Submitted to: Journal of American Water Works Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/6/1997
Publication Date: N/A
Interpretive Summary: A major problem in the water industry is the inability to detect and remove pathogenic organisms that are not culturable by classic methods. Cryptosporidium is one such organism that can be potentially fatal for immunosuppressed persons. Chemical analysis of lipids revealed differences between species of the parasite and between infectious and noninfectious oocysts (the infective stage). These findings suggest a high probability that a single direct chemical assay can identify the species of Cryptosporidium as well as infectious stages in drinking water. In fact this chemical analysis of oocysts based on lipids can be performed with equipment already in use in water utilities. It will provide detection/identification of specific lipids and will allow for an independent determination of infectious potential of the oocysts, at least under some conditions at the required sensitivity. Further resources could allow the development of an automated system to protect drinking water from this and other non-culturable but infectious agents.
Technical Abstract: Unique signature lipid biomarkers were found in oocysts of Cryptosporidium parvum. This makes possible rapid detection and identification and potential infectivity directly from drinking water membrane filter retentates. Signature lipid analysis showed marked shifts in composition when oocysts were subjected to conditions that rendered them noninfectious for neonatal mice. Oocyst lipids were analyzed after extraction with one phase Bligh/Dwyer solvent, fractionation into neutral lipids, glycolipids, and polar lipids by silicic acid and thin layer chromatography followed by alkaline and acid methanolysis. Correlations between the lipid composition of oocysts and infectivity to neonatal BALB/c mice showed a marked shift in fatty acid patterns and a loss of 10-OH 18:0 in the PE. Marked differences in the fatty acid patterns were demonstrated between C. parvum and C. muris in the polar lipids and neutral lipids of the oocysts.