Molecular Characterization of Carbapenemase-Producing Pseudomonas aeruginosa of Czech Origin and Evidence for Clonal Spread of Extensively Resistant Sequence Type 357 Expressing IMP-7 Metallo-beta-Lactamase
Abstract
The objective of this study was to perform molecular surveillance for assessing the spread of carbapenemase-producing Pseudomonas aeruginosa in Czech hospitals. One hundred thirty-six carbapenemase-producing isolates were recovered from 22 hospitals located throughout the country.
Sequence type 357 (ST357) dominated (n = 120) among carbapenemase producers. One hundred seventeen isolates produced IMP-type (IMP-7 [n 116] and IMP-1 [n 1]) metallo--lactamases (MLs), 15 produced the VIM-2 ML, and the remaining isolates expressed the GES-5 enzyme.
The blaIMP-like genes were located in three main integron types, with Inp110-like being the most prevalent (n 115). The two other IMP-encoding integrons (In1392 and In1393) have not been described previously. blaVIM-2-carrying integrons included In59-like, In56, and a novel element (In1391). blaGES-5 was carriedby In717.
Sequencing data showed that In-p110-like was associated with a Tn4380-like transposon inserted in genomic island LESGI-3 in the P. aeruginosa chromosome. The other integrons were also integrated into the 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.