Molecular characterization of carbapenemase-producing Pseudomonas aeruginosa of Czech origin: evidence for clonal spread of extensively resistant ST357 expressing IMP-7 metallo-{beta}-lactamase [PublishAheadOfPrint]

The objective of this study was to perform molecular surveillance for assessing the spread of carbapenemase-producing P. aeruginosa in Czech hospitals. One-hundred thirty-six carbapenemase-producing isolates were recovered from 22 hospitals, located throughout the country. ST357 dominated (n=120) among carbapenemase producers. One-hundred seventeen isolates produced IMP-type (IMP-7 [n=116] and IMP-1 [n=1]) metallo-β-lactamases (MβLs), fifteen produced the VIM-2 MβL, while the remaining isolates expressed the GES-5 enzyme. The bla_IMP-like genes were located in three main integron types, with In-p110-like being the most prevalent (n=115). The two other IMP-encoding integrons (In1392 and In1393) have not been described previously. bla_VIM-2-carrying integrons included In59-like, In56, and a novel element (In1391). bla_GES-5 was carried by In717. Sequencing data showed that In-p110-like was associated with a Tn4380-like transposon inserted in genomic island LESGI-3, in P. aeruginosa chromosome. The other integrons were also integrated into P. aeruginosa chromosome. These findings indicated the clonal spread of ST357 P. aeruginosa, carrying the IMP-7-encoding integron In-p110, in Czech hospitals. Additionally, the sporadic emergence of P. aeruginosa producing different carbapenemase types, associated with divergent or novel integrons, punctuated the ongoing evolution of these bacteria.

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