The anti-giardial effectiveness of fungal and commercial chitosan against Giardia intestinalis cysts in vitro.

Chitosan with poly-N-acetylglucosamine sequences is a deacetylated derivative of chitin that can be found in the exoskeletons of crabs, shrimp and lobsters, the cuticles of insects and the cell walls of fungi. The aim of the present study was to compare the effects of fungal chitosan (FC) prepared from the cell walls of Penicillium viridicatum and Penicillium aurantiogriseum with commercially available chitosan (CC) against Giardia intestinalis cysts in vitro. The giardia cysts were isolated using a sucrose method. Four concentrations (50, 100, 200 and 400 μg/ml) of each type of prepared chitosan were applied for 10, 30, 60 and 180 min. The viability of the cysts was checked via 0.1 % eosin staining. Our results indicate that P. viridicatum (with a 47.5 % DD) and P. aurantiogriseum (with a 47.3 % DD) at different concentrations after 180 min precipitated, respectively, 56, 69, 81 and 100 %, and 63, 75, 86 and 100 % mortality rates. CC (with a 54 % DD) showed 79, 84, 93 and 100 % mortality rates. In conclusion, both FC and CC at 400 μg/ml concentrations after 180 min of exposure showed the most potent effect against G. intestinalis cysts. Accordingly, chitosan could be suggested as a new natural nanoform agent for future research in the safe and effective treatment of Giardia infections.