title: Does the activity of the combination of imipenem and colistin in vitro exceed the problem of resistance in metallo-beta-lactamase-producing Klebsiella pneumoniae isolates?
abstract: Using time-kill methodology, we investigated the interactions of an imipenem-colistin combination against 42 genetically distinct Klebsiella pneumoniae clinical isolates carrying a bla(VIM-1)-type gene. Irrespective of the imipenem MIC, the combination was synergistic (50%) or indifferent (50%) against colistin-susceptible strains, while it was antagonistic (55.6%) and rarely synergistic (11%) against non-colistin-susceptible strains (with synergy being observed only against strains with colistin MICs of 3 to 4 microg/ml). The combination showed improved bactericidal activity against isolates susceptible either to both agents or to colistin.
authors.affiliation: 4th Department of Internal Medicine, Athens University School of Medicine, University General Hospital Attikon, Chaidari, Greece. msouli@med.uoa.gr
authors.forename: Maria
authors.initials: M
authors.lastname: Souli
authors.forename: Panagiota Danai
authors.initials: PD
authors.lastname: Rekatsina
authors.forename: Zoi
authors.initials: Z
authors.lastname: Chryssouli
authors.forename: Irene
authors.initials: I
authors.lastname: Galani
authors.forename: Helen
authors.initials: H
authors.lastname: Giamarellou
authors.forename: Kyriaki
authors.initials: K
authors.lastname: Kanellakopoulou
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003091:Colistin / Q000494:pharmacology*; D004347:Drug Interactions; D024881:Drug Resistance, Bacterial; D004359:Drug Therapy, Combination; D006801:Humans; D015378:Imipenem / Q000494:pharmacology*; D007711:Klebsiella pneumoniae / Q000145:classification / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D008826:Microbial Sensitivity Tests; D001618:beta-Lactamases / Q000096:biosynthesis / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D015378:Imipenem; C417264:VIM-1 metallo-beta-lactamase; D001618:beta-Lactamases; D003091:Colistin