两株具有广谱抗菌性的缓征链球菌的安全性评价

Safety evaluation of two strains of Streptococcus mitis with broad-spectrum antibacterial activity

目的通过动物实验对分离于健康儿童口咽部的2株缓征链球菌菌株4-2、4-19进行安全性评价,为呼吸道益生菌的制备提供安全依据。方法对SPF级昆明种小鼠灌胃给予含有菌株4-2和4-19的菌液,观察实验动物是否出现死亡、急性毒性体征、体质量变化、采食量变化、血清淀粉样蛋白A变化和细菌移位生长情况,并对结果进行统计学分析。结果给药后,未发现实验小鼠死亡及急性毒性体征,未观察到细菌移位生长情况,给予菌株4-2后雌性和雄性剂量组与对照组间差异没有统计学意义(F=0.697 0,P=0.567 0;F=1.289 0,P=0.312 0)。给予菌株4-2的1 d后,雌性小鼠低、中剂量组较其他组别体质量变化量小(F=4.402 0,P=0.019 0),雄性小鼠高、中、低剂量组体质量变化量小于对照组(t=-0.800 0,P=0.035 0;t=1.000 0,P=0.011 0;t=-0.800 0,P=0.035 0);给予菌株4-19的1 d后,雌性、雄性小鼠体质量变化量与对照组差异无统计学意义(F=2.024 0,P=0.151 0;F=2.507 0,P=0.096 0)。给予菌株4-2的7 d内,雌性小鼠中剂量组和低剂量组采食量大于对照组(t=0.171 4,P<0.001 0;t=1.276 1,P=0.001 0),雄性小鼠剂量组与对照组采食量差异无统计学意义(F=0.327 0,P=0.806 0);给予菌株4-19的7 d内,低剂量组采食量大于对照组(t=2.137 5,P=0.036 0),雄性小鼠剂量组与对照组采食量差异无统计学意义(F=2.631 0,P=0.073 0)。结论菌株4-2、4-19在为期7 d的急性毒性动物实验中,未发现毒性表现,可用于呼吸道益生菌菌株的选择。

Objective To evaluate the safety of two Streptococcus lentus strains 4-2 and 4-19 isolated from the oropharynx of healthy children through animal experiments, and provide a basis for the safe preparation of respiratory probiotics. Methods SPF grade Kunming mice were intragastrically administered bacterial liquid containing the strains 4-2 and 4-19 to observe whether the experimental animals occur death, acute toxicity signs, body weight changes, feed intake changes, serum amyloid A changes, and bacterial translocation, and analyze the results using statistical method. Results After administration, no signs of death and acute toxicity were found, and no bacterial growth was observed in the experimental mice. There were no significant differences in serum amyloid A between the observation groups and the control group. The differences in body weight and feed intake were significantly higher in the observation groups than in the control group. Conclusion No toxicity of the strains 4-2 and 4-19 was found in the 7-day acute toxicity animal experiment;the two strains may be used as alternative candidates of probiotics for respiratory tract.