engleski

ARRIVAL OF KPC-PRODUCING KLEBSIELLA PNEUMONIAE IN CROATIA

Objectives 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. Material and methods 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 antibiotic therapy that he received prior to isolation of resistant strain included: vankomycin, ceftazidime, gentamicin, meropenem, penicillin and piperacillin/tazobactam. The patient died from intracerebral bleeding in April 2011. The antimicrobial susceptibility to a wide range of antibiotics was determined by broth microdilution method in Mueller-Hinton broth and 96 well microtiter plates according to CLSI guidelines. A double-disk-synergy test was performed to detect ESBLs. 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. Transconjugant was selected on the combined plates containing meropenem (1 mg/L) and rifampicin (128 mg/mL). The frequency of conjugation was expressed relatively to the number of donor cells. 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. Sequences were analyzed using BioEdit v.7.0.9. (Ibis Biosciences) program. Designation of bla genes based on identified mutations was done according to: Bush K, Jacoby GA. Amino acid sequences for TEM, SHV and OXA extended-spectrum and inhibitor resistant β-lactamases. Published by the Lahey Clinic ; 2002. Available from: http:// www.lahey.org/studies/). Genotyping of the strain was performed by MLST. Results 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. Conclusions 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; meropenem

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