Klebsiella pneumoniae Carbapenemase Producers in South Korea between 2013 and 2015.

Eun-Jeong Yoon,Ji Woo Yang,Kwang Jun Lee,Dokyun Kim,Hyukmin Lee,Seok Hoon Jeong,Jung Ok Kim

doi:10.3389/fmicb.2018.00056

Abstract

Between 2014 and 2015, the Klebsiella pneumoniae carbapenemase (KPC) was becoming endemic in South Korea. To assess this period of transition, we analyzed KPC producers in terms of molecular epidemiology. A total of 362 KPC-producing Enterobacteriaceae strains, including one from 2013, 13 from 2014, and 348 from 2015, were actively collected from 60 hospitals throughout the peninsula. Subtypes of KPC were determined by PCR and direct sequencing, and isotypes of Tn4401 (the transposon flanking the blaKPC gene) were specified by PCR using isotype-specific primers and direct sequencing. Sporadic occurrence of KPC-producing Enterobacteriaceae was initially observed around Seoul, which is the most crowded district of the country, and these strains rapidly disseminated in 2014, to the other parts of the country in 2015. The bacterial clones responsible for the extreme epidemiological transition were K. pneumoniae ST307 (46.2%) and ST11 (21.3%). Less frequently, E. coli (4.7%), Enterobacter spp. (1.4%), and other Enterobacteriaceae members (1.7%) producing the enzyme were identified. The blaKPC-2 gene bracketed by Tn4401a (72.1%) was the most prevalent mobile genetic element responsible for the dissemination, and the same gene carried either by Tn4401b (2.2%) or Tn4401c (6.6%) was identified at a lesser frequency. The genes blaKPC-3 (1.6%) and blaKPC-4 (6.4%), both flanked by Tn4401b, were occasionally identified. This study showed endemic dissemination of KPC producers in 2015 due to a clonal spread of two K. pneumoniae strains. Further systemic surveillance is needed to monitor dissemination of KPC-producers.

Highlights

Carbapenemases often jeopardize chemotherapy for infectious diseases caused by common nosocomial pathogens
The blaKPC-2 gene bracketed by Tn4401a (72.1%) was the most prevalent mobile genetic element responsible for the dissemination, and the same gene carried either by Tn4401b (2.2%) or Tn4401c (6.6%) was identified at a lesser frequency
This study showed endemic dissemination of Klebsiella pneumoniae carbapenemase (KPC)

Summary

INTRODUCTION

Carbapenemases often jeopardize chemotherapy for infectious diseases caused by common nosocomial pathogens. The blaKPC gene was detected by PCR using gene-specific primers The rapid dissemination of the blaKPC gene is known to be derived from the clonal spread of K. pneumoniae sequence type 258 (ST258) (Munoz-Price et al, 2013; Pitout et al, 2015). Horizontal gene transfer drives KPC dissemination via a Tn3-type active transposon Tn4401 enclosing the blaKPC gene. The population of KPC producers and the inter-regional movement of core clones needed to be further investigated and, in this study, the molecular epidemiology was assessed with actively collected. To determine the isotypes of Tn4401, isotype-specific forward primers for the five most common isotypes (a to e) (Naas et al., 2012) were newly designed (Supplementary Table) and PCR was carried out with a universal reverse primer targeting the blaKPC gene. The nucleotide sequences obtained for both DNA strands were compared with sequences in the MLST database for each species (http://bigsdb.web.pasteur.fr/klebsiella for K. pneumoniae and http://mlst.warwick.ac.uk/mlst/dbs/Ecoli for E. coli), to determine allelic numbers and STs

MATERIALS AND METHODS

RESULTS

DISCUSSION

ETHICS STATEMENT