Investigation of antibiotic resistance by total analysis of cell wall biosynthesis in methicillin-resistant

通过全分析甲氧西林耐药细胞壁生物合成研究抗生素耐药性

• 批准号: 14570238
• 负责人: KOMATSUZAWA Hitoshi
• 金额: $ 2.24万
• 依托单位: HIROSHIMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14570238/
• 关键词: Staphylococcus aureus; vancomycin; methicillin; moenomycin; cell wall; transposon; antibiotic resistance; transglycosylase; 細胞壁合成; MRSA; 細胞膜

We investigated the expression levels of 30 factors involved in cell wall biosynthesis by differential display method in methicillin/vancomycin-resistant and -sensitive Staphylococcus aureus, and found no difference between them. Since we previously found that vancomycin-intermediate S.aureus showed the moenomycin-resistance, we focused on two monofunctional transglycosylases, sgtA and sgtB. We constructed their knockout mutants and the mutants overexpressing SgtA or SgtB. Both overexpressed mutants showed the decreased susceptibility to moenomycin and vancomycin. Then, we isolated the moenomycin-resistant mutants from 5 clinical S.aureus strains, and found that all mutants showed decreased susceptibility to vancomycin and increased susceptibility to methicillin. However, these mutants did not alter the expression of SgtA and SgtB. These results indicate that SgtA and SgtB are associated with the susceptibility to vancomycin, but other factors are also involved. Then, we isolated two Tn551-insertional mutants, which increased the moenomycin-susceptibility. Both mutants also showed the decreased susceptibility to vancomycin. We identified the genes, lysC and fmtC, in which Tn551 inserted. lysC is involved in lysine biosynthesis, and fmtC is involved in the synthesis of lysyl-phosphatidylglycerol in bacterial membrane. These are novel factors affecting the vanocmycin-susceptibility in S.aureus

我们采用差异显示技术研究了30个参与细胞壁生物合成的因子在耐甲氧西林/万古霉素金黄色葡萄球菌和敏感金黄色葡萄球菌中的表达水平，发现它们之间没有差异。由于我们以前发现万古霉素中间体金黄色葡萄球菌显示出莫诺霉素耐药性，我们将重点放在两个单功能转糖基酶，sgtA和sgtB。我们构建了它们的敲除突变体和过表达SgtA或SgtB的突变体。两种过表达的突变体均显示对默诺霉素和万古霉素的敏感性降低。然后，我们从5株临床分离的金黄色葡萄球菌中分离出莫诺霉素耐药突变株，发现所有突变株对万古霉素的敏感性降低，对甲氧西林的敏感性增加。然而，这些突变体没有改变SgtA和SgtB的表达。这些结果表明，SgtA和SgtB与万古霉素的敏感性有关，但也涉及其他因素。然后，我们分离了两个Tn 551插入突变体，这增加了莫诺霉素的敏感性。两种突变体对万古霉素的敏感性均降低。我们鉴定了Tn 551插入的基因lysC和fmtC。lysC参与赖氨酸的生物合成，fmtC参与细菌膜上赖氨酰-磷脂酰甘油的合成。这些是影响金黄色葡萄球菌对万古霉素敏感性的新因素

项目成果

Hiromi Nishi: "Moenomycin-resistance is associated with vancomycin-intermediate susceptibility in Staphylococcus aureus"Microbiology and Immunology. 47. 927-935 (2003)

Hiromi Nishi：“金黄色葡萄球菌中的默诺霉素耐药性与万古霉素中度敏感性相关”微生物学和免疫学。

Nishi H. et al.: "Moenomycin-resistance is associated with vancomycin -intermediate susceptibility in Staphylococcus aureus"Microbiology and Immunology. 47. 927-935 (2003)

Nishi H.等人：“金黄色葡萄球菌中默诺霉素耐药性与万古霉素中度敏感性相关”微生物学和免疫学。

H.Komatsuzawa: "Increased glycan-chain length distribution and decreased susceptibility to moenomycin in a vancomycin-resistant Staphylococcus aureus mutant"Antimicrobial Agents and Chemotherapy. 46. 75-81 (2002)

H.Komatsuzawa：“万古霉素耐药金黄色葡萄球菌突变体中聚糖链长度分布增加，对莫诺霉素的敏感性降低”抗菌剂和化疗。