Resumo

Carbapenem resistance in Klebsiella pneumoniae due the KPC production has been reported in worldwide. The blaKPC genes are commonly encoded on plasmid transferable and transposons, which explains the rapid spread of this resistance determinant. The aim of this study was perform the molecular characterization of genetically related K. pneumoniae clinical isolates carrying blaKPC gene with distinct susceptibility profiles to carbapenems. The isolates (KPN132 and KPN133) were collected with one week of interval from the same patient. The minimal inhibitory concentrations (MIC) were determined using microdilution broth. The blaKPC, blaTEM, blaSHV, blaCTX-M genes, class 1 integron elements, plasmid typing, determining of sequence type (ST) and analysis of the genetic environment blaKPC gene were investigated by PCR. The plasmid DNA obtained with Plasmid Mini Kit (QIAGEN) was used for transformation experiments in the DH5α recipient strain. The isolates were resistant to all beta-lactams tested and ciprofloxacin. Molecular analyzes revealed the presence of blaKPC-2, blaTEM, blaCTX-M-2-like genes and class 1 integron in both isolates their transformants. Despite the presence of the same resistance genes, the KPN133 isolate showed higher MIC values for cefotaxime, cefepime, meropenem and ertapenem compared to isolated KPN132. The plasmid analysis indicated the presence of a 39 kb plasmid, which belongs to the group IncK, in KPN 132 and KPN133 transformant cells, suggesting the blaKPC-2 location. The analysis of the genetic environment of blaKPC-2 gene revealed the presence of a transposon Tn4401b, the most widespread isoform in Brazil. MLST analysis resulted in ST11, part of CC258, the clonal complex more disseminated in the world, often reported in Brazil. The distinct phenotypic profiles to carbapenems presented by isolates should be a result of regulatory mechanisms of the expression of blaKPC gene, as previously reported. Further analysis will be performed to identify these mechanisms.