'Preparation and Treatment Effects on Cryptosporidium parvum Oocysts in the Cell Culture FDM-MPN Assay'

摘要

Isolation and purification of Cryptosporidium parvum oocysts from bovine calf feces varies by vendor. Vendor preparations and laboratory pretreatment methods include the use of sucrose cesium chloride gradients or diethyl ether followed by sheathers gradients. These differences may lead to deviations in oocyst infectivity results. Cell culture has been used to detect infectivity and these variations. Treatments such as bleach surface sterilization or the use of antibiotics may also effect cell culture results. These variations were evaluated using cell-culture foci-detection method-most probable number (FDM-MPN). Vendor 1 oocysts were purified by diethyl ether and sheathers gradient. These samples showed minimal contamination within cell culture and showed similar infection with bleach, antibiotic, and "no treatment". Vendor 2 oocysts were purified using sucrose cesium chloride gradients followed by sheathers gradients. Contamination occurred using these oocysts in approximately 50% of the cell culture assays with antibiotics and without treatment. There was no significant difference in infectivity between the treatments in Vendor 2 samples. No cell culture contamination occurred in any of the bleach treated samples. A standard method for the preparation and treatment of C. parvum oocysts would settle discrepancies in viability and disinfection results; and would allow for more uniform approaches on methods to inactivate C. parvum oocysts. Industry needs the most accurate results to evaluate the potential risk of C. parvum in drinking water.