Genetic Characterization of Carbapenem-Resistant Enterobacteriaceae and the Spread of Carbapenem-Resistant Klebsiella pneumonia ST340 at a University Hospital in Thailand.

Thidarat Netikul,Pattarachai Kiratisin,M Hong Nguyen

doi:10.1371/journal.pone.0139116

Thidarat Netikul, Pattarachai Kiratisin + Show 1 more

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https://doi.org/10.1371/journal.pone.0139116

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Journal: PloS one	Publication Date: Sep 25, 2015
Citations: 56	License type: CC BY 4.0

Affiliation: Siriraj Hospital, Mahidol University

Abstract

Carbapenem-resistant Enterobacteriaceae (CRE) has increasingly spread worldwide in the past decade. The prevalence and characteristics of CRE in Thailand are unknown. In this study, we conducted a 2-year surveillance of CRE among 12,741 clinical isolates of Enterobacteriaceae at the largest university hospital in Thailand with molecular characterization of beta-lactamase (bla) genes, including carbapenemase genes. The CRE prevalence was 1.4%. bla KPC-13 and bla IMP-14a were the only carbapenemase genes detected among these CRE isolates. bla KPC-13 gene was found in a single isolate of Escherichia coli, Enterobacter cloacae and Citrobacter freundii, and bla IMP-14a was found in four isolates of Klebsiella pneumoniae. Carbapenem-resistant K. pneumoniae (CRKP) isolates were resistant to multiple carbapenems at a higher ratio than other CRE species, and thus were further characterized for resistance phenotypes, bla genotypes and molecular epidemiology. Most CRKP isolates harboured multiple bla genes, especially those related to extended-spectrum beta-lactamases. Seven CRKP isolates were resistant to all tested carbapenems, and showed decreased ompK35 and/or ompK36 porin gene expression. Molecular typing of CRKP based on pulsed-field gel electrophoresis (PFGE) demonstrated several unrelated clones. Multilocus sequence typing (MLST) was partially concordant with PFGE results and revealed that ST340, a member of drug-resistant K. pneumoniae clonal complex 258, was the most predominant clone, followed by ST48, ST11 and ST273. The novel ST1645 was identified from this study. ST340 has neither been shown to be predominated among CRKP from other studies, nor been reported in Thailand. Therefore, it emphases a critical concern to monitor and control the spread of CRKP.

Highlights

Carbapenems are broad-spectrum beta-lactam agents frequently used in treatment of infections caused by multidrug resistant gram-negative bacteria
Among E. coli, E. cloacae, C. freundii and K. pneumoniae carbapenem-resistant Enterobacteriaceae (CRE) isolates, all isolates were resistant to ertapenem, and 4 (23.5%), 35 (28.5%), 2 (40%) and 19 (52.8%) isolates, respectively, were resistant to multiple carbapenems
Previous surveys showed that the rates of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in Thailand were approximately 40–50% and were relatively high comparing to other countries in the Asia-Pacific region [36], [37]

Summary

Introduction

Carbapenems are broad-spectrum beta-lactam agents frequently used in treatment of infections caused by multidrug resistant gram-negative bacteria. Enterobacteriaceae that are resistant to carbapenems, known as carbapenem-resistant Enterobacteriaceae (CRE), have gradually emerged and strictly limiting options for treatment [2]. A decrease in expression of outer membrane proteins (OMPs), especially OmpK35 and OmpK36 porins, has been shown to be associated with increased MICs of both cephalosporins and carbapenems in K. pneumoniae, including outbreak strains [14], [15]. It may not be the major component of carbapenem resistance, i.e. only carbapenemase production without defective porin expression could strongly elevate carbapenem MICs [16], [17]

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