Abstract
The emergence of pan-resistant Klebsiella pneumoniae strains is an increasing concern. In the present study, we describe a cluster of 9 pan-resistant K. pneumoniae sequence type 147 (ST147) isolates encountered in 4 patients over nearly 1 year in 3 hospitals of the United Arab Emirates (UAE). The isolates exhibited highly similar genotypes. All produced chromosomally encoded OXA-181, and the majority also produced the NDM-5 carbapenemase. As with the previously described single isolate from the UAE, MS6671, the mgrB was disrupted by a functional, ISEcp1-driven bla(OXA-181) insertion causing resistance to carbapenems. The mutation was successfully complemented with an intact mgrB gene, indicating that it was responsible for colistin resistance. bla(NDM-5) was located within a resistance island of an approximately 100-kb IncFII plasmid carrying ermB, mph(A), blaTEM-1B, rmtB, bla(NDM-5,) sul1, aadA2, and dfrA12 resistance genes. Sequencing this plasmid (pABC143-NDM) revealed that its backbone was nearly identical to that of plasmid pMS6671E from which several resistance genes, including blaNDM-5, had been deleted. More extensive similarities of the backbone and the resistance island were found between pABC143C-NDM and the bla(NDM-5)-carrying IncFII plasmids of two K. pneumoniae ST147 isolates from South Korea, one of which was colistin resistant, and both also produced OXA-181. Notably, one of these strains was isolated from a patient transferred from the UAE. Our data show that this pan-resistant clone has an alarming capacity to maintain itself over an extended period of time and is even likely to be transmitted internationally.