AIMS: The aim of this study was to evaluate the in vitro activity of doripenem (DOR) alone and in combination with a variety of commonly used anti-Acinetobacter chemotherapeutic agents against 22 primary multidrug-resistant (MDR) Acinetobacter baumannii isolates (including 17 isolates that were resistant to DOR) from Intensive Care Unit patients. Antibiotic interactions were evaluated using the chequerboard method and the time-kill assay. RESULTS: Considering all antimicrobials in combination with DOR, chequerboard analysis showed synergy in 13 A. baumannii strains (54.2%). Seven strains (29.2%) showed ≥2 synergistic interactions. DOR showed synergy in combination with tigecycline (TIG) (eight strains), colistin (COL) (eight strains), amikacin (AMK) (four strains), ampicillin/sulbactam (two strains), and rifampicin (one strain). Remarkably, synergistic effects were detected only in DOR nonsusceptible strains. Time-kill assays confirmed synergy in eight isolates (giving 10 synergistic interactions) for DOR in combination with TIG (n=4), COL (n=5), and AMK (n=1). No antagonistic interactions were observed with both methods. CONCLUSIONS: This study demonstrates the in vitro synergistic activity of DOR in combination with TIG, COL, and AMK against DOR-resistant A. baumannii strains, opening the way to in vivo assessment of novel combination therapies for treatment of infections caused by MDR A. baumannii.
AIMS: The aim of this study was to evaluate the in vitro activity of doripenem (DOR) alone and in combination with a variety of commonly used anti-Acinetobacter chemotherapeutic agents against 22 primary multidrug-resistant (MDR) Acinetobacter baumannii isolates (including 17 isolates that were resistant to DOR) from Intensive Care Unit patients. Antibiotic interactions were evaluated using the chequerboard method and the time-kill assay. RESULTS: Considering all antimicrobials in combination with DOR, chequerboard analysis showed synergy in 13 A. baumannii strains (54.2%). Seven strains (29.2%) showed ≥2 synergistic interactions. DOR showed synergy in combination with tigecycline (TIG) (eight strains), colistin (COL) (eight strains), amikacin (AMK) (four strains), ampicillin/sulbactam (two strains), and rifampicin (one strain). Remarkably, synergistic effects were detected only in DOR nonsusceptible strains. Time-kill assays confirmed synergy in eight isolates (giving 10 synergistic interactions) for DOR in combination with TIG (n=4), COL (n=5), and AMK (n=1). No antagonistic interactions were observed with both methods. CONCLUSIONS: This study demonstrates the in vitro synergistic activity of DOR in combination with TIG, COL, and AMK against DOR-resistant A. baumannii strains, opening the way to in vivo assessment of novel combination therapies for treatment of infections caused by MDR A. baumannii.
Authors: Rajbharan Yadav; Cornelia B Landersdorfer; Roger L Nation; John D Boyce; Jürgen B Bulitta Journal: Antimicrob Agents Chemother Date: 2015-02-02 Impact factor: 5.191
Authors: Jessica M A Blair; Mark A Webber; Alison J Baylay; David O Ogbolu; Laura J V Piddock Journal: Nat Rev Microbiol Date: 2014-12-01 Impact factor: 60.633
Authors: Rebekah Henry; Bethany Crane; David Powell; Deanna Deveson Lucas; Zhifeng Li; Jesús Aranda; Paul Harrison; Roger L Nation; Ben Adler; Marina Harper; John D Boyce; Jian Li Journal: J Antimicrob Chemother Date: 2015-01-14 Impact factor: 5.790