Epidemiological typing of isolates was performed by rep-
PCR (DiversiLab System; bioMe´rieux, Nu¨rtingen, Germany) as
previously described.15 Isolates that clustered 95% were
considered related. Clusters were compared to our in-house
library of worldwide carbapenem-resistant isolates to determine
their epidemiological background.14 Pulsed-field gel
electrophoresis (PFGE) was used as an additional method of
typing as described previously.16 PFGE banding patterns were
analysed with the Molecular Analyst software (BioRad) using
Dice coefficient and the UPGMA (unweighted pair group
method with arithmetic averages) algorithm.