title: Urinary tract infections in a South American population: dynamic spread of class 1 integrons and multidrug resistance by homologous and site-specific recombination.
abstract: One hundred four bacterial strains mediating urinary tract infections in separate individuals from a Uruguayan community were isolated. Forty-six strains conferred a multidrug resistance phenotype. All 104 strains were examined for the presence of class 1, 2, and 3 integrons. Class 1 integrons were found in 21 isolates across four distinct bacterial genera. A large class 1 integron in a Klebsiella pneumoniae strain was fully sequenced and was 29,093 bp in length. This integron probably arose by homologous recombination since it was embedded in a hybrid Tn21-like transposon backbone which comprised a Tn5036-like tnp transposition module at the IRi integron end and a Tn21 mer module at the IRt integron end. The parent integron/transposon that contributed the Tn5036 module was not related to Tn1696 since the integron insertion points in the transposon backbones were 16 bases apart. Examination of the other 20 class 1 integron-containing strains revealed further evidence of genetic exchange. This included a strain that possessed a Tn5036 module at the IRt end but not at the IRi end and another that possessed a tnp module beyond IRi that was a hybrid of Tn21 and Tn5051 and that is presumed to have arisen by site-specific recombination. This study highlights the ability of different genetic elements to act cooperatively to spread and rearrange antibiotic resistance in a community.
authors.affiliation: Instituto de Química Biológica, Facultad de Ciencias-UDELAR, Montevideo, Uruguay.
authors.forename: Carolina
authors.initials: C
authors.lastname: Márquez
authors.forename: Maurizio
authors.initials: M
authors.lastname: Labbate
authors.forename: Claudia
authors.initials: C
authors.lastname: Raymondo
authors.forename: Jimena
authors.initials: J
authors.lastname: Fernández
authors.forename: Alicia M
authors.initials: AM
authors.lastname: Gestal
authors.forename: Marita
authors.initials: M
authors.lastname: Holley
authors.forename: Graciela
authors.initials: G
authors.lastname: Borthagaray
authors.forename: H W
authors.initials: HW
authors.lastname: Stokes