High Prevalence of ESBL-Producing Klebsiella pneumoniae Causing Community-Onset Infections in China.

Jing Zhang,Lina Zhao,Yonghong Xiao,Kai Zhou,Beiwen Zheng,Zeqing Wei,Jinru Ji,Lanjuan Li,Ping Shen,Jianying Zhou

doi:10.3389/fmicb.2016.01830

Abstract

The aim of this work was to investigate the epidemiological and genetic characteristics of ESBL-producing Klebsiella pneumoniae (ESBL-Kp) causing community-onset infections. K. pneumoniae isolates were collected from 31 Chinese secondary hospitals between August 2010 and 2011. Genes encoding ESBL and AmpC beta-lactamases were detected by PCR. The isolates were assigned to sequence types (STs) using multi-locus sequence typing (MLST). Eleven ESBL-Kp strains were selected for whole-genome sequencing (WGS) for investigating the genetic environment and plasmids encoding ESBL genes. A total of 578 K. pneumoniae isolates were collected, and 184 (31.8%) carried ESBL genes. The prevalence of ESBL-Kp varied from different geographical areas of China (10.2–50.3%). The three most prevalent ESBL genes were blaCTX-M-14 (n = 74), blaCTX-M-15 (n = 60), and blaCTX-M-3 (n = 40). MLST assigned 127 CTX-M-14 and CTX-M-15 producers to 54 STs, and CC17 was the most prevalent population (12.6%). STs (23, 37, and 86) that were known frequently associated with hypervirulent K. pneumoniae (hvKP) account for 14.1% (18/127). Phylogenetic analysis by concatenating the seven loci of MLST revealed the existence of ESBL-producing K. quasipneumoniae (two strains) and K. varricola (one strain), which was further confirmed by WGS. This study highlights the challenge of community-onset infections caused by ESBL-Kp in China. The prevalence of STs frequently associating with hvKP should be of concern. Surveillance of ESBL-KP causing community-onset infections now appears imperative.

Highlights

Extended-spectrum β-lactamases (ESBLs) have increased dramatically among clinical Enterobacteriaceae isolates during last three decades
This study illustrated the epidemiological and genetic characteristics of ESBL-producing Klebsiella pneumoniae (ESBL-Kp) causing community-onset infections in 31 secondary hospitals distributed in areas across China
A multi-center study on tertiary hospitals in China showed that ST11 was the most prevalent sequence types (STs) (12.2%) among 74 STs identified in 155 ESBL-Kp (An et al, 2012), whereas ST17 was the most prevalent one in our study (12.6%)

Summary

Introduction

Extended-spectrum β-lactamases (ESBLs) have increased dramatically among clinical Enterobacteriaceae isolates during last three decades. In most of the Europe countries, CTX-M-15 is the most prevalent ESBL type (Pitout, 2013), and recently disseminated in America, Canada, and Latin America (Denisuik et al, 2013; Wang G. et al, 2013; Kazmierczak et al, 2015). It has been suggested that the frequent acquirement of plasmids harboring blaCTX-M is largely responsible for the increase of CTX-M-producing Enterobacteriaceae. The blaCTX-M genes are found to associate with certain replicon types of plasmids, mainly including IncF, IncI, IncN, IncHI2, IncL/M, and IncK groups (Zhao and Hu, 2013). The blaCTX-M-3 gene is mainly harbored by plasmids of IncL/M and IncI1, and blaCTX-M-9 gene by IncHI2 plasmids (Zhao and Hu, 2013). E.g., ISEcp and ISCR1, are involved in the mobilization of blaCTX-M genes as well (Shahid et al, 2012; Zhao and Hu, 2013)

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