title: Clonal dissemination of KPC-2 producing Klebsiella pneumoniae ST11 clone with high prevalence of oqxAB and rmtB in a tertiary hospital in China: results from a 3-year period.
abstract: BACKGROUND
  Carbapenemase-producing Klebsiella pneumoniae (CPKP) strains have emerged as a major problem for healthcare systems. The aim of this study was to determine the circulating clones and analyze the clinical and molecular characteristics of CPKP in our hospital.
  
  
  METHODS
  A total of 74 carbapenemase producers collected from our hospital from 2012 to 2014 were analyzed for the prevalence of extended-spectrum β-lactamase (ESBLs), plasmid-mediated quinolone resistance genes (PMQRs), exogenously acquired 16S rRNA methyltransferase (16S-RMTase), and plasmid-mediated AmpC enzyme (pAmpCs) by PCR and DNA sequencing. The sequence types (STs) of the carbapenemase producers were analyzed by multi-locus sequence typing (MLST). And Pulsed-field gel electrophoresis (PFGE) was performed to investigate the genetic relationship of KPC-2 producing strains. Clinical data were retrieved from the medical records.
  
  
  RESULTS
  KPC-2 (n = 72) was the predominant enzyme followed by NDM-1 (n = 2); The genes blaCTX-M, blaSHV, blaTEM-1, blaDHA-1, rmtB, armA, oqxA, oqxB, and qnrB were present in 29 (39.2 %), 27 (36.5 %), 46 (62.2 %), 2 (2.7 %), 25 (33.8 %), 1 (1.4 %), 60 (81.1 %) and 56 (75.7 %), 6 (8.1 %) isolates, respectively. MLST analysis revealed 10 different STs. The most dominant ST was ST11 (78.4 %, 58/74), followed by ST15 (8.1 %, 6/74). PFGE patterns of the KPC-2 producing K. pneumoniae isolates exhibited clonal dissemination of ST11 and ST15 clones as well as a genetic diversity of the remaining strains.
  
  
  CONCLUSIONS
  The intra- and inter-hospital cross-transmission of KPC-2-producing K. pneumoniae ST11 co-carrying oqxAB and rmtB in our hospital strongly suggested that rapid identification of colonized or infected patients and screening of carriers is quite necessary to prevent a scenario of endemicity.
authors.affiliation: Department of Laboratory Medicine, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Zhongshan Road, 321#, Gulou District, Nanjing, Jiangsu, People's Republic of China. chenglimed@163.com.
authors.forename: Li
authors.initials: L
authors.lastname: Cheng
authors.affiliation: Department of Laboratory Medicine, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Zhongshan Road, 321#, Gulou District, Nanjing, Jiangsu, People's Republic of China. cao-xiao-li@163.com.
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Cao
authors.affiliation: Department of Laboratory Medicine, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Zhongshan Road, 321#, Gulou District, Nanjing, Jiangsu, People's Republic of China. njzhangzf@hotmail.com.
authors.forename: Zhi-Feng
authors.initials: ZF
authors.lastname: Zhang
authors.affiliation: Department of Laboratory Medicine, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Zhongshan Road, 321#, Gulou District, Nanjing, Jiangsu, People's Republic of China. nmz780714@sina.com.
authors.forename: Ming-Zhe
authors.initials: MZ
authors.lastname: Ning
authors.affiliation: Department of Laboratory Medicine, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Zhongshan Road, 321#, Gulou District, Nanjing, Jiangsu, People's Republic of China. xxuejing@hotmail.com.
authors.forename: Xue-Jing
authors.initials: XJ
authors.lastname: Xu
authors.affiliation: Department of Laboratory Medicine, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Zhongshan Road, 321#, Gulou District, Nanjing, Jiangsu, People's Republic of China. zwq_096@163.com.
authors.forename: Wanqing
authors.initials: W
authors.lastname: Zhou
authors.affiliation: Department of Laboratory Medicine, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Zhongshan Road, 321#, Gulou District, Nanjing, Jiangsu, People's Republic of China. nj_cjh@aliyun.com.
authors.forename: Jun-Hao
authors.initials: JH
authors.lastname: Chen
authors.affiliation: Department of Laboratory Medicine, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Zhongshan Road, 321#, Gulou District, Nanjing, Jiangsu, People's Republic of China. zhangjinhua0908@163.com.
authors.forename: Jin-Hua
authors.initials: JH
authors.lastname: Zhang
authors.affiliation: Department of Laboratory Medicine, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Zhongshan Road, 321#, Gulou District, Nanjing, Jiangsu, People's Republic of China. shenhan10366@sina.com.
authors.forename: Han
authors.initials: H
authors.lastname: Shen
authors.affiliation: Department of Laboratory Medicine, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Zhongshan Road, 321#, Gulou District, Nanjing, Jiangsu, People's Republic of China. 13505151066@163.com.
authors.forename: Kui
authors.initials: K
authors.lastname: Zhang
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002681:China / Q000453:epidemiology; D006801:Humans; D007710:Klebsiella Infections / Q000453:epidemiology / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000145:classification / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification*; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D015995:Prevalence; D062606:Tertiary Care Centers / Q000706:statistics & numerical data; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D001618:beta-Lactamases; C547585:beta-lactamase KPC-2, Klebsiella pneumoniae; C063912:carbapenemase