COMPARISON OF IMS-FREE AND IMS REAL-TIME PCR DETECTION OF Giardia lamblia FROM SURFACE WATER

摘要

Giardia lamblia is one of the most important water-borne pathogenic protozoa. Its occurrence in source and drinking water threatens human health seriously. In this study, four quantitative real-time PCR protocols involving Envirochek filtration, flat membrane filtration, immuno-magnetic separation (IMS) and IMS-free separation to detect G. lamblia from surface water were compared. The results showed that acceptable recoveries of 21-28% could be obtained from all of the protocols with 500 cysts spiked into the samples. However, the flat membrane filtration methods were not applicable for its ready being clogged. The Envirochek protocols with or without IMS were comparable with a recovery range of 24-34% when lower volume (5 L) water was tested with different cysts spiked; but for larger volume (15 L), only Envirochek - IMS protocol worked, which suggested that the much cheaper and simpler IMS-free protocol should be an option for clean source water or drinking water, or small volume samples; while the IMS one could be used for contaminated source water with higher turbidity and more PCR inhibitors.