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Volume 45, Number 1, February 2012

Clonal spread of multidrug-resistant Acinetobacter baumannii in eastern Taiwan


Kai-Chih Chang, Ming-Feng Lin, Nien-Tsung Lin, Wen-Jui Wu, Han-Yueh Kuo, Teng-Yi Lin, Tsai-Lian Yang, Yu-Chuan Chen, Ming-Li Liou


Received: May 29, 2010    Revised: September 9, 2010    Accepted: November 24, 2010   

 

Corresponding author:

Ming-Li Liou , Department of Medical Laboratory Science and Biotechnology, Yuanpei University, Hsin-Chu City, Taiwan
Corresponding author. Department of Medical Laboratory Science and Biotechnology, Yuanpei University, Number 306, Yuanpei Street, Hsin-Chu, Taiwan 30015, ROC.



 

Background and purpose: 

This study was conducted to investigate the molecular epidemiology and antimicrobial susceptibility of multidrug-resistant (MDR) Acinetobacter baumannii to three types of antibiotics.



 

Methods:

One hundred and thirty-four specimens of MDR A baumannii were collected from three branches (Taipei, Dalin, and Hualien branches) of Buddhist Tzu Chi Hospital, which are located in northern, southern, and eastern Taiwan, during 2007. Genotyping was performed by pulsed-field gel electrophoresis. Antibiotic susceptibilities to colistin, rifampicin, and tigecycline were determined. The synergistic effects of rifampin and colistin were also evaluated.



 

Results:

Antibiotic susceptibility testing showed that 10.4%, 47.8% and 45.5% of the MDR A baumannii isolates are resistant to colistin, rifampicin, and tigecycline, respectively. A majority of the rifampicin-resistant isolates (62.7%) were found in the Haulien branch, whereas 62.2% of tigecycline-resistant isolates were found in the Taipei branch. The combination of colistin and rifampicin had a synergistic effect on all of the isolates. Genotyping by pulsed-field gel electrophoresis identified 17, 23, and 11 pulsotypes in the Taipei, Dalin, and Haulien branches, respectively. Furthermore, 74.5% of isolates in the Haulien branch were identified as one of three pulsotypes. Among 37 rifampicin-resistant and 22 tigecycline-resistant MDR A baumannii isolates found in the Haulien branch, 51.3% (19/37) and 50% (11/22) of the isolates belonged to the same clone, respectively.



 

Conclusion:

This study confirms the high prevalence of resistance to rifampicin and tigecycline in MDR A baumannii in the three hospitals that were studied, and the high proportion of identical strains that exist in eastern Taiwan.

 



 

Key words:

Acinetobacter baumannii, Colistin, Rifampicin, Tigecycline