title: Limitations of tpi and bg genes sub-genotyping for characterization of human Giardia duodenalis isolates.
abstract: The intestinal protozoan Giardia duodenalis includes 2 genetically distinct assemblages, A and B, which are responsible for human infections. Little is known so far on the genotypes of G. duodenalis human isolates in France. The present characterization of 19 French clinical isolates was aimed at determining their genotype patterns and associations with clinical symptoms, and in vivo metronidazole resistance, respectively. Based on both triose-phosphate isomerase (tpi) and β-giardin (bg) gene sequences, twelve isolates were identified as assemblage A, and 7 as assemblage B for the 2 gene loci. Sub-genotyping heterogeneities were observed in 15/19 isolates attributed to either A or B assemblage. They include frequent mismatches and intra-assemblage discordances and mixed positions, which were found more frequently in tpi than in bg sequences, and in assemblage B than in assemblage A sequences. No association was found between sub-genotypes, clinical symptoms and metronidazole sensitivity. Present data underline the need for improvements in the standardization of G. duodenalis multilocus genotyping approach for further molecular epidemiologic studies of giardiasis.
authors.affiliation: Laboratory of Parasitology, ADEN-EA 4311-IFR 23, Rouen University Hospital, Rouen, France. bonhomme-j@chu-caen.fr
authors.forename: Julie
authors.initials: J
authors.lastname: Bonhomme
authors.forename: Laetitia
authors.initials: L
authors.lastname: Le Goff
authors.forename: Véronique
authors.initials: V
authors.lastname: Lemée
authors.forename: Gilles
authors.initials: G
authors.lastname: Gargala
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Ballet
authors.forename: Loïc
authors.initials: L
authors.lastname: Favennec
mesh_terms: D000328:Adult; D000818:Animals; D001483:Base Sequence; D002648:Child; D002675:Child, Preschool; D003598:Cytoskeletal Proteins / Q000235:genetics*; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D005243:Feces / Q000469:parasitology; D005602:France; D005838:Genotype; D016829:Giardia lamblia / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D005873:Giardiasis / Q000469:parasitology*; D006801:Humans; D007223:Infant; D051379:Mice; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D015800:Protozoan Proteins / Q000235:genetics*; D017422:Sequence Analysis, DNA; D014305:Triose-Phosphate Isomerase / Q000235:genetics*
chemical_list: D003598:Cytoskeletal Proteins; D016054:DNA, Protozoan; D015800:Protozoan Proteins; C038207:giardin protein, Giardia lamblia; D014305:Triose-Phosphate Isomerase