Genomic islands 1 and 2 play key roles in the evolution of extensively drug-resistant ST235 isolates of Pseudomonas aeruginosa

Abstract

Pseudomonas aeruginosa are noscomially acquired, opportunistic pathogens that pose a major threat to the health of burns patients and the immunocompromised. We sequenced the genomes of P. aeruginosa isolates RNS_PA1, RNS_PA46 and RNS_PAE05, which displayed resistance to almost all frontline antibiotics, including gentamicin, piperacillin, timentin, meropenem, ceftazidime and colistin. We provide evidence that the isolates are representatives of P. aeruginosa sequence type (ST) 235 and carry Tn6162 and Tn6163 in genomic islands 1 (GI1) and 2 (GI2), respectively. GI1 disrupts the endA gene at precisely the same chromosomal location as in P. aeruginosa strain VR-143/97, of unknown ST, creating an identical CA direct repeat. The class 1 integron associated with Tn6163 in GI2 carries a blaGES-5–aacA4–gcuE15–aphA15 cassette array conferring resistance to carbapenems and aminoglycosides. GI2 is flanked by a 12 nt direct repeat motif, abuts a tRNA-gly gene, and encodes proteins with putative roles in integration, conjugative transfer as well as integrative conjugative element-specific proteins. This suggests that GI2 may have evolved from a novel integrative conjugative element. Our data provide further support to the hypothesis that genomic islands play an important role in de novo evolution of multiple antibiotic resistance phenotypes in P. aeruginosa.

Accessory genome contributes to the virulence and resistance of the ocular isolate of Pseudomonas aeruginosa: A complete genome analysis

“…An exoU -island of 7.5 Kbp carrying five open reading frames was observed in PA34 (RGP7). In contrast to other exoU -islands that contain genes associated with integration, transposition, conjugations and sometimes antibiotic resistance (51), the exoU island observed here contains only three genes that have homology to a site-specific integrase (Fig. 4A).…”

Lateral gene transfer, bacterial genome evolution, and the Anthropocene

“…This increased the size, complexity, and diversity of the ICEs. Expansion of the gene content of ICEs and genomic islands expands the number of phenotypes with relevance for human welfare, and has done so in many species of clinical importance, including Pseudomonas aeruginosa , Acinetobacter baumannii , and Escherichia coli …”

Clonal Dissemination of Pseudomonas aeruginosa Sequence Type 235 Isolates Carrying bla IMP-6 and Emergence of bla GES-24 and bla IMP-10 on Novel Genomic Islands PAGI-15 and -16 in South Korea

“…These genomic islands typically carry genes for integration, transfer, and maintenance, which confer self-transferability to the composite ICE, along with genes conferring metabolic, virulence, and heavy metal resistance capability, which offer extra benefit to the bacterial host. Although PAGIs associated with antimicrobial resistance are rare, some examples have been identified, e.g., derivatives of PAGI-1 and PAGI-2 (13).…”