engleski

First report of KPC-producing Klebsiella pneumoniae strain in Croatia

Acquired resistance to carbapenems in uncommon in Enterobacteriaceae although extended-spectrum β-lactamase resistance in these organisms is well established. However, β-lactamase mediated resistance to carbapenems has been reported in Klebsiella pneumoniae, mostly due to the expression of class A KPC β-lactamases susceptible to the inhibition by clavulanic acid, class B metallo-β-lactamases (IMP or VIM) or OXA-48 β-lactamase belonging to the class D β-lactamases. Furtermore, carbapenem resistance can be mediated by hyperproduction of ESBLs or plasmid-mediated AmpC β-lactamases combined with porin loss. In February 2011. a 78 old male patient was admitted to Clinical Hospital Center Zagreb with subdural haematoma. He was previously diagnosed with acute myeloblastic leukemia. After surgical removal of haematoma he developed purulent meningtis. K. pneumoniae with reduced susceptibility to carbapenems was isolated. The antimicrobial susceptibility to a wide range of antibiotics was determined by broth microdilution method. Modified Hodge Test (MHT) was used to screen for production of carbapenemases. MBL E-test was used to screen for production of metallo-β-lactamases. The transferability of meropenem resistance was determined by conjugation (broth mating method) employing E. coli A15R- strain resistant to rifampicin. The presence of genes encoding ESBLs (blaSHV, blaTEM, blaCTX-M), plasmid mediated ampC beta-lactamases and carbapenemases blaKPC, blaOXA-48, blaOXA-NDM, blaVIM and blaIMP was determined by PCR using protocols and conditions as desribed previously.Genotyping of the strain was performed by MLST. The isolate showed resistance or intermediate susceptibility to expanded-spectrum cephalosporins, β-lactam combinations with inhibitors, carbapenems and gentamicin but remained susceptible only to ciprofloxacin and colistin. Modified Hodge test was consistent with the activity of carbapenemases. The MBL test for metallo-β-lactamase was negative indicating the absence of metallo β-lactamase. Imipenem resistance was not transferred to E. coli recipient strain by conjugation. PCR revealed the presence of blaKPC, blaTEM genes and blaSHV genes. Sequencing of blaKPC gene revealed the presence of KPC-2 beta-lactamase. The strain also possessed intrinsic SHV-1 β-lactamase of K. pneumoniae. Neither plasmid-mediated ampC β-lactamase nor OXA-48 β-lactamase were found. The strain was found belong to ST37 clone by MLST. Infection control efforts limited the spread of KPC-producing clone of K. pneumoniae in our hospital so far. The patient was successfully treated with ciprofloxacin. To our knowledge this is the first report of a KPC-producing K. pneumoniae in Croatia. KPC-2 beta-lactamase with similar properties was previously reported from USA, United Kingdom, Israel and Greece. This report demonstrates the need to monitor both hospitalized patients for the further emergence of carbapenem resistance in K. pneumoniae. Continuos surveillance in tracking KPC-producing K. pneumoniae in the the hospitals is necessary to prevent their spread to other hospitals and community.

KPC beta-lactamase ; Klebsiella pneumoniae ; carbapenems

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