Das intra- und extraluminale Mikrobiom in kindlichen Appendizes – eine Vergleichsstudie

Intestinal microbiota is involved in metabolic processes and the pathophysiology of various gastrointestinal disorders. We aimed to characterize the microbiome of the appendix in acute pediatric appendicitis comparing extraluminal and intraluminal samples. Between January and June 2015, 29 children (3–17 years, mean age 10.7±3.4 years, sex M:F=2.6:1) undergoing laparoscopic appendectomy for acute appendicitis were prospectively included in the study. Samples for bacterial cultures (n=29) and 16S ribosomal desoxyribonucleic acid (rDNA) sequencing (randomly chosen n=16/29) were taken intracorporeally from the appendiceal surface before preparation (“extraluminal”) and from the appendiceal lumen after removal (“intraluminal”). The degree of inflammation was histologically classified into catarrhal, phlegmonous, and gangrenous appendicitis. Seventeen bacterial species were cultivated in 28 of 29 intraluminal samples and 4 species were cultivated in 2 of 29 extraluminal samples. Using 16S rDNA sequencing, 267 species were detected in intraluminal but none in extraluminal samples. Abundance and diversity of detected species differed significantly between histological groups of acute appendicitis in bacterial cultures (P=.001), but not after 16S rDNA sequencing. The appendiceal microbiome showed a high diversity in acute pediatric appendicitis. The intraluminal microbial composition differed significantly depending on the degree of inflammation. As bacteria were rarely found extraluminally by culture and not at all by sequencing, the inflammation in acute appendicitis may start inside the appendix and spread transmurally

Das intra- und extraluminale Mikrobiom in kindlichen Appendizes – eine Vergleichsstudie

Intestinal microbiota is involved in metabolic processes and the pathophysiology of various gastrointestinal disorders. We aimed to characterize the microbiome of the appendix in acute pediatric appendicitis comparing extraluminal and intraluminal samples. Between January and June 2015, 29 children (3–17 years, mean age 10.7±3.4 years, sex M:F=2.6:1) undergoing laparoscopic appendectomy for acute appendicitis were prospectively included in the study. Samples for bacterial cultures (n=29) and 16S ribosomal desoxyribonucleic acid (rDNA) sequencing (randomly chosen n=16/29) were taken intracorporeally from the appendiceal surface before preparation (“extraluminal”) and from the appendiceal lumen after removal (“intraluminal”). The degree of inflammation was histologically classified into catarrhal, phlegmonous, and gangrenous appendicitis. Seventeen bacterial species were cultivated in 28 of 29 intraluminal samples and 4 species were cultivated in 2 of 29 extraluminal samples. Using 16S rDNA sequencing, 267 species were detected in intraluminal but none in extraluminal samples. Abundance and diversity of detected species differed significantly between histological groups of acute appendicitis in bacterial cultures (P=.001), but not after 16S rDNA sequencing. The appendiceal microbiome showed a high diversity in acute pediatric appendicitis. The intraluminal microbial composition differed significantly depending on the degree of inflammation. As bacteria were rarely found extraluminally by culture and not at all by sequencing, the inflammation in acute appendicitis may start inside the appendix and spread transmurally

The oral microbiome - the relevant reservoir for acute pediatric appendicitis?

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 January and June 2015, 21 children undergoing appendectomy for acute appendicitis and 28 healthy controls were prospectively enrolled in the study. All individuals underwent thorough dental examination and laboratory for inflammatory parameters. Samples of inflamed appendices and the gingival sulcus were taken for 16S rDNA sequencing. 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 phlegmonous appendices, Bacteroidetes and Porphyromonas were discovered as dominant phylum and genus. In sulcus samples, Firmicutes and Streptococcus were detected predominantly. P. stomatis, E. corrodens, and F. nucleatum were identified in each group. Viable amounts of P. stomatis were increased in sulci of children with acute appendicitis compared to sulci of healthy controls. In inflamed appendices, viable amounts of E. corrodens and F. nucleatum were decreased compared to sulci of children with appendicitis. 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