title: In vitro synergy test of meropenem and sulbactam against clinical isolates of Acinetobacter baumannii.
abstract: Meropenem and imipenem are often the drugs of choice for the treatment of infections due to multidrug-resistant Acinetobacter baumannii. The present study aimed at evaluating the interaction between meropenem and sulbactam through microdilution and checkerboard methods against 48 clinical isolates of A. baumannii collected from Brazilian hospitals. All the isolates presented elevated minimum inhibitory concentration (>or=2 microg/mL) to either meropenem or sulbactam. The checkerboard method with the combination of meropenem and sulbactam demonstrated 29.2% (14/48) synergism, 47.9% (23/48) partial synergism, 10.5% (5/48) additive, 6.2% (3/48) indifference, and 6.2% (3/48) antagonism (SigmaFIC(min)=0.09 and SigmaFIC(max)=8). Thus, combinations of meropenem and sulbactam may show synergism or partial synergism for most A. baumannii isolates. Further studies may help identify treatment options for patients with infections caused by these organisms, particularly with this combination, where both drugs have time-dependent activities and might be suitable for therapy optimization studies.
authors.affiliation: Advisory Group on Antimicrobials and Clinical Microbiology, Fleury Institute, 04344-070 Jabaquara-Sao Paulo-SP, Brazil. carlos.kiffer@fleury.com.br
authors.forename: Carlos R V
authors.initials: CR
authors.lastname: Kiffer
authors.forename: Jorge L M
authors.initials: JL
authors.lastname: Sampaio
authors.forename: Sumiko
authors.initials: S
authors.lastname: Sinto
authors.forename: Carmen P
authors.initials: CP
authors.lastname: Oplustil
authors.forename: Paula C M
authors.initials: PC
authors.lastname: Koga
authors.forename: Andréa C
authors.initials: AC
authors.lastname: Arruda
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Turner
authors.forename: Caio
authors.initials: C
authors.lastname: Mendes
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004357:Drug Synergism; D006801:Humans; D000077731:Meropenem; D008826:Microbial Sensitivity Tests / Q000379:methods; D013407:Sulbactam / Q000494:pharmacology*; D013845:Thienamycins / Q000494:pharmacology*; D001618:beta-Lactamases / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D013845:Thienamycins; D001618:beta-Lactamases; D000077731:Meropenem; D013407:Sulbactam