Extensively drug-resistant Pseudomonas aeruginosa isolates containing bla_VIM-2and elements of Salmonella genomic island 2: A new genetic resistance determinant in northeast Ohio

Carbapenems are a mainstay of treatment for infections caused by Pseudomonas aeruginosa. Carbapenem resistance mediated by metallo - β-lactamases (MBLs) remains uncommon in the United States, despite the worldwide emergence of this group of enzymes. Between March 2012 and May 2013,we detected MBL-producing P. aeruginosa in a university-affiliated health care system in northeast Ohio . We examined the clinical characteristics and outcomes of patients, defined the resistance determinants and structure of the genetic element harboring the bla_MBLgene through genome sequencing, and typed MBL-producing P. aeruginosa isolates using pulsed-field gel electrophoresis (PFGE), repetitive sequence-based PCR (rep-PCR), and multilocus sequence typing (MLST). Seven patients were affected that were hospitalized at three community hospitals, a long-term-care facility, and a tertiary care center; one of the patients died as a result of infection. Isolates belonged to sequence type 233 (ST233) and were extensively drug resistant (XDR), including resistance to all fluoroquinolones, aminoglycosides, and β-lactams; two isolates were nonsusceptible to colistin. The bla_MBLgene was identified as bla_VIM-2contained within a class 1 integren (In559), similar to the cassette array previously detected in isolates from Norway, Russia, Taiwan, and Chicago, IL. Genomic sequencing and assembly revealed that In559 was part of a novel 35-kb region that also included a Tn501-like transposen and Salmonella genomic island 2 (SGI2)-homologous sequences. This analysis of XDR strains producing VIM-2 from northeast Ohio revealed a novel recombination event between Salmonella and P. aeruginosa, heralding a new antibiotic resistance threat in this region's health care system.