248. In vitro antimicrobial synergy testing of colistin with sulbactam, meropenem, tigecycline aganist carbapenem resistant Acinetobacter baumannii isolated from intensive care unit patients by using Etest.
Session: Poster Abstract Session: Diagnostic Microbiology; Antimicrobial Sensitivities
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
Posters
  • IDweek poster Dr Arzu Yetkin.pdf (186.5 kB)
  • Background:

    Acinetobacter baumannii is a frequent cause of health-care associated infections particularly in patients admitted to intensive care units in most hospitals all over the world, as well as Turkey. The bacteria develop high resistance to most of the antimicrobials, leading to difficulties in treatment. The aim of this study is to search the in vitro antimicrobial susceptibility of colistin, meropenem, tigecycline and sulbactam alone and in combinations against carbapenem resistant Acinetobacter baumannii strains, by using Etest.

    Methods:

    Eighteen non-duplicate clinical isolates of carbapenem resistant Acinetobacter baumannii isolated from patients admitted to intensive care units were included into the study. Antimicrobial susceptibility testing of colistin, meropenem, tigecycline, sulbactam and in vitro activity of antimicrobial of combinations was tested by Etest.

    Results:

    Of the 18 isolates, all of them were resistant to meropenem (MIC ≥16 µg/ml) and sulbactam (MIC ≥16 µg/ml); all sensitive to colistin (MIC ≤2 µg/ml); for tigecycline 2/18 were found sensitive (MIC ≤2 µg/ml); and 16 found intermediately sensitive (MIC 4-6 µg/ml). Combinations of colistin with meropenem, and tigecycline with meropenem were synergistic for all of the tested isolates. No synergistic effect was detected between in the combinations of colistin with tigecycline or sulbactam.  Additive effect was detected between the combinations of colistin with tigecycline 5.6% (1/18), colistin with sulbactam 38.9% (7/18). Additionally, indifference was detected on 83.3% (15/18) and 61.1% (11/18) of the isolates between the combination of colistin with tigecycline and colistin with sulbactam, respectively.  Antagonism was detected on 11.1% (2/18) of the isolates between colistin and tigecycline combination.  

    Conclusion:

    As a synergistic effect was detected between colistin meropenem and tigecycline meropenem, these combinations might be used for the treatment options of the clinical cases caused by carbapenem resistant Acinetobacter baumannii isolates.

    Sevim Yilmaz1, Meltem Arzu Yetkin2, Aliye Bastug2, Bircan Kayaaslan2, Halide Aslaner2, Dilek Kanyilmaz2, Berrin Sari2, Esragül Akinci3 and Hürrem Bodur3, (1)Infectious Diseases and Clinical Microbiology Specialist, Kelkit State Hospital, Gumushane, Turkey, (2)Ankara Numune Research and Training Hospital, Ankara, Turkey, (3)Ankara Numune Research and Training Hospital, Ankara, Turkey

    Disclosures:

    S. Yilmaz, None

    M. A. Yetkin, None

    A. Bastug, None

    B. Kayaaslan, None

    H. Aslaner, None

    D. Kanyilmaz, None

    B. Sari, None

    E. Akinci, None

    H. Bodur, None

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