KPC-9, a novel carbapenemase from clinical specimens in Israel

Abstract

A bla(KPC-9) carbapenemase variant was discovered in isolates of Klebsiella pneumoniae and Escherichia coli from a single patient. It differed from bla(KPC-3) by one amino acid substitution (Val239Ala). The K. pneumoniae isolate was typed as ST258, as was the epidemic Israeli KPC-3 clone. bla(KPC-9) was found on a plasmid indistinguishable from pKpQIL that carries bla(KPC-3) in the epidemic clone. Compared to KPC-3, KPC-9 conferred less resistance to carbapenems and higher resistance to ceftazidime.

Fig 1

(A) PFGE (XbaI restricted) of Kp154 (lane 2) and Kp141 (lane 3). Lanes 1 and 10, lambda ladder (New England BioLabs, Ipswich, MA). (B and C) PFGE of plasmids after S1 treatment and a Southern blot after bla_KPC labeling. Lanes 4 and 11, Ec136; lanes 5 and 12, Ec136-TC; lanes 6 and 13, Kp141; lanes 7 and 14, Kp141-TC; lanes 8 and 15, Kp154; lanes 9 and 16, Kp154.

Fig 2

SDS-PAGE showing total proteins from freeze-thaw supernatants. Lane 1, uninduced pZA24-KPC-9 (due to its leaky expression, a faint band is seen at 28.5 kDa); lane 2, Precision Plus Protein standards (Bio-Rad, Hercules, CA); lane 3, induced pZA24-KPC-3; lane 4, induced pZA24-KPC-9; lane 5, induced pZ-Bgl (an identical plasmid expressing a higher-molecular-mass protein; no protein is seen at the size of KPC).