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Volume 44, Number 5, October 2011

Microbial isolation and emergence of antimicrobial resistance associated with tigecycline usage


Li-Yuan Chen, Tun-Chieh Chen, Yen-Hsu Chen, Chun-Yu Lin, Wei-Ru Lin, Po-Liang Lu


Received: April 29, 2010    Revised: June 30, 2010    Accepted: August 16, 2010   

 

Corresponding author:

Po-Liang Lu, Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
Graduate Institute of medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
Division of Infectious Diseases, Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan



 

Background and purpose: 

With the increasing experience of tigecycline usage, its ecological impact on microorganisms raises concerns but remains unknown. We aimed to analyze the difference in microorganisms isolated before, during, and after tigecycline usage and their susceptibility to antimicrobial agents.



 

Methods:

Between July 2008 and August 2009, 66 patients who received tigecycline monotherapy for more than 2 days at a Taiwan medical center were enrolled. Antimicrobial susceptibility testing was performed by broth microdilution method with VITEK-2 system and was analyzed according to the Clinical and Laboratory Standards Institute guidelines, except for tigecycline. We followed USA Food and Drug Administration criteria for interpretation of susceptibility to tigecycline.



 

Results:

The median duration of tigecycline monotherapy was 13.4 days. After tigecycline treatment, the isolation frequency of Acinetobacter baumannii, methicillin-resistant Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae decreased, but that of Pseudomonas aeruginosa, Proteus sp, and Stenotrophomonas maltophilia did not change. A baumannii and P aeruginosa were the two most common pathogens when tigecycline was administered. The tigecycline susceptibility rate of A baumannii isolates decreased after the administration of tigecycline.



 

Conclusion:

The most common pathogens isolated in patients receiving tigecycline were A baumannii and P aeruginosa. Tigecycline usage decreased the isolation frequency of A baumannii, methicillin-resistant S aureus, E coli, and K pneumoniae. Exposure to tigecycline may be associated with a decreased susceptibility rate of A baumannii for tigecycline.



 

Key words:

Microbial ecology, Resistance, Tigecycline