The Mechanism of Antibiotic-Resistance in Oral Streptococci

口腔链球菌的抗生素耐药机制

• 批准号: 10671703
• 负责人: ONO Tsuneko
• 金额: $ 2.05万
• 依托单位: The University of Tokushima
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10671703/
• 关键词: Streptococcus mitis; Streptococcus oralis; macrolide resistance; erm gene; mefE gene; ketolide; マクロライド耐性; トランスポゾン; 薬剤排出ポンプ

The susceptibility of Streptococcus mitis and Streptococcus oralis isolated from the human oral and nasal cavities to macrolides and benzylpenicillin was determined. Benzylpenicillin yielded a MIC of 【less than or equal】0.002 to 4 μg/ml. Approximately 20% of the isolates were moderately resistant to benzylpenicillin with MICs of 0.12 to 1 μg/ml while one, isolate was highly resistant with an MIC of 2 μg/ml. The MIC range for erythromycin was 0.016 μg/ml to 516 μg/ml. Thirteen isolates were resistant to erythromycin and five, of these were constitutively resistant to azithromycin and clarithromycin, and inducibly resistant to rokitamycin. One isolate was. constitutively resistant to all the, macrolides used in this study. Six strains were highly resistant to erythromycin with an MIC of >512 μg/ml. DNA from all of the. highly erythronrycin-resistant strains and one of the moderately erythromycin-resistant strains gave expected bands as deduced from the corresponding erm gene by PCR ampli … More fication. Also DNA from Staphylococcus epidermidis and S. salivarius isolated from the same patient from which the erm positive streptococcal strains were isolated, produced expected bands as deduced from the erm gene. However, the nucleotide homology of the genes between Streptococcus and Staphylococcus was approximately 50%. This suggests that they are not, of the, same origin. Additionally, DNA from a highly resistant and two moderately resistant strains gave. an mefE PCR product of expected size : as predicted from the corresponding mefE sequence. The mefE-positive. strains possessed erythromycin efflux ability. We examined the antibacterial activity of a new ketolide HMR 3647 to Streptococcus mitis and S. oralis isolates carrying macrolide-resistant genes ermB, mefE and unknown genes. HMR 3647 was highly active to ermB positive, strains compared to erythromycin A and clarithromycin, and more active. than rokitamycin. Although HMR 3647 induced resistance to rokitamycin in ermB positive trains, still active against the resulted strains. Less

测定了口腔和鼻腔分离的轻型链球菌和口腔链球菌对大环内酯类抗生素和青霉素类药物的敏感性。青霉素对青霉素的最低抑菌浓度为0.002~4μg/ml，约20%的菌株对青霉素中度耐药，最低抑菌浓度为0.12~1μg/ml，1株高度耐药，最低抑菌浓度为2μg/ml。红霉素的最低抑菌浓度范围为0.016~516μg/ml，其中13株对红霉素耐药，5株对阿奇霉素和克拉霉素呈结构性耐药，对罗吉霉素具有诱导性耐药。其中一株是。对本研究中使用的所有大环内酯类抗生素都具有结构性抗性。6株菌株对红霉素高度耐药，最低抑菌浓度为512μg/ml。其中一株红霉素高度耐药株和一株中度红霉素耐药株的扩增产物与相应的erm基因的…扩增结果一致。更有说服力。从同一患者分离的表皮葡萄球菌和唾液葡萄球菌的DNA也产生了从erm基因推导出的预期条带。然而，链球菌和葡萄球菌基因的核苷酸同源性约为50%。这表明它们不是同源的。此外，从一个高度抗性和两个中抗性菌株的DNA给出了。预期大小的mefE聚合酶链式反应产物：根据相应的mefE序列预测。MefE阳性的。菌株具有红霉素外排能力。我们检测了一种新的酮内酯HMR 3647对携带大环内酯类耐药基因ermB、mefE和未知基因的轻型链球菌和口腔链球菌的抗菌活性。与红霉素A和克拉霉素相比，HMR 3647对ermB阳性的菌株具有很高的活性，而且活性更高。而不是罗吉他霉素。虽然HMR 3647在ermB阳性菌株中诱导了对罗吉霉素的耐药性，但仍对所产生的菌株具有活性。较少

项目成果

Tsuneko Ono, et al.: "Susceptibility of oral and nasal isolates of Streptococcus mitis and Streptococcus oralis to macrolides and PCR detection of resistant genes."Antimicrobial Agents and Chemotherapy. (in press).

Tsuneko Ono 等人：“轻症链球菌和口腔链球菌的口腔和鼻分离株对大环内酯类药物的敏感性以及耐药基因的 PCR 检测。”抗菌药物和化疗。

Tsuneko Ono: "Susceptibility of oral and nasal isolates of Streptococcus mitis and Streptococcus oralis to macrolides and PCR detaction of resistance genes"Antimicrobial Agents and Chemotherapy. 44.4(in press). (2000)

Tsuneko Ono：“轻症链球菌和口腔链球菌的口腔和鼻腔分离株对大环内酯类药物的敏感性和耐药基因的 PCR 检测”抗菌药物和化疗。

Tsuneko Ono: "Susceptibility of oral and nasal isolates of Streptococcus mitis and Streptococcus oralis to macrolides and PCR detection of resistance genes"Antimicrobial Agents and Chemotherapy. 44.4(in press). (2000)

小野恒子：“轻症链球菌和口腔链球菌口腔和鼻腔分离株对大环内酯类药物的敏感性和耐药基因的 PCR 检测”抗菌药物和化疗。