Browsing by Author "Suutarinen, Maiju"

Imbalance of intestinal microbiota is called dysbiosis. Signs of dysbiosis are altered abundance of different bacterial species and reduced diversity together with altered interactions between bacterial species and microbiota and the host. Dysbiosis of intestinal microbiota is connected to many intestinal diseases and today many studies are focused to find so called “next generation” probiotics to be used for the alleviation of dysbiosis instead of traditional antibiotic treatments. The study was made in the Human Microbiome Research Program, Faculty of Medicine, University of Helsinki. Aim of the study was to isolate spore-forming bacterial species for the treatment of intestinal inflammation and infections with bacterial therapy. For this purpose, feces from a healthy adult who had acted as a donor for fecal microbiota transplantation was used to isolate spore-forming commensal bacteria. The isolated bacteria were identified and their ability to adhere into intestinal epithelium and strengthen it was investigated. Also anti-inflammatory potential of these isolated bacterial strains was investigated. For isolating bacteria three different heat treatments and ethanol and methanol treatments were used as a pre-treatment step. Pre-treated samples were cultivated on YCFA-media and isolates were picked from plates at different growth points for further cultivation. Selected isolates were purified, their DNA was isolated and they were identified by partial 16S rRNA -gene sequencing. From these identified isolates four isolates were chosen for further investigation and their full length 16S rRNA -gene was sequenced. These isolates were studied also by using API and aerotolerance tests. Potential anti-inflammatory and adhesion properties of the isolates were investigated by attenuation, adhesion and TER-experiments. In the isolation, the effect of different pre-treatments on the recovery of isolates was clear and based on sequencing isolates that were spore-forming anaerobic bacteria were selected for further investigation. Three of the isolates were Clostridium butyricum and one Blautia wexlerae species. Anti- and pro-inflammatory properties of these isolates were very different depending on isolate and one of them was potentially anti-inflammatory. Isolates also adhered differentially and two of them possibly strengthened gut epithelial barrier so they are promising for further research and in the future investigation with these isolates continues. Experience and results with different cultivation methods can be used to for further development of cultivation for anaerobic intestinal bacteria.