Diverse Mobilized Class 1 Integrons Are Common in the Chromosomes of Pathogenic Pseudomonas aeruginosa Clinical Isolates

Abstract

dEleven 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.

Tn 6249 , a New Tn 6162 Transposon Derivative Carrying a Double-Integron Platform and Involved with Acquisition of the bla VIM-1 Metallo-β-Lactamase Gene in Pseudomonas aeruginosa

“…In fact, the two transposons were inserted at the same position in an apparently identical PACS171b-like GI (the PA143/97 GI was identical to that of strain 37308, at least over the length of the available 17,625-bp DNA sequence); moreover, in the two strains, the GIs were inserted at the same chromosomal position as that reported for the PACS171b GI in the PACS171b strain (19,23).…”

“…However, few GIs associated with resistance genes have been described (18,(22)(23)(24), and only two of them have been fully sequenced (22,24). To the best of our knowledge, PA143/97 GI represents the third completely sequenced GI associated with resistance genes from a P. aeruginosa clinical isolate, providing new insight into the role of these elements in resistance dissemination.…”

Molecular Characterization of bla NDM-1 in a Sequence Type 235 Pseudomonas aeruginosa Isolate from France

“…The orfD cassette, already described in In1 and In51, was generally associated with bla oxa-2 or aadA6 genes (19,20). The structure is also close to the chromosomal class 1 integron sequence in Tn6162 with an aacA7 cassette insertion (21) and from In51 (19), already described in P. aeruginosa.…”

“…This is the first report describing the genetic environment of bla NDM-1 in P. aeruginosa. The presence of the association of ISPa7 upstream of a new CR1-borne sul-type integron and a bla NDM-1 region, classically found in plasmids in E. coli or in A. lwoffi, highlights the high plasticity of the P. aeruginosa genome (21). The ability of P. aeruginosa to accumulate overproduction of intrinsic resistance mechanisms, as well as the combination of various genetic determinants, including nonplasmid lateral exchange of resistance regions (21), results in multidrug-resistant or extensively drug-resistant isolates.…”

“…The presence of the association of ISPa7 upstream of a new CR1-borne sul-type integron and a bla NDM-1 region, classically found in plasmids in E. coli or in A. lwoffi, highlights the high plasticity of the P. aeruginosa genome (21). The ability of P. aeruginosa to accumulate overproduction of intrinsic resistance mechanisms, as well as the combination of various genetic determinants, including nonplasmid lateral exchange of resistance regions (21), results in multidrug-resistant or extensively drug-resistant isolates. Multilocus sequence typing, conducted according to published protocols (28; http://pubmlst.org/paeruginosa/), assigned HIABP11 to sequence type 235 (ST235), which has been encountered in clinical and environmental isolates of different countries (29,30), including Serbia (31).…”