title: In vitro activity of colistin sulfate against Enterobacteriaceae producing extended-spectrum β-lactamases.
abstract: 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.
authors.affiliation: Division of Infectious Disease, Department of Internal Medicine, Chi Mei Hospital - Liu Ying, Tainan City, Taiwan.
authors.forename: Yee-Huang
authors.initials: YH
authors.lastname: Ku
authors.affiliation: Department of Medical Research, Chi Mei Medical Center, Tainan City, Taiwan.
authors.forename: Mei-Feng
authors.initials: MF
authors.lastname: Lee
authors.affiliation: Department of Medical Research, Chi Mei Medical Center, Tainan City, Taiwan; Department of Internal Medicine, Chi Mei Hospital, Tainan City, Taiwan.
authors.forename: Yin-Ching
authors.initials: YC
authors.lastname: Chuang
authors.affiliation: Department of Medical Research, Chi Mei Medical Center, Tainan City, Taiwan.
authors.forename: Chi-Chung
authors.initials: CC
authors.lastname: Chen
authors.affiliation: Department of Intensive Care Medicine, Chi Mei Medical Center, Tainan City, Taiwan; Department of Medicine, Taipei Medical University, Taipei, Taiwan. Electronic address: yuleon_md@yahoo.com.tw.
authors.forename: Wen-Liang
authors.initials: WL
authors.lastname: Yu
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003091:Colistin / Q000494:pharmacology*; D016972:Enterobacter cloacae / Q000187:drug effects* / Q000302:isolation & purification / Q000378:metabolism; D004756:Enterobacteriaceae Infections / Q000188:drug therapy; D004926:Escherichia coli / Q000187:drug effects* / Q000302:isolation & purification / Q000378:metabolism; D006801:Humans; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000302:isolation & purification / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D008911:Minocycline / Q000031:analogs & derivatives / Q000494:pharmacology; D012706:Serratia marcescens / Q000187:drug effects* / Q000302:isolation & purification / Q000378:metabolism; D000078304:Tigecycline; D001618:beta-Lactamases / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D000078304:Tigecycline; D001618:beta-Lactamases; D008911:Minocycline; D003091:Colistin
keywords: Colistin; ESBL; Enterobacteriaceae; Tigecycline