肠膜明串珠菌细菌素抗金黄色葡萄球菌的生物学特性分析

Biological characterization of a bacteriocin produced by Leuconostoc mesenteroides inhibiting Staphylococcus aureus

摘要:

【背景】 金黄色葡萄球菌(Staphylococcus aureus)是导致全球耐药负担加重的重要原因，乳酸菌细菌素是治疗致病性细菌感染的一种新型的手段，具有广阔的应用前景。【目的】 筛选抑制金黄色葡萄球菌的乳酸菌细菌素。【方法】 采用琼脂扩散法筛选产细菌素的乳酸菌；通过16S rRNA基因测序鉴定菌株，并利用MEGA 11构建系统发育树；排除酸和过氧化氢影响后，经生物学特性分析确定菌株细菌素的抗酶解性、pH稳定性和稳定性；测定菌株的生长曲线、产酸能力并观察其生长特性；对菌株进行模拟胃液耐受能力的检测。【结果】 从延吉南瓜中分离获得一株肠膜明串珠菌(Leuconostoc mesenteroides) WJY-6，该菌株分泌的细菌素对不同源金黄色葡萄球菌表现出抑菌效果，并且具有良好的抗酶解性，在100 ℃和121 ℃处理后抑菌活性仍能维持在35%以上，该细菌素在pH 3.0-5.0条件下抑菌活性最佳；该菌株培养8 h时pH值下降到5.0以下，抑菌效果稳步增加，在18 h进入生长稳定期；该菌株在模拟胃液中有极强的存活能力，并能够大幅增殖。【结论】 肠膜明串珠菌WJY-6有着极强的产酸能力，在模拟胃液中耐受能力良好，其所分泌的细菌素具备优异的理化特性，并且对金黄色葡萄球菌存在显著的抑制活性，有望成为防治金黄色葡萄球菌感染相关疾病的新型替代抗生素产品。

关键词:金黄色葡萄球菌;乳酸菌;肠膜明串珠菌;细菌素;生物学特性

Abstract:

[Background] Staphylococcus aureus is a key reason for the increase in the global drug resistance burden. Bacteriocins produced by lactic acid bacteria are a new method to treat pathogenic bacterial infections and has broad application prospects. [Objective] To screen the bacteriocins of lactic acid bacteria that inhibit S. aureus. [Methods] The agar diffusion method was used to screen the bacteriocin-producing lactic acid bacteria. Strains were identified by 16S rRNA gene sequencing and a phylogenetic tree was constructed using MEGA 11. After the effects of acids and hydrogen peroxide were excluded, the anti-enzymolysis property, pH stability, and thermostability of the bacteriocin produced by this strain were characterized. The growth curve, acid production capacity, and tolerance to simulated gastric fluid of the strain were studied. [Results] A strain named Leuconostoc mesenteroides WJY-6 was isolated from pumpkin in Yanji. It secreted a bacteriocin showing inhibitory effects on S. aureus from different sources. The bacteriocin exhibited a good anti-enzymolysis property and maintained over 35% of the inhibitory effect after being treated at 100 ℃ and 121 ℃. The bacteriocin showcased the strongest inhibitory activity at pH 3.0-5.0. The strain entered a stable growth phase after 18 h, with the pH dropping below 5.0 after 8 h, which steadily improved the inhibitory effect. The strain showed strong survival ability and proliferated actively in the simulated gastric fluid. [Conclusion] L. mesenteroides WJY-6 has a strong acid production ability and good tolerance to simulated gastric fluid. Moreover, it secretes a bacteriocin with excellent physical and chemical properties and inhibitory effect on S. aureus. The bacteriocin is expected to become a new alternative of antibiotics for the prevention and treatment of S. aureus.

Key words:Staphylococcus aureus;lactic acid bacteria;Leuconostoc mesenteroides;bacteriocins;biological characteristics