Identification of blaVIM-1 Gene in ST307 and ST661 Klebsiella pneumoniae Clones in Italy: Old Acquaintances for New Combinations.

In the past years, the Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae sequence type 258 (ST258) became an important worldwide spread nosocomial pathogen. Recent evidence shows that the global epidemiology is changing, with the rise of new lineages. In this study we report the microbiological and genomic features of two VIM-1-producing K. pneumoniae isolates belonging to the emerging ST307. Two extensively drug-resistant K. pneumoniae strains, collected between May and June 2017, were confirmed as blaVIM positive by GeneXpert system. The whole-genome sequencing revealed that both KpV_S_1 and KpV_S_2 isolates harbored blaVIM-1 and blaCTX-M-15 genes, besides qnrS1 and qnrB1, strB, mphA, tetR, and tetA determinants. KpV_S_1 and KpV_S_2 isolates belonged to ST661 and ST307, respectively. Both STs have been recently reported as responsible of outbreaks in several European countries. The detection of blaVIM-1 gene in nonpredominant K. pneumoniae clones in a hospital setting should alert on the changing of the epidemiological situation in Italy, usually endemic reservoir of KPC enzyme.