Acquisition of plasmid-borne blaIMP-19 gene by a VIM-1-positive Pseudomonas aeruginosa of the sequence type 235 epidemic lineage.

Sir, Acquired metallo-b-lactamases (MBLs) are the most common acquired carbapenemases in Pseudomonas aeruginosa. They confer a broad-spectrum b-lactam resistance profile, including resistance to the antipseudomonal penicillins, cephalosporins and carbapenems, that is not antagonized by the available b-lactamase inhibitors. Most MBL-producing strains exhibit a multidrug resistance profile, also including resistance to non-b-lactams, due to the accumulation of additional resistance determinants. Although several types of acquired MBLs have been detected in P. aeruginosa, the IMPand VIM-type enzymes are currently the most widespread. A number of genes encoding these enzymes (e.g. blaVIM-1, blaVIM-2, blaVIM-4 and blaIMP-1) have become associated with high-risk clones, such as clonal complex (CC) 235 and CC111, which has promoted their dissemination in Europe and other continents. IMP-19 is an IMP allelic variant that was originally detected in Enterobacter cloacae (GenBank/EMBL accession no. AB201264) and P. aeruginosa (GenBank/EMBL accession no. AB184976) from Japan and, subsequently, in an Aeromonas caviae isolated in France. More recently, it has been reported in Achromobacter xylosoxidans and Acinetobacter spp. isolates from Japan. Here, we report on the first detection of the blaIMP-19 gene in Italy, in a multidrug-resistant (MDR) P. aeruginosa clinical isolate that also produced VIM-1 and belonged to the CC235 epidemic lineage. Research letters