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Volume 43, Number 5, October 2010

Clinical Outcome of Mycobacterium abscessus Infection and Antimicrobial Susceptibility Testing


Yi-Ching Huang, Meei-Fang Liu, Gwan-Han Shen, Chin-Fu Lin, Chih-Chuan Kao, Po-Yu Liu, Zhi-Yuan Shi


Received: April 30, 2009    Revised: June 30, 2009    Accepted: August 19, 2009   

 

Corresponding author:

Zhi-Yuan Shi, Section of Infectious Diseases, Department of Internal Medicine, Taichung Veterans General
Hospital, 160 Section 3, Chung-Kang Road, Taichung 40705, Taiwan.
E-mail: ychuang@vghtc.gov.tw



 

Background and purpose: 

Mycobacterium abscessus is the most resistant and rapidly growing mycobacterium and causes a wide range of clinical infectious diseases. The relationship between antimicrobial susceptibility and clinical outcome needs to be further evaluated.



 

Methods:

Forty M. abscessus isolates were obtained from clinical specimens of 40 patients at the
Taichung Veterans General Hospital from January 2006 to December 2008. Antimicrobial susceptibility testing was performed using the broth microdilution method according to the recommendations of the National Committee for Clinical Laboratory Standards. The clinical manifestations and outcomes were reviewed from medical records.



 

Results:

Twenty-two patients were diagnosed with M. abscessus infection. Cough (86.3%), hemoptysis (31.8%) and fever (18.1%) were the most common symptoms. The radiographic findings included reticulonodular   opacities (50.0%), consolidation (31.8%) and cavitary lesions (18.1%). The 40 isolates were susceptible
to amikacin (95.0%), cefoxitin (32.5%), ciprofloxacin (10.0%), clarithromycin (92.5%), doxycycline (7.5%), imipenem (12.5%), moxifloxacin (22.5%), sulfamethoxazole (7.5%) and tigecycline (100%). The rate of treatment failure was 27.3% at the end of the 12th month after the start of treatment, although these
patients were treated with a combination of clarithromycin and other antimicrobial agents.



 

Conclusion:

M. abscessus is naturally susceptible to clarithromycin and amikacin, variably susceptible to cefoxitin and imipenem, and resistant to most other antimicrobial drugs. Combination therapy withclarithromycin, amikacin and other active antimicrobial agents may lead to clinical improvement; however, the rate of treatment failure is still high.



 

Key words:

Mycobacterium abscessus, rapidly growing mycobacteria, susceptibility testing