Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 100-106).

Abstract Purpose: The oral microbiome has been related to numerous extra oral diseases. Recent studies detected a high abundance of oral bacteria in inflamed appendices in pediatric patients. To elucidate the role of oral bacteria in acute pediatric appendicitis, we studied the oral and appendiceal microbiome of affected children compared to healthy controls. Methods: Between 1-6/2015, 21 children undergoing appendectomy for acute appendicitis and 28 healthy controls were prospectively enrolled in the study. All individuals underwent thorough dental examination as well as laboratory for CRP, neutrophil and leukocyte count. Samples of inflamed appendices and the gingival sulcus were taken for 16S rDNA sequencing. Additionally, RT-qPCR of Fusobacterium nucleatum, Peptostreptococcus stomatis and Eikenella corrodens was performed and their viability was tested under acidic conditions to mimic gastric transfer. Results: In appendices, Bacteriodetes and Porphyromonas were discovered as dominant phylum and genus. In sulcus samples, Firmicutes and Streptococcus were detected predominantly. Peptostreptococcus stomatis, Eikenella corrodens and Fusobacterium nucleatum were identified in each sample group. In contrast to controls, viable amounts of Peptostreptococcus stomatis were increased in appendices and correlated with leukocyte count and CRP levels. Postprandial viability could be demonstrated for all tested bacteria. Conclusion: In children with acute appendicitis, we identified several oral bacterial pathogens. Based on postprandial viability of selected species, a viable migration from the oral cavity through the stomach to the appendix seems possible. Thus, the oral cavity could be a relevant reservoir for acute appendicitis.