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Borgmästars E, Persson S, Hellmér M, Simonsson M, Eriksson R. Comparison of Skimmed Milk and Lanthanum Flocculation for Concentration of Pathogenic Viruses in Water. FOOD AND ENVIRONMENTAL VIROLOGY 2021; 13:380-389. [PMID: 33974212 DOI: 10.1007/s12560-021-09477-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 04/16/2021] [Indexed: 05/14/2023]
Abstract
Concentration of viruses in water is necessary for detection and quantification of the viruses present, in order to evaluate microbiological barriers in water treatment plants and detect pathogenic viruses during waterborne outbreaks, but there is currently no standardised procedure. In this study, we implemented a previously described fast and simple lanthanum-based protocol for concentration of norovirus genogroup I (GI), genogroup II (GII) and hepatitis A virus (HAV) in drinking and surface water. We compared the results with those of a widely used skimmed milk flocculation method, followed by nucleic acid extraction and RT-qPCR detection. Three seeding levels, with intended concentrations 5 × 103, 5 × 104 and 5 × 105 genome copies/10 L, were added to drinking water or surface water. All seed levels were detected with both flocculation methods. Samples extracted with skimmed milk flocculation had on average 1.82, 1.86 and 1.38 times higher measured concentration of norovirus GI, GII and HAV, respectively, than those extracted with lanthanum flocculation, across all seeding levels and water types tested. Mengovirus was used as a positive process control. Mengovirus recovery was higher for skimmed milk (40.7% in drinking water, 26.0% in surface water) than for lanthanum flocculation (24.4% in drinking water, 9.7% in surface water). Together, this indicates that skimmed milk flocculation provides higher viral recovery than lanthanum flocculation. However, lanthanum-based flocculation can be performed much faster than skimmed milk flocculation (1.5 h versus 16 h flocculation time) and thus could be a good alternative for rapid monitoring of viruses in water.
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Affiliation(s)
- Emmy Borgmästars
- Science Division, Biology Department, Swedish Food Agency, Hamnesplanaden 5, 75319, Uppsala, Sweden.
- Department of Surgical and Perioperative Sciences, Surgery, Umeå University, Umeå, Sweden.
| | - Sofia Persson
- Science Division, Biology Department, Swedish Food Agency, Hamnesplanaden 5, 75319, Uppsala, Sweden
- European Union Reference Laboratory (EURL) for Foodborne Viruses, Uppsala, Sweden
| | - Maria Hellmér
- Science Division, Biology Department, Swedish Food Agency, Hamnesplanaden 5, 75319, Uppsala, Sweden
- European Union Reference Laboratory (EURL) for Foodborne Viruses, Uppsala, Sweden
| | - Magnus Simonsson
- Science Division, Biology Department, Swedish Food Agency, Hamnesplanaden 5, 75319, Uppsala, Sweden
- European Union Reference Laboratory (EURL) for Foodborne Viruses, Uppsala, Sweden
| | - Ronnie Eriksson
- Science Division, Biology Department, Swedish Food Agency, Hamnesplanaden 5, 75319, Uppsala, Sweden.
- European Union Reference Laboratory (EURL) for Foodborne Viruses, Uppsala, Sweden.
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Wu X, Huang X, Zhu Y, Li J, Hoffmann MR. Synthesis and application of superabsorbent polymer microspheres for rapid concentration and quantification of microbial pathogens in ambient water. Sep Purif Technol 2020; 239:116540. [PMID: 32421015 PMCID: PMC7045201 DOI: 10.1016/j.seppur.2020.116540] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A portable, hand-pressed 3D-printed system with SAP microspheres was developed. This system could achieve efficient concentration of environmental microorganisms. Superior performance was achieved with varying ionic strengths in a short time. Optimized SAP microspheres could be reused 20 times with simple procedures.
Even though numerous methods have been developed for the detection and quantification of waterborne pathogens, the application of these methods is often hindered by the very low pathogen concentrations in natural waters. Therefore, rapid and efficient sample concentration methods are urgently needed. Here we present a novel method to pre-concentrate microbial pathogens in water using a portable 3D-printed system with super-absorbent polymer (SAP) microspheres, which can effectively reduce the actual volume of water in a collected sample. The SAP microspheres absorb water while excluding bacteria and viruses by size exclusion and charge repulsion. To improve the water absorption capacity of SAP in varying ionic strength waters (0–100 mM), we optimized the formulation of SAP to 180 g⋅L−1 Acrylamide, 75 g⋅L−1 Itaconic Acid and 4.0 g⋅L−1 Bis-Acrylamide for the highest ionic strength water as a function of the extent of cross-linking and the concentration of counter ions. Fluorescence microscopy and double-layer agar plating respectively showed that the 3D-printed system with optimally-designed SAP microspheres could rapidly achieve a 10-fold increase in the concentration of Escherichia coli (E. coli) and bacteriophage MS2 within 20 min with concentration efficiencies of 87% and 96%, respectively. Fold changes between concentrated and original samples from qPCR and RT-qPCR results were found to be respectively 11.34–22.27 for E. coli with original concentrations from 104 to 106 cell·mL−1, and 8.20–13.81 for MS2 with original concentrations from 104 to 106 PFU·mL−1. Furthermore, SAP microspheres can be reused for 20 times without performance loss, significantly decreasing the cost of our concentration system.
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Affiliation(s)
- Xunyi Wu
- Linde+ Robinson Laboratories, California Institute of Technology, Pasadena, CA 91125, United States
| | - Xiao Huang
- Linde+ Robinson Laboratories, California Institute of Technology, Pasadena, CA 91125, United States
| | - Yanzhe Zhu
- Linde+ Robinson Laboratories, California Institute of Technology, Pasadena, CA 91125, United States
| | - Jing Li
- Linde+ Robinson Laboratories, California Institute of Technology, Pasadena, CA 91125, United States
| | - Michael R Hoffmann
- Linde+ Robinson Laboratories, California Institute of Technology, Pasadena, CA 91125, United States
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Inducing flocculation of non-floc-forming Escherichia coli cells. World J Microbiol Biotechnol 2018; 34:185. [PMID: 30506280 DOI: 10.1007/s11274-018-2563-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 11/19/2018] [Indexed: 10/27/2022]
Abstract
The present article reviews several approaches for inducing flocculation of Escherichia coli cells. The common industrially used bacterium E. coli does not naturally have floc-forming ability. However, there are several approaches to induce flocculation of E. coli cells. One is induction by flocculants-polyvalent inorganic salts, synthetic polymeric flocculants, or bio-based polymeric materials, including polysaccharide derivatives. Another method is the induction of spontaneous flocculation by changing the phenotypes of E. coli cells; several studies have shown that physical treatment or gene modification can endow E. coli cells with floc-forming ability. Coculturing E. coli with other microbes is another approach to induce E. coli flocculation. These approaches have particular advantages and disadvantages, and remain open to clarification of the flocculation mechanisms and improvement of the induction processes. In this review, several approaches to the induction of E. coli flocculation are summarized and discussed. This review will be a useful guide for the future development of methods for the flocculation of non-floc-forming microorganisms.
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Jansson L, Eriksson R, Hedman J, Lavander M. Evaluation and modification of lanthanum-based flocculation for isolation of bacteria from water samples. ACTA ACUST UNITED AC 2018; 19:e00267. [PMID: 29992101 PMCID: PMC6036863 DOI: 10.1016/j.btre.2018.e00267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 12/15/2017] [Accepted: 06/15/2018] [Indexed: 11/10/2022]
Abstract
A published lanthanum-based flocculation protocol is evaluated for four bacterial species The success of lanthanum-based flocculation is determined by both the bacterial species and the nature of the water sample Addition of 20 mM bicarbonate significantly improve the flocculation efficiency for tap water
Molecular detection of pathogenic microorganisms in drinking and natural water is often challenged by low concentrations of the sought-after agents. Convenient methods to concentrate bacteria from water samples ranging from 1-10 L are highly warranted. Here we account for the evaluation of a lanthanum-based flocculation method to concentrate bacteria from water samples, applying four different bacterial species in tap water as well as river water. Our results show that the success of lanthanum-based flocculation is determined by both the bacterial species and the nature of the water sample. For tap water, satisfying flocculation efficiencies (above 60 %) were only reached for autoclaved water samples. However, the performance of the lanthanum-based flocculation method for non-autoclaved water was markedly improved by the addition of 20 mM bicarbonate to increase alkalinity. Our modified flocculation protocol may be applied as an alternative concentration method for bacteria in water samples of one liter or more.
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Affiliation(s)
- Linda Jansson
- Applied Microbiology, Lund University, SE-221 00 Lund, Sweden.,Swedish National Forensic Centre, SE-581 94, Linköping, Sweden
| | - Ronnie Eriksson
- Science Division, Biology Department, National Food Agency, SE-753 19, Uppsala, Sweden
| | - Johannes Hedman
- Applied Microbiology, Lund University, SE-221 00 Lund, Sweden.,Swedish National Forensic Centre, SE-581 94, Linköping, Sweden
| | - Moa Lavander
- Science Division, Biology Department, National Food Agency, SE-753 19, Uppsala, Sweden
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Deng C, Li X, Xue X, Pashley RM. The effects of low levels of trivalent ions on a standard strain of Escherichia coli (ATCC 11775) in aqueous solutions. Microbiologyopen 2018; 7:e00574. [PMID: 29334190 PMCID: PMC6011944 DOI: 10.1002/mbo3.574] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/16/2017] [Accepted: 11/20/2017] [Indexed: 12/13/2022] Open
Abstract
Considering the ever‐growing usage of trivalent salts in water treatment, for example, lanthanum salts in rare earth, AlCl3 and FeCl3, the effects of different trivalent cations on the bacterium Escherichia coli (E. coli) ATCC 11775 strain have been studied in aqueous solutions. From colony incubation studies, the colony‐forming unit (CFU) densities were found to decrease significantly in the presence of even low levels (10−5 mol/L) of lanthanum chloride. This level of reduction in CFU number is comparable to the results obtained using the known bacteriocidal cationic surfactant, C14TAB. By comparison, exposure of the cells to low levels of trivalent ion, aluminum and chromium ion solutions produced only modest reductions in CFU density. The results from the incubation studies suggest that the bacteriostatic mechanism of La3+ ions has similarities to that of the cationic surfactant, and different to that of the other trivalent ions. Size distribution and zeta potential measurements of E. coli cells and phospholipid vesicles in the presence of trivalent cations solutions suggested significant cell shrinkage probably caused by membrane disruption.
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Affiliation(s)
- Can Deng
- POWERCHINA Water Environment Governance, Shenzhen, China
| | - Xinpeng Li
- POWERCHINA Water Environment Governance, Shenzhen, China
| | - Xinkai Xue
- POWERCHINA Water Environment Governance, Shenzhen, China
| | - Richard M Pashley
- School of Physical, Environmental & Mathematical Sciences, Canberra, Australia
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Zhang Y, Riley LK, Lin M, Purdy GA, Hu Z. Development of a virus concentration method using lanthanum-based chemical flocculation coupled with modified membrane filtration procedures. J Virol Methods 2013; 190:41-8. [PMID: 23557666 DOI: 10.1016/j.jviromet.2013.03.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 03/20/2013] [Accepted: 03/25/2013] [Indexed: 12/24/2022]
Abstract
Direct membrane filtration is often used to concentrate viruses in water but it may suffer from severe membrane fouling and clogging. Here, a lanthanum-based flocculation method coupled with modified membrane filtration procedures was developed and evaluated to detect viruses in large volume (40 L) water samples. The lanthanum-based flocculation method could easily reduce the water sample volume by a factor of 40. Additional volume reduction was achieved by a two-step membrane filtration approach. First, selected membrane filters (including 1MDS electropositive filters and nitrocellulose electronegative filters-Millipore HATF filters) were used to reduce water sample volume further and compare their efficiencies in virus recovery. The Mg²⁺-modified HATF membrane performed better on MS2 retention with an average virus recovery of 83.4% (±4.5% [standard deviation]). After HATF membrane filtration and elution, centrifugal ultrafiltration through a 30 kDa cut-off membrane resulted in an overall concentration factor of 20,000. Results from the infectivity assay showed that the MS2 recovery efficiencies from the NanoCeram- and 1MDS-based direct filtration and the lanthanum-based concentration coupled with the modified filtration procedure were 10.1% (±1.0%), 3.3% (±0.1%), and 17.5% (±1.1%), respectively. Results from the PCR analysis showed that the virus recoveries of the lanthanum-based method were 20.6% (±2.9%) and 19.5% (±3.4%) for MS2 and adenovirus, respectively, while no adenovirus could be detected through the NanoCeram- and 1MDS-based direct filtration. The lanthanum-based concentration method coupled with modified membrane filtration procedures is therefore a promising method for detecting waterborne viruses.
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Affiliation(s)
- Yanyan Zhang
- Department of Civil and Environmental Engineering, University of Missouri, Columbia, MO 65211, USA
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Zhang Y, Riley LK, Lin M, Hu Z. Determination of low-density Escherichia coli and Helicobacter pylori suspensions in water. WATER RESEARCH 2012; 46:2140-2148. [PMID: 22342315 DOI: 10.1016/j.watres.2012.01.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 01/23/2012] [Accepted: 01/24/2012] [Indexed: 05/31/2023]
Abstract
Determination of low-density of bacteria, especially those of pathogenic strains in water, has proven difficult and challenging. Here, we developed and evaluated a lanthanum-based concentration method coupled with quantitative real-time PCR to concentrate and detect selected bacteria (Escherichia coli and Helicobacter pylori) in water. To improve qPCR efficiency, the flocs with enmeshed bacteria after chemical flocculation need to be dissolved before PCR detection. Ethylenediaminetetraacetic acid (EDTA) salt successfully dissolved the flocs from a lanthanum-based flocculation process, but not those from the traditional processes using chemicals such as FeCl(3) or Al(2)(SO(4))(3). Lanthanum-based concentration coupled with real-time PCR successfully determined E. coli at a concentration of 15 cells/mL in raw and finished water and H. pylori at a concentration of about 1 cell/mL in the finished water prior to disinfection. The H. pylori detection sensitivity could be easily increased to 60 cells/L by reducing the final volume of the DNA samples from 3 mL to 60 μL. With the elimination of membrane-clogging problem that is often encountered in direct membrane filtration, the lanthanum-based chemical flocculation coupled with qPCR is a promising method for determination of low-density of microbial suspensions in water.
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Affiliation(s)
- Yanyan Zhang
- Department of Civil and Environmental Engineering, University of Missouri, Columbia, MO 65211, USA
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