Standardization of in vitro culture media for Giardia Lamblia

Abstract

To date, the diagnosis of giardiasis is made by demonstrating cysts and trophozoites of the parasite in the feces of symptomatic and asymptomatic patients. However, the sensitivity of these techniques depends on the experience of the observer, the time spent on each observation, and the amount of cysts excreted.   The purpose of this research was to evaluate the effectiveness of the Diamond's modification TYI-S-33 medium for the in vitro culture of Giardia lamblia. Having the culture of this parasite will allow the production of antigens that will be used when implementing new diagnostic techniques for the infection and determining the presence of specific antibodies in symptomatic and asymptomatic patients. If favorable results are obtained, this method can be used in clinical and epidemiological studies.   Fresh fecal samples were collected that showed more than 6 cysts per field (40x) of Giardia lamblia. Each sample was purified, the cysts were concentrated with distilled water, which were subsequently decystified. The trophozoites obtained were inoculated in the TYI-S-33 medium, Diamond's modification, and incubated at 37°C.   It was demonstrated that the purification, concentration and decystment techniques are effective, easy to carry out and reproducible (tables 1, 2 and 3) while the TYI-S-33 medium, Diamond's modification, under the conditions in which the study was carried out, was not effective for culturing the parasite (table 4).   Further studies are recommended to evaluate the effectiveness of Diamond's modification of TYI-S-33 medium for culturing Giardia lamblia, which will allow the production of antigens that will be used to implement new diagnostic techniques for the infection and determine the presence of specific antibodies in asymptomatic and symptomatic patients.