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Volume 44, Number 1, February 2011

Emergence and dissemination of blaOXA-23-carrying imipenem-resistant Acinetobacter sp in a regional hospital in Taiwan


Ming-Feng Lin, Han-Yueh Kuo, Hui-Wen Yeh, Chih-Man Yang, Chih-Hung Sung, Chi-Chao Tu, Mei-Luan Huang, Ming-Li Liou


Received: October 1, 2009    Revised: November 2, 2009    Accepted: January 14, 2010   

 

Corresponding author:

Department of Medical Laboratory Science and Biotechnology, Yuanpei University, No. 306, Yuanpei Street, Hsin-Chu, Taiwan 30015.
E-mail address: d918229@gmail.com (M.-L. Liou).



 

Background and purpose: 

The distribution and characterization of OXA-type carbapenemases in Acinetobacter sp in Taiwan has less been reported. The aim of the study was to investigate the molecular epidemiology and OXA-type carbapenemase genes in a regional hospital in Taiwan.



 

Methods:

Imipenem-resistant Acinetobacter sp were collected between 2005 and 2007 in a regional hospital. Genotyping was performed by pulsed-field gel electrophoresis. OXA-type carbapenemase genes were determined by multiplex polymerase chain reaction (PCR) and gene sequencing.



 

Results:

A total of 136 isolates were collected. Fifty-six pulsotypes were identified. None of the pulsotypes established predominance throughout the 3-year period. Multiplex PCR of blaOXA genes showed that 99% (135/136) of the Acinetobacter sp possessed blaOXA51-like genes. The coexistences of blaOXA51-like/blaOXA-23-like and blaOXA51-like/blaOXA-24-like were detected in 19% (26/136) and 1% (2/136) of the isolates, respectively. Among blaOXA-23-like gene-carrying isolates, two isolates (Pulsotypes 18 and 20) were found in 2006 and the remainder (n Z 24), including Pulsotypes 27 (n Z 18), 29 (n Z 1), 52 (n Z 3), and 53 (nZ2), were found in 2007. Sequencing performed on the 26 representative isolate confirmed the presence of the blaOXA-23 carbapenemase gene. Analysis of the genetic content of blaOXA-23 showed that these genes were presumably chromosomal and associated with the upstream-located insertion sequence ISAba1.



 

Conclusion:

The emergence and imminent widespread of blaOXA-23-carrying imipenemresistant Acinetobacter sp appeared in Taiwan during the period from 2006 to 2007.



 

Key words:

Acinetobacter sp; blaOXA-23 gene; blaOXA-51 gene; ISAba1; Pulsed-field gel electrophoresis