Carbapenemases on the move: it\u2019s good to be on ICEs

João Botelho,Luísa Peixe,Ricardo León-Sampedro,Filipa Grosso,Adam P Roberts

doi:10.1186/s13100-018-0141-4

Abstract

BackgroundThe evolution and spread of antibiotic resistance is often mediated by mobile genetic elements. Integrative and conjugative elements (ICEs) are the most abundant conjugative elements among prokaryotes. However, the contribution of ICEs to horizontal gene transfer of antibiotic resistance has been largely unexplored.ResultsHere we report that ICEs belonging to mating-pair formation (MPF) classes G and T are highly prevalent among the opportunistic pathogen Pseudomonas aeruginosa, contributing to the spread of carbapenemase-encoding genes (CEGs). Most CEGs of the MPFG class were encoded within class I integrons, which co-harbour genes conferring resistance to other antibiotics. The majority of the integrons were located within Tn3-like and composite transposons. Conserved attachment site could be predicted for the MPFG class ICEs. MPFT class ICEs carried the CEGs within composite transposons which were not associated with integrons.ConclusionsThe data presented here provides a global snapshot of the different CEG-harbouring ICEs and sheds light on the underappreciated contribution of these elements to the evolution and dissemination of antibiotic resistance on P. aeruginosa.

Highlights

The evolution and spread of antibiotic resistance is often mediated by mobile genetic elements
A plethora of carbapenemase-encoding genes was identified in a subset of Pseudomonas species From the total Pseudomonas genomes analysed (n = 4565), 313 Carbapenemase-encoding gene (CEG) were identified in 297 genomes (Fig. 1 and Additional file 1: Table S1)
BlaVIM-2 represents the majority of the CEGs found among Pseudomonas spp., being detected mainly in P. aeruginosa, followed by P. plecoglocissida, P. guariconensis, P. putida, P. stutzeri and 16 genomes corresponding to unidentified species (Additional file 1: Table S1)

Summary

Introduction

The evolution and spread of antibiotic resistance is often mediated by mobile genetic elements. Carbapenem-resistant P. aeruginosa is in the “critical” category of the World Health Organization’s priority list of bacterial pathogens for which research and development of new antibiotics is urgently required [11]. Besides P. aeruginosa, carbapenem resistance has been reported in other Pseudomonas spp. and is often mediated by the acquisition of carbapenemase-encoding genes (CEGs) [12,13,14]. Mobile genetic elements (MGEs) such as transposons, plasmids and integrative and conjugative elements (ICEs), are responsible for the spread of ARGs [19,20,21,22,23]

Results

Discussion

Conclusion