RESUMEN
Drug resistant Pseudomonas aeruginosa represents a therapeutic challenge. To assess the diversity of P. aeruginosa antibiotic resistant variants, isolates were recovered from hospital patients in Colombia. Thirty of 60 isolates contained class 1 integrons and five were of Sequence Type ST235 having appeared in a single intensive care unit. All five possessed an unusual integron but showed differences in gene cassette content and the presence/absence of insertion sequence IS26. This showed that differences can arise rapidly, even within a single ICU. Also, the emergence of IS26 in P. aeruginosa is contributing to the evolution of resistance in this bacterium.
Asunto(s)
Infección Hospitalaria/microbiología , Farmacorresistencia Bacteriana Múltiple , Infecciones por Pseudomonas/microbiología , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/aislamiento & purificación , Antibacterianos/farmacología , Colombia/epidemiología , Infección Hospitalaria/epidemiología , Humanos , Unidades de Cuidados Intensivos/estadística & datos numéricos , Pruebas de Sensibilidad Microbiana , Infecciones por Pseudomonas/epidemiología , Pseudomonas aeruginosa/clasificación , Pseudomonas aeruginosa/genéticaRESUMEN
Eleven clinical class 1 integron-containing Pseudomonas aeruginosa isolates from Australia and Uruguay were investigated for the genomic locations of these elements. Several novel class 1 integrons/transposons were found in at least four distinct locations in the chromosome, including genomic islands. These elements seem to be undergoing successful dispersal by lateral gene transfer since integrons were identified across several lineages and more than one clonal line.
Asunto(s)
Cromosomas Bacterianos/genética , Integrones/genética , Infecciones por Pseudomonas/microbiología , Pseudomonas aeruginosa/genética , Australia , Farmacorresistencia Bacteriana/genética , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Electroforesis en Gel de Campo Pulsado , Genes Bacterianos/genética , Islas Genómicas/genética , Pruebas de Sensibilidad Microbiana , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Infecciones por Pseudomonas/genética , UruguayRESUMEN
A class 2 integron was found in an Escherichia coli isolate mediating a urinary tract infection. Unlike other class 2 integrons from pathogens, the encoded IntI2 protein was functional. The integron possessed a dfrA14 cassette, and a second novel cassette in which a lipoprotein signal peptidase gene is predicted.
Asunto(s)
Infecciones por Escherichia coli/microbiología , Proteínas de Escherichia coli/genética , Escherichia coli/genética , Escherichia coli/patogenicidad , Integrasas/genética , Integrones , Infecciones Urinarias/microbiología , Farmacorresistencia Bacteriana Múltiple/genética , Escherichia coli/enzimología , Escherichia coli/aislamiento & purificación , Genes Bacterianos , Humanos , Datos de Secuencia Molecular , Plásmidos/genética , Recombinación GenéticaRESUMEN
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.