Beneficial Gut Bacteria Could Prevent Dangerous Bloodstream Infections in Cancer Patients

Scientists in the United States have developed an innovative treatment using carefully selected beneficial gut bacteria to protect vulnerable blood cancer patients from potentially life-threatening bloodstream infections. Researchers from City of Hope, Memorial Sloan Kettering Cancer Center and Seres Therapeutics investigated a new experimental therapy called SER-155, which contains 16 specially chosen bacterial strains designed to restore a healthier intestinal microbiome following intensive cancer treatment. Patients receiving donor stem-cell transplants are particularly susceptible to serious infections because chemotherapy, antibiotics and immune suppression can disrupt the normal balance of gut microorganisms. In a multicentre Phase I clinical trial, researchers administered the bacterial treatment in capsule form before transplantation and again afterwards, finding that the introduced bacteria successfully established themselves in the digestive system. Encouragingly, treated patients experienced fewer bloodstream infections and lower levels of harmful bacteria associated with infection, while no treatment-related safety problems were identified. Unlike conventional probiotics, SER-155 uses a precisely selected combination of microorganisms intended to compete with dangerous pathogens and support immune regulation. Although the early results are promising, the trial was primarily designed to assess safety, and larger studies are needed to establish its effectiveness before it can become a routine treatment. The discovery offers an exciting new approach to reducing severe infection risks and improving recovery for people undergoing intensive blood cancer therapy.