Emergence of blaKPC carbapenemase genes in Australia

bla(KPC) encoding resistance to carbapenems are increasingly widely reported and are now endemicin parts of several countries, but only one Klebsiella pneumoniae isolate carrying bla(KPC-2) had previously been reported in Australia, in 2010. Here we characterised this isolate, six additional K. pneumoniae and one Escherichia coli carrying bla(KPC) and another K. pneumoniae lacking bla(KPC), all isolated in Australia in 2012. Seven K. pneumoniae belonged to clonal complex (CC) 292, associated with bla(KPC) in several countries. Five with bla(KPC-2) plus the isolate lacking a bla(KPC) gene were sequence type 258 (ST258) and the seventh was the closely related ST512 with bla(KPC-3). The eighth K. pneumoniae isolate, novel ST1048, and the E. coli (ST131) also carried bla(KPC-2). bla(KPC) genes were associated with the most common Tn4401a variant, which gives the highest levels of expression, in all isolates. The ST258 isolates appeared to sharea similar set of plasmids, with IncFII(K), IncX3 and ColE-type plasmids identified in most isolates. All K. pneumoniae isolates had a characteristic insertion in the ompK35 gene resulting in a frameshift and early termination, but only the ST512 isolate had a GlyAsp insertion in loop 3 of OmpK36 that may contribute to increased resistance. The clinical epidemiology of bla(KPC) emergence in Australia thus appears to reflect the global dominance of K. pneumoniae CC292 (and perhaps E. coli ST131). Some, but not all, patients carrying these isolates had previously been hospitalised outside Australia, suggesting multiple discrete importation events of closely related strains, as well as undetected nosocomial spread. Crown Copyright (C) 2014 Published by Elsevier B.V. on behalf of International Society of Chemotherapy. All rights reserved.