THE MICROBIOME OF HUMAN APPENDICES FROM PATIENTS FOLLOWING APPENDECTOMY

Aim & Background:

Appendicitis is a common disease of inflamed appendix which causes right lower quadrant pain, along with nausea, vomiting, loss of appetite and fever. Acute appendicitis occurs after appendix outlet obstruction and bacterial overgrowth as a secondary consequence. Some investigators have argued that the obstruction is the result, rather than the cause of appendicitis. Our research aim is to determine the bacterial composition of human inflamed appendices compared to none-inflamed ones (normal).

Methods:

Seventy-four appendix samples were collected from patients following appendectomy. All of the appendices underwent pathological diagnosis to determine the degree of inflammation. Bacterial 16S rRNA genes were sequenced using the Illumina MiSeq platform and microbiome analysis was performed using QIIME (version 1.8.0).

Results:

From 74 appendices, 69 were diagnosed with acute appendicitis and 5 were normal. Female to male ratio was 34/40 with a mean age of 28.45. Principal Coordinate Analysis (PCoA) plot, that was performed based on Unweighted UniFrac distance matrix, demonstrated significance (p < 0.001) differences in bacterial composition between acute appendicitis and normal appendices samples. Using the Chao1 measure, bacterial richness was significantly higher (p = 0.001) in normal appendices samples. The relative abundance of Fusobacteria and Synergistetes phyla were significantly higher in acute appendicitis samples (p = 0.004 and 0.01, respectively).

Conclusions:

To conclude, acute appendicitis has a different bacterial composition which is less diverse compared to a normal appendix. It is associated with high abundance of members of the Fusobacteria and Synergistetes phyla. Based on these results, further examination of the bacterial effect on the disease should be done in order to examine options for treatment, prevention and even using bacteria as biomarkers.