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Bile Salt-induced Biofilm Formation in Enteric Pathogens: Techniques for Identification and Quantification
Published on: May 6, 2018
Profiling gut microbiota and bile acid metabolism in critically ill children
Iain Robert Louis Kean1, Joseph Wagner2,3, Anisha Wijeyesekera4
1Department of Paediatrics, University of Cambridge, Cambridge, United Kingdom. irlk2@cam.ac.uk.
Insights
Critically ill children show gut microbiome shifts, with Lachnospiraceae recovery linked to improved bile acid profiles. Measuring fecal bile acids may assess gut microbiota recovery in critical illness.
Area of Science:
- Microbiology
- Gastroenterology
- Critical Care Medicine
Background:
- Broad-spectrum antimicrobials impact gut fermentation, host immunity, and bile acid metabolism in critical illness.
- Previous work showed reduced fecal fermentation capacity in critically ill children at hospital admission.
- This study investigates the dynamic relationship between the gut microbiome and bile acid profiles in critically ill children over time.
Purpose of the Study:
- To explore the time-course of the gut microbiome and bile acid profile in critically ill children.
- To identify specific microbial shifts, like Lachnospiraceae recovery, during hospitalization.
- To determine if bile acid profiles can serve as a marker for gut microbiota recovery.
Main Methods:
- Faecal samples were collected from critically ill children.
- Microbiome composition was analyzed using 16S rRNA gene sequencing.
- Faecal water bile acids were quantified via liquid chromatography-mass spectrometry.
Main Results:
- Lachnospiraceae members recovered in late-acute phase samples (days 8-10) compared to admission samples.
- Patients with infections had lower Lachnospiraceae proportions than controls.
- Keystone species associated with ecological recovery declined with longer Pediatric Intensive Care Unit (PICU) admission, especially in severe cases.
Conclusions:
- Bile acid composition rapidly recovers after critical illness interventions, potentially facilitated by Lachnospiraceae shifts.
- Fecal bile acid measurements offer a potential method for assessing gut microbiota recovery in critically ill patients.
Abstract:
Broad-spectrum antimicrobial use during the treatment of critical illness influences gastrointestinal fermentation endpoints, host immune response and metabolic activity including the conversion of primary to secondary bile acids. We previously observed reduced fermentation capacity in the faecal microbiota of critically ill children upon hospital admission. Here, we further explore the timecourse of the relationship between the microbiome and bile acid profile in faecal samples collected from critically ill children. The microbiome was assayed by sequencing of the 16S rRNA gene, and faecal water bile acids were measured by liquid chromatography mass spectrometry. In comparison to admission faecal samples, members of the Lachnospiraceae recovered during the late-acute phase (days 8-10) of hospitalisation. Patients with infections had a lower proportion of Lachnospiraceae in their gut microbiota than controls and patients with primary admitting diagnoses. Keystone species linked to ecological recovery were observed to decline with the length of PICU admission. These species were further suppressed in patients with systemic infection, respiratory failure, and undergoing surgery. Bile acid composition recovers quickly after intervention for critical illness which may be aided by the compositional shift in Lachnospiraceae. Our findings suggest gut microbiota recovery can be readily assessed via measurement of faecal bile acids.
