Abstract: | Giardia duodenalis (syn. lamblia; syn.
intestinalis) susceptibility testing is not routinely performed because
the classical culture methods are very time-consuming and laborious. We developed
a novel flow cytometry (FC) assay to evaluate the susceptibility of G.
duodenalis trophozoites to metronidazole (MTZ). Different concentrations of
MTZ were added to cultures of trophozoites (10
5
/mL) and the cultures were incubated for different periods. The 50%
inhibitory concentration was calculated and propidium iodide (PI) was used to
quantify the number of dead cells. After treatment, PI-positive trophozoites
increased with increasing drug concentration and exposure time. An excellent
correlation was found between FC and the classical method. A novel, accurate and
reliable method is now available to evaluate G. duodenalis
viability. |