Molecular characterization and risk analysis of Giardia duodenalis assemblages in corticosteroid-treated and non-treated patients in Ismailia, Arab Republic of Egypt

Abstract Background Giardia duodenalis (G. duodenalis) is an intestinal protozoan parasite of human and animal hosts. The present study investigated and compared the assemblages of G. duodenalis-infected faecal samples in patients on corticosteroid therapy (POCT) and control patients-not on corticosteroid therapy (CONT) and differentiated its assemblages and/or sub-assemblages’ relationship with associated risk factors. Methods Utilizing multi-locus sequence typing (MLST) with three loci targeted—triosephosphate isomerase (tpi), ꞵ-giardin (bg), and glutamate dehydrogenase (gdh)—G. duodenalis isolated from POCT and CONT were analyzed. Risk factors linked with Giardia infection and its assemblages were investigated. Results In total, 52 G. duodenalis-infected patients were enrolled: 21 POCT and 31 CONT. The mean age was 12.3 years, the majority were male (59.6%), and 73.1% lived in rural areas. The POCT group was 36 times more likely than the CONT group to have a concurrent parasitic infection. About 73% (38/52) of Giardia samples were genotyped and/or sub-genotyped in at least one of the three loci. MLST identified sixteen isolates (42.0%) as assemblage B, ten isolates (26.3%) as assemblage A, and twelve isolates (31.6%) as a mixed infection of A + B and B + E. Most individuals of the POCT group were infected with G. duodenalis assemblage A while most of the CONT group were infected with assemblage B. Sub-assemblage AII was identified by phylogenetic analysis in the isolates of both groups under investigation. Conclusion This research advances giardiasis epidemiology in Arab Republic of Egypt (ARE) and reflects how corticosteroid-treated patients differ from those non-treated in Giardia assemblage pattern and their susceptibility to concomitant infection. Overall, Giardia assemblage patterns in this research populations reflect anthroponotic and zoonotic transmission, emphasizing the importance of public health policy and giardiasis prevention of illness transmission, particularly among those on corticosteroid therapy in ARE.