Genome plasticity favours double chromosomal Tn4401b-blaKPC-2 transposon insertion in the Pseudomonas aeruginosa ST235 clone

Abstract

Background Pseudomonas aeruginosa Sequence Type 235 is a clone that possesses an extraordinary ability to acquire mobile genetic elements and has been associated with the spread of resistance genes, including genes that encode for carbapenemases. Here, we aim to characterize the genetic platforms involved in resistance dissemination in bla KPC-2 - positive P. aeruginosa ST235 in Colombia. Results In a prospective surveillance study of infections in adult patients attended in five ICUs in five distant cities in Colombia, 58 isolates of P. aeruginosa were recovered, of which, 27 (46.6%) were resistant to carbapenems. The molecular analysis showed that 6 (22.2%) and 4 (14.8%) isolates harboured the bla VIM and bla KPC-2 genes, respectively. The four bla KPC-2 -positive isolates showed a similar PFGE pulsotype and belonged to ST235. Complete genome sequencing of a representative ST235 isolate shows a unique chromosomal contig of 7097.241 bp with eight different resistance genes identified and five transposons: a Tn 6162-like with ant(2″)-Ia , two Tn 402-like with ant(3″)-Ia and bla OXA-2 and two Tn 4401b with bla KPC-2 . All transposons were inserted into the genomic islands. Interestingly, the two Tn 4401b copies harbouring bla KPC-2 were adjacently inserted into a new genomic island (PAGI-17) with traces of a replicative transposition process. This double insertion was probably driven by several structural changes within the chromosomal region containing PAGI-17 in the ST235 background. Conclusion This is the first report of a double Tn 4401b chromosomal insertion in P. aeruginosa , just within a new genomic island (PAGI-17). This finding indicates once again the great genomic plasticity of this microorganism . Electronic supplementary material The online version of this article (10.1186/s12866-019-1418-6) contains supplementary material, which is available to authorized users.

Pseudomonas aeruginosa Coharboring BlaKPC-2 and BlaVIM-2 Carbapenemase Genes

“…Currently, three genetic platforms have been reported mobilizing the bla KPC-2- positive Tn 4401b transposon in P. aeruginosa, two different plasmid backbones (8 kb and 31.5 kb) belonging to the IncU and IncP-6 incompatibility groups [43,44], and a double chromosomal insertion within a new genomic island named PAGI-17 [45]. The specific primers were designed to amplify DNA fragments for each platform (Table 2).…”

Diversity and Distribution of Resistance Markers in Pseudomonas aeruginosa International High-Risk Clones

“…In the US, bla PSE-1 was detected however, in Mexico bla GES-1 , bla GES-19 , bla GES-9-like , whereas in Brazil, bla CTXM-2 was reported [ 12 ]. Additionally, bla KPC-2 was confirmed in samples from Colombia and Nigeria [ 12 , 55 , 56 , 57 ].…”

Phenotypic and Genomic Comparison of the Two Most Common ExoU-Positive Pseudomonas aeruginosa Clones, PA14 and ST235

“…Most ST235 strains were collected between 1998 and 2007. They are susceptible to the common antipseudomonal agents in contrast to the ST235 isolates reported from the last decade that were typically either multidrug or extensively drug resistant (21,22,(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49). Thus, our strains may be of interest for the research community to study the unusual features of ST235 in a normal antibiotic-sensitive background.…”

“…This work now introduces the high-risk clone ST235 to be the third most common clone in the P. aeruginosa population. So far, almost all publications have dealt with the infection epidemiology and antimicrobial resistance of the ExoU-positive ST235 clone (subject of 88% of publications, PubMed, search term Pseudomonas aeruginosa ST235, assessed 6 March 2020) (37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49). Antibiotic resistance determinants of MDR and extensively drugresistant (XDR) ST235 strains have been characterized in detail (40-43, 45-47, 49); otherwise, our current knowledge about the lifestyle, physiology, and metabolism of the pandemic ST235 clone is scarce (50).…”

“…The combination of mutation and import of sequences initially generated clone-specific signatures of lifestyle, genome mobility, and virulence. The drug-sensitive representatives that are the subject of this report then rapidly diversified in regional MDR and XDR sublineages (21,22,30,(38)(39)(40)(41)(42)(43)(45)(46)(47).…”