Data for: Treatment-refractory giardiasis is predominantly an imported infection from South Asia associated with Giardia sub-assemblage BIII: a five-year study from the Czech Republic.

Giardiasis is a cosmopolitan parasitic infection caused by a protozoan pathogen Giardia intestinalis. A high number of failures complicates the metronidazole (MTZ) treatment. However, long-term studies characterising the parasites associated with MTZ treatment failures are lacking. This study was designed to map Giardia genotypes, clinical manifestations and geographical origin of giardiasis in a patient cohort from the Czech Republic. A multilocus genotyping was applied to 93 Giardia DNA isolates collected over five years in a tertiary care hospital diagnostic facility, and corresponding patient data, including the treatment outcomes, were evaluated. We found that treatment refractory giardiasis (32.9% of infections) was always symptomatic, associated with South-Asian origin and caused mainly by sub-assemblage BIII parasites. This study confirms the limited efficacy of MTZ treatment, especially in travellers returning from South Asia. The datasets below support the molecular epidemiological study of Giardia intestinalis in the Czech Republic, focusing on clinical treatment failure.