Oral Presentation Australian Society for Microbiology Annual Scientific Meeting 2022

Conjugation efficient hybrid interference plasmids to cure target antibiotic resistance plasmids in vivo (82390)

Muhammad Kamruzzaman 1 , Qin Qi 1 , Jon Iredell 2
  1. The Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW, Australia
  2. Westmead Hospital, Westmead, NSW, Australia

The steady rise of transmissible antimicrobial resistance (AMR) in bacterial species Enterobacteriaceae is a serious concern for human health. Almost all high-profile antibiotic resistance (β-lactam, carbapenem, colistin) is mobile, carried on plasmids. We developed conjugative interference plasmids to cure target AMR plasmids from bacteria in vivo by exploiting plasmid replication incompatibility and toxin-antitoxin systems. In this study, we present a novel approach to construct hybrid interference plasmids with high conjugation efficiency that successfully targeted and cured AMR plasmids of two incompatibility groups that are associated with clinically relevant antibiotic resistance genes. This was achieved by incorporating the replication incompatibility region and antitoxin gene(s) of target plasmids into the backbone of an unrelated plasmid with a highly efficient conjugation machinery. We constructed two interference plasmids that target IncC plasmids and a novel conjugative plasmid pKPC_UVA01 with an unknown Inc type, responsible for the wide dissemination of blaKPC carbapenemase gene in the United States. We identified the genetic region that is required for the incompatibility of pKPC_UVA01. The theta replicon and the higA antitoxin gene of IncC plasmid were integrated into the backbone of an IncM interference plasmid to construct hybrid interference plasmids pCure_IncC that target IncC plasmids. Similarly, the novel replication incompatibility region and the ccdA-like antitoxin of pKPC_UVA01 were combined into the same IncM interference plasmid to generate pCure_KPC. Crucially, we demonstrated that these hybrid interference plasmids can successfully eradicate IncC plasmids (types 1 and 2) of clinical origins and the pKPC_UVA01 plasmid from Escherichia coli host cells in a murine gastrointestinal tract model in vivo, highlighting the therapeutic potential of these bespoke curing plasmids.