In vitro activities of carbapenem/sulbactam combination, colistin, colistin/rifampicin combination and tigecycline against carbapenem-resistant Acinetobacter baumannii

Joon-Young Song, Sae Yoon Kee, In Sook Hwang, Yu Bin Seo, Hye Won Jeong, Woo Joo Kim, Hee-Jin Cheong

Research output: Contribution to journalArticle

90 Citations (Scopus)


Objectives: To determine the in vitro activities and interactions of imipenem, colistin and tigecycline with old antibacterial agents against carbapenem-resistant Acinetobacter baumannii. Methods: Forty-three carbapenem-resistant A. baumannii isolates from the intensive care unit of a university hospital were collected and their MICs of imipenem, colistin and tigecycline were determined. With eight randomly selected carbapenem-resistant isolates, an in vitro time-kill study was performed for the evaluation of antibacterial activity of colistin, tigecycline, imipenem/sulbactam and colistin/rifampicin. Results: The time-kill study of colistin demonstrated bactericidal activity against A. baumannii at concentrations of 4 × MIC and 8 × MIC, whereas tigecycline showed bacteriostatic activity at all concentrations. The combination regimens of imipenem/sulbactam and colistin/rifampicin were synergistic and bactericidal at 1 × MIC. Conclusions: Imipenem/sulbactam combination, colistin and tigecycline showed good in vitro activities against carbapenem-resistant A. baumannii isolates. Even though colistin is bactericidal against carbapenem-resistant A. baumannii, the colistin/rifampicin combination is more warranted in order to be certain.

Original languageEnglish
Pages (from-to)317-322
Number of pages6
JournalJournal of Antimicrobial Chemotherapy
Issue number2
Publication statusPublished - 2007 Aug 1



  • A. baumannii
  • Synergy
  • Time-kill assay

ASJC Scopus subject areas

  • Pharmacology
  • Microbiology

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