title: Prevalence and molecular characterization of carbapenemase-producing gram-negative bacteria from a university hospital in China.
abstract: BACKGROUND
  The increasing emergence of carbapenem resistance in gram-negative bacteria associated with carbapenemase prompted the initiation of this study.
  
  
  METHODS
  A total of 3139 gram-negative bacteria were recovered from a 3380-bed university hospital in Wenzhou during 2008 and 2012. Antimicrobial susceptibility was determined using the VITEK2 Compact System and agar dilution method. The phenotype and genotype of carbapenemase were demonstrated using the modified Hodge test, PCR and sequencing. A conjugation experiment was performed to reveal the transferability of resistant genes. The location of the carbapenemase gene was studied by plasmid analysis and southern blot hybridization. Clonal relatedness of the isolates was investigated by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST).
  
  
  RESULTS
  Overall, 751 of 3139 isolates (71/2055 Enterobacteriaceae, 510/620 Acinetobacter baumannii and 170/464 Pseudomonas aeruginosa) exhibited resistance to carbapenem. Carbapenemase-encoding genes were detected in 70.4% (50/71) of carbapenem-resistant Enterobacteriaceae, including blaKPC (80%) and blaIMP (20%). All A. baumannii subjected to genotype analysis were positive for blaOXA-51-like and co-harboured blaOXA-23-like (80.4%) and blaIMP (7.8%). ISAba1 was found upstream of blaOXA-23-like and blaOXA-51-like. Eight and seven strains of 170 P. aeruginosa carried blaIMP and blaVIM, respectively. PFGE analysis identified at least one dominant genotype in certain species. Four KPC-2-producing Klebsiella pneumoniae belonged to the same sequence type ST11. The plasmids carrying blaKPC were successfully transferred into recipient strains.
  
  
  CONCLUSIONS
  This study highlights the challenge of increasing prevalence of carbapenem resistance associated with carbapenemase genes and dissemination of epidemic clones in Wenzhou, China.
authors.affiliation: a From the Department of Clinical Laboratory , The First Affiliated Hospital of Wenzhou Medical University , Wenzhou and.
authors.forename: Yao
authors.initials: Y
authors.lastname: Sun
authors.affiliation: a From the Department of Clinical Laboratory , The First Affiliated Hospital of Wenzhou Medical University , Wenzhou and.
authors.forename: Meimei
authors.initials: M
authors.lastname: Li
authors.affiliation: a From the Department of Clinical Laboratory , The First Affiliated Hospital of Wenzhou Medical University , Wenzhou and.
authors.forename: Lijiang
authors.initials: L
authors.lastname: Chen
authors.affiliation: a From the Department of Clinical Laboratory , The First Affiliated Hospital of Wenzhou Medical University , Wenzhou and.
authors.forename: Huale
authors.initials: H
authors.lastname: Chen
authors.affiliation: b From the School of Laboratory Medicine and Life Science , Wenzhou Medical University , Wenzhou , Zhejiang Province , China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Yu
authors.affiliation: a From the Department of Clinical Laboratory , The First Affiliated Hospital of Wenzhou Medical University , Wenzhou and.
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Ye
authors.affiliation: a From the Department of Clinical Laboratory , The First Affiliated Hospital of Wenzhou Medical University , Wenzhou and.
authors.forename: Yapei
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: a From the Department of Clinical Laboratory , The First Affiliated Hospital of Wenzhou Medical University , Wenzhou and.
authors.forename: Chuanling
authors.initials: C
authors.lastname: Ma
authors.affiliation: a From the Department of Clinical Laboratory , The First Affiliated Hospital of Wenzhou Medical University , Wenzhou and.
authors.forename: Tieli
authors.initials: T
authors.lastname: Zhou
mesh_terms: D040981:Acinetobacter baumannii / Q000145:classification / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000378:metabolism*; D002681:China / Q000453:epidemiology; D003227:Conjugation, Genetic; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D004755:Enterobacteriaceae / Q000145:classification / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D022761:Gene Transfer, Horizontal; D005838:Genotype; D016905:Gram-Negative Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology*; D006785:Hospitals, University; D006801:Humans; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D010641:Phenotype; D010957:Plasmids; D016133:Polymerase Chain Reaction; D015995:Prevalence; D011550:Pseudomonas aeruginosa / Q000145:classification / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D017422:Sequence Analysis, DNA; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D001618:beta-Lactamases; C063912:carbapenemase
keywords: Carbapenemase; PFGE; carbapenem-resistant; gram-negative bacteria