Molecular Epidemiology of Metallo-β-Lactamase-Producing Pseudomonas aeruginosa Isolates from Norway and Sweden Shows Import of International Clones and Local Clonal Expansion

Abstract

Scandinavia is considered a region with a low prevalence of antimicrobial resistance. However, the number of multidrug-resistant (MDR) Gram-negative bacteria is increasing, including metallo-␤-lactamase (MBL)-producing Pseudomonas aeruginosa. In this study MBL-producing P. aeruginosa isolates identified in Norway (n ‫؍‬ 4) and Sweden (n ‫؍‬ 9) from 1999 to 2007 were characterized. Two international clonal complexes (CC), CC111 (n ‫؍‬ 8) and CC235 (n ‫؍‬ 2), previously associated with MBL-producing isolates, were dominant. CC111 isolates (ST111/229; serotype O12; bla VIM-2 ) included clonally related isolates identified in Skåne County, Sweden (n ‫؍‬ 6), and two isolates associated with importation from Greece and Denmark. In all CC111 isolates, bla VIM-2 was located in integron In59.2 or In59 variants. The two CC235 isolates (ST235/ST230; serotype O11; bla VIM-4 ) were imported from Greece and Cyprus, were possibly clonally related, and carried bla VIM-4 in two different integron structures. Three isolates imported from Ghana (ST233; serotype O6; bla VIM-2 ), Tunisia (ST654; serotype O11; bla VIM-2 ), and Thailand (ST260; serotype O6; bla IMP-14 ) were clonally unrelated. ST233 was part of a new CC (CC233) that included other MBL-producing isolates, while ST654 could also be part of a new CC associated with MBL producers. In the isolates imported from Ghana and Tunisia, bla VIM-2 was part of unusual integron structures lacking the 3 conserved segment and associated with transposons. The bla VIM gene was found to be located on the chromosome in all isolates. Known risk factors for acquisition of MBL were reported for all patients except one. The findings suggest that both import of successful international clones and local clonal expansion contribute to the emergence of MBL-producing P. aeruginosa in Scandinavia.

Primary mechanisms mediating aminoglycoside resistance in the multidrug-resistant Pseudomonas aeruginosa clinical isolate PA7

“…Sekiguchi et al, 2007;Samuelsen et al, 2010), while others pointed out that upregulation of the MexXY efflux system and acquisition of AMEs co-existed in the same clinical P. aeruginosa strains (e.g. Henrichfreise et al, 2007;Hocquet et al, 2007).…”

“…O12 is a predominant serotype associated with multidrug resistance to a number of antibiotic classes, including aminoglycosides and b-lactams, although it represents a minor serotype in the environment (Legakis et al, 1982;Pitt et al, 1990;Bert et al, 1996;Samuelsen et al, 2010). The presence of the oprA gene in P. aeruginosa might be more advantageous for its survival in the presence of aminoglycosides, other antimicrobials such as b-lactams (e.g.…”

“…A significant relationship between antibiotic use, for example, aminoglycoside, fluoroquinolone and cefepime, and the incidence of MexXY-overproducing P. aeruginosa has been reported (Hocquet et al, 2008). AMEs are also common determinants of aminoglycoside resistance in P. aeruginosa, except for CF isolates (Vogne et Henrichfreise et al, 2007;Sekiguchi et al, 2007;Samuelsen et al, 2010;Poole, 2011). Each AME has limited substrate specificity, but individual aminoglycoside-resistant P. aeruginosa isolates can carry multiple (2-5) AMEs and thus exhibit broad-spectrum aminoglycoside resistance (Poole, 2005).…”

“…Henrichfreise Sekiguchi et al, 2007;Samuelsen et al, 2010;Poole, 2011). Each AME has limited substrate specificity, but individual aminoglycoside-resistant P. aeruginosa isolates can carry multiple (2-5) AMEs and thus exhibit broad-spectrum aminoglycoside resistance (Poole, 2005).…”

Outbreaks, persistence, and high mortality rates of multiresistant Pseudomonas aeruginosa infections in a hospital with AIDS-predominant admissions

“…[1][2][3][4][5][6][7][8] These infections are usually associated with high mortality rates. [1][2][3][4][5][6] Also, in patients with human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS), authors have described persistent and recurrent infections caused by non-MR-PA strains.…”