Gut microbiota composition does not associate with Toxoplasma infection in rats

Toxoplasma infection in intermediate host species closely associates with
inflammation. This association has led to suggestions that the behavioural
changes associated with infection may be indirectly driven by the
resulting sustained inflammation rather than a direct behavioural
manipulation by the parasite. If this is correct, sustained inflammation
in chronically infected rodents should present as widespread changes in
the gastrointestinal microbiota due to the dependency between the
composition of these microbiota and sustained inflammation. We conducted a
randomized controlled experiment in rats that were assigned to a
Toxoplasma-treatment, placebo-treatment or negative control group. We
sacrificed rats during the chronic phase of infection, collected their
cecal stool samples and sequenced the V3-V4 region of the 16S rRNA gene to
characterise the bacterial community in these samples. Toxoplasma
infection did not induce widespread changes in the bacterial community
composition of the gastrointestinal tract of rats. Rather, we found sex
differences in the bacterial community composition of rats. We conclude
that it is unlikely that sustained inflammation is the mechanism driving
the highly specific behavioural changes observed in Toxoplasma-positive
rats.