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Enteric bifidobacteria: isolation from human infants and challenge studies in mice
M Locascio1, A P Holgado, G Perdigón
1Centro de Referencia para Lactobacilos, Tucumán, Argentina.
Abstract:
Bifidobacteria from breast-fed infants, formula-fed infants, or premature babies fed by parenteral methods were isolated and identified. The persistence of these microorganisms in the gastrointestinal tract of mice, after oral administration, was studied to determine the optimal dose and frequency of translocation to the liver and spleen. The rate of isolation among infants varied between 19 and 82% depending on the origin of the samples, with the highest values seen in breast-fed babies. The predominant species found in all cases was Bifidobacterium adolescentis. The optimal dose for oral administration of bifidobacteria to mice was 10(7) cells per day per animal for up to 2, 5, or 7 days. These bacteria remained up to 5 days postfeeding, even if feeding was interrupted. The results of bacterial translocation assays showed differences for the different strains and doses tested.
Insights
This study isolated Bifidobacteria from infants and found Bifidobacterium adolescentis predominant. Optimal oral administration in mice involved 10(7) cells daily, with persistence up to 5 days, showing strain and dose-dependent translocation.
Area of Science:
- Microbiology
- Gastroenterology
- Infant Nutrition
Background:
- Bifidobacteria are crucial gut microbes, with prevalence varying based on infant feeding methods (breast milk, formula, parenteral).
- Understanding Bifidobacteria's persistence and translocation is vital for assessing probiotic efficacy and infant gut health.
Purpose of the Study:
- To isolate and identify Bifidobacteria from diverse infant feeding groups.
- To evaluate the persistence and gastrointestinal tract colonization of orally administered Bifidobacteria in a mouse model.
- To determine the optimal dosage and frequency for Bifidobacteria administration and assess bacterial translocation to liver and spleen.
Main Methods:
- Isolation and identification of Bifidobacteria from breast-fed, formula-fed, and parenterally fed premature infants.
- Oral administration of isolated Bifidobacteria to mice at varying doses (10(7) cells/day) and durations (2, 5, 7 days).
- Monitoring bacterial persistence in the mouse gastrointestinal tract and assessing translocation to the liver and spleen.
Main Results:
- Bifidobacteria isolation rates ranged from 19% to 82%, highest in breast-fed infants.
- Bifidobacterium adolescentis was the predominant species across all infant groups.
- Optimal oral dose in mice was 10(7) cells/day, with bacteria persisting up to 5 days post-administration, irrespective of feeding interruption.
- Bacterial translocation to liver and spleen varied significantly based on bacterial strain and administered dose.
Conclusions:
- Breast milk promotes higher Bifidobacteria colonization in infants.
- Bifidobacterium adolescentis is a key species in infant gut microbiota.
- A daily oral dose of 10(7) Bifidobacteria cells is effective for colonization in mice, with notable persistence.
- Strain-specific and dose-dependent bacterial translocation occurs, highlighting the need for careful selection in probiotic applications.