Tn 6350, a Novel Transposon Carrying Pyocin S8 Genes Encoding a Bacteriocin with Activity against Carbapenemase-Producing Pseudomonas aeruginosa

Abstract

A novel transposon belonging to the Tn3-like family was identified on the chromosome of a commensal strain of Pseudomonas aeruginosa sequence type 2343 (ET02). Tn6350 is 7,367 bp long and harbors eight open reading frames (ORFs), an ATPase (IS481 family), a transposase (DDE catalytic type), a Tn3 resolvase, three hypothetical proteins, and genes encoding the new pyocin S8 with its immunity protein. We show that pyocin S8 displays activity against carbapenemase-producing P. aeruginosa, including IMP-1, SPM-1, VIM-1, GES-5, and KPC-2 producers.

Keywords: Pseudomonas aeruginosa; S-type pyocins; bacteriocin; metallo-β-lactamases; transposon.

FIG 1

Genetic organization of Tn6350 (GenBank accession number KY347015), which harbors genes encoding pyocin S8. Predicted coding regions are represented by thick arrows indicating the direction of transcription. This element contains eight ORFs, including an ATPase (orf1), a transposase (int), a resolvase (tnpR), a cytotoxic subunit of pyocin S8 (pys8), an immunity subunit of pyocin S8 (imm), and three more hypothetical proteins (ofr4, orf7, and orf8). The inverted repeat (IR) sequences flanking the element are marked by black triangles (IRL, inverted repeat left; IRR, inverted repeat right). They have 48 bp and 100% identity. The element is flanked by short direct repeats (DRs) rich in CG dinucleotide.