cyprus International Institute for Environmental and Public Health in association with the Harvard School of Public Health, Cyprus University of Technology, Limassol, Cyprus
| |
Collapse
|
15
|
AMANIDAZ N, ZAFARZADEH A, MAHVI AH. The Interaction between Heterotrophic Bacteria and Coliform, Fecal Coliform, Fecal Streptococci Bacteria in the Water Supply Networks. IRANIAN JOURNAL OF PUBLIC HEALTH 2015; 44:1685-92. [PMID: 26811820 PMCID: PMC4724742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/29/2022]
Abstract
BACKGROUND This study investigated the interaction between heterotrophic bacteria and coliform, fecal coliforms, fecal streptococci bacteria in water supply networks. METHODS This study was conducted during 2013 on water supply distribution network in Aq Qala City, Golestan Province, Northern Iran and standard methods were applied for microbiological analysis. The surface method was applied to test the heterotrophic bacteria and MPN method was used for coliform, fecal coliform and fecal streptococci bacteria measurements. RESULTS In 114 samples, heterotrophic bacteria count were over 500 CFU/ml, which the amount of fecal coliform, coliform, and fecal streptococci were 8, 32, and 20 CFU/100 ml, respectively. However, in the other 242 samples, with heterotrophic bacteria count being less than 500 CFU/ml, the amount of fecal coliform, coliform, and fecal streptococci was 7, 23, and 11 CFU/100ml, respectively. The relationship between heterotrophic bacteria, coliforms and fecal streptococci was highly significant (P<0.05). We observed the concentration of coliforms, fecal streptococci bacteria being high, whenever the concentration of heterotrophic bacteria in the water network systems was high. CONCLUSION Interaction between heterotrophic bacteria and coliform, fecal coliforms, fecal streptococci bacteria in the Aq Qala City water supply networks was not notable. It can be due to high concentrations of organic carbon, bio-films and nutrients, which are necessary for growth, and survival of all microorganisms.
Collapse
Affiliation(s)
- Nazak AMANIDAZ
- Dept. of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali ZAFARZADEH
- Research Center for Environmental Health, Department of Environmental Health Engineering, School of Public Health, Golestan University of Medical Sciences, Gorgan, Iran
| | - Amir Hossein MAHVI
- Dept. of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran,Center for Solid Waste Research, Institute for Environmental Research, Tehran University of Medical Sciences, Tehran, Iran,Corresponding Author:
| |
Collapse
|
16
|
Roi IY, Klimenko NA, Zdorovenko GM, Goncharuk VV. Phylogenetic diversity of aqueous microorganisms separated after the advanced tertiary of tap water. J WATER CHEM TECHNO+ 2014. [DOI: 10.3103/s1063455x14040067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
17
|
Culotti A, Packman AI. Pseudomonas aeruginosa promotes Escherichia coli biofilm formation in nutrient-limited medium. PLoS One 2014; 9:e107186. [PMID: 25198725 PMCID: PMC4157881 DOI: 10.1371/journal.pone.0107186] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 08/14/2014] [Indexed: 11/19/2022] Open
Abstract
Biofilms have been implicated as an important reservoir for pathogens and commensal enteric bacteria such as Escherichia coli in natural and engineered water systems. However, the processes that regulate the survival of E. coli in aquatic biofilms have not been thoroughly studied. We examined the effects of hydrodynamic shear and nutrient concentrations on E. coli colonization of pre-established Pseudomonas aeruginosa biofilms, co-inoculation of E. coli and P. aeruginosa biofilms, and P. aeruginosa colonization of pre-established E. coli biofilms. In nutritionally-limited R2A medium, E. coli dominated biofilms when co-inoculated with P. aeruginosa, and successfully colonized and overgrew pre-established P. aeruginosa biofilms. In more enriched media, P. aeruginosa formed larger clusters, but E. coli still extensively overgrew and colonized the interior of P. aeruginosa clusters. In mono-culture, E. coli formed sparse and discontinuous biofilms. After P. aeruginosa was introduced to these biofilms, E. coli growth increased substantially, resulting in patterns of biofilm colonization similar to those observed under other sequences of organism introduction, i.e., E. coli overgrew P. aeruginosa and colonized the interior of P. aeruginosa clusters. These results demonstrate that E. coli not only persists in aquatic biofilms under depleted nutritional conditions, but interactions with P. aeruginosa can greatly increase E. coli growth in biofilms under these experimental conditions.
Collapse
Affiliation(s)
- Alessandro Culotti
- Department of Civil and Environmental Engineering, McCormick School of Engineering, Northwestern University, Evanston, Illinois, United States of America
| | - Aaron I. Packman
- Department of Civil and Environmental Engineering, McCormick School of Engineering, Northwestern University, Evanston, Illinois, United States of America
- * E-mail:
| |
Collapse
|
18
|
Baron JL, Vikram A, Duda S, Stout JE, Bibby K. Shift in the microbial ecology of a hospital hot water system following the introduction of an on-site monochloramine disinfection system. PLoS One 2014; 9:e102679. [PMID: 25033448 PMCID: PMC4102543 DOI: 10.1371/journal.pone.0102679] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 06/22/2014] [Indexed: 01/14/2023] Open
Abstract
Drinking water distribution systems, including premise plumbing, contain a diverse microbiological community that may include opportunistic pathogens. On-site supplemental disinfection systems have been proposed as a control method for opportunistic pathogens in premise plumbing. The majority of on-site disinfection systems to date have been installed in hospitals due to the high concentration of opportunistic pathogen susceptible occupants. The installation of on-site supplemental disinfection systems in hospitals allows for evaluation of the impact of on-site disinfection systems on drinking water system microbial ecology prior to widespread application. This study evaluated the impact of supplemental monochloramine on the microbial ecology of a hospital's hot water system. Samples were taken three months and immediately prior to monochloramine treatment and monthly for the first six months of treatment, and all samples were subjected to high throughput Illumina 16S rRNA region sequencing. The microbial community composition of monochloramine treated samples was dramatically different than the baseline months. There was an immediate shift towards decreased relative abundance of Betaproteobacteria, and increased relative abundance of Firmicutes, Alphaproteobacteria, Gammaproteobacteria, Cyanobacteria and Actinobacteria. Following treatment, microbial populations grouped by sampling location rather than sampling time. Over the course of treatment the relative abundance of certain genera containing opportunistic pathogens and genera containing denitrifying bacteria increased. The results demonstrate the driving influence of supplemental disinfection on premise plumbing microbial ecology and suggest the value of further investigation into the overall effects of premise plumbing disinfection strategies on microbial ecology and not solely specific target microorganisms.
Collapse
Affiliation(s)
- Julianne L. Baron
- Department of Infectious Diseases and Microbiology, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, Pennsylvania, United States of America
- Special Pathogens Laboratory, Pittsburgh, Pennsylvania, United States of America
| | - Amit Vikram
- Department of Civil and Environmental Engineering, University of Pittsburgh, Swanson School of Engineering, Pittsburgh, Pennsylvania, United States of America
| | - Scott Duda
- Special Pathogens Laboratory, Pittsburgh, Pennsylvania, United States of America
| | - Janet E. Stout
- Special Pathogens Laboratory, Pittsburgh, Pennsylvania, United States of America
- Department of Civil and Environmental Engineering, University of Pittsburgh, Swanson School of Engineering, Pittsburgh, Pennsylvania, United States of America
| | - Kyle Bibby
- Department of Civil and Environmental Engineering, University of Pittsburgh, Swanson School of Engineering, Pittsburgh, Pennsylvania, United States of America
- Department of Computational and Systems Biology, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania, United States of America
| |
Collapse
|
19
|
Abdel-Nour M, Duncan C, Low DE, Guyard C. Biofilms: the stronghold of Legionella pneumophila. Int J Mol Sci 2013; 14:21660-75. [PMID: 24185913 PMCID: PMC3856027 DOI: 10.3390/ijms141121660] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 09/07/2013] [Accepted: 10/14/2013] [Indexed: 11/28/2022] Open
Abstract
Legionellosis is mostly caused by Legionella pneumophila and is defined as a severe respiratory illness with a case fatality rate ranging from 5% to 80%. L. pneumophila is ubiquitous in natural and anthropogenic water systems. L. pneumophila is transmitted by inhalation of contaminated aerosols produced by a variety of devices. While L. pneumophila replicates within environmental protozoa, colonization and persistence in its natural environment are also mediated by biofilm formation and colonization within multispecies microbial communities. There is now evidence that some legionellosis outbreaks are correlated with the presence of biofilms. Thus, preventing biofilm formation appears as one of the strategies to reduce water system contamination. However, we lack information about the chemical and biophysical conditions, as well as the molecular mechanisms that allow the production of biofilms by L. pneumophila. Here, we discuss the molecular basis of biofilm formation by L. pneumophila and the roles of other microbial species in L. pneumophila biofilm colonization. In addition, we discuss the protective roles of biofilms against current L. pneumophila sanitation strategies along with the initial data available on the regulation of L. pneumophila biofilm formation.
Collapse
Affiliation(s)
- Mena Abdel-Nour
- Ontario Agency for Health Protection and Promotion (OAHPP), Toronto, ON M9P 3T1, Canada; E-Mails: (M.A.-N.); (C.D.)
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 1A8, Canada
- Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Carla Duncan
- Ontario Agency for Health Protection and Promotion (OAHPP), Toronto, ON M9P 3T1, Canada; E-Mails: (M.A.-N.); (C.D.)
| | - Donald E. Low
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 1A8, Canada
- Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Cyril Guyard
- Ontario Agency for Health Protection and Promotion (OAHPP), Toronto, ON M9P 3T1, Canada; E-Mails: (M.A.-N.); (C.D.)
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 1A8, Canada
- Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-416-880-1339; Fax: +1-416-235-6281
| |
Collapse
|
20
|
Janjaroen D, Ling FQ, Monroy G, Derlon N, Morgenroth E, Boppart SA, Liu WT, Nguyen TH. Roles of ionic strength and biofilm roughness on adhesion kinetics of Escherichia coli onto groundwater biofilm grown on PVC surfaces. WATER RESEARCH 2013; 47:2531-42. [PMID: 23497979 PMCID: PMC3922059 DOI: 10.1016/j.watres.2013.02.032] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 02/11/2013] [Accepted: 02/12/2013] [Indexed: 05/22/2023]
Abstract
Mechanisms of Escherichia coli attachment on biofilms grown on PVC coupons were investigated. Biofilms were grown in CDC reactors using groundwater as feed solution over a period up to 27 weeks. Biofilm physical structure was characterized at the micro- and meso-scales using Scanning Electron Microscopy (SEM) and Optical Coherence Tomography (OCT), respectively. Microbial community diversity was analyzed with Terminal Restricted Fragment Length Polymorphism (T-RFLP). Both physical structure and microbial community diversity of the biofilms were shown to be changing from 2 weeks to 14 weeks, and became relatively stable after 16 weeks. A parallel plate flow chamber coupled with an inverted fluorescent microscope was also used to monitor the attachment of fluorescent microspheres and E. coli on clean PVC surfaces and biofilms grown on PVC surfaces for different ages. Two mechanisms of E. coli attachment were identified. The adhesion rate coefficients (kd) of E. coli on nascent PVC surfaces and 2-week biofilms increased with ionic strength. However, after biofilms grew for 8 weeks, the adhesion was found to be independent of solution chemistry. Instead, a positive correlation between kd and biofilm roughness as determined by OCT was obtained, indicating that the physical structure of biofilms could play an important role in facilitating the adhesion of E. coli cells.
Collapse
Affiliation(s)
- Dao Janjaroen
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Gea-Izquierdo E, Loza-Murguia MG. Calidad del agua y Salud: Las biopelículas y Legionella. JOURNAL OF THE SELVA ANDINA RESEARCH SOCIETY 2013. [DOI: 10.36610/j.jsars.2012.030200112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
22
|
Lascowski KMS, Guth BEC, Martins FH, Rocha SPD, Irino K, Pelayo JS. Shiga toxin-producing Escherichia coli in drinking water supplies of north Paraná State, Brazil. J Appl Microbiol 2013; 114:1230-9. [PMID: 23279284 DOI: 10.1111/jam.12113] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 12/07/2012] [Accepted: 12/18/2012] [Indexed: 11/28/2022]
Abstract
AIM To determine the occurrence and characteristics of Shiga toxin-producing Escherichia coli (STEC) in drinking water supplies treated and untreated. METHODS AND RESULTS Drinking water samples (n = 1850) were collected from 41 municipalities in the north of Paraná State between February 2005 and January 2006. Escherichia coli isolates (n = 300) were recovered from water and investigated for the presence of virulence markers related to STEC by PCR. STEC isolates recovered were then characterized for both phenotypic and genotypic traits. A total of 12 isolates (11 from untreated water and one from treated water) were positive for stx, including five positive for both stx1 and stx2, two positive for stx1 and five positive for stx2. None of the STEC isolates contained eae, but other virulence genes were observed such as ehxA (100%), saa (100%), lpfAO113 (75%), iha (42%), subAB (25%) and cdtV (8%). Multidrug resistance was identified in 25% of the STEC isolates. The 12 STEC isolates belonged to seven distinct serotypes and pulsed-field gel electrophoresis typing revealed the presence of two clusters and two clones in this region. CONCLUSION Drinking water, especially from untreated water supplies, can be source of STEC strains potentially pathogenic for humans. SIGNIFICANCE AND IMPACT OF THE STUDY The investigation of the drinking water supplies for pathogenic E. coli, as STEC, may be useful to prevent waterborne outbreaks.
Collapse
Affiliation(s)
- K M S Lascowski
- Department of Microbiology, Immunology and Parasitology - Escola Paulista de Medicina, Federal University of São Paulo, São Paulo, SP, Brazil
| | | | | | | | | | | |
Collapse
|
23
|
Van Nevel S, Hennebel T, De Beuf K, Du Laing G, Verstraete W, Boon N. Transparent exopolymer particle removal in different drinking water production centers. WATER RESEARCH 2012; 46:3603-3611. [PMID: 22537844 DOI: 10.1016/j.watres.2012.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2011] [Revised: 03/13/2012] [Accepted: 04/02/2012] [Indexed: 05/31/2023]
Abstract
Transparent exopolymer particles (TEP) have recently gained interest in relation to membrane fouling. These sticky, gel-like particles consist of acidic polysaccharides excreted by bacteria and algae. The concentrations, expressed as xanthan gum equivalents L⁻¹ (μg X(eq) L⁻¹), usually reach hundred up to thousands μg X(eq) L⁻¹ in natural waters. However, very few research was performed on the occurrence and fate of TEP in drinking water, this far. This study examined three different drinking water production centers, taking in effluent of a sewage treatment plant (STP), surface water and groundwater, respectively. Each treatment step was evaluated on TEP removal and on 13 other chemical and biological parameters. An assessment on TEP removal efficiency of a diverse range of water treatment methods and on correlations between TEP and other parameters was performed. Significant correlations between particulate TEP (>0.4 μm) and viable cell concentrations were found, as well as between colloidal TEP (0.05-0.4 μm) and total COD, TOC, total cell or viable cell concentrations. TEP concentrations were very dependent on the raw water source; no TEP was detected in groundwater but the STP effluent contained 1572 μg X(eq) L⁻¹ and the surface water 699 μg X(eq) L⁻¹. Over 94% of total TEP in both plants was colloidal TEP, a fraction neglected in nearly every other TEP study. The combination of coagulation and sand filtration was effective to decrease the TEP levels by 67%, while the combination of ultrafiltration and reverse osmosis provided a total TEP removal. Finally, in none of the installations TEP reached the final drinking water distribution system at significant concentrations. Overall, this study described the presence and removal of TEP in drinking water systems.
Collapse
Affiliation(s)
- Sam Van Nevel
- Faculty of Bioscience Engineering, Laboratory of Microbial Ecology and Technology-LabMET, Ghent University, Coupure Links 653, B-9000 Gent, Belgium
| | | | | | | | | | | |
Collapse
|
24
|
Metagenomic analyses of drinking water receiving different disinfection treatments. Appl Environ Microbiol 2012; 78:6095-102. [PMID: 22729545 DOI: 10.1128/aem.01018-12] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A metagenome-based approach was used to assess the taxonomic affiliation and function potential of microbial populations in free-chlorine-treated (CHL) and monochloramine-treated (CHM) drinking water (DW). In all, 362,640 (averaging 544 bp) and 155,593 (averaging 554 bp) pyrosequencing reads were analyzed for the CHL and CHM samples, respectively. Most annotated proteins were found to be of bacterial origin, although eukaryotic, archaeal, and viral proteins were also identified. Differences in community structure and function were noted. Most notably, Legionella-like genes were more abundant in the CHL samples while mycobacterial genes were more abundant in CHM samples. Genes associated with multiple disinfectant mechanisms were identified in both communities. Moreover, sequences linked to virulence factors, such as antibiotic resistance mechanisms, were observed in both microbial communities. This study provides new insights into the genetic network and potential biological processes associated with the molecular microbial ecology of DW microbial communities.
Collapse
|
25
|
Analysis of structure and composition of bacterial core communities in mature drinking water biofilms and bulk water of a citywide network in Germany. Appl Environ Microbiol 2012; 78:3530-8. [PMID: 22389373 DOI: 10.1128/aem.06373-11] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The bacterial core communities of bulk water and corresponding biofilms of a more than 20-year-old drinking water network were compared using 16S rRNA single-strand confirmation polymorphism (SSCP) fingerprints based on extracted DNA and RNA. The structure and composition of the bacterial core community in the bulk water was highly similar (>70%) across the city of Braunschweig, Germany, whereas all biofilm samples contained a unique community with no overlapping phylotypes from bulk water. Biofilm samples consisted mainly of Alphaproteobacteria (26% of all phylotypes), Gammaproteobacteria (11%), candidate division TM6 (11%), Chlamydiales (9%), and Betaproteobacteria (9%). The bulk water community consisted primarily of Bacteroidetes (25%), Betaproteobacteria (20%), Actinobacteria (16%), and Alphaproteobacteria (11%). All biofilm communities showed higher relative abundances of single phylotypes and a reduced richness compared to bulk water. Only biofilm communities sampled at nearby sampling points showed similar communities irrespective of support materials. In all of our bulk water studies, the community composition determined from 16S rRNA was completely different from the 16S rRNA gene-based community composition, whereas in biofilms both molecular fractions resulted in community compositions that were similar to each other. We hypothesize that a higher fraction of active bacterial phylotypes and a better protection from oxidative stress in drinking water biofilms are responsible for this higher similarity.
Collapse
|
26
|
Abreu Acosta N, Rodríguez Gómez LE, Alvarez Díaz M. Effect of oxygen injection in a reclaimed wastewater pipeline on the microbiological quality of water. ENVIRONMENTAL TECHNOLOGY 2012; 33:497-505. [PMID: 22629622 DOI: 10.1080/09593330.2011.581312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In this work the influence of oxygen injection on the inactivation of microbiological indicators during reclaimed wastewater transportation was studied. Experiments were carried out in a completely filled gravity pipe (62 km long), at two different periods of the year and with three different oxygen doses (7, 15 and 30 mg L(-1)). Microbiological parameters studied were faecal coliforms, Escherichia coli, enterococci and somatic coliphages. As a consequence of the oxygen injection, a significant inactivation of the microbiological parameters was observed during the aerobic stretch of the pipe. Later, once the oxygen had been consumed, inactivation stopped and even a slight regrowth of the microbial population took place. Inactivations were within the range of 0.6-1.0 log10 units, in most cases. No significant differences between inactivations for the different microbiological parameters were found, except for the somatic coliphages. A relationship between the inactivation degree and oxygen dose and organic matter content was observed. The biofilm played an important role in the inactivation process. The injection of oxygen contributes to improving the microbiological quality of reclaimed wastewater during its transport by pipelines, helping to diminish the subsequent on-site disinfection requirements.
Collapse
Affiliation(s)
- N Abreu Acosta
- INFULAB S.L. Mencey Romén 7, 38530, Candelaria, Tenerife, Spain
| | | | | |
Collapse
|
27
|
Pachepsky Y, Morrow J, Guber A, Shelton D, Rowland R, Davies G. Effect of biofilm in irrigation pipes on microbial quality of irrigation water. Lett Appl Microbiol 2012; 54:217-24. [PMID: 22150421 DOI: 10.1111/j.1472-765x.2011.03192.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS The focus of this work was to investigate the contribution of native Escherichia coli to the microbial quality of irrigation water and to determine the potential for contamination by E. coli associated with heterotrophic biofilms in pipe-based irrigation water delivery systems. METHODS AND RESULTS The aluminium pipes in the sprinkler irrigation system were outfitted with coupons that were extracted before each of the 2-h long irrigations carried out with weekly intervals. Water from the creek water and sprinklers, residual water from the previous irrigation and biofilms on the coupons were analysed for E. coli. High E. coli concentrations in water remaining in irrigation pipes between irrigation events were indicative of E. coli growth. In two of the four irrigations, the probability of the sample source, (creek vs sprinkler), being a noninfluential factor, was only 0.14, that is, source was an important factor. The population of bacteria associated with the biofilm on pipe walls was estimated to be larger than that in water in pipes in the first three irrigation events and comparable to one in the fourth event. CONCLUSION Biofilm-associated E. coli can affect microbial quality of irrigation water and, therefore, should not be neglected when estimating bacterial mass balances for irrigation systems. SIGNIFICANCE AND IMPACT OF THE STUDY This work is the first peer-reviewed report on the impact of biofilms on microbial quality of irrigation waters. Flushing of the irrigation system may be a useful management practice to decrease the risk of microbial contamination of produce. Because microbial water quality can be substantially modified while water is transported in an irrigation system, it becomes imperative to monitor water quality at fields, rather than just at the intake.
Collapse
Affiliation(s)
- Y Pachepsky
- USDA-ARS, Environmental Microbial and Food Safety Laboratory, Beltsville, MD 20705, USA.
| | | | | | | | | | | |
Collapse
|
28
|
Choi S, Bang J, Kim H, Beuchat L, Ryu JH. Survival and colonization of Escherichia coli O157:H7 on spinach leaves as affected by inoculum level and carrier, temperature and relative humidity. J Appl Microbiol 2011; 111:1465-72. [DOI: 10.1111/j.1365-2672.2011.05175.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
29
|
Wingender J. Hygienically Relevant Microorganisms in Biofilms of Man-Made Water Systems. ACTA ACUST UNITED AC 2011. [DOI: 10.1007/978-3-642-19940-0_9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
|
30
|
|
31
|
Klayman BJ, Volden PA, Stewart PS, Camper AK. Escherichia coli O157:H7 requires colonizing partner to adhere and persist in a capillary flow cell. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:2105-2111. [PMID: 19368221 DOI: 10.1021/es802218q] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
UNLABELLED The ability of a strain of waterborne Escherichia coli O157:H7 to colonize a glass flow cell and develop microcolonies when grown alone and with Pseudomonas aeruginosa PAO1 was examined. When introduced alone, planktonic E. coil were unable to attach to the glass surface. When introduced simultaneously with P. aeruginosa (co-inoculation), the two species coadhered to the surface. When E. coliwere introduced into a flow cell precolonized with a P. aeruginosa biofilm (precolonized), 10-fold more cells were retained than in the co-inoculated case. Both species were monitored nondestructively by time-lapse confocal microscopy, direct microscopy of the filtered effluent, and effluent plate counts. While more E. coli initially adhered in the precolonized system, E. coli microcolony formation occurred only in the co-inoculated system, where E. coil comprised 1% of the total surface-associated biovolume but greater than 50% of the biovolume near the edges of the flow cell. The hydrodynamics in the flow cell were evaluated using the finite volume analysis program CFX, revealing that shear stress was likely important in both initial attachment and steady-state colonization patterns. This research elucidates key factors which promote retention and subsequent biofilm development of E. coli 0157:H7. INTRODUCTION Bacteria exist in nature primarily in communities known as biofilms. These biofilms are usually characterized by differentiated structures, exhibit a different phenotype than their planktonic counterparts, and in nature most often consist of multispecies consortia (1, 2). An important process in shaping the formation and structure of some multispecies biofilms is the ability of certain species to coaggregate. In this process, planktonic cells adhere to genetically distinct cells in a biofilm or to other planktonic cells (3), thereby increasing biofilm formation. This process is growth-phase-dependent and is turned on and off by cells, suggestive that it may also play a role in dispersal and dissemination (4). Due to these and other complexities of the biofilm mode of growth, multiple species can coexist despite one organism having a much higher growth rate than another (5-7). In many cases, bacteria have been shown to gain a fitness advantage when residing in a mixed-species versus single-
Collapse
Affiliation(s)
- Benjamin J Klayman
- Center for Biofilm Engineering, Montana State University, 366 EPS Building, Bozeman, Montana 59717, USA.
| | | | | | | |
Collapse
|
32
|
|
33
|
Bjergbaek L, Haagensen J, Molin S, Roslev P. Effect of oxygen limitation and starvation on the benzalkonium chloride susceptibility ofEscherichia coli. J Appl Microbiol 2008; 105:1310-7. [DOI: 10.1111/j.1365-2672.2008.03901.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
34
|
Carrico BA, Digiano FA, Love NG, Vikesland P, Chandran K, Fiss M, Zaklikowski A. Effectiveness of switching disinfectants for nitrification control. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/j.1551-8833.2008.tb09751.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
35
|
Besner MC, Servais P, Prévost M. Efficacy of disinfectant residualon microbial intrusion: A review of experiments. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/j.1551-8833.2008.tb09752.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
36
|
Murphy HM, Payne SJ, Gagnon GA. Sequential UV- and chlorine-based disinfection to mitigate Escherichia coli in drinking water biofilms. WATER RESEARCH 2008; 42:2083-2092. [PMID: 18242660 DOI: 10.1016/j.watres.2007.12.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2006] [Revised: 12/04/2007] [Accepted: 12/21/2007] [Indexed: 05/25/2023]
Abstract
This study was designed to examine the potential downstream benefits of sequential disinfection to control the persistence of Escherichia coli under conditions relevant to drinking water distribution systems. Eight annular reactors (four polycarbonate and four cast iron) were setup in parallel to address various factors that could influence biofilm growth in distribution systems. Eight reactors were treated with chlorine, chlorine dioxide and monochloramine alone or in combination with UV to examine the effects on Escherichia coli growth and persistence in both the effluent and biofilm. In general, UV-treated systems in combination with chlorine or chlorine dioxide and monochloramine achieved greater log reductions in both effluent and biofilm than systems treated with chlorine-based disinfectants alone. However, during UV-low chlorine disinfection, E. coli was found to persist at low levels, suggesting that the UV treatment had instigated an adaptive mutation. During UV-chlorine-dioxide treatment, the E. coli that was initially below the detection limit reappeared during a low level of disinfection (0.2 mg/L) in the cast iron systems. Chloramine was shown to be effective in disinfecting suspended E. coli in the effluent but was unable to reduce biofilm counts to below the detection limit. Issues such as repair mechanism of E. coli and nitrification could help explain some of these aberrations. Improved understanding of the ability of chlorine-based disinfectant in combination with UV to provide sufficient disinfection will ultimately effect in improved management and safety of drinking water.
Collapse
Affiliation(s)
- H M Murphy
- Department of Civil & Resources Engineering, Dalhousie University, Halifax, NS, Canada
| | | | | |
Collapse
|
37
|
Liu Y, Li J. Role of Pseudomonas aeruginosa biofilm in the initial adhesion, growth and detachment of Escherichia coli in porous media. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:443-9. [PMID: 18284144 DOI: 10.1021/es071861b] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
This study systematically investigated the impact of Pseudomonas aeruginosa biofilm on the initial adhesion, growth, and detachment of indicator bacteria Escherichia coli JM109 in porous media. Two P. aeruginosa strains, the mucoid PD0300 and wide type PA01 with different extracellular polymeric substance (EPS) composition and secretion capability, were used to grow biofilm in packed beds. Results from the column breakthrough curves and retained JM109 profiles show that the amount and composition of P. aeruginosa biofilm EPS have a profound impact on the deposition and retention of E. coli in porous media. PAO1 biofilm coating improved E. coli retention in the column, whereas PDO300 biofilm coating had only a small impact on E. coli removal. Biofilm surface hydrophobicity and polymeric interactions between the biofilm and E. coli cell surfaces were found to play important roles in controlling the distribution of E. coli along the columns. After initial attachment, E. coli bacteria were able to survive and grow at similar growth rates in columns coated with either PAO1 or PDO300 biofilms with a relatively low nutrient supply. Biofilm detachment was the major mechanism that introduced E. coli bacteria to the bulk fluid long after the contamination event when E. coli cells became an integral part of the biofilm. Findings of this study suggest that biofilm plays a significant role in controlling the initial attachment, growth, and survival of bacteria in porous media, and that the interaction between bacteria and biofilm surfaces should be considered when predicting bacterial and pathogen migration in the environment.
Collapse
Affiliation(s)
- Yang Liu
- Department of Civil Engineering and Mechanics, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, USA
| | | |
Collapse
|
38
|
Helbling DE, Vanbriesen JM. Free chlorine demand and cell survival of microbial suspensions. WATER RESEARCH 2007; 41:4424-34. [PMID: 17624396 DOI: 10.1016/j.watres.2007.06.006] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Revised: 03/21/2007] [Accepted: 06/04/2007] [Indexed: 05/02/2023]
Abstract
The utility of chlorine residual and chlorine demand as a surrogate for microbial contamination in the water distribution system was evaluated. The chlorine demanded by and cell survival of pure culture suspensions of Escherichia coli, Staphylococcus epidermidis, and Mycobacterium aurum were quantified in solutions with initial free chlorine concentrations of 0.20, 0.40, and 0.80 mg/L. The chlorine demand increased with initial concentration of cells and free chlorine for all species. At equivalent initial cell concentrations, chlorine demand was greatest for M. aurum, followed by S. epidermidis and E. coli. The chlorine contact time required for a 3-log inactivation of E. coli, S. epidermidis, and M. aurum was calculated as 0.032+/-0.009, 0.221+/-0.080, and 42.9+/-2.71 mg min/L, respectively. The ultimate chlorine demand and cell survival were directly proportional. No chlorine demand was observed at cell concentrations less than 10(5)CFU/mL for E. coli or 10(4)CFU/mL for S. epidermidis. M. aurum demanded chlorine at all initial cell concentrations including 10(3)CFU/mL, which was the detection limit of the cell quantification assay. Chlorine demand was determined to be a suitable surrogate indicator of the organisms studied and its utility may be enhanced in locations of the water distribution system that maintain a higher free chlorine residual.
Collapse
Affiliation(s)
- Damian E Helbling
- Department of Civil and Environmental Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA.
| | | |
Collapse
|
39
|
Juhna T, Birzniece D, Larsson S, Zulenkovs D, Sharipo A, Azevedo NF, Ménard-Szczebara F, Castagnet S, Féliers C, Keevil CW. Detection of Escherichia coli in biofilms from pipe samples and coupons in drinking water distribution networks. Appl Environ Microbiol 2007; 73:7456-64. [PMID: 17720845 PMCID: PMC2168204 DOI: 10.1128/aem.00845-07] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fluorescence in situ hybridization (FISH) was used for direct detection of Escherichia coli on pipe surfaces and coupons in drinking water distribution networks. Old cast iron main pipes were removed from water distribution networks in France, England, Portugal, and Latvia, and E. coli was analyzed in the biofilm. In addition, 44 flat coupons made of cast iron, polyvinyl chloride, or stainless steel were placed into and continuously exposed to water on 15 locations of 6 distribution networks in France and Latvia and examined after 1 to 6 months exposure to the drinking water. In order to increase the signal intensity, a peptide nucleic acid (PNA) 15-mer probe was used in the FISH screening for the presence or absence of E. coli on the surface of pipes and coupons, thus reducing occasional problems of autofluorescence and low fluorescence of the labeled bacteria. For comparison, cells were removed from the surfaces and examined with culture-based or enzymatic (detection of beta-d-glucuronidase) methods. An additional verification was made by using PCR. Culture method indicated presence of E. coli in one of five pipes, whereas all pipes were positive with the FISH methods. E. coli was detected in 56% of the coupons using PNA FISH, but no E. coli was detected using culture or enzymatic methods. PCR analyses confirmed the presence of E. coli in samples that were negative according to culture-based and enzymatic methods. The viability of E. coli cells in the samples was demonstrated by the cell elongation after resuscitation in low-nutrient medium supplemented with pipemidic acid, suggesting that the cells were present in an active but nonculturable state, unable to grow on agar media. E. coli contributed to ca. 0.001 to 0.1% of the total bacterial number in the samples. The presence and number of E. coli did not correlate with any of physical and/or chemical characteristic of the drinking water (e.g., temperature, chlorine, or biodegradable organic matter concentration). We show here that E. coli is present in the biofilms of drinking water networks in Europe. Some of the cells are metabolically active but are often not detected due to limitations of traditionally used culture-based methods, indicating that biofilm should be considered as a reservoir that must be investigated further in order to evaluate the risk for human health.
Collapse
Affiliation(s)
- T Juhna
- Riga Technical University, Department of Water Engineering and Technology, 16/20 Azenes Street, Riga LV 1048, Latvia.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Juhna T, Birzniece D, Rubulis J. Effect of Phosphorus on survival of Escherichia coli in drinking water biofilms. Appl Environ Microbiol 2007; 73:3755-8. [PMID: 17416695 PMCID: PMC1932671 DOI: 10.1128/aem.00313-07] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The effect of phosphorus addition on survival of Escherichia coli in an experimental drinking water distribution system was investigated. Higher phosphorus concentrations prolonged the survival of culturable E. coli in water and biofilms. Although phosphorus addition did not affect viable but not culturable (VBNC) E. coli in biofilms, these structures could act as a reservoir of VBNC forms of E. coli in drinking water distribution systems.
Collapse
Affiliation(s)
- Talis Juhna
- Department of Water Engineering and Technology, Riga Technical University, Riga LV-1658, Latvia.
| | | | | |
Collapse
|
41
|
Lehtola MJ, Torvinen E, Kusnetsov J, Pitkänen T, Maunula L, von Bonsdorff CH, Martikainen PJ, Wilks SA, Keevil CW, Miettinen IT. Survival of Mycobacterium avium, Legionella pneumophila, Escherichia coli, and caliciviruses in drinking water-associated biofilms grown under high-shear turbulent flow. Appl Environ Microbiol 2007; 73:2854-9. [PMID: 17337541 PMCID: PMC1892874 DOI: 10.1128/aem.02916-06] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Most of the bacteria in drinking water distribution systems are associated with biofilms. In biofilms, their nutrient supply is better than in water, and biofilms can provide shelter against disinfection. We used a Propella biofilm reactor for studying the survival of Mycobacterium avium, Legionella pneumophila, Escherichia coli, and canine calicivirus (CaCV) (as a surrogate for human norovirus) in drinking water biofilms grown under high-shear turbulent-flow conditions. The numbers of M. avium and L. pneumophila were analyzed with both culture methods and with peptide nucleic acid fluorescence in situ hybridization (FISH) methods. Even though the numbers of pathogens in biofilms decreased during the experiments, M. avium and L. pneumophila survived in biofilms for more than 2 to 4 weeks in culturable forms. CaCV was detectable with a reverse transcription-PCR method in biofilms for more than 3 weeks. E. coli was detectable by culture for only 4 days in biofilms and 8 days in water, suggesting that it is a poor indicator of the presence of certain waterborne pathogens. With L. pneumophila and M. avium, culture methods underestimated the numbers of bacteria present compared to the FISH results. This study clearly proved that pathogenic bacteria entering water distribution systems can survive in biofilms for at least several weeks, even under conditions of high-shear turbulent flow, and may be a risk to water consumers. Also, considering the low number of virus particles needed to result in an infection, their extended survival in biofilms must be taken into account as a risk for the consumer.
Collapse
Affiliation(s)
- Markku J Lehtola
- Environmental Microbiology Laboratory, National Public Health Institute, Department of Environmental Health, P.O. Box 95, FI-70701 Kuopio, Finland.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Friedemann M. Enterobacter sakazakii in food and beverages (other than infant formula and milk powder). Int J Food Microbiol 2007; 116:1-10. [PMID: 17331606 DOI: 10.1016/j.ijfoodmicro.2006.12.018] [Citation(s) in RCA: 209] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2006] [Revised: 12/28/2006] [Accepted: 12/29/2006] [Indexed: 11/29/2022]
Abstract
The ubiqitous microorganism Enterobacter sakazakii is a rare contaminant of infant formula and may cause severe systemic infection in neonates. So far, other food is not known to cause E. sakazakii-infections. The scarce information about the ecology of E. sakazakii and the uncertainty concerning the source of infection in children and adults warrant a summary of the current knowledge about the presence of this opportunistic microorganism in food other than infant formula. This review systematizes publications on the presence of E. sakazakii in food and beverages until June 2006. Food other than infant formula has been rarely investigated for the presence of E. sakazakii. Nevertheless, this microorganism could be isolated from a wide spectrum of food and food ingredients. E. sakazakii was isolated from plant food and food ingredients like cereal, fruit and vegetables, legume products, herbs and spices as well as from animal food sources like milk, meat and fish and products made from these foods. The spectrum of E. sakazakii-contaminated food covers both raw and processed food. The kind of processing of E. sakazakii-contaminated food was not restricted to dry products. Fresh, frozen, ready-to-eat, fermented and cooked food products as well as beverages and water suitable for the preparation of food, were found to be contaminated by E. sakazakii. Although E. sakazakii-contaminated food do not have general public health significance, measures for prevention should consider the presence of E. sakazakii in food, food ingredients, their processing and preparation as possible source of contamination, colonization or infection.
Collapse
Affiliation(s)
- Miriam Friedemann
- Bundesinstitut für Risikobewertung (BfR), Federal Institute for Risk Assessment (BfR), Alt-Marienfelde 17-21, D-12277 Berlin, Germany.
| |
Collapse
|
43
|
Li J, McLellan S, Ogawa S. Accumulation and fate of green fluorescent labeled Escherichia coli in laboratory-scale drinking water biofilters. WATER RESEARCH 2006; 40:3023-3028. [PMID: 16904721 DOI: 10.1016/j.watres.2006.06.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Revised: 06/15/2006] [Accepted: 06/27/2006] [Indexed: 05/11/2023]
Abstract
Biological filters combining microbial activity and rapid sand filtration are used in drinking water treatment plants for enhanced biodegradable organic matters (BOM) removal. Biofilms formed on filter media comprised of bacteria enclosed in a polymeric matrix are responsible for the adsorption of BOM and attachment of planktonic microorganisms. This study investigated the removal of Escherichia coli cells injected into laboratory-scale biofilters and the role of biofilm in retaining the injected E. coli. Green fluorescent protein was used as a specific marker to detect and quantify E. coli in the biofilms. About 35% of the total injected E. coli cells were observed in the filter effluents, when initial cell concentrations were measured at 7.4 x 10(6) CFU/mL and 1.6 x 10(7) CFU/mL in two separate experiments. The results from real-time PCR and plate count analysis indicated that 95% of the E. coli retained inside the filters were either non-viable or could not be recovered by colony counting techniques. Injected cells were unevenly distributed inside the filter with more than 70% located at the top 1/5 of the filter. Images obtained from an epifluorescent microscope showed that E. coli cells were embedded inside the biofilm matrix and presented mainly as microcolonies intertwined with other microorganisms, which was consistent with findings from standard plate count methods and qPCR.
Collapse
Affiliation(s)
- J Li
- Department of Civil Engineering and Mechanics, University of Wisconsin-Milwaukee, EMS 784, 3200 N. Cramer Street, Milwaukee, WI 53201, USA.
| | - S McLellan
- Great Lakes WATER Institute, University of Wisconsin-Milwaukee, 600 E. Greenfield Ave., Milwaukee, WI 53204, USA
| | - S Ogawa
- Department of Civil Engineering and Mechanics, University of Wisconsin-Milwaukee, EMS 784, 3200 N. Cramer Street, Milwaukee, WI 53201, USA; Great Lakes WATER Institute, University of Wisconsin-Milwaukee, 600 E. Greenfield Ave., Milwaukee, WI 53204, USA
| |
Collapse
|
44
|
Berry D, Xi C, Raskin L. Microbial ecology of drinking water distribution systems. Curr Opin Biotechnol 2006; 17:297-302. [PMID: 16701992 DOI: 10.1016/j.copbio.2006.05.007] [Citation(s) in RCA: 238] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2006] [Revised: 04/25/2006] [Accepted: 05/05/2006] [Indexed: 11/16/2022]
Abstract
The supply of clean drinking water is a major, and relatively recent, public health milestone. Control of microbial growth in drinking water distribution systems, often achieved through the addition of disinfectants, is essential to limiting waterborne illness, particularly in immunocompromised subpopulations. Recent inquiries into the microbial ecology of distribution systems have found that pathogen resistance to chlorination is affected by microbial community diversity and interspecies relationships. Research indicates that multispecies biofilms are generally more resistant to disinfection than single-species biofilms. Other recent findings are the increased survival of the bacterial pathogen Legionella pneumophila when present inside its protozoan host Hartmannella vermiformis and the depletion of chloramine disinfectant residuals by nitrifying bacteria, leading to increased overall microbial growth. Interactions such as these are unaccounted for in current disinfection models. An understanding of the microbial ecology of distribution systems is necessary to design innovative and effective control strategies that will ensure safe and high-quality drinking water.
Collapse
Affiliation(s)
- David Berry
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, 48109-2125, USA
| | | | | |
Collapse
|
45
|
Lehner A, Riedel K, Eberl L, Breeuwer P, Diep B, Stephan R. Biofilm formation, extracellular polysaccharide production, and cell-to-cell signaling in various Enterobacter sakazakii strains: aspects promoting environmental persistence. J Food Prot 2005; 68:2287-94. [PMID: 16300064 DOI: 10.4315/0362-028x-68.11.2287] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Enterobacter sakazakii is considered an opportunistic pathogen and has been implicated in food-associated cases of meningitis or enteritis, especially in neonates and infants. The organism has been detected in various types of food and in food production units, but so far only powdered infant formula has been linked to outbreaks of disease. Survival and persistence in such environments requires the ability to adapt to high osmotic potentials and/or dry conditions. Fifty-six E. sakazakii strains were evaluated for several features important for persistence and survival: (i) biofilm formation and the putative production of cellulose as one of the components of the extracellular matrix, (ii) adherence to hydrophilic and hydrophobic surfaces, (iii) the production of extracellular polysaccharides, and (iv) the ability of E. sakazakii to produce cell-to-cell signaling molecules. Pellicle and flock formation was observed in 21 of the strains grown in Luria-Bertani broth and in 44 of the strains grown in brain heart infusion broth. Calcofluor-stained fibrils, observed microscopically in every (fragile or rigid) pellicle, suggested the presence of cellulose as an extracellular compound in this type of biofilm. Twelve isolates did not form any pellicle or flocks under either condition. Twenty-three of the isolates exhibited the potential to adhere to glass surfaces in shaken cultures, and 33 strains showed biofilm formation at the air-solid interface of polyvinyl chloride microtiter wells. Sixteen isolates adhered to both surfaces. Twenty-four of the isolates tested produced a milky, viscous mass, considered as extracellular polysaccharide. High-performance liquid chromatography analysis of the polysaccharide revealed the presence of glucose, galactose, fucose, and glucuronic acid. Thin-layer chromatography analyses performed on ethyl acetate extracts of cell-free supernatants of the 56 strains indicated the presence of two different types of acylated homoserine lactones (3-oxo-C6-HSL and 3-oxo-C8-HSL). These findings illustrate the ability of E. sakazakii to produce cell-to-cell signaling molecules.
Collapse
Affiliation(s)
- Angelika Lehner
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, CH-8057 Zurich, Switzerland
| | | | | | | | | | | |
Collapse
|
46
|
Abstract
Indwelling prosthetic joints may become colonized by microbial biofilms, although the biofilm structure, composition of the microbial community, and physiologic activity of the organisms in these devices are not well understood. New approaches that rely on the use of fluorescent stain technology can be used to characterize the structure and community composition in a way that earlier methods, which relied on culturing or scanning electron microscopy, could not. Model systems incorporating parameters relevant for indwelling prosthetic joints also can be designed to evaluate the efficacy of treatments for preventing or eradicating biofilms from these devices. Effectively treating microbial biofilms on indwelling medical devices such as prosthetic joints is a challenging proposition. A clearer understanding of the process in vivo and a defined approach for evaluating treatment strategies provide the best hope for success.
Collapse
Affiliation(s)
- Rodney M Donlan
- Centers for Disease Control and Prevention, Division of Healthcare Quality Promotion, Atlanta, GA 30333, USA.
| |
Collapse
|
47
|
Ortolano GA, McAlister MB, Angelbeck JA, Schaffer J, Russell RL, Maynard E, Wenz B. Hospital water point-of-use filtration: a complementary strategy to reduce the risk of nosocomial infection. Am J Infect Control 2005; 33:S1-19. [PMID: 15940112 DOI: 10.1016/j.ajic.2005.03.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Cholera, hepatitis and typhoid are well-recognized water-borne illnesses that take the lives of many every year in areas of uncontrollable flood, but far less attention is afforded to the allegedly safe potable water in affluent nations and the presumed healthful quality of water in communities and hospitals. Recent literature, however, points to increasing awareness of serious clinical sequelae particularly experienced by immunocompromised patients at high risk for disease and death from exposure to water-borne microbes in hospitals. This review reflects the literature indicting hospital water as an important source for nosocomial infections, examines patient populations at greatest risk, uncovers examples of failures in remedial water treatment methods and the reasons for them, and introduces point-of-use water filtration as a practical alternative or complementary component of an infection control strategy that may reduce the risk of nosocomial infections.
Collapse
|
48
|
Rickard AH, Stead AT, O'May GA, Lindsay S, Banner M, Handley PS, Gilbert P. Adhaeribacter aquaticus gen. nov., sp. nov., a Gram-negative isolate from a potable water biofilm. Int J Syst Evol Microbiol 2005; 55:821-829. [PMID: 15774669 DOI: 10.1099/ijs.0.63337-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A Gram-negative bacterium was isolated from a freshwater biofilm developed on a stainless steel surface under a fluid velocity of 0·26 m s−1. The strain, MBRG1.5T, was cultivated on R2A agar and formed pink colonies. Light microscopy and negative staining in a transmission electron microscope showed that the cells were rod-shaped, approximately 2·8–4·1 μm long by 0·9–1·7 μm wide in size and produced large quantities of extracellular fibrillar material. Additionally, following growth in batch culture, transmission electron microscopy showed that many cells plasmolysed. Stationary-phase cells were more variable in size and shape. The DNA G+C content was 40·0 mol%. The most abundant fatty acids were 15 : 0 iso (22·5 %), followed by 16 : 1ω5c (16·9 %) and 15 : 0 iso 2-OH (16·5 %). Phylogenetic analysis of the 16S rRNA gene showed that the strain was a member of the family ‘Flexibacteraceae’ of the Cytophaga–Flavobacterium–Bacteroides group. Phenotypic and genotypic analyses indicated that the strain could not be assigned to any recognized genus; therefore a novel genus and species, Adhaeribacter aquaticus gen. nov., sp. nov., is proposed, with MBRG1.5T (=DSM 16391T=NCIMB 14008T) as the type strain.
Collapse
Affiliation(s)
- A H Rickard
- School of Pharmacy, University of Manchester, Manchester M13 9PL, UK
| | - A T Stead
- School of Biological Sciences, University of Manchester, Manchester M13 9PL, UK
| | - G A O'May
- Molecular and Cellular Pathology, University of Dundee, Dundee DD1 7SY, UK
| | - S Lindsay
- School of Pharmacy, University of Manchester, Manchester M13 9PL, UK
| | - M Banner
- School of Biological Sciences, University of Manchester, Manchester M13 9PL, UK
| | - P S Handley
- School of Biological Sciences, University of Manchester, Manchester M13 9PL, UK
| | - P Gilbert
- School of Pharmacy, University of Manchester, Manchester M13 9PL, UK
| |
Collapse
|
49
|
Thomas V, Bouchez T, Nicolas V, Robert S, Loret JF, Lévi Y. Amoebae in domestic water systems: resistance to disinfection treatments and implication in Legionella persistence. J Appl Microbiol 2005; 97:950-63. [PMID: 15479410 DOI: 10.1111/j.1365-2672.2004.02391.x] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS Monitoring of microbial changes during and after application of various disinfection treatments in a model domestic water system. METHODS AND RESULTS A pilot-scale domestic water system consisting of seven galvanized steel re-circulation loops and copper dead legs was constructed. Culture techniques, confocal laser scanning microscopy after fluorescent in situ hybridization and viability staining with the BacLight LIVE/DEAD kit were used for planktonic and biofilm flora monitoring. Before starting the treatments, the system was highly contaminated with Legionella pneumophila and biofilm populations mainly consisted of beta-proteobacteria. In the water and the biofilm of the loops, continuous application of chlorine dioxide (0.5 mg l(-1)), or chlorine (2.5 mg l(-1)) were very effective in reducing the microbial flora, including L. pneumophila. Heterotrophic bacteria, although strongly reduced, were still detectable after ozone application (0.5 mg l(-1)), whereas with monochloramine (0.5 mg l(-1)) and copper-silver ionization (0.8/0.02 mg l(-1)), the contamination remained significantly higher. Monochloramine and copper-silver did not remove the biofilm. During copper-silver application, Legionella re-growth was observed. Only chlorine dioxide led to detectable effects in the dead leg. Amoebae could not be eliminated, and after interrupting the treatments, L. pneumophila quickly recovered their initial levels, in all cases. CONCLUSIONS Chlorine dioxide, applied as a continuous treatment, was identified in this study as the most efficient for controlling L. pneumophila in a domestic water system. Chlorine dioxide showed a longer residual activity, leading to improved performance in the dead leg. Amoebae resisted to all the treatments applied and probably acted as reservoirs for L. pneumophila, allowing a quick re-colonization of the system once the treatments were interrupted. SIGNIFICANCE AND IMPACT OF THE STUDY Control of microbial contamination requires maintenance of a constant disinfectant residual throughout the water system. Treatment strategies targeting free-living amoebae should lead to improved control of L. pneumophila. Such treatment strategies still have to be investigated.
Collapse
Affiliation(s)
- V Thomas
- Department of Public Health-Environment, School of Pharmacy, University of Paris, Châtenay-Malabry Cedex, France.
| | | | | | | | | | | |
Collapse
|
50
|
Williams MM, Santo Domingo JW, Meckes MC. Population diversity in model potable water biofilms receiving chlorine or chloramine residual. BIOFOULING 2005; 21:279-88. [PMID: 16522541 DOI: 10.1080/08927010500452695] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Most water utilities use chlorine or chloramine to produce potable water. These disinfecting agents react with water to produce residual oxidants within a water distribution system (WDS) to control bacterial growth. While monochloramine is considered more stable than chlorine, little is known about the effect it has on WDS biofilms. Community structure of 10-week old WDS biofilms exposed to disinfectants was assessed after developing model biofilms from unamended distribution water. Four biofilm types were developed on polycarbonate slides within annular reactors while receiving chlorine, chloramine, or inactivated disinfectant residual. Eubacteria were identified through 16S rDNA sequence analysis. The model WDS biofilm exposed to chloramine mainly contained Mycobacterium and Dechloromonas sequences, while a variety of alpha- and additional beta-proteobacteria dominated the 16S rDNA clone libraries in the other three biofilms. Additionally, bacterial clones distantly related to Legionella were found in one of the biofilms receiving water with inactivated chlorine residual. The biofilm reactor receiving chloraminated water required increasing amounts of disinfectant after 2 weeks to maintain chlorine residual. In contrast, free chlorine residual remained steady in the reactor that received chlorinated water. The differences in bacterial populations of potable water biofilms suggest that disinfecting agents can influence biofilm development. These results also suggest that biofilm communities in distribution systems are capable of changing in response to disinfection practices.
Collapse
|