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Volume 48, Number 6, December 2015

In vitro activity of colistin sulfate against Enterobacteriaceae producing extended-spectrum β-lactamases 


Yee-Huang Ku, Mei-Feng Lee, Yin-Ching Chuang, Chi-Chung Chen, Wen-Liang Yu


Received: May 4, 2013    Revised: August 3, 2013    Accepted: November 11, 2013   

 

Corresponding author:

Wen-Liang Yu
Correspondence
Corresponding author. Department of Intensive Care Medicine, Chi Mei Medical Center, Number 901 Zhonghua Road, Yongkang District, 710 Tainan City, Taiwan. 



 

Background and purpose: 

The widespread multidrug-resistant Enterobacteriaceae pose a serious therapeutic challenge. Colistin and tigecycline are potential antimicrobial agents for treating infections caused by extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae. We evaluated the in-vitro activity of colistin sulfate against 253 ESBL producers isolated from patients admitted to a medical center in southern Taiwan (Escherichia coli, n = 82; Klebsiella pneumoniae, n = 102; Enterobacter cloacae, n = 34; and Serratia marcescens, n = 35). Colistin showed promising in-vitro activity against E. coli, K. pneumoniae, and E. cloacae, but not S. marcescens. One ESBL-producing K. pneumoniae strain with resistance to carbapenems (ertapenem, imipenem, and meropenem) was selected for time-killing studies. A combination of colistin and tigecycline showed synergism, but there was an inoculum effect. In conclusion, colistin was active against most ESBL-producing Enterobacteriaceae, and a combination of colistin with tigecycline was synergistic against some highly resistant strains, even those with carbapenem resistance. 



 

Key words:

Colistin, Enterobacteriaceae, ESBL, Tigecycline