Results Five isolates were phenotypically positive for ESBL production, exhibited resistance to cefepime, ceftazidime, aztreonam and meropenem, and carried the blaPER-1 gene. MLST showed that they belonged to sequence type (ST) 235, which belongs to the international clonal complex 11. Four isolates had the same PFGE pattern. Southern blotting revealed the chromosomal location of the blaPER-1 gene. Analysis of the blaPER-1 flanking regions showed identity to transposon Tn1213 downstream and 1406 bp upstream of blaPER-1. Further upstream, an orfA gene and ISPa12 were identified; both were truncated by the insertion of IS6100.
Conclusions This study confirmed the presence of PER-1-producing P. aeruginosa strains in Greece. The chromosomal location of blaPER-1, as part of a truncated transposon, suggests clonal expansion rather than horizontal gene transfer.
