This Article Full Text Full Text (PDF) Other Versions of this Article: JCM.01922-06v1 45/10/3309    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kim, T.-E. Articles by Kwon, H.-J. Search for Related Content PubMed PubMed Citation Articles by Kim, T.-E. Articles by Kwon, H.-J.

 Previous Article  |  Next Article 

Journal of Clinical Microbiology, October 2007, p. 3309-3315, Vol. 45, No. 10
0095-1137/07/$08.00+0     doi:10.1128/JCM.01922-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Chronological Study of Antibiotic Resistances and Their Relevant Genes in Korean Avian Pathogenic Escherichia coli Isolates

Laboratory of Avian Diseases,¹ Laboratory of Influenza Virus, Zoonotic Disease Institute (ZooDI),² College of Veterinary Medicine and BK21 for Veterinary Science, Seoul National University, San 56-1, Shillim-Dong, Gwanak-Gu, Seoul, 151-742, Korea³

Received 16 September 2006/ Returned for modification 15 November 2006/ Accepted 24 July 2007

Antibiograms and relevant genotypes of Korean avian pathogenic Escherichia coli (APEC) isolates (n = 101) recovered between 1985 and 2005 were assessed via disc diffusion test, PCR, restriction enzyme analysis, and sequencing. These isolates were highly resistant to tetracycline (84.2%), streptomycin (84.2%), enrofloxacin (71.3%), and ampicillin (67.3%), and most of the tetracycline, streptomycin, enrofloxacin, and ampicillin resistances were associated with tetA and/or tetB, aadA and/or strA-strB, mutations in gyrA and/or parC, and TEM, respectively. Class 1 integrons were detected in 40 isolates (39.6%), and a variety of gene cassettes conferring streptomycin (aadA), gentamicin (aadB), and trimethoprim (dfr) resistances were identified: aadA1a (27.5%), dfrV-orfD (2.5%), aadB-aadA1a (2.5%), dfrI-aadA1a (47.5%), dfrXVII-aadA5 (12.5%), and dfrXII-orfF-aadA2 (7.5%). In addition, several types of common promoters (P_ant) of the gene cassettes (hybrid P1, weak P1, or weak P1 plus P2) and single-nucleotide polymorphisms in aadA1a were identified. The results of a chronological analysis demonstrated significant and continuous increases in the frequencies of resistances to several antibiotics (tetracycline, streptomycin, enrofloxacin, ampicillin, and trimethoprim-sulfamethoxazole) and of the relevant resistance genes (tetA, strA-strB, and TEM), mutations in gyrA and parC, and multidrug-resistant APEC strains during the period 2000 to 2005.

Published ahead of print on 8 August 2007.