Abstract
Background:
The intestinal microbiome is a critical component of host defense and metabolic regulation in both humans and animals. Parasitic infections such as amebiasis disrupt microbial enzyme activities, potentially influencing host physiology.

Aim:
To investigate functional differences in gut microbial enzymes between humans infected with Entameba histolytica and healthy controls and to provide insights relevant to comparative parasitic pathobiology.

Methods:
Stool samples collected from patients diagnosed with amebiasis, as well as from healthy control individuals, were analyzed using 16S rRNA gene sequencing. KEGG-based annotation tools were used to generate functional enzyme predictions, and differential pathway enrichment was assessed across hierarchical metabolic levels.

Results:
The results showed that healthy controls displayed greater representation of metabolic, genetic, and environmental information pathways. In contrast, amebiasis patients showed enrichment in membrane transport and energy metabolism. Glycolytic and oxidative stress-related enzymes, including 6-phosphofructokinase, phosphoglycerate mutase, and peroxiredoxin, were significantly more abundant in the infected group. Conversely, enzymes linked to amino acid biosynthesis and DNA repair—such as phosphoglycolate phosphatase and NADH: ubiquinone reductase—were markedly reduced, indicating a functional shift toward energy mobilization and stress adaptation.

Conclusion:
In conclusion, amebiasis induces the reorganization of gut microbial enzyme functions, enhancing glycolytic and transport activities while suppressing biosynthetic and repair processes. These findings may also provide valuable comparative insights for veterinary medicine, as similar host–parasite–microbiome interactions occur in several protozoal infections affecting domestic and wild animals. Understanding microbial enzyme responses during protozoal infection could therefore contribute to improved interpretation of microbiome-associated pathophysiology in veterinary parasitology.

Key words: Amebiasis; Enzyme function; Gut microbiota; KEGG pathway; Microbial metabolism.