title: In vitro activity and in vivo efficacy of clavulanic acid against Acinetobacter baumannii.
abstract: Clavulanic acid (CLA) exhibits low MICs against some Acinetobacter baumannii strains. The present study evaluates the efficacy of CLA in a murine model of A. baumannii pneumonia. For this purpose, two clinical strains, Ab11 and Ab51, were used; CLA MICs for these strains were 2 and 4 mg/liter, respectively, and the imipenem (IPM) MIC was 0.5 mg/liter for both. A pneumonia model in C57BL/6 mice was used. The CLA dosage (13 mg/kg of body weight given intraperitoneally) was chosen to reach a maximum concentration of the drug in serum similar to that in humans and a time during which the serum CLA concentration remained above the MIC equivalent to 40% of the interval between doses. Six groups (n = 15) were inoculated with Ab11 or Ab51 and were allocated to IPM or CLA therapy or to the untreated control group. In time-kill experiments, CLA was bactericidal only against Ab11 whereas IPM was bactericidal against both strains. CLA and IPM both decreased bacterial concentrations in lungs, 1.78 and 2.47 log10 CFU/g (P < or = 0.001), respectively, in the experiments with Ab11 and 2.42 and 2.28 log10 CFU/g (P < or = 0.001), respectively, with Ab51. IPM significantly increased the sterility of blood cultures over that for the controls with both strains (P < or = 0.005); CLA had the same effect with Ab51 (P < 0.005) but not with Ab11 (P = 0.07). For the first time, we suggest that CLA may be used for the treatment of experimental severe A. baumannii infections.
authors.affiliation: Servicio de Microbiología-Unidad de Investigación, Complejo Hospitalario Universitario Juan Canalejo, 15006 La Coruña, Spain.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Beceiro
authors.forename: Rafael
authors.initials: R
authors.lastname: López-Rojas
authors.forename: Juan
authors.initials: J
authors.lastname: Domínguez-Herrera
authors.forename: Fernando
authors.initials: F
authors.lastname: Docobo-Pérez
authors.forename: Germán
authors.initials: G
authors.lastname: Bou
authors.forename: Jerónimo
authors.initials: J
authors.lastname: Pachón
mesh_terms: D000151:Acinetobacter Infections / Q000188:drug therapy / Q000382:microbiology; D040981:Acinetobacter baumannii / Q000187:drug effects*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D019818:Clavulanic Acid / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D008826:Microbial Sensitivity Tests; D011014:Pneumonia / Q000188:drug therapy / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents; D019818:Clavulanic Acid