Scientists discovered a special strain of good bacteria called L. rhamnosus P118 that can help protect against Salmonella food poisoning. They tested this bacteria in lab animals and found it works in several ways: it directly fights harmful germs, helps good gut bacteria grow, and produces helpful chemicals that reduce inflammation. The bacteria was found in fermented yogurt and healthy animal intestines. When given before Salmonella exposure, it significantly reduced illness and death rates by strengthening the body’s natural defenses and keeping the gut microbiome balanced.

The Quick Take

  • What they studied: How a specific probiotic bacteria strain protects against Salmonella food poisoning
  • Who participated: Laboratory mice and microscopic worms, with bacteria isolated from fermented yogurts and healthy pig intestines
  • Key finding: The probiotic bacteria significantly reduced death rates and illness severity from Salmonella infections
  • What it means for you: This research may lead to better probiotic supplements for preventing food poisoning, though human studies are still needed

The Research Details

Researchers first screened 290 different bacteria strains from yogurt and healthy animal intestines to find the most promising candidates. They tested these bacteria using both traditional lab methods and a unique approach involving tiny worms called C. elegans that can get infected with Salmonella. The best performing strain, P118, was then tested in mice that were given the probiotic before being exposed to deadly amounts of Salmonella bacteria. Scientists tracked survival rates, measured inflammation levels, analyzed gut bacteria populations, and studied the chemical compounds produced in the intestines. They used advanced genetic sequencing and chemical analysis techniques to understand exactly how the probiotic works at the molecular level.

This multi-step approach is important because it combines traditional safety testing with innovative screening methods and comprehensive analysis of how the probiotic affects the entire gut ecosystem, not just the harmful bacteria.

The study used multiple testing methods and animal models, analyzed both the microbiome and chemical metabolites, and identified specific mechanisms of action, which strengthens confidence in the results.

What the Results Show

The L. rhamnosus P118 strain showed remarkable protective effects against Salmonella infection through multiple pathways. When mice were given this probiotic before Salmonella exposure, they had significantly higher survival rates and less severe illness. The bacteria worked by directly killing Salmonella germs, preventing them from attaching to and invading intestinal walls, and reducing harmful inflammation in the gut. Laboratory tests showed that even the liquid from P118 bacterial cultures had strong antibacterial properties. The probiotic also helped maintain a healthy balance of gut bacteria, preventing the disruption that typically occurs during Salmonella infections.

Chemical analysis revealed that P118 increases production of beneficial compounds derived from tryptophan, an amino acid. These include indole-3-acrylic acid, indole, and 5-hydroxytryptophan, which help reduce inflammation and support gut health. The probiotic also decreased levels of harmful bacteria like Klebsiella and Anaeroplasma while promoting beneficial microbes. Immune system analysis showed reduced inflammatory responses in intestinal immune cells called macrophages.

While other Lactobacillus strains have shown protective effects against infections, this study provides unusually detailed insight into the specific mechanisms involved, particularly the role of tryptophan-derived metabolites in protection against Salmonella.

This research was conducted only in laboratory animals and microscopic worms, so results may not directly translate to humans. The study doesn’t specify exact dosages or timing that would be optimal for human use, and long-term safety data isn’t available.

The Bottom Line

While promising, this research is still in early stages and human clinical trials are needed before specific recommendations can be made. People interested in probiotics for gut health should consult healthcare providers about existing, well-studied probiotic strains.

People frequently exposed to foodborne illnesses, those with compromised immune systems, and individuals interested in preventive gut health measures should follow this research area, though they shouldn’t make changes based solely on these animal studies.

Human clinical trials would likely take 2-5 years to complete, so practical applications are still several years away from being available as consumer products.

Want to Apply This Research?

  • Track digestive symptoms, food poisoning episodes, and overall gut health indicators like bowel movement regularity and digestive comfort
  • Focus on consuming diverse fermented foods and maintaining gut health through established probiotic foods while staying informed about emerging research
  • Log digestive health patterns, food safety practices, and any probiotic supplement use to establish baseline health metrics for future comparison

This research was conducted in laboratory animals only. Do not use this information to self-treat or prevent infections. Always consult healthcare providers before starting new supplements or making significant dietary changes, especially if you have underlying health conditions or take medications.