Aim: To compare caecal microbiota from mdr1a– ⁄ – and wild type (FVB) mice
to identify differences in the bacterial community that could influence the
Methods and Results: Caecal microbiota of mdr1a– ⁄ – and FVB mice were evaluated
at 12 and 25 weeks of age using denaturing gradient gel electrophoresis
(DGGE) and quantitative real-time PCR. DGGE fingerprints of FVB and
mdr1a– ⁄ – mice (with no intestinal inflammation) at 12 weeks revealed differences
in the presence of DNA fragments identified as Bacteroides fragilis,
B. thetaiotaomicron, B. vulgatus and an uncultured alphaproteobacterium.
Escherichia coli and Acinetobacter sp. were only identified in DGGE profiles of
mdr1a– ⁄ – mice at 25 weeks (with severe intestinal inflammation), which also
had a lower number of total bacteria in the caecum compared with FVB mice
at same age.
Conclusions: Differences found in the caecal microbiota of FVB and mdr1a– ⁄ –
mice (12 weeks) suggest that the lack of Abcb1 transporters in intestinal cells
due to the disruption of the mdr1a gene might lead to changes in the caecal
microbiota. The altered microbiota along with the genetic defect could contribute
to the development of intestinal inflammation in mdr1a– ⁄ – mice.
Significance and Impact of the Study: Differences in caecal microbiota of
mdr1a– ⁄ – and FVB mice (12 weeks) suggest genotype specific colonization. The
results provide evidence that Abcb1 transporters may regulate host interactions
with commensal bacteria. Future work is needed to identify the mechanisms
involved in this possible cross-talk between the host intestinal cells and