The Effect Of Debaryomyces Hansenii On The Bacteria In The Intestinal Contents Of Mice With Antibiotic-associated Diarrhea

Objective:To investigate the effects of Debaryomyces hansenii on bacterial diversity and bacterial lactese gene diversity from intestinal content in antibiotic-associated diarrhea（AAD）mice.In order to provide experimental evidence for clinical treatment of antibiotic-associated diarrhea and to development of Debaryomyces hansenii as a new microecologics.Methods:1 Intestinal bacterial diversity:Eighteen specific pathogen-free（SPF）Kunming（KM）mice were randomly selected into three groups:healthy control group,diarrhea control group and diarrhea treated group.The healthy control group was gavaged with 0.35 mL sterile water.The diarrhea groups were treated with antibiotics mixture composed of gentamycin sulfate and cefradine at the concentration of 62.5g·L^-1(23.33 mL·kg^-1·day^-1,40000 U·mL^-1)by intragastric administration.After diarrhea was induced,D.hansenii solution(0.35 mL,10¹⁰·mL^-1)was administrated twice a day for 4 days in diarrhea treated group.The intestinal contents and were then collected for total DNA extraction and further 16S rDNA sequencing.2 Intestinal bacterial lactase gene diversity:The methods for grouping and modeling were the same as bacterial diversity.After diarrhea was induced,D.hansenii solution(0.35 mL,10¹⁰·mL^-1)was administrated twice a day for 3 days in diarrhea treated group.The intestinal contents were then collected for total DNA extraction and further highthrough-put sequencing.Results:1 Bacterial diversity from intestinal contents:D.hansenii improved the bacterial population and restored the uniformity and richness of intestinal bacteria to a certain extent while had no significant effect on community structure of bacteria from intestinal contents.D.hansenii increased the relative abundance of Bifidobacterium and restored the abundance of Bacteroidales S24-7.2 Bacterial lactase gene diversity from intestinal contents:D.hansenii reduced the population of lactase-producing bacteria and changed its community structure from intestinal contents while had no significant effect on uniformity and richness.D.hansenii improved the relative abundance of lactase gene originated from Enterobacter sp.638,Modestobacter and some unclassified bacteria,as well as restored the abundance of Fretibacterium significantly.Conclusion:1 D.hansenii improved the growth of some beneficial bacteria so as to suppress the multiplication of harmful bacteria and regulate the balance of intestinal flora.2 D.hansenii improved the growth of some bacteria that secrete lactase with catalytic activity to regulate the activity of intestinal lactase,thus treating AAD.