Journal Article

Plasmid-mediated 16S rRNA methylases conferring high-level aminoglycoside resistance in <i>Escherichia coli</i> and <i>Klebsiella pneumoniae</i> isolates from two Taiwanese hospitals

Jing-Jou Yan, Jiunn-Jong Wu, Wen-Chien Ko, Shu-Huei Tsai, Chin-Luan Chuang, Hsiu-Mei Wu, Ying-Jiun Lu and Jau-Dai Li

in Journal of Antimicrobial Chemotherapy

Published on behalf of British Society for Antimicrobial Chemotherapy

Volume 54, issue 6, pages 1007-1012
Published in print December 2004 | ISSN: 0305-7453
Published online December 2004 | e-ISSN: 1460-2091 | DOI:
Plasmid-mediated 16S rRNA methylases conferring high-level aminoglycoside resistance in Escherichia coli and Klebsiella pneumoniae isolates from two Taiwanese hospitals

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  • Medical Oncology
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Objectives: This study was conducted to investigate the occurrence of 16S rRNA methylases that confer high-level aminoglycoside resistance in Klebsiella pneumoniae and Escherichia coli isolates from two Taiwanese hospitals and the characteristics of these isolates.

Methods: A total of 1624 K. pneumoniae and 2559 E. coli isolates consecutively collected over an 18 month period from a university hospital and seven E. coli and eight K. pneumoniae isolates that were resistant to amikacin from a district hospital were analysed. Two 16S rRNA methylase genes, armA and rmtB, were detected by PCR-based assays. β-Lactamase characteristics were determined by phenotypic and genotypic methods.

Results: Overall, 28 armA-positive and seven rmtB-positive isolates were identified, and extended-spectrum β-lactamases (ESBLs) were detected in 33 (94.3%) isolates. The prevalence rates of armA and rmtB at the university hospital were 0.9% (n=15) and 0.3% (n=5) in K. pneumoniae and 0.4% (n=10) and 0.04% (n=1) in E. coli. CTX-M-3, CTX-M-14, SHV-5-like ESBLs, and CMY-2 were detected alone or in combination in 21, 6, 11, and 2, respectively, of the 28 armA-positive isolates. CTX-M-14 was detected in six of the seven rmtB-positive isolates. Fingerprinting of conjugative plasmids revealed the dissemination of closely related plasmids containing both armA and blaCTX-M-3. PFGE suggests that armA and rmtB spread by both horizontal transfer and clonal spread.

Conclusions: This is the first report of the emergence of 16S rRNA methylases in Enterobacteriaceae in Taiwan. The spread of the multidrug-resistant isolates producing both ESBLs and 16S rRNA methylases may become a clinical problem.

Keywords: resistance genes; multidrug resistance; armA; rmtB; extended-spectrum β-lactamases

Journal Article.  4280 words.  Illustrated.

Subjects: Medical Oncology ; Critical Care

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