Microbial Composition of Human Appendices from Patients following

ABSTRACT The human appendix has historically been considered a vestige of evolutionary development with an unknown func-tion. While limited data are available on the microbial composition of the appendix, it has been postulated that this organ could serve as a microbial reservoir for repopulating the gastrointestinal tract in times of necessity. We aimed to explore the microbial composition of the human appendix, using high-throughput sequencing of the 16S rRNA gene V4 region. Seven patients, 5 to 25 years of age, presenting with symptoms of acute appendicitis were included in this study. Results showed considerable diver-sity and interindividual variability among the microbial composition of the appendix samples. In general, however, Firmicutes was the dominant phylum, with the majority of additional sequences being assigned at various levels to Proteobacteria, Bacte-roidetes, Actinobacteria, and Fusobacteria. Despite the large diversity in the microbiota found within the appendix, however, a fewmajor families and genera were found to comprise the majority of the sequences present. Interestingly, also, certain taxa not generally associated with the human intestine, including the oral pathogensGemella, Parvimonas, and Fusobacterium, were identified among the appendix samples. The prevalence of genera such as Fusobacterium could also be linked to the severity of inflammation of the organ.We conclude that the human appendix contains a robust and varied microbiota distinct from the microbiotas in other niches within the humanmicrobiome. The microbial composition of the human appendix is subject to ex-treme variability and comprises a diversity of biota that may play an important, as-yet-unknown role in human health