Researchers search for microbes that offer protection against Salmonella

Scientists have identified how a bacteria in the gut can act as a protective species against Salmonella infection.

A team at the University of Cambridge in England revealed a novel role for the commensal bacterium Enterocloster clostridioformis as helping to protect against salmonellosis.

Virginia Pedicord, Benjamin Beresford-Jones, and researchers at the University of Cambridge found Enterocloster clostridioformis could protect the host against bacterial pathogens like Salmonella by inducing protective responses in gut cells and increasing anti-inflammatory immune cells in the gut. Findings were published in the journal Microbiome.

The gut microbiota has previously been implicated in providing resistance against Salmonella infection. Commensal bacteria can inhibit colonization of pathogens through competition for metabolites including carbon sources, iron, and oxygen as well as production of inhibitory substances.

Help guide development of treatments
Researchers monocolonized germ-free mice with mouse-derived commensal microbes to examine the microbiota’s ability to enhance resistance to Salmonella Typhimurium.

They found that Enterocloster clostridioformis induces a transcriptional response in cecal epithelial cells and elicits an increase in the number of local regulatory T cells. These effects lessened tissue pathology in infected mice and significantly prolonged their survival.

Germ-free mice were sensitive to Salmonella Typhimurium infection, resulting in rapid weight loss and death within two days of infection. A total of 18 commensal bacterial isolates were screened for their impact on Salmonella infection.

Although all mice did eventually die, monocolonization with Enterocloster clostridioformis increased resistance to infection, delaying and reducing the rate of weight loss and increasing survival. Mortality at 1-day post-infection was reduced from 76 percent in germ-free mice to 0 percent following Enterocloster clostridioformis treatment.

“These findings reveal new ways good gut bacteria could protect the host against certain bad bacteria and may guide the development of innovative treatments for these infections. They could also change how we understand other gut diseases, including inflammatory bowel disease and irritable bowel syndrome,” said scientists.

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