A Study of the Tolerability of Streptococcus faecalis for pH, Gastric Juice,Intestinal Juice and Bile Salt

To investigate the tolerability of Streptococcus faecalis for pH,gastric juice,intestinal juice and bile salt,the survival rate of Streptococcus faecalis was determined after treatment by different levels of pH,bovine tumors gastric juice,artificial gastric juice,artificial intestinal juice and bile salt at different time.The results showed that:(1)the acid tolerance of Streptococcus faecalis was relatively strong,but the tolerance was poor for base,especially strong base(pH=10);(2)the survival rate of Streptococcus faecalis was not greatly affected by the 0.2%-0.4% concentration of bile salt,but the survival rate was greatly influenced by high concentration(0.5%) bile salt;the survival rate decreased obviously with the treating time;(3)the tolerance of Streptococcus faecalis was quite strong in natural bovine tumors gastric juice,the survival rate was still more than 95% after being treated for 3 hours;but the tolerability was decreased by the artificial gastric juice,which was only 37.93% after being treated for 3 hours;(4)the tolerability of Streptococcus faecalis was strong within 2-4 hours in the artificial intestinal fluid,the survival rate was 72.64%;but the survival rate was relatively low over 4 hours.In conclusion: Streptococcus faecalis is tolerant to lower pH,gastric juice,intestinal juice,bile salt,so it is relatively stable in gastrointestinal tract.