title: Evaluation of Giardia duodenalis viability after metronidazole treatment by flow cytometry.
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.
authors.affiliation: Serviço de Microbiologia, Centro de Investigação em Tecnologias e Sistemas de Informação em Saúde, Faculdade de Medicina, Universidade do Porto, Porto, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Barbosa
authors.affiliation: Serviço de Microbiologia, Centro de Investigação em Tecnologias e Sistemas de Informação em Saúde, Faculdade de Medicina, Universidade do Porto, Porto, Portugal.
authors.forename: Acácio Gonçalves
authors.initials: AG
authors.lastname: Rodrigues
authors.affiliation: Faculdade de Ciências, Universidade de Vigo, Vigo, Galiza, Espanha.
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Pérez
authors.affiliation: Serviço de Microbiologia, Centro de Investigação em Tecnologias e Sistemas de Informação em Saúde, Faculdade de Medicina, Universidade do Porto, Porto, Portugal.
authors.forename: Cidália
authors.initials: C
authors.lastname: Pina-Vaz
mesh_terms: D000981:Antiprotozoal Agents / Q000494:pharmacology*; D005434:Flow Cytometry; D016829:Giardia lamblia / Q000187:drug effects* / Q000502:physiology; D020128:Inhibitory Concentration 50; D008795:Metronidazole / Q000494:pharmacology*; D050296:Microbial Viability / Q000187:drug effects*; D021261:Parasitic Sensitivity Tests; D011419:Propidium
chemical_list: D000981:Antiprotozoal Agents; D008795:Metronidazole; D011419:Propidium