MICROBIOLOGICAL AND MOLECULAR CHARACTERIZATION OF EXTREME DRUG-RESISTANT CARBAPENEMASE-PRODUCING KLEBSIELLA PNEUMONIAE ISOLATES

Fifteen Klebsiella pneumoniae clinical isolates showing non-susceptibility to carbapenems and resistant to colistin were collected in an Italian hospital. All isolates resulted negative to AmpC, MBL and ESBL production but positive to modified Hodge test, therefore were evaluated as KPC producers. The presence of blaKPC genes was verified by polymerase chain reaction (PCR) and sequencing. Furthermore, molecular typing was performed by multilocus sequence typing (MLST). PCR analysis and nucleotide sequencing revealed that all 15 isolates carried the blaKPC-3 gene. MLST analysis attributed the isolates from all patients to belong to the sequence type ST512. All isolates showed extensively drug-resistant (XDR) phenotype. The emergence of colistin-resistant K pneumoniae underscores the implementation of strict control measures to prevent the dissemination of these organisms in hospitals.