マクロライド耐性口腔連鎖球菌に対するtelithromycinの抗菌力の検討  [in Japanese] In vitro activities of telithromycin against macroride-resistant oral streptococci  [in Japanese]

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Abstract

歯性感染症の主要分離菌であるoral streptococci 140株に対するtelithromycin (TEL), azithromycin (AZM), clarithromycin (CAM), roxithromycin (RXM), levofloxacin (LVFX), ampicillin (ABPC) およびerythromycin (EM) の抗菌力を測定すると共に, 実験的に誘導して得られたマクロライド高度耐性株に対するケトライド系抗菌薬TELの抗菌力を検討した。また, EM耐性株について<I>erm</I>遺伝子および<I>mef</I>遺伝子について検討を行った。14員環および15員環マクロライドの4薬剤はいずれもビリダンスグループの<I>Streptococcus mitis</I>でMIC<SUB>90</SUB>が高く, その値は1~8μg/mLであったが, TELのMICは0.5μg/mL以下ですべての菌の発育を阻止し, 他のマクロライド薬と交叉耐性を認めず, ABPCおよびLVFXを含めた試験薬剤のなかでもっとも優れた抗菌力を示した。CAM耐性誘導試験の結果<I>Streptcoccus intermedius</I>は誘導の前後変化が認められなかった。<I>S.mitis</I>は耐性誘導後CAMのIC値が16倍に上昇した。<I>Streptcoccus oralis</I> 2株では耐性誘導後CAMのMIC値が16および256倍に上昇した。TELのMICはCAMの耐性誘導株に対しても0.03μg/mLから0.12μg/mLと軽度の上昇にとどまった。<I>ermB</I>遺伝子, <I>mefA</I>遺伝子保有株においてもTELは14および15員環マクロライド系抗菌薬と交叉耐性を示さなかった。

The antibacterial activities of telithromycin (TEL), azithromycin, clarithromycin, roxithromycin, levofloxacin (LVFX), ampicillin (ABPC) and erythromycin (EM) were determined against 140 strains of oral streptococci, the major pathogens in dental infbctions. Atthesame time, the antibacterial activities of ketolide-antibiotics were tested against experimentally induced strains that werehighly resistant to macrolides. In the EM-resistant strains, the presence of <I>erm</I> and <I>mef</I> genes was investigated. The MIC<SUB>90</SUB> of each of the fbur 14-or 15-member ring macrolide antibiotics was high against <I>Streptcoccus mitis</I> in the viridans group (1 to 8μg/mL); howeverthe MIC of TEL wasbelow 0.5μg/mL, which was sufficient to inhibit the growth of all the organisms. TEL also did not exhibit cross resistance with macrolides, and displayed the most outstanding antibacterial activity among the test agents, including ABPC and LVFX. No changes were noted in <I>Streptococcus intermedius</I> befbre and after clarithromycin (CAM) resistance induction. After resistance induction, the MIC of CAM against <I>S. mitis</I> rose 16 times. Against two strains of <I>Streptococcus oralis</I>, the MIC of CAM rose to 16 and 256, respectively, after resistance induction. The MIC of TEL rose only slightly (from 0.03 to 0.12μg/mL) against the strains into which CAM resistance had been induced. TEL did not exhibit cross resistance with 14-or 15-member ring macrolides in <I>ermB</I> or <I>mefA</I> gene Carrying Strains.

Journal

  • Japanese Journal of Chemotherapy

    Japanese Journal of Chemotherapy 50(1), 11-15, 2002-01-25

    Japanese Society of Chemotherapy

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