Thesis Type: Doctorate
Institution Of The Thesis: Gazi Üniversitesi, Sağlık Bilimleri Enstitüsü, Turkey
Approval Date: 2015
Student: SERAP SÜZÜK
Supervisor: AYŞE MELTEM YALINAY
Abstract:The importance and effect of the intestinal flora on human health and pathogenesis of various diseases have been gained even more importance with the human microbiome project coming into the agenda.The intestinal microbiota is a dynamic system showing individual differences in both the number and species of microorganisms. Dietary habits , lifestyle, age, genetic predisposition of the host and use of antibiotics also affect the intestinal flora. The aim of this study is to carry out a quantitative comparison as regards the Bifidobacterium spp, Bacteriodes fragilis, Lactobacillus spp, Akkermansia mucinophilia and Fecalobacterium prausnitzii, which are the important bacterial species of the intestinal microbiota before and after antibiotic therapy with tetracycline and metronidazole in patients who are positive for Helicobacter pylori (HP) and to determine the effects of antibiotic use on the microbiota. 39 patients who applied to the Gastroenterology Clinic of Gazi University Medical Faculty and were diagnosed as HP-positive were included in this study. While 39 of the patients did not give stool sample before antibiotic therapy, 18 patients gave stool sample after antibiotic therapy. The stool samples of 200 mg in weight were collected from the patients who were included in the evaluation. A special extraction kit (QIAmp DNA Stool Mini Kit, QIAgen, GERMANY) was used for DNA isolation procedure because of the presence of DNA isolation inhibitors in large amount in stool. Primers specific for the 16S rRNA region of the bacteria included in the study were used for the amplification of the target region. ATCC strains of the related bacteria were evaluated for optimization of the quantification procedure and verification of the specificity of primers. Following the extraction of bacteria on the stool samples collected from both HP-positive patients and healthy volunteers, all the bacteria were subjected to real-time quantification procedure with PCR (Polymerase Chain reaction) method on Rotor-Gene® 20 device (Qiagen, Germany). As a result of the quantification before and after antibiotic use in patients receiving HP treatment, statistically significant decreases were observed in Bifidobacterium spp (p=0,000), Bacteriodes fragilis (p=0,000), Lactobacillus spp (p=0,000), A. mucinophilia (p=0,000) and F. prausnitzii. Based on the data obtained, it can be said that tetracycline and metronidazole used to treat HP can prepare the ground that could result in dysbiosis in microbiota