In Vitro Activity of Doripenem in Combination with Various Antimicrobials Against Multidrug-Resistant Acinetobacter baumannii: Possible Options for the Treatment of Complicated Infection

• DOI: 10.1089/mdr.2012.0250
• Publication Date: 2013-05-09T15:15:09Z
• Authors: Luigi Principe; Alessandro Capone; Antonio Mazzarelli; Silvia D'Arezzo; Eugenio Bordi; Antonino Di Caro; Nicola Petrosillo
• Keywords: Acinetobacter baumannii; Colistin; Tigecycline; Doripenem; Amikacin; Sulbactam

Aims: The aim of this study was to evaluate the in vitro activity doripenem (DOR) alone and combination with a variety commonly used anti-Acinetobacter chemotherapeutic agents against 22 primary multidrug-resistant (MDR) Acinetobacter baumannii isolates (including 17 that were resistant DOR) from Intensive Care Unit patients. Antibiotic interactions evaluated using chequerboard method time-kill assay. Results: Considering all antimicrobials DOR, analysis showed synergy 13 A. strains (54.2%). Seven (29.2%) ≥2 synergistic interactions. DOR tigecycline (TIG) (eight strains), colistin (COL) amikacin (AMK) (four ampicillin/sulbactam (two rifampicin (one strain). Remarkably, effects detected only nonsusceptible strains. Time-kill assays confirmed eight (giving 10 interactions) for TIG (n=4), COL (n=5), AMK (n=1). No antagonistic observed both methods. Conclusions: This demonstrates TIG, COL, DOR-resistant strains, opening way vivo assessment novel therapies treatment infections caused by MDR baumannii.