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Arona JC, Hall TJ, Mckinnirey F, Deng F. Comparison of four commercial immunomagnetic separation kits for the detection of Cryptosporidium. JOURNAL OF WATER AND HEALTH 2023; 21:1580-1590. [PMID: 37902211 PMCID: wh_2023_217 DOI: 10.2166/wh.2023.217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2023]
Abstract
Cryptosporidium spp. are protozoan parasites of significant health importance found in environmental waters globally. Four commercially available Cryptosporidium-specific immunomagnetic separation (IMS) kits used in various water sample matrices were analysed and compared. Beads were characterised by flow cytometry and tested for the recovery efficiencies for oocysts spiked into different matrices: river water sediment, clay sample, and filter backwash sample. Results showed that Dynabeads™ Cryptosporidium and Waterborne Crypto-Grab™ kits contained immunoglobulin IgM antibody-coated beads. In contrast, the BioPoint CryptoBead and the TCS Isolate kits contained immunoglobulin IgG antibody-coated beads. BioPoint CryptoBead was significantly coated with more antibodies and were able to capture oocysts more rapidly compared to the other beads. Recovery efficiencies of Dynabeads™, TCS Isolate® beads, and BioPoint CryptoBead ranged from 55 to 93% when tested against different sample matrices, with BioPoint CryptoBead resulting in the highest at 93% in reagent-grade water and Dynabeads™ at 55%, the lowest against clay samples. The Waterborne beads did not perform well on any samples, with recovery efficiencies ranging from 0 to 8%. Fluorescence microscopy analyses showed that both the IMS method and the sample matrix processed affect the quality of the membranes, with the cleanest samples for microscopy examination observed from BioPoint CryptoBead.
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Affiliation(s)
- Jeanne Claudeen Arona
- Graduate School of BioMedical Engineering, University of New South Wales, Sydney 2052, Australia E-mail:
| | - Timothy J Hall
- Graduate School of BioMedical Engineering, University of New South Wales, Sydney 2052, Australia
| | - Flyn Mckinnirey
- Graduate School of BioMedical Engineering, University of New South Wales, Sydney 2052, Australia
| | - Fei Deng
- Graduate School of BioMedical Engineering, University of New South Wales, Sydney 2052, Australia
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Hassan EM, Dixon BR, Sattar SA, Stalker A, Örmeci B, DeRosa MC. Highly sensitive magnetic-microparticle-based aptasensor for Cryptosporidium parvum oocyst detection in river water and wastewater: Effect of truncation on aptamer affinity. Talanta 2020; 222:121618. [PMID: 33167272 DOI: 10.1016/j.talanta.2020.121618] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/15/2020] [Accepted: 08/31/2020] [Indexed: 12/22/2022]
Abstract
Many methods have been reported to detect Cryptosporidium parvum (C. parvum) oocysts in the water environment using monoclonal antibodies. Herein, we report the use of DNA aptamers as an alternative ligand. We present the highly sensitive detection of C. parvum oocysts in wastewater samples based on aptamer-conjugated magnetic beads. A previously selected DNA aptamer (R4-6) that binds to C. parvum oocysts with high affinity and selectivity was rationally truncated into two minimer aptamers (Min_Crypto1 and Min_Crypto2), and conjugated to micro-magnetic beads. In flow cytometry tests with phosphate buffer, river water, and wastewater samples, both the minimers showed improved affinity and specificity toward C. parvum oocysts than the parent R4-6. Moreover, Min_Crypto2 showed higher affinity to its target than the parent aptamer when testing in wastewater, indicating superior binding properties in a complex matrix. Using a fluorescence microplate-based assay, and when incubated with different numbers of oocysts, Min_Crypto2 showed a limit of detection as low as 5 C. parvum oocysts in 300 μL of wastewater. Results described here indicate that Min_Crypto2 has superior specificity and sensitivity for the detection of C. parvum oocysts, and has a strong potential to be used successfully in a sensor.
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Affiliation(s)
- Eman M Hassan
- Department of Civil and Environmental Engineering, Carleton University, 1125 Colonel By Drive, Ottawa, K1S 5B6, Canada; Metrology Research Centre, National Research Council Canada, Ottawa, ON, K1A 0R6, Canada
| | - Brent R Dixon
- Bureau of Microbial Hazards, Food Directorate, Health Canada, Ottawa, K1A 0K9, Canada
| | - Syed A Sattar
- CREM Co Labs, Units 1-2, 3403 American Drive, Mississauga, ON, L4V 1T4, Canada; Emeritus of Microbiology, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Andrew Stalker
- Centre for Biologics Evaluation, Biologics and Genetic Therapies Directorate, Health Canada, K1A 0K9, Canada
| | - Banu Örmeci
- Department of Civil and Environmental Engineering, Carleton University, 1125 Colonel By Drive, Ottawa, K1S 5B6, Canada.
| | - Maria C DeRosa
- Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, K1S 5B6, Canada.
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Porter J. Flow cytometry and environmental microbiology. CURRENT PROTOCOLS IN CYTOMETRY 2008; Chapter 11:Unit 11.2. [PMID: 18770789 DOI: 10.1002/0471142956.cy1102s27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This survey unit discusses many of the issues involved for flow cytometry in the field of microbiology, particularly the preparative procedures, which are far more stringent than many other procedures using larger cells. For instance, it is often necessary to filter laboratory agents multiple times to obtain the true particle-free solutions needed for flow cytometry of microbes. It is difficult enough to recognize bacteria in cell extracts from soil, sediment, or sludge given the background of same-size particles. This unit provides an excellent overview of a potentially large application area in flow cytometry and is written by one of the most respected scientists in the field.
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Montemayor M, Galofré B, Ribas F, Lucena F. Comparative study between two laser scanning cytometers and epifluorescence microscopy for the detection ofCryptosporidium oocysts in water. Cytometry A 2007; 71:163-9. [PMID: 17279570 DOI: 10.1002/cyto.a.20373] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Cryptosporidium detection in water and environmental samples has increased during the last years, largely due to an increase in the number of reported waterborne outbreaks of cryptosporidiosis and the implementation of new regulations about Cryptosporidium monitoring in water supplies. The aim of this study was to validate and compare the capacity of two laser scanning cytometers commercially available (LSC and ChemScanRDI), against manual microscopic enumeration of Cryptosporidium oocysts in surface water and reference material samples. METHODS Reference material and surface water samples were analysed by two laser scanning cytometers methodologies and by manual epifluorescence microscopy. Two mAbs from commercial suppliers were used to evaluate background reduction. RESULTS Highly significant correlations were obtain between both cytometers (R(2) = 0.99) and with manual microscopy (R(2) = 0.98), showing that oocysts counts made by cytometers were equivalent to those obtained with conventional methods. We observed a variability in oocysts counts when different antibodies where used with laser scanning cytometers and manual microscopy. CONCLUSIONS This study showed the efficacy of the laser scanning technology (LSC and ChemScanRDI), as an automated and a more standardized alternative to manual epifluorescence microscopy examination, for Cryptosporidium detection in water samples. High quality antibodies are needed for automated enumeration as well as for manual microscope observations.
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Affiliation(s)
- Michel Montemayor
- Department of Microbiology, University of Barcelona, Barcelona, Spain
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Ferrari BC, Bergquist PL. Quantum dots as alternatives to organic fluorophores forCryptosporidium detection using conventional flow cytometry and specific monoclonal antibodies: Lessons learned. Cytometry A 2007; 71:265-71. [PMID: 17279568 DOI: 10.1002/cyto.a.20381] [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: 11/11/2022]
Abstract
BACKGROUND Significant developments in biological applications are occurring through the incorporation of Quantum Dots (QDs) as biological labels. The demonstration of QDs unique optical properties may have important implications for the study of environmental samples, where microorganisms of interest need to be isolated away from the background debris. METHODS Flow cytometric analysis was used to determine the fluorescence intensity of oocysts after mAb staining by QDs or organic fluorophore conjugates. In addition, the level of non-specific binding to detrital particles within a control water concentrate was estimated using the optimal staining concentration determined for each mAb analyzed. RESULTS Under 488 nm excitation, oocysts stained with QD-conjugates exhibited significantly lower fluorescence intensity than organic conjugates. Moreover, the level of non-specific binding by QD-conjugates to detrital particles present in the water concentrate was significantly higher that of the organic conjugates. CONCLUSIONS While QDs are noted for their superior spectral characteristics, they have been shown here to be unsuitable for conventional flow cytometric detection of Cryptosporidium. Therefore, we conclude that in their current form, QD's are severely limited for fluorescent detection of pathogens in environmental applications.
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Affiliation(s)
- B C Ferrari
- Department of Chemistry and Biomolecular Sciences, Environmental Biotechnology CRC and Biotechnology Research Institute, Macquarie University Sydney, New South Wales 2109, Australia.
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Hsu BM, Wu NM, Jang HD, Shih FC, Wan MT, Kung CM. Using the flow cytometry to quantify the Giardia cysts and Cryptosporidium oocysts in water samples. ENVIRONMENTAL MONITORING AND ASSESSMENT 2005; 104:155-62. [PMID: 15931984 DOI: 10.1007/s10661-005-1608-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The flow cytometry (FC) has been used to detect Giardia cysts and Cryptosporidium oocysts quantitatively and instantaneously in this study. The experimental results showed that FC is potential to become a more precise method for the detection of Giardia and Cryptosporidium in water. This study also evaluated the staining efficiencies for three commercial antibodies. After staining Cryptosporidium oocysts with direct immunofluorescent antibodies in water samples, two populations were detected in the scatter-plots (FL1 versus SSC) of the FC. The Cryptosporidium oocysts and Giardia cysts are significantly separated from other particles while stained with direct immunofluorescent antibodies produced by Meridian Diagnostics and Waterborne Inc.
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Affiliation(s)
- Bing-Mu Hsu
- Department of Bioenvironmental Engineering, Chung Yuan Christian University, Chung-Li, Taiwan, ROC.
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Dumètre A, Dardé ML. Immunomagnetic separation of Toxoplasma gondii oocysts using a monoclonal antibody directed against the oocyst wall. J Microbiol Methods 2005; 61:209-17. [PMID: 15722147 DOI: 10.1016/j.mimet.2004.11.024] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2004] [Revised: 11/26/2004] [Accepted: 11/26/2004] [Indexed: 11/26/2022]
Abstract
Recent outbreaks of waterborne toxoplasmosis have stimulated the development of sensitive methods to detect Toxoplasma gondii oocysts in samples suspected to be contaminated. The immunomagnetic separation (IMS) have been standardised to detect waterborne protozoa, but it did not exist for Toxoplasma oocysts. In this study, we describe two monoclonal antibodies (mAbs 3G4 and 4B6) produced against the oocyst wall, and the incorporation of mAb 3G4 in an IMS procedure. We found that an indirect IMS method gave better mean recoveries than a direct one (69.4% and 25.2%, respectively). Dissociation of oocyst_magnetic bead complexes was greatly improved by using a 2% aqueous H2SO4 solution instead of a 0.1 N HCl solution (82.8% and 17.4%, respectively). With these parameters, mean recoveries of less than 1000 oocysts ranged from 44.6% to 82.9%, depending on incubating temperature and buffer. Age of oocysts (1 or 12 months old) does not influence IMS performances. Results of this study indicate that the described IMS is an efficient technique to recover Toxoplasma oocysts.
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Affiliation(s)
- Aurélien Dumètre
- UPRES EA3174, Neuroparasitologie et Neuroépidémiologie Tropicale, Faculté de Médecine, 2 Rue du Dr Marcland, F-87025 Limoges, France
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Bellamy JEC. Quality assurance considerations for detection of waterborne zoonotic parasites using Cryptosporidium oocyst detection as the main example. Vet Parasitol 2004; 126:235-48. [PMID: 15567587 DOI: 10.1016/j.vetpar.2004.09.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
A laboratory quality assurance (QA) program can minimize errors and provide confidence in the validity of laboratory test results. The structure of a QA program varies somewhat among laboratories but usually requires addressing a QA manual, QA goals, quality of resources, standard operating procedures, internal quality control, and external QA procedures. This paper reviews these general components and discusses some of the more particular QA considerations specific to filtration, immunomagnetic separation (IMS), immunofluorescence microscopy (FA), vital dye staining, differential interference contrast (DIC) microscopy, and molecular methods, which are involved in the detection and enumeration of Cryptosporidium oocysts.
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Affiliation(s)
- James E C Bellamy
- Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, PEI, Canada C1A 4P3.
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Ferrari BC, Veal D. Analysis-only detection of Giardia by combining immunomagnetic separation and two-color flow cytometry. Cytometry A 2003; 51:79-86. [PMID: 12541282 DOI: 10.1002/cyto.a.10009] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Giardia is a protozoan parasite of concern to water utilities. Giardia detection relies on cyst isolation and confirmation with the use of fluorescence microscopy. It is of interest to develop a flow cytometric (FCM) method that reliably detects one cyst in 10 L of water. To date all available antibodies have targeted the same epitope on the cyst wall. To achieve a reliable method, two independent probes are required. METHODS Giardia cysts were spiked into a backwash water sample with and without prior hybridization to peptide nucleic acid (PNA) probes. Immunomagnetic separation (IMS) as a pre-enrichment step was compared with filtration of the water sample. Cysts were recovered with two-color FCM. Those cysts hybridized with PNA and fluorescein isothiocyanate (FITC) were dual stained with monoclonal antibody (mAb) conjugated to phycoerythrin (PE); those not hybridized to PNA were dual stained with mAb-FITC and mAb-PE. RESULTS A fourfold increase in fluorescent signal intensity was obtained when combining the mAb-PE and PNA probe compared with two-color antibody staining. When combined with IMS, Giardia was successfully identified by FCM, with no false positives detected. CONCLUSIONS Analysis-only FCM detection of Giardia in water is feasible. Further method development incorporating PNA probe hybridization after IMS is necessary.
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Affiliation(s)
- Belinda C Ferrari
- Centre for Fluorometric Applications in Biotechnology, School of Biological Sciences, Macquarie University, Sydney, Australia.
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Affiliation(s)
- S A Sincock
- Purdue Cytometry Laboratories, Department of Basic Medical Sciences, Purdue University, West Lafayette, Indiana 47907, USA
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Veal DA, Deere D, Ferrari B, Piper J, Attfield PV. Fluorescence staining and flow cytometry for monitoring microbial cells. J Immunol Methods 2000; 243:191-210. [PMID: 10986415 DOI: 10.1016/s0022-1759(00)00234-9] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Large numbers of microbiological samples are analysed annually using traditional culture-based techniques. These techniques take hours to days to yield a result, are tedious and are not suitable for non-culturable microorganisms. Further, culture-based techniques do not provide real-time information on the physiological status of the organism in situ which is important in the industrial manufacture of many microbial products. Flow cytometry offers the prospect of real-time microbial analysis of individual microorganisms, without dependency on microbial culture. However, flow cytometry has not been extensively used as a tool for routine microbial analysis. This has been mainly due to the high cost and complexity of instrumentation, the need for trained flow cytometrists and the lack of assay kits with appropriate biological reagents for specific applications. Many modern instruments are now relatively simple to operate, due to improvements in the user-interface, and no longer need a specialist operator. However, most cytometers are still reliant on analogue technology first developed 20-30 years ago. The incorporation of modern, solid state opto-electronics combined with micro-fabrication and digital signal processing technology offers the prospect of simple to use, low cost and robust instruments suitable for microbial analyses. Advances are being made in the development of a range of biological reagents and these are now being formulated into simple to use kits for microbiological applications. Currently, these kits are largely restricted to simple analyses, for example to assay for total or viable numbers of microorganisms present. However, technologies are available to selectively label specific types of microorganisms. For example, fluorescent antibodies can be used to label microorganisms according to expression of particular antigens, fluorescent in situ hybridisation to label according to phylogeny and fluorogenic enzymatic substrates to label according to expression of specific enzyme activities. Reagents are also available that stain viruses sufficiently brightly to enable their direct detection in environments such as sea water. Microorganisms need to be detected in a variety of different matrices (e.g., water, mud, food, and beverages) and these matrices may be highly variable in nature (e.g., tap water compared to river water). Many matrices have high background autofluorescence (e.g., algae and minerals in water samples) or may bind non-specifically to the fluorescent biological reagents used (e.g., protein micelles in milk). Formulation of biological reagents and sample pre-treatments are critical to the development of suitable microbiological assays. Here, developments in instrumentation and biological reagents for microbiological applications are reviewed with specific examples from environmental or industrial microbiology. The broader considerations for the development of microbial assays for flow cytometry are also considered.
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Affiliation(s)
- D A Veal
- Centre for Development of Fluorimetric Applications in Biotechnology, Department of Biological Sciences, Macquarie University, 2109, Sydney, NSW, Australia.
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Weir C, Vesey G, Slade M, Ferrari B, Veal DA, Williams K. An immunoglobulin G1 monoclonal antibody highly specific to the wall of Cryptosporidium oocysts. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2000; 7:745-50. [PMID: 10973448 PMCID: PMC95949 DOI: 10.1128/cdli.7.5.745-750.2000] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/1999] [Accepted: 05/17/2000] [Indexed: 11/20/2022]
Abstract
The detection of Cryptosporidium oocysts in drinking water is critically dependent on the quality of immunofluorescent reagents. Experiments were performed to develop a method for producing highly specific antibodies to Cryptosporidium oocysts that can be used for water testing. BALB/c mice were immunized with six different antigen preparations and monitored for immunoglobulin G (IgG) and IgM responses to the surface of Cryptosporidium oocysts. One group of mice received purified oocyst walls, a second group received a soluble protein preparation extracted from the outside of the oocyst wall, and the third group received whole inactivated oocysts. Three additional groups were immunized with sequentially prepared oocyst extracts to provide for a comparison of the immune response. Mice injected with the soluble protein extract demonstrated an IgG response to oocysts surface that was not seen in the whole-oocyst group. Mice injected with whole oocysts showed an IgM response only, while mice injected with purified oocyst walls showed little increase in IgM or IgG levels. Of the additional reported preparations only one, BME (2-mercaptoethanol treated), produced a weak IgM response to the oocyst wall. A mouse from the soluble oocyst extract group yielding a high IgG response was utilized to produce a highly specific IgG(1) monoclonal antibody (Cry104) specific to the oocyst surface. Comparative flow cytometric analysis indicated that Cry104 has a higher avidity and specificity to oocysts in water concentrates than other commercially available antibodies.
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Affiliation(s)
- C Weir
- BioTechnology Frontiers, North Ryde BC, New South Wales 1670, Australia.
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Ferrari BC, Vesey G, Davis KA, Gauci M, Veal D. A novel two-color flow cytometric assay for the detection ofCryptosporidium in environmental water samples. ACTA ACUST UNITED AC 2000. [DOI: 10.1002/1097-0320(20001101)41:3<216::aid-cyto9>3.0.co;2-r] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Höglund CE, Stenström TAB. Survival ofCryptosporidium parvumoocysts in source separated human urine. Can J Microbiol 1999. [DOI: 10.1139/w99-066] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The survival of Cryptosporidium parvum in source separated urine was investigated as part of a broader study on microbial risks associated with the reuse of human urine for sustainable agriculture. A dye permeability assay and in vitro excystation were the primary methods used to assess viability. In the collected urine most of the nitrogen is present as ammonia and the pH is generally around 9. Parallel investigations were made in buffers to compare possible toxic effects of urine to actual pH effects. Oocysts in the untreated urine were inactivated below the detection limit (1/300) within 63 days. This inactivation rate was significantly higher (P < 0.01) than in urine adjusted to pH 5 or 7 according to the dye permeability assay. The corresponding difference between different pH values was not seen in buffers, suggesting that the antiprotozoan effect of urine was mediated by other factors besides pH. The Swedish practice of storing urine for six months before its use thus appears satisfactory for the inactivation of Cryptosporidium oocysts.Key words: Cryptosporidium parvum, oocysts, human urine, survival, source separation.
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Affiliation(s)
- S D Richardson
- National Exposure Research Laboratory, U.S. Environmental Protection Agency, Athens, Georgia 30605, USA
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