Comparative Analysis of Gut Microbiota in Humans Living with and Without Companion Animals

Cohabitation with companion animals (CAs) has been suggested as a significant modifier of gut microbial diversity. This study investigated the influence of cohabitation with CAs on human gut microbiota composition. Using 16S rRNA gene sequencing, we analyzed the gut microbiota of 20 families with CAs (40 adults, 20 children) and 20 families without CAs (40 adults, 20 children). Alpha and beta diversity analyses were performed, and the differentially abundant genera were identified. There were significant differences in beta diversity across the groups (<i>p</i>-value = 0.001). The <i>Bacillota</i>/<i>Bacteroidota</i> ratio was considerably lower in the CAs group (0.67) than in the without-CAs group (1.02). <i>Prevotellaceae</i>_UCG-003 (log2 fold change: 7.3; adjusted <i>p</i>-value ≤ 0.001), <i>Ruminococcaceae</i> (log2 fold change: 6.3; adjusted <i>p</i>-value ≤ 0.001), and <i>Oscillospira</i> (log2 fold change: 5.1; adjusted <i>p</i>-value = 0.012) were elevated in the group cohabiting with CAs, whereas <i>Megamonas</i> (with CAs: 3.81%; without CAs: 13.52%) and <i>Veillonella</i> (with CAs: 3.77%; without CAs: 6.50%) were more prevalent in the group without CAs. Cohabitation with CAs may positively influence the gut microbiota by promoting the presence of beneficial bacteria and reducing the <i>Bacillota</i>/<i>Bacteroidota</i> ratio. This study highlights the potential for cohabitation with CAs to promote gut microbial health.