in vitro effect of folic acid and cobalamin (vitamin b12) on adhesion and growth of giardia lamblia

giardia lamblia is one of the most common intestinal protozoan parasites infecting human in the world. the goal of this study was searching for in-vitro effect of folic acid and cobalamin on adhesion and growth of g. lamblia as two important mechanisms in the pathogenesis in tyi-s-33 medium. g. lamblia trophozoites were obtained by in- vitro excystation procedure. three groups of giardia trophozoites were analyzed: control group, g.lamblia was cultured in tyi-s-33 without any vitamin, 2nd group with 0.1 µg/ml vitamin b12 or folic acid, and 3rd group with 0.5 µg/ml of vitamin b12 or folic acid. all culture media tubes incubated at 37 ºc. after 2 h of incubation, the adherence into borosilicate culture tubes, and after 24 h the growth of trophozoites were measured .the results showed that in vitamin b12 groups, the growth was increased significantly (p≤ 0.05) but the adherence decreased significantly (p≤ 0.05). folic acid inhibited the growth rate significantly (p≤ 0.05), but it increased adherence in axenic culture significantly (p≤ 0.05). the results showed that vitamin b12 and folic acid altogether might reduce pathogenesis of g. lamblia by reducing adherence and growth, respectively.