康宁木霉（Trichoderma koningii）SMF2分泌的peptaibols类抗菌肽Trichokonins抑菌活性研究

Peptaibols是一类来源于土壤微生物，由非核糖体合成酶（nonribosomal peptide synthetase， NRPS）合成的富含α 氨基异丁酸（α aminoisobutyric acid, Aib）的抗菌肽的总称. Trichokonins属于长链peptaibols第一亚家族，其对普通金黄色葡萄球菌和1株临床分离的多抗金黄色葡萄球菌的最低抑菌浓度（minimum inhibitory concentration, MIC）均为50?μg/mL，但时间杀菌曲线表明后者对MIC浓度的Trichokonins耐受性明显大于前者. 在含50?μg/mL浓度Trichokonins的培养基中连续转接20次后普通金黄色葡萄球菌和多抗金黄色葡萄球菌对Trichokonins的敏感性都明显降低，MIC值均提高到200?μg/mL以上, 表明金黄色葡萄球菌对Trichokonins产生了明显的抗性. 这与目前普遍认为的抗菌肽不易产生抗性的观点不一致, 其抗性产生的具体机制有待于进一步的研究.

Antimicrobial activities of Trichokonins: Peptaibol-like antimicrobial peptides produced by Trichoderma koningii SMF2

Peptaibols is a kind of Aib riching peptide antibiotics mostly produced by soil fungi and synthesized by nonribosomal peptide synthetase (NRPS). Trichokonins, with full length of 20 amino acids, belong to the first subfamily of peptaibols. The minimal inhibitory concentration (MIC) of Trichokonins against ordinary Staphylococcus aureus and a multi drug resistant Staphylococcus aureus strain are both 50?μg/mL. It can be observed from the time killing curves that the multi drug resistant strain shows a higher survival rate in the presence of 50?μg/mL Trichokonins. When they were inoculated for 20 times in 50 μg/mL Trichokonins, the sensitivity of both strains to Trichokonins decreased greatly, and the MICs increased to higher than 200?μg/mL. The results indicate that both strains become resistant to Trichokonins after the treatment. The mechanism of the resistance requires further experimentation for its disagreement with the existing views.