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Title: Analysis of the infant gut microbiota and investigation of bifidobacterial diversity and anti-microbial activity
Author: Aldis, Gary
Awarding Body: University of Reading
Current Institution: University of Reading
Date of Award: 2008
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Selected bacterial groups within the infant gut micro biota were investigated in relation to mode of delivery, initial diet (i.e. breast-fed versus formula-fed) and weaning. Colonic bacteria from 50 faecal samples (obtained from 30 infants during the milk-fed and, post-weaning phases) were enumerated by fluorescence in situ hybridisation. The probes used were as follows: Bac 303 (bacteroides), Bif 164 (bifidobacteria), Chis 150 (Clostridium clusters I and II), Erec 482 (Clostridium cluster XIVa), EC 1531 (Escherichia coli), Lab 158 (lactobacilli/enterococci group) and the DAPI nucleic acid stain (total cell count). In all cases bifidobacteria were identified as the major group. The mode of delivery did not influence the composition of the gut microbiota. Exclusively breast-fed infants had significantly lower Clostridium cluster XIVa counts than those exclusively formula-fed. Infants fed predominantly breast-milk had significantly lower Clostridium cluster XIVa, and higher total and bifidobacterial counts than predominantly formula-fed infants. Amongst the samples obtained following the introduction of solid food, no differences were observed following segregation into original cohorts (of delivery mode and initial diet). Furthermore, such faecal samples had significantly lower E. coli, total bacterial and bifidobacterial counts than those obtained during the milk-fed phase. Subsequently, the bifidobacterial component was further examined in relation to diversity and anti-microbial activity. Predominant biotypes (as determined by genetic fingerprinting of isolates) were identified by partial16S rRNA gene sequencing as five recognised bifidobacterial species, novel Bifidobacterium spp., Enterococcus faecalis and Lactobacillus plantarum. B. breve was the principle species isolated. However the bifidobacterial composition differed between infant cohorts.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available