Molecular analysis of OXA-48-carrying conjugative IncL/M-like plasmids in clinical isolates of Klebsiella pneumoniae in Ireland.

This study characterized an IncL/M-like plasmid containing a bla(OXA-48)-encoding gene from a clinical isolate of Klebsiella pneumoniae, denoted as E71T. Investigation of this plasmid sequence identified unique regions of interest along with conserved regions detected in eight other clinical carbapenem-resistant isolates. A 63-kb plasmid (pE71T) from K. pneumoniae E71T was sequenced and found to be highly similar to the recently published K. pneumoniae pOXA-48a (JN626286). Two copies of the insertion sequence element IS1R were identified, one of which was located adjacent to the bla(OXA-48)-encoding gene forming part of a composite transposon Tn1999.2 and the second located 16-kb downstream. Plasmid profiling and PCR assays confirmed that the pE71T backbone was conserved among the eight other clinical bla(OXA-48)-positive isolates, and in all cases, the OXA-48 genes were part of the Tn1999.2 composite transposon. This is the first report of a bla(OXA-48) and IS1R arrangement-containing plasmid in Ireland.