Extensively Drug-Resistant Pseudomonas aeruginosa Isolates ContainingblaVIM-2and Elements of Salmonella Genomic Island 2: a New Genetic Resistance Determinant in Northeast Ohio

Abstract

ABSTRACTCarbapenems are a mainstay of treatment for infections caused byPseudomonas 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-producingP. aeruginosain 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 theblaMBLgene through genome sequencing, and typed MBL-producingP. aeruginosaisolates 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. TheblaMBLgene was identified asblaVIM-2contained within a class 1 integron (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 transposon andSalmonellagenomic island 2 (SGI2)-homologous sequences. This analysis of XDR strains producing VIM-2 from northeast Ohio revealed a novel recombination event betweenSalmonellaandP. aeruginosa, heralding a new antibiotic resistance threat in this region's health care system.