First report of the distribution of Locus of Adhesion and Autoaggregation (LAA) pathogenicity island in LEE-negative Shiga toxin-producing Escherichia coli isolates from Argentina

• DOI: 10.1016/j.micpath.2018.07.011
• Publication Date: 2018-07-23T14:33:04Z
• Authors: Rocío Colello; María Victoria Vélez; Juliana González; David A. Montero; Ana V. Bustamante; Felipe Del Canto; Analía I. Etcheve...; Roberto Vidal; Nora Lía Padola
• Keywords: Genetic Markers; 0301 basic medicine; Genomic Islands; Argentina; LEE-negative STEC; Shiga Toxin 1; Shiga Toxin 2; 03 medical and health sciences; LOCUS OF ADHESION AND AUTOAGGREGATION; Bacterial Proteins; https://purl.org/becyt/ford/1.6; Escherichia coli; Animals; Cluster Analysis; LEE-NEGATIVE STEC; Serotyping; https://purl.org/becyt/ford/1; Escherichia coli Infections; Phylogeny; 2. Zero hunger; Locus of Adhesion and Autoaggregation; Adhesins, Escherichia coli; LAA positive STEC; Shiga-Toxigenic Escherichia coli; Escherichia coli Proteins; Phosphoproteins; 3. Good health; LAA POSITIVE STEC; Hemagglutinins; Animals, Domestic; Cattle; Genome, Bacterial

Shiga toxin-producing Escherichia coli (STEC) are important foodborne pathogens that can cause severe disease. The ability to adhere to epithelial cells is an important virulence trait and pathogenicity islands (PAIs) play an important role. Recently, researchers identified a member of the Heat-resistant agglutinin family and characterized this antigen named Hemagglutinin from Shiga toxin-producing E. coli (Hes). More importantly, they showed that hes and other genes such as iha, pagC and agn43 were integrated in each of the four modules present in the new PAI named Locus of Adhesion and Autoaggregation (LAA) whose presence is associated with severe disease linked to with LEE-negatives STEC. The distribution of LAA among STEC strains isolates from different origins between 2000 and 2015 from cattle, the farm environment, and food and harboring diverse virulence was investigated. The STEC strains were characterized by PCR to detect three modules of LAA and agn43 (as marker of module IV), and phylogenetic groups were determined. LAA was found in 46% of LEE-negative STEC corresponding to serogroups O91, O174, O113, O171, O178, O130 and others. The presence of this PAI is associated with strains harboring stx2 (56%) and belonging to phylogroup B1 (91%). LAA is a novel pathogenicity island associated with strains isolated from Hemolytic Uremic Syndrome cases. Therefore, the results of this study contribute to a better understanding regarding the pathogenicity of this emergent subset of STEC strains harboring LAA as a predictor of virulence of LEE-negative STEC strains.