Arrival of Klebsiella pneumoniae producing KPC carbapenemase

Background: KPC-type carbapenemases are increasingly prevalent in parts of the USA and Israel and are an emerging concern in South America, Europe and China. We investigated the UK’s first two KPC-producing Klebsiella pneumoniae isolates. Methods: The isolates were referred to the UK’s national reference laboratory for confirmation of carba-penem resistance. Susceptibilities were determined by agar dilution, and blaKPC and Tn4401-like elements were sought by PCR and sequencing. Isolates were compared by PFGE of XbaI- and SpeI-digested genomic DNA. Results: The isolates were from patients in different UK hospitals, with no epidemiological connection. Both were resistant to carbapenems (MICs> 16 mg/L), with imipenem MICs unchanged by EDTA, and also to all other b-lactams (including inhibitor combinations), tobramycin, amikacin and ciprofloxacin. They were susceptible to gentamicin (MICs 1 mg/L) and colistin (MICs 0.5 mg/L), with intermediate susceptibility to tigecycline (MICs 1–2 mg/L). The isolates belonged to the same PFGE-defined strain, highly related to a disseminated KPC-producing strain characterized previously in Tel Aviv, Israel. Like this Israeli strain, the UK isolates produced KPC-3 carbapenemase, with the blaKPC-3 gene located within a Tn4401-like element