JAC Advance Access originally published online on March 20, 2008
Journal of Antimicrobial Chemotherapy 2008 61(6):1234-1239; doi:10.1093/jac/dkn111
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Original research |
Prevalence of Qnr determinants among bloodstream isolates of Escherichia coli and Klebsiella pneumoniae in a Taiwanese Hospital, 1999–2005
1 Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan 2 Department of Internal Medicine, National Cheng Kung University Hospital, Tainan 70428, Taiwan 3 Department of Pathology, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan 4 Department of Pathology, National Cheng Kung University Hospital, Tainan 70428, Taiwan
Received 2 October 2007; returned 3 December 2007; revised 14 February 2008; accepted 19 February 2008
* Correspondence address. Department of Pathology, National Cheng Kung University Hospital, 138 Sheng-Li Road, Tainan 70428, Taiwan. Tel: +886-6-235-3535; Fax: +886-6-276-6195; E-mail: jingjou{at}mail.ncku.edu.tw
Objectives: To determine the prevalence and characteristics of bloodstream isolates of Escherichia coli and Klebsiella pneumoniae with qnr genes in a Taiwanese hospital.
Methods: A total of 2035 E. coli and 1147 K. pneumoniae isolates collected between 1999 and 2005 were screened for qnrA, qnrB and qnrS by PCR and colony hybridization. β-Lactamase genes, genetic relatedness and transferability were examined by PCR, PFGE and conjugation, respectively.
Results: The prevalence of qnr genes was 7.8% and 0.6% for K. pneumoniae and E. coli, respectively. The prevalence rates of qnrB2, qnrB4 and qnrS1 genes for K. pneumoniae were 2.3%, 3.6% and 2.8%, respectively, and for E. coli were 0.2%, 0% and 0.4%, respectively. The prevalence of qnrB4 in K. pneumoniae increased remarkably from 0% to 7.6% over the 7 study years. qnrA was not detected. Overall, the SHV-5-related, CTX-M-14, CTX-M-3, CMY-2, DHA-1 and IMP-8 β-lactamases were detected alone or in combination in 82.0% of qnr-positive K. pneumoniae isolates and 41.7% of qnr-positive E. coli isolates. Notably, all qnrB4-positive isolates possessed the DHA-1 enzyme, and the majority of the qnrB2-positive isolates (E. coli, 100%; K. pneumoniae, 80.8%) produced SHV-5-related β-lactamases. Genetic diversity was demonstrated by PFGE. Conjugation experiments revealed co-transfer of blaSHV-12, blaDHA-1 and blaSHV-5 with qnrB2, qnrB4 and qnrS1, respectively.
Conclusions: qnr genes remained rare in E. coli but appeared to be increasing in K. pneumoniae in our hospital. Horizontal transfer may play a major role in the intra-hospital spread of qnr.
Keywords: quinolones , cephalosporinases , extended-spectrum β-lactamases , metallo-β-lactamases
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  E. S. Kim, J.-Y. Jeong, J.-B. Jun, S.-H. Choi, S.-O. Lee, M.-N. Kim, J. H. Woo, and Y. S. Kim Prevalence of aac(6')-Ib-cr Encoding a Ciprofloxacin-Modifying Enzyme among Enterobacteriaceae Blood Isolates in Korea Antimicrob. Agents Chemother., June 1, 2009; 53(6): 2643 - 2645. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. B. Kim, C. H. Park, C. J. Kim, E.-C. Kim, G. A. Jacoby, and D. C. Hooper Prevalence of Plasmid-Mediated Quinolone Resistance Determinants over a 9-Year Period Antimicrob. Agents Chemother., February 1, 2009; 53(2): 639 - 645. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J.-J. Wu, W.-C. Ko, C.-S. Chiou, H.-M. Chen, L.-R. Wang, and J.-J. Yan Emergence of Qnr determinants in human Salmonella isolates in Taiwan J. Antimicrob. Chemother., December 1, 2008; 62(6): 1269 - 1272. [Abstract] [Full Text] [PDF]
|
|