Giardiasis may be a disease of the ecology of the GI tract

Colonization by the human and animal parasite, Giardia, changed the species composition of the mouse microbiome in a way that might be harmful.

"This shift is generally characterized by more aerobic bacteria and less diversity of anaerobic species in the gastrointestinal tract," said coauthor Scott C. Dawson, Associate Professor of Microbiology and Molecular Genetics, the University of California, Davis. "This suggests that Giardia infection could -- at least in part -- be an ecological disease, with parasite colonization disrupting the previously stable ecology of the gut."

Indeed, "We found changes in the host microbial community throughout the entire gastrointestinal tract," said Dawson. These findings challenge the conventional wisdom that Giardia is a disease of the small intestine.

"We infected mice with Giardia, sacrificed them at different times post-infection, and sequenced specific regions throughout the entire gastrointestinal tract using high-throughput 16S ribosomal RNA sequencing," said Dawson. This enabled the investigators to quantify the shifts in microbial diversity in each part of the GI tract, following infection. They also pre-treated one cohort of mice with antibiotics, to determine if that pretreatment resulted in different shifts in the microbiome as compared to those in mice not receiving antibiotics (it did so).

See:

N. R. Barash, J. G. Maloney, S. M. Singer, S. C. Dawson. Giardia alters commensal microbial diversity throughout the murine gut. Infection and Immunity, 2017; IAI.00948-16 DOI: 10.1128/IAI.00948-16

Posted by Dr. Tim Sandle