Gut Microbiota of Sarawak's "Orang Ulu" Indigenous Community in East Malaysia Reveals Vanish Microbes: A Comparison With Urban Communities.

The Sarawak Indigenous community exhibited the highest gut microbial diversity compared to semi-urbanized and urban groups.

• Study included 86 Indigenous participants from Sarawak, 45 Malaysian Indigenous participants from Selangor, and 18 Urban citizens from Kuala Lumpur.
• Diversity ranked in order: Sarawak Indigenous (highest), followed by Peninsular Indigenous (Selangor), and Urban (Kuala Lumpur) groups.
• The V4 hypervariable region of the 16S rRNA gene was sequenced and analyzed using QIIME2 bioinformatics platform.
• Sarawak Indigenous groups represented were the Orang Ulu subethnic groups Kayan and Kenyah, and Selangor Indigenous were the Proto Malay subtribe Temuan.

The Prevotella/Bacteroides (P/B) ratio differed markedly across the three communities, with Sarawak Indigenous showing the highest Prevotella prevalence.

• Sarawak Indigenous community showed the highest presence of Prevotella at 88.3%.
• Kuala Lumpur Urban residents had a predominantly Bacteroides composition at 61%.
• The Selangor Indigenous community exhibited a Prevotella-dominant profile at 75.5%.
• Results suggest a gradient from Prevotella dominance in rural/Indigenous communities to Bacteroides dominance in urban communities.

VANISH microbes were identified as dominant genera in the Sarawak Indigenous gut microbiota, while BIoSSUM microbes dominated in the urban Kuala Lumpur cohort.

• VANISH (Vanishing in Absence of Ancestral/traditional diet and lifestyle) microbes identified in Sarawak Indigenous gut included Prevotella, Faecalibacterium, and Succinivibrio.
• BIoSSUM microbe identified in the Kuala Lumpur urban cohort was Bacteroidaceae.
• This contrast aligns with the broader pattern of urbanization-associated microbiome shifts described in the literature.
• This is the first study to characterize the gut microbiota of Sarawak's Indigenous communities.

Urbanization correlates with reduced gut microbial diversity and shifts in gut microbiota composition in the Malaysian context.

• The study design was cross-sectional, comparing rural Indigenous, semi-urbanized Indigenous, and urban populations.
• Urban citizens resided in Kuala Lumpur City, representing a modern urban lifestyle setting.
• The findings highlight the impact of urbanization on gut microbiota composition during lifestyle transitions.
• The Sarawak Indigenous communities had no prior characterization of their gut microbiota before this study.