Perturbation of the intestinal microbiota of mice infected with Cryptosporidium parvum.

Understanding the interaction between the intestinal microbiota (microbiome) and enteric pathogens is of interest in the development of alternative treatments that do not rely on chemotherapy and do not lead to drug resistance. We undertook research in a rodent model of cryptosporidiosis to assess whether the bacterial gut microbiota is impacted by infection with the protozoan pathogen Cryptosporidium parvum. The profile of the faecal bacterial microbiota in infected and uninfected animals was compared using 16S amplicon sequencing. In four independent experiments, the intestinal microbiota of infected mice differed from that of uninfected animals, regardless of the C. parvum isolate used to infect mice. The use of replicated treatment groups demonstrated that microbiota divergence between treatments was driven by the infection and did not result from spontaneous changes in the intestinal ecosystem unrelated to the infection. Microbiota perturbation induced by C. parvum appeared to be reversible, as we observed a tendency for the phylogenetic distance between infected and uninfected mice to diminish after mice cleared the infection. As mice infected with C. parvum do not develop diarrhoea, these observations indicate that microbiota perturbation results from other mechanisms than an accelerated movement of gut content.