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38 μg/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27.44 mg/L，拌饲喂食法测得LC50为35.44 mg/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 38 μg/mL with the does-time-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 LC50 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.