Cryptosporidiosis worsened by commonly used probiotic

By Sally Robertson, B.Sc.Reviewed by Kate Anderton, B.Sc. (Editor)Aug 31 2018

Researchers have found that infection with the intestinal parasite Cryptosporidium parvum is worsened in mice that have been administered a probiotic.

Image Credit: Alpha Tauri 3D Graphics / Shutterstock

As reported in the journal Applied and Environmental Microbiology, the team discovered that compared to control mice, those that were given the probiotic had altered gut microflora and more parasites in their feces.

Professor Giovanni Widmer and colleagues from Tufts University had assumed that a healthy microbiome could prevent or reduce the severity of infection.

However, contrary to their expectations, they found that the consumption of a commercially available probiotic actually increased the severity of infection.

Cryptosporidiosis is one of the main causes of diarrhea in developing countries. According to The Lancet, the infection killed around 48,000 individuals in 2016. There are no drugs that can treat the infection and no vaccines that can prevent it.

Antibiotics, which often cause an imbalance in the normal gut microbiota, can make people more susceptible to gut infections. On the other hand, a healthy balance of microflora can prevent infection or reduce its severity.

Prof. Widmer and colleagues therefore posited that a probiotic made up of the microflora found in healthy intestines would reduce the severity of cryptosporidiosis in a mouse model of the disease.

Mitigating the disease's severity may be sufficient to prevent diarrhea, or shorten its duration, and enable the immune system to naturally control the infection.

Professor Giovanni Widmer, Lead Researcher

Although the outcome of the study was contrary to their hypothesis, the fact that cryptosporidium growth can be affected by diet has meant Widmer and colleagues now think that it may still be possible to design probiotics that will mitigate the infection.

Widmer says that the aim now is to find a find a mechanistic link between microflora and cryptosporidium proliferation and ultimately design a simple nutritional supplement that helps the body fight the infection.

Identifying specific mechanisms that alter pathogen virulence in response to diet may enable the development of simple pre- or probiotics capable of modifying the composition of the microbiota to reduce the severity of cryptosporidiosis.”