放线菌AF1代谢粗提物对无乳链球菌的抗菌活性

Bioactivity of Streptommyces galilaeus AF1 metabolites against Streptococcus agalactiae

为了确定放线菌AF1代谢粗提物对无乳链球菌的抗菌效果,试验采用分光光度计和平板计数法确定菌株AF1代谢物对无乳链球菌的抗菌作用,并与几种常见无乳链球菌抗菌药物的效果进行比较。结果表明,放线菌AF1代谢粗提物对无乳链球菌有较强的抗菌作用,最小抑菌质量浓度(MIC)为38μg/mL,对无乳链球菌的杀菌作用表现出明显的时间剂量关系。扫描电镜结果表明作用后的无乳链球菌细胞壁严重破裂。静态法测得放线菌AF1代谢粗提物对斑马鱼的LC_(50)为27.44mg/L,拌饲喂食法测得LC_(50)为35.44mg/L,急性毒性表现为低毒。放线菌AF1代谢粗提物对无乳链球菌具有良好的抗菌活性,该研究可为无乳链球菌的防治提供新的线索。

To investigate the antimicrobial activities of the Streptommyces galilaeus AF1 metabolites on Streptococcus agalactiae,a spectrophotometer and counting plate colony was used to detect the effect of the metabolites against S.agalactiae and a comparative test on the efficacy with certain antimicrobial agents was conducted.The results showed that the metabolites of S.galilaeus AF1 have strong effects against S.agalactiae and the minimal inhibitory concentration was 38μg/mL with the doestime-effect relationship.The scanning electron microscopy results indicated that the cell walls of S.agalactiae were ruptured severely after being treated with the metabolites.The 96 h LC_（50） value for zebrafish were 27.44 mg/L and 35.44 mg/L by static method and feeding method,respectively and the acute toxicity was low.This study showed that the metabolites of S.galilaeus AF1 have good antibacterial activity against S.agalactiae and provides a new clue for prevention and control of S.agalactiae.