Low-frequency ultrasound treatment reduces susceptibility to Salmonella infection in aged mice

ABSTRACT Increased susceptibility of elderly populations to infection is a major concern, as recently experienced by the coronavirus pandemic. Therefore, the treatment of infected elderly individuals is of immediate interest. Here, we report the use of ultrasound treatment to reduce Salmonella infection in elderly individuals. Salmonella enterica serovar Typhimurium enters the human body through the ingestion of contaminated food or water and causes gastroenteritis. The Centers for Disease Control (CDC) reports 420 deaths per year in the United States caused by the Salmonella pathogen, especially in the elderly population. In this study, we investigated the susceptibility to Salmonella infection in young and old mice by enumerating the number of viable bacteria in the liver 3 days post-infection. We then explored the effect of ultrasound treatment (low-frequency ultrasound [LFU]) prior to infecting aged mice with Salmonella. We observed a higher colonization of Salmonella infection in the livers of old mice compared to young mice. Colonization was significantly reduced when old mice were treated with LFU prior to infection, which significantly reduced colonization. Chemokine analysis revealed a significant increase in ICAM-1, SDF-1, and KC/CXCL1 in aged, treated mice. Ultrasound treatment rejuvenated the immune system in old mice, reducing their susceptibility to Salmonella infection.IMPORTANCEOur study demonstrates the efficacy of low-frequency ultrasound (LFU) treatment in significantly rejuvenating the immune system in aged mice and reducing their susceptibility to Salmonella infection. These findings underscore the potential of LFU as a therapeutic intervention to boost immune function in elderly populations, reducing the risk of infectious diseases.