Evaluation of cyst loss in standard procedural steps for detecting ofGiardia lamblia andCryptosporidium parvum in water |
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Authors: | Kyung-Ju Kim Hyang-Hee Jung Kisay Lee |
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Institution: | (1) School of Biotechnology and Environmental Engineering, Myongji University, 449-728 Yongin, Korea |
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Abstract: | The standard procedure outlined by the United States Environmental Protection Agency (US EPA) in Method 1623 for analyzingGiardia lamblia cysts andCryptosporidium parvum oocysts in water samples consists of filtration, elution, centrifugal concentration, immunomagnetic separation (IMS), and
immunofluorescence assay (IFA) followed by microscopic examination. In this study, the extent of (oo)cyst loss in each step
of this procedure was evaluated by comparing recovery yields in segmented analyses: (i) IMS+IFA, (ii) concentration +IMS+IFA,
and (iii) filtration/elution + concentration +IMS+IFA. The complete (oo)cyst recovery by the full procedure was 52–57%. The
(oo)cyst loss in the IMS step was only 0–6%, implying that IMS is a fairly reliable method for (oo)cyst purification. Centrifugal
concentration of the eluted sample and pellet collection before IMS resulted in a loss of 8–14% of the (oo)cysts. The largest
(oo)cyst loss occurred in the elution step, with 68–71% of the total loss. The permeated loss of (oo)cysts was negligible
during filtration of the water sample with a 1.0-μm pore polyethersulfone (PES) capsule. These results demonstrated that the
largest fraction of (oo)cyst loss in this procedure occurred due to poor elution from the filter matrix. Improvements in the
elution methodology are therefore required to enhance the overall recovery yield and the reliability of the detection of these
parasitic protozoa. |
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Keywords: | Cryptosporidium parvum Giardia lamblia detection and analysis Method 1623 (oo)cysts recovery loss |
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