title: Effects of various antibiotics alone or in combination with doripenem against Klebsiella pneumoniae strains isolated in an intensive care unit.
abstract: Colistin, tigecycline, levofloxacin, tobramycin, and rifampin alone and in combination with doripenem were investigated for their in vitro activities and postantibiotic effects (PAEs) on Klebsiella pneumoniae. The in vitro activities of tested antibiotics in combination with doripenem were determined using a microbroth checkerboard technique. To determine the PAEs, K. pneumoniae strains in the logarithmic phase of growth were exposed for 1 h to antibiotics, alone and in combination. Recovery periods of test cultures were evaluated using viable counting after centrifugation. Colistin, tobramycin, and levofloxacin produced strong PAEs ranging from 2.71 to 4.23 h, from 1.31 to 3.82 h, and from 1.35 to 4.72, respectively, in a concentration-dependent manner. Tigecycline and rifampin displayed modest PAEs ranging from 1.18 h to 1.55 h and 0.92 to 1.19, respectively. Because it is a beta-lactam, PAEs were not exactly induced by doripenem (ranging from 0.10 to 0.18 h). In combination, doripenem scarcely changed the duration of PAE of each tested antibiotic alone. The findings of this study may have important implications for the timing of doses during K. pneumoniae therapy with tested antibiotics.
authors.affiliation: Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Istanbul University, Beyazit, 34116 Istanbul, Turkey.
authors.forename: Berna
authors.initials: B
authors.lastname: Ozbek Celik
authors.affiliation: Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Istanbul University, Beyazit, 34116 Istanbul, Turkey.
authors.forename: Emel
authors.initials: E
authors.lastname: Mataraci-Kara
authors.affiliation: Department of Infectious Diseases and Clinical Microbiology, Faculty of Medicine, University of Istanbul Medipol, 34083 Istanbul, Turkey.
authors.forename: Mesut
authors.initials: M
authors.lastname: Yilmaz
mesh_terms: D015780:Carbapenems / Q000008:administration & dosage*; D003091:Colistin / Q000008:administration & dosage; D000077726:Doripenem; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D006801:Humans; D007362:Intensive Care Units; D007710:Klebsiella Infections / Q000188:drug therapy* / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000187:drug effects*; D064704:Levofloxacin / Q000008:administration & dosage; D008911:Minocycline / Q000008:administration & dosage / Q000031:analogs & derivatives; D012293:Rifampin / Q000008:administration & dosage; D000078304:Tigecycline; D014031:Tobramycin / Q000008:administration & dosage
chemical_list: D015780:Carbapenems; D004338:Drug Combinations; D064704:Levofloxacin; D000078304:Tigecycline; D000077726:Doripenem; D008911:Minocycline; D012293:Rifampin; D014031:Tobramycin; D003091:Colistin