# Microbiota evaluation in acute appendicitis: a preliminary study of appendix and childhood oral microbiota

## TL;DR

This study explores the connection between oral and intestinal microbiota in children with acute appendicitis, finding microbial differences linked to disease severity.

## Contribution

The study is the first to compare oral and appendix microbiota in children with acute appendicitis, considering dental caries status.

## Key findings

- Complicated appendicitis showed higher intestinal Bacteroidetes, Firmicutes, and Fusobacterium nucleatum compared to oral levels.
- Bacteroidetes in the appendix correlated strongly with oral bacteria in complicated appendicitis.
- No significant microbial differences were found in non-complicated appendicitis cases.

## Abstract

Despite the uncertainty of the sequence of events leading to appendicitis, the microbiome is presumed to play a central role in the pathogenesis. This preliminary cross-sectional study aimed to evaluate the intestinal microbes in distinct phases of acute appendicitis compared to the oral microbiota, considering the status of dental caries. Twenty children under 12 years were assigned into two groups: non-complicated appendicitis (NCA, n = 11) and complicated appendicitis (CA, n = 9). Biological material from the oral cavity (saliva) and appendix (mucosal scrapings) was submitted to microbial analysis to quantify Bacteroidetes, Firmicutes, and Fusobacterium nucleatum by qPCR. Data were assessed using ANOVA and Pearson's correlation (α = 5%). Considering CA, significant differences were found between the mouth and appendix for Bacteroidetes, Firmicutes, and Fusobacterium nucleatum levels (p < 0.05), with increased amounts in the intestinal niche. Conversely, there was no statistical difference (p > 0.05) regarding NCA. Bacteroidetes levels in the intestinal appendix significantly correlate to all of the studied bacteria in the mouth (p < 0.05, r = 0.66–0.89), while in the NCA pattern, this happened only with Bacteroidetes. Caries conditions were similar between the two groups. In conclusion, a relationship is suggested between the intestinal appendix and oral bacteria, in a comparable caries index, in distinct phases of acute appendicitis. The severity of the children's appendix condition seems to correlate with the magnitude of microbial changes.