Emergence of KPC-producing Klebsiella pneumoniae in Uruguay: infection control and molecular characterization.

C Marquez,V Odizzio,A Acevedo,A Ingold,G Borthagaray,J Viroga,E Nuñez,A Galiana,K Etulain,N Echeverría,H Albornoz,V García-Fulgueiras,O Gonzalez,R Vignoli

doi:10.1002/nmi2.40

Abstract

We describe the first outbreak of Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-KP), the infection control measures adopted and the shift in resistance patterns of isolates during antibiotic treatment. The ST258 KPC-KP strain exhibited a multiresistant antibiotic phenotype including co-resistance to gentamycin, colistin and tigecycline intermediate susceptibility. Isolates before and after treatment had different behaviour concerning their antibiotic susceptibility and the population analysis profile study. A progressive increase in the aminoglycosides (acquiring amicacin resistance) and β-lactam MICs, and a decreased susceptibility to fosfomycin was observed throughout the administration of combined antimicrobial regimens including meropenem. A high meropenem resistance KPC-KP homogeneous population (MIC 256 Jg/mL), could arise from the meropenem heterogeneous low-level resistance KPC-KP population (MIC 8 Jg/mL), by the selective pressure of the prolonged meropenem therapy. The kpc gene was inserted in a Tn4401 isoform a, and no transconjugants were detected. The core measures adopted were successful to prevent evolution towards resistance dissemination.

Highlights

Carbapenems are recommended for severe infections caused by extended spectrum b-lactamase (ESBL) -producing Enterobacteria, because of their resistance to third-generation cephalosporins and associated resistance to almost all other antibiotics
The worldwide spread of Klebsiella pneumoniae carbapenemases (KPC)-producing K. pneumoniae strains (KPC-KP) has revealed the successful dissemination of a major clone defined as sequence type 258 (ST258)
The intensive care unit (ICU) remained closed to new admissions while KPC-KP-infected patients were still hospitalized

Summary

Introduction

Carbapenems are recommended for severe infections caused by extended spectrum b-lactamase (ESBL) -producing Enterobacteria, because of their resistance to third-generation cephalosporins and associated resistance to almost all other antibiotics. The emergence of carbapenem-resistance in Enterobacteria is worrying, and could be related to several combined mechanisms involving outer membrane permeability defects, hyperproduction of AmpC cephalosporinases, ESBL and carbapenemase production [1]. Klebsiella pneumoniae carbapenemases (KPC) are the most frequent carbapenemases found in Klebsiella pneumoniae and are mostly plasmid encoded, but chromosomal location has been reported [2]. As the gene encoding KPC usually resides on transferable plasmids, it is capable of disseminating to other Gram-negative genera [3]. The worldwide spread of KPC-producing K. pneumoniae strains (KPC-KP) has revealed the successful dissemination of a major clone defined as sequence type 258 (ST258). Since 2006, KPC-KP has arisen in South America, in countries bordering Uruguay— Argentina and Brazil [4,5]

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