in vitro culture and isoenzyme analysis of giardia lamblia

Diamond et al. (1978) does not enhance the growth of G.lamblia in bilesupplemented
medium. Bile, therefore, among other factors apparently obviates
the need for vitamin supplementation. Giardia are unable to synthesise their own
membrane phospholipids, thus the mechanism by which bile promotes parasite
growth is related to the requirement of pre-formed phospholipid which is abundant
in bile and whose uptake is facilitated by presence of conjugated bile salts
(Farthing, 1989).
Certain factors can affect in vitro Giardia cultures.
• Although many antibiotics such as the penicillins, gentamycin, streptomycin,
clindamycin and amphotericin B do not affect the growth of Giardia
trophozoites in vitro (Jakubowski et al., 1988), some however. can impede it's
propagation and growth, e.g. Amikacin, an aminoglycoside, can be toxic to the
trophozoites at high concentrations.
• Bacterial and viral endosymbionts have been found in Giardia of human and
animal origin (Feely et al., 1990). The presence of bacteria in trophozoite
cultures was reported to cause the rate of Giardia multiplication to decrease
markedly (Meyer, 1976) while viral endosymbionts in Giardia trophozoites are
associated with decreased adherence and growth rate (Adam, 1991).
• Low cysteine concentration, high oxygen tension and low temperature cause
detachment of trophozoites from the culture vessel.
Although it is difficult to culture Giaqrdia lamblia, many workers from various parts
of the world have successfully axenised these organisms: Portland (Meyer, 1976);
Atlanta (Visvesvara, 1980); Maryland (Gillin & Diamond, 1981a,b; Keister, 1983);
Australia (Phillips et al., 1984); Belgium (Gordts et al., 1985); Poland (Kasprzak &
105