Studies on combination of antibiotics (I): In vitro combined effect of piperacillin, ticarcillin and dibekacin against clinically isolated pseudomonas aeruginosa

Seiichi Aonuma, Kikuo Onuma, Akira Watanabe, Masako Sasaki, Kotaro Oizumi, Kiyoshi Konno

    Research output: Contribution to journalArticlepeer-review

    12 Citations (Scopus)

    Abstract

    (1) When used alone, MIC of PIPC was found most frequently at 6.25 µg/ml and that of TIPC at 50 µg/ml. Thus it was found that the antipseudomonal activity of PIPC was almost 3 times as strong as that of TIPC. (2) Synergistic inhibitory effects of PIPC plus DKB (FIC index≤0.5) were observed on 26 strair.s (74.3%) and those of TIPC plus DKB on 23 strains (65.7%). Thus synergistic growth-inhibitory effects by combination of PIPC and DKB were found to be somewhat superior to those of TIPC DKB. (3) Synergistic potentiation of bactericidal activity (FBC index≤0.5) of PIPC plus DKB was found against 23 strains (65.7%), while that of TIPC plus DKB against 18 strains (51.4%). Thus, PIPC was found to show more remarkable effects than TIPC when combined with DKB. (4) Test strains in this experiment were divided into the following two groups : in group I, MIC of PIPC and TIPC respectively was 6.25 µg/ml and below, and in group II, 12.5 µg/ml and above. Combined effects of PIPC plus DKB and those TIPC of DKB respectively were compared between group I and group II. As shown by FIC- and FBC- indices, the combined effects were more evident in group II than in group I. These results indicated the advantage of combinding β-lactam antibiotics with DKB, as evidenced by enhanced synergistic growth-inhibitory effects on the strains that are not very sensitive to β-lactams. MIC of PIPC and TIPC respectively was decreased by addition of a small amount of DKB. When used alone, MIC of 6.25 µg/ml and below was found for PIPC in 19 strains (54. 3%) and for TIPC in 2 strains (5.7%) respectively. In the presence of 0.2 µg/ml of DKB, on the other hand, MIC of 6.25 µg/ml and below was found for PIPC in 33 strains (94.3%) and for TIPC in 23 strains (65.7%) respectively. Similarly, MBC (without partner drug) of 6.25 µg/ml and below was found for PIPC in 15 strains (42.9%) and for TIPC in 2 strains (5.7%) respectively. When combined with 0.2 µg/ml of DKB, MBC of 6.25 µg/ml and below was found for PIPC in 29 strains (82.9%) and for TIPC in 16 strains (45.7%) respectively.

    Original languageEnglish
    Pages (from-to)149-153
    Number of pages5
    JournalChemotherapy
    Volume30
    Issue number2
    DOIs
    Publication statusPublished - 1982 Jan 1

    ASJC Scopus subject areas

    • Pharmacology (medical)
    • Infectious Diseases
    • Pharmacology
    • Drug Discovery
    • Oncology

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