Host litter‐associated gut dynamics affect Escherichia coli abundance and adhesion genotype in rats

Abstract

The probability of detecting Escherichia coli varies between host species with different diets and body sizes. An experimental study that mimicked the effect of different carnivore body masses found that digesta transit times influence E. coli abundance. In this study, we investigated how the host's gastrointestinal dynamics affected E. coli abundance and genotype in a system that reflected an herbivorous host. Forty rats from nine litters were fed a diet high in fermentable fibre. We found a small effect of fibre concentration on the difference between the liquid and particle digesta retention times. However, the rats' litter membership explained the majority of the retention time differences (79%). In turn, we found that as the difference between liquid and particle retention times increased, E. coli faecal cell densities decreased, while the likelihood that an animal's dominant E. coli strain possessed a gene involved in adhesion (agn43) increased. Thus, this experiment revealed an unanticipated high degree of association between the hosts' litter, their gastrointestinal dynamics and the E. coli genotypes. Furthermore, by comparing our findings to previous work, we show that the presence of fermentable fibre in the diet appears to change the relationship between the host's phenotype and E. coli.

Escherichia coli diversity in the lower intestinal tract of humans

“…Alternatively, the abiotic and biotic conditions present in lower gastrointestinal tract of a host may favour a particular phylogroup, and it is strains of these phylogroups that are most likely to establish and persist in the host. There is considerable evidence to indicate that host characteristics play a role in determining what strains are found in a host (Gordon and Cowling, ; O'Brien and Gordon, ; Blyton et al ., ). It is possible to distinguish between the two explanations.…”

Within‐host evolution versus immigration as a determinant of Escherichia coli diversity in the human gastrointestinal tract

“…Therefore, the results of the survey studies indicate that the interactions among host diet, gut morphology and dynamics are important determinants of the genetic structure of E. coli populations in different host species. Experimental studies support the notion that diet and gut dynamics influence the diversity of E. coli present in the host (O'Brien and Gordon, ; Blyton et al ., ).…”

Effects of dispersal limitation in the face of intense selection via dietary intervention on the faecal microbiota of rats

“…There were three different diets: low fibre, high fibre and beans. These diets were selected on the basis of previous experiments and were chosen to produce particular outcomes with regards to gastrointestinal transit times and morphology (O'Brien and Gordon, 2011;Blyton et al, 2015). Hills Pet prescription diet i/d canine (Hill's Pet Nutrition) was used for the low-fibre diet; Hills prescription diet w/d canine was used for the high-fibre diet; and the bean diet was produced by mixing cooked red kidney beans (40% w/w) with Hills Pet prescription diet i/d canine (60% w/w).…”

“…Few studies have experimentally examined the outcome of the interaction of selection and dispersal limitation on the structure and composition of microbial communities. The current study seeks to address this question, by analysing the gut microbial communities of rats from different litters, at weaning (week 3) and after 14 weeks (week 17) raised on one of three diets known to cause changes in gastrointestinal morphology and dynamics (O'Brien and Gordon, 2011;Blyton et al, 2015).…”