title: Characterization of the variable region in the class 1 integron of antimicrobial-resistant Escherichia coli isolated from surface water.
abstract: Fecal bacteria are considered to be a potential reservoir of antimicrobial resistance genes in the aquatic environment and could horizontally transfer these genes to autochthonous bacteria when carried on transferable and/or mobile genetic elements. Such circulation of resistance genes constitutes a latent public health hazard. The aim of this study was to characterize the variable region of the class 1 integron and relate its genetic content to resistance patterns observed in antimicrobial-resistant Escherichia coli isolated from the surface waters of Patos Lagoon, Southern Brazil. Genetic diversity of the isolates and presence of the qacEΔ1 gene, which confers resistance to quaternary ammonium compounds, were also investigated. A total of 27 isolates were analyzed. The variable region harbored dfrA17, dfrA1 and dfrA12 genes, which confer resistance to trimethoprim, and aadA1, aadA5 and aadA22 genes that encode resistance to streptomycin/spectinomycin. Most of the isolates were considered resistant to quaternary ammonium compounds and all of them carried the qacEΔ1 gene at the 3' conserved segment of the integron. ERIC-PCR analyses of E. coli isolates that presented the integrons showed great genetic diversity, indicating diverse sources of contamination in this environment. These results suggest that fecal bacteria with class 1 integrons in aquatic environments are potentially important reservoirs of antibiotic-resistance genes and may transfer these elements to other bacteria that are capable of infecting humans.
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
authors.forename: Natália
authors.initials: N
authors.lastname: Canal
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
authors.forename: Karine Lena
authors.initials: KL
authors.lastname: Meneghetti
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
authors.forename: Clara Ponzi
authors.initials: CP
authors.lastname: de Almeida
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
authors.forename: Marina
authors.initials: M
authors.lastname: da Rosa Bastos
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
authors.forename: Letícia Muner
authors.initials: LM
authors.lastname: Otton
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil. Electronic address: corcao@ufrgs.br.
authors.forename: Gertrudes
authors.initials: G
authors.lastname: Corção
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001938:Brazil; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D005618:Fresh Water / Q000382:microbiology*; D014644:Genetic Variation; D032023:Integrons; D010802:Phylogeny
chemical_list: D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins
keywords: Antibiotic resistance; Class 1 integron; Escherichia coli; Superficial water