PFGE Typing of Carbapenem-Resistant E. cloacae

PFGE of XbaI-digested (TaKaRa, Japan) genomic DNA of bla_NDM-1-positive E. cloacae and reference marker Salmonella serotype Braenderup strain (H9812) was performed using a contour-clamped homogeneous electric field (CHEF)-Mapper XA PFGE system (Bio-Rad, USA) for 22 h at 6 V/cm and 14°C, with a pulse angle of 120° and pulse times from 5 to 35 s. Comparison of the PFGE patterns was performed with InfoQuest FP software version 4.5 (Bio-Rad Laboratories, USA) using the Dice similarity coefficient. Clusters were defined as DNA patterns sharing >85% similarity. MLST was carried out as described previously[18 (link)], the database available at http://pubmlst.org/ecloacae was used for assigning STs.