Comparison between two common methods for measuring Giardia lamblia susceptibility to antiparasitic drugs in vitro

• Published in: Acta tropica 2003-10, Vol.88 (2), p.131-135
• Main Authors: Cruz, Agostinho, Isaura Sousa, M, Azeredo, Zaida, Carolina Silva, M, Figueiredo de Sousa, J.C, Manso, Olga, Cabral, Miguel
• Format: Article
• Language: English
• Subjects: Albendazole; Albendazole - pharmacology; Animals; Antibiotics. Antiinfectious agents. Antiparasitic agents; Antiparasitic agents; Antiparasitic Agents - pharmacology; Biological and medical sciences; Giardia lamblia; Giardia lamblia - drug effects; Logistic Models; Medical sciences; Metronidazole; Metronidazole - pharmacology; Parasitic Sensitivity Tests - methods; Pharmacology. Drug treatments; Susceptibility; Tropical medicine
• ISSN: 0001-706X; 1873-6254
• DOI: 10.1016/S0001-706X(03)00196-7

In this study a comparison between two different methods for measuring the susceptibility of Giardia lamblia trophozoites to metronidazole and albendazole is performed. Modifications of Meloni’s method, based on the loss of adherence of parasites to surfaces, and the Hill method, based on the loss of parasite division capacity, are compared. A logistic model was used to calculate the inhibitory concentrations IC 10, IC 50 and IC 90 that were further compared using the respective standard errors. The results obtained, after contact of parasites with the antiparasitic drugs for 24 h, show that the adherence method is more sensitive than the multiplication method for low and moderate inhibitory concentrations of albendazole. Conversely for metronidazole the multiplication method seems to be more sensitive for high inhibitory concentrations of the drug. For screening the IC 50, both methods seem to be effective, however, the inhibition of adherence method have even better performance for the benzimidazole like drugs.