title: Description and plasmid characterization of the qnrD determinant in Proteeae in Wenzhou, Southern China.
abstract: OBJECTIVE
  Only limited information is available about the detailed characteristics of qnrD, a plasmid-mediated quinolone resistance (PMQR) gene. This study aimed to understand the distribution of qnrD and the characterization of qnrD-carrying plasmids in Proteeae.
  
  
  METHODS
  The distribution of qnrD genes was investigated by polymerase chain reaction (PCR) amplification in 203 consecutive nonduplicate clinical isolates of Proteeae collected from inpatients at the First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China. The minimum inhibitory concentrations (MICs) of antibiotics were measured by agar dilution method and other PMQR determinants were also determined by PCR. qnrD was positioned via Southern hybridization and the transferability of qnrD-carrying plasmids was achieved by conjugation experiment. The genetic environment of qnrD was investigated by sequencing, and chromosomal polymorphism for qnrD-positive strains was analyzed by pulsed-field gel electrophoresis (PFGE).
  
  
  RESULTS
  Forty strains carried qnrD, showing decreased fluoroquinolone susceptibility or low-level fluoroquinolone resistance. qnrD was encoded on the plasmid of about 2.7 kb or 5.2 kb in length, which cannot be transferred by liquid conjugation or filter mating, but can be successfully transferred by transduction. The transformants showed 62.5-300-fold increases in the MICs of quinolones compared with the recipient. The plasmids carrying qnrD showed a high similarity with that of Providencia spp. and Proteus vulgaris. PFGE analysis demonstrated that these isolates were divergent and not clone related.
  
  
  CONCLUSIONS
  qnrD could have originated from Proteeae or presented in these bacteria as a reservoir; furthermore, qnrD could be transferred and spread within the same or across different bacterial species if the plasmids acquired mobile elements under antimicrobial selective pressures.
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Lijiang
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Clinical Laboratory, Zhejiang Hospital, Hangzhou, Zhejiang, China.
authors.forename: Yapei
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Du
authors.affiliation: Department of Clinical Laboratory, Jinan Fourth People's Hospital, Jinan, Shandong, China.
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Meimei
authors.initials: M
authors.lastname: Li
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Huale
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Yu
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China. Electronic address: wyztli@163.com.
authors.forename: Tieli
authors.initials: T
authors.lastname: Zhou
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D015139:Blotting, Southern; D002681:China; D002876:Chromosomes, Bacterial; D026942:DNA Topoisomerases / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects / Q000235:genetics*; D016521:Electrophoresis, Gel, Pulsed-Field; D004755:Enterobacteriaceae / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D024841:Fluoroquinolones / Q000494:pharmacology; D005798:Genes, Bacterial / Q000235:genetics*; D006801:Humans; D008826:Microbial Sensitivity Tests; D009154:Mutation; D010957:Plasmids / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D011514:Proteus vulgaris / Q000235:genetics; D011532:Providencia / Q000235:genetics; D015363:Quinolones / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D024841:Fluoroquinolones; D015363:Quinolones; D026942:DNA Topoisomerases
keywords: Proteeae; fluoroquinolone; plasmid; qnrD