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Faecal microflora and urease activity during the first six months of infancy
M George1, K E Nord, G Ronquist
1Department of Anaesthesiology, Uppsala University, Sweden.
Insights
Urea breakdown in infant guts may affect acid-base balance and breathing. This study tracked infant gut bacteria and urease activity, finding changes that warrant further investigation into infant health.
Area of Science:
- Infant physiology
- Gastroenterology
- Microbiology
Background:
- Urea degradation in the gastrointestinal tract may influence infant acid-base balance and respiratory control.
- Infant gut microflora composition and activity are critical during early development.
Purpose of the Study:
- To investigate the relationship between gastrointestinal urea degradation and infant physiological regulation.
- To analyze changes in fecal microflora and urease activity in infants from birth to six months.
Main Methods:
- Collected fecal samples from thirteen infants at multiple time points (3 days, 2, 3, and 6 months).
- Determined fecal microflora composition via aerobic and anaerobic cultivation.
- Assessed fecal urease activity and pH after aerobic and anaerobic preincubation.
Main Results:
- Fecal pH increased from approximately 5.30 to 5.90 over six months.
- Nitric oxide production increased significantly (10-fold), while urease activity decreased (3-5 fold).
- Nitrate, nitrite, and nitric oxide demonstrated inhibitory effects on fecal urease activity.
Conclusions:
- Gastrointestinal urea metabolism in infants shows dynamic changes.
- Nitrous oxides may play a role in modulating fecal urease activity.
- Further research is needed to explore the implications for infant health, including Sudden Infant Death Syndrome (SIDS).
Abstract:
Gastrointestinal degradation of urea might, according to a new hypothesis, have consequences for the regulation of acid-base balance as well as control of breathing during infancy. Thirteen infants were investigated from their first few days of life to the age of 6 months by collecting faecal samples at the age of 3 days, 2, 3, and 6 months, respectively. The faecal microflora was determined after aerobic and anaerobic cultivation and the faecal urease activity was assessed after 36 h aerobic and anaerobic preincubation. The infants were mostly breast fed and had a faecal microflora containing anaerobic bacteria such as Bifidobacteria, Bacterioides and Lactobacilli but also aerobics such as Escherichia coli, Enterococci and sometimes Klebsiella. The faecal pH increased from approximately 5.30 to 5.90, the pH after anaerobic preincubation being on an average 0.2 pH units lower than after aerobic preincubation. Simultaneously the nitric oxide production of the faecal specimens increased approximately 10-fold and the urease activity decreased by a factor of 3 to 5. We also found an inhibitory action of nitrate, nitrite (in mumolar concentration) and nitric oxide (in parts per million concentration) on the faecal urease activity. Hence, the present results warrant further research in order to determine more precisely the action of different concentrations of various nitrous oxides on individual bacterial species, and furthermore, to assay the faecal urease activity in victims of sudden infant death syndrome as well as in infants dead due to other causes.