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Impact of intestinal parasites on microbiota and cobalamin gene sequences: a pilot study
Rojelio Mejia1,2, Ashish Damania3, Rebecca Jeun3
1National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA. rmejia@bcm.edu.
Insights
Gastrointestinal parasites in children disrupt gut bacteria, decreasing vitamin B12 (cobalamin) synthesis. Infections like Giardia and helminths alter microbiota, potentially impacting child development.
Area of Science:
- Microbiology
- Parasitology
- Human Health
Background:
- Gastrointestinal parasitic infections affect approximately 30% of children globally.
- Parasites can disrupt the intestinal bacterial microbiota, impacting essential vitamin biosynthesis.
Purpose of the Study:
- To investigate the impact of parasitic infections (Giardia and helminths) on the gut microbiota composition and function in children.
- To analyze changes in bacterial diversity, taxonomy, and vitamin B12 biosynthesis pathways associated with parasitic infections.
Main Methods:
- Collected stool samples from 37 asymptomatic Argentinian children.
- Utilized real-time quantitative PCR for parasite detection and whole-genome sequencing for bacterial microbiota analysis.
- Analyzed data comparing uninfected, Giardia-only, helminth-only, and co-infected groups.
Main Results:
- Giardia infections reduced microbiota biodiversity and shifted taxonomy towards Prevotella, correlating with infection intensity.
- Helminth-only infections increased diversity, while co-infections decreased it.
- Cobalamin (vitamin B12) synthesis was reduced in Giardia-infected children and in co-infected groups.
Conclusions:
- Parasitic infections may promote anaerobic bacteria like Prevotella, altering vitamin B12 biosynthesis.
- These alterations in microbiota and vitamin synthesis may have implications for child growth and development.
Background:
Approximately 30% of children worldwide are infected with gastrointestinal parasites. Depending on the species, parasites can disrupt intestinal bacterial microbiota affecting essential vitamin biosynthesis.
Methods:
Stool samples were collected from 37 asymptomatic children from a previous cross-sectional Argentinian study. A multi-parallel real-time quantitative PCR was implemented for Ascaris lumbricoides, Ancylostoma duodenale, Necator americanus, Strongyloides stercoralis, Trichuris trichiura, Cryptosporidium spp., Entamoeba histolytica and Giardia duodenalis. In addition, whole-genome sequencing analysis was conducted for bacterial microbiota on all samples and analyzed using Livermore Metagenomic Analysis Toolkit and DIAMOND software. Separate analyses were carried out for uninfected, Giardia-only, Giardia + helminth co-infections, and helminth-only groups.
Results:
For Giardia-only infected children compared to uninfected children, DNA sequencing data showed a decrease in microbiota biodiversity that correlated with increasing Giardia burden and was statistically significant using Shannon's alpha diversity (Giardia-only > 1 fg/µl 2.346; non-infected group 3.253, P = 0.0317). An increase in diversity was observed for helminth-only infections with a decrease in diversity for Giardia + helminth co-infections (P = 0.00178). In Giardia-only infections, microbiome taxonomy changed from Firmicutes towards increasing proportions of Prevotella, with the degree of change related to the intensity of infection compared to uninfected (P = 0.0317). The abundance of Prevotella bacteria was decreased in the helminths-only group but increased for Giardia + helminth co-infections (P = 0.0262). Metagenomic analysis determined cobalamin synthesis was decreased in the Giardia > 1 fg/µl group compared to both the Giardia < 1 fg/µl and the uninfected group (P = 0.0369). Giardia + helminth group also had a decrease in cobalamin CbiM genes from helminth-only infections (P = 0.000754).
Conclusion:
The study results may provide evidence for an effect of parasitic infections enabling the permissive growth of anaerobic bacteria such as Prevotella, suggesting an altered capacity of vitamin B12 (cobalamin) biosynthesis and potential impact on growth and development in children .
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