2株乳酸菌抑菌作用研究及安全性评价

Bacteriostasis and safety evaluation of two lactic acid bacteria

  • 摘要: 该研究利用无菌操作技术对2株乳酸菌乳酸菌S60 (干酪乳杆菌Lactobacillus casei) 和S72 (植物乳杆菌Lactobacillus plantarum)开展了常规生化检测、药敏实验、体外抑菌实验和动物实验,验证了其作为渔用益生菌的可行性和安全性。结果显示,2株乳酸菌均能在pH为4.5和0.1%的胆盐环境中存活,对水产动物常见病原菌嗜水气单胞菌 (Aeromonas hydrophila) 等均有一定的抑制作用,且抑菌物质分析结果显示,其有效抑菌物质与其代谢过程中产生的有机酸类相关。安全性评价实验结果显示2株乳酸菌无分解明胶和溶血的能力。死亡统计和血液生化指标结果显示,高达1.0×109 CFU·mL−1的活菌腹腔注射攻毒并未引起实验鱼类异育银鲫 (Carassius auratus)的严重死亡和机体损伤。可见2株乳酸菌作为口服益生菌具有较高的安全性。此外,耐药特性研究表明,2株乳酸菌对所用药物中的氨基糖苷类和磺胺甲唑耐受能力强,对氨苄青霉素、恩诺沙星、氟苯尼考和多西环素敏感。因此,2株乳酸菌的应用需要注意管理过程中药物的选择。

     

    Abstract: In this study, two strains of lactic acid bacteria Lactobacillus casei (S60) and L. plantarum (S72) were tested by aseptic technique, including routine biochemical detection, susceptibility test, in vitro bacteriostasis test and animal experiment. Their feasibility and safety as probiotics for fishing were also verified. Results show that the two lactic acid bacteria could tolerate acid (pH 4.0) and bile salt (0.1%), and exhibit different antibacterial activities against six pathogens including Aeromonas hydrophila. The results of antimicrobial substances analysis shows that the effective antimicrobial substances were related to the organic acids produced in metabolic process. The results of safety evaluation shows that the two strains of lactic acid bacteria had no ability to decompose gelatin and hemolysis. The results of death statistics and blood biochemical indicators show that the intraperitoneal injection of live bacteria as high as 1.0×109 CFU·mL−1 did not cause serious death and body injury in experimental fish. It is included that the two strains of lactic acid bacteria have high safety as oral probiotics. Drug resistance studies show that the two strains of lactic acid bacteria had strong tolerance to aminoglycosides and sulfamethoxazole, and were sensitive to ampicillin, enrofloxacin, florfenicol and doxycycline. Therefore, the application of the two strains of lactic acid bacteria should pay attention to the selection of drugs in management process.

     

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