in vitro culture and isoenzyme analysis of giardia lamblia

SA24 , SA29 and SA305.
Table 5.4. Culture results using in vivo excysted trophozoites as inoculum. Thirty
percent of the culture initiates were lost through contamination, while 40% failed to
establish cultures.
ExcystationlT otal
inoculations
Contaminated
No contamination
but died out
*No contaminationsurvived
20/53 (38%)
6/20 (30%)
8/20(40%)
6/20 (30%)
*6 isolates axenised (30% success).
5.4 Observations
Behaviour of trophozoites in vitro
For fresh isolates, during the initial period of culture, the trophozoites adhered to
the bottom of the culture tube mostly as individual cells without signs of division
(Plate 5.1). This inert period varied with different isolates (from 10 to 15days) and
could be as long as twenty days in some instances after which they showed signs
of division (Plate 5.2). However, as the organisms became adapted to the culture
environment, this period became shorter. When the trophozoites are continuously
passaged they can be seen dividing by day three after subculture. A confluent
monolayer of cells was seen by day 18 in some isolates (Plates 5.3 and 5.4)
However one isolate took 32 days to start dividing; the concentration of fetal
bovine serum was increased from 10 to 15% on day 24 and confluent growth was
reached after 55 days. Interestingly, some trophozoites continually swam around,
never adhering to the surface of the tube.
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