Researchers at Texas Tech University School of Veterinary Medicine have made significant strides in understanding how Salmonella bacteria adapt metabolically for survival, shedding light on their remarkable versatility. Devendra H. Shah, DVM, PhD, shared insights from the 20-year-long study at the 2023 North Central Avian Disease Conference, emphasizing Salmonella’s ability to thrive with just 4,000 genes while being adaptable across different environments and species.
The breakthroughs in the study include the identification of a cluster of 21 genes forming a Salmonella pathogenicity island, crucial for the bacteria’s metabolism. Knocking out these genes hindered Salmonella’s ability to infect human cell lines. Collaborative efforts over the years, involving USDA microbiologist Jake Elder and National Poultry Research Center’s Jean Guard, delved deeper into the metabolic pathways.
The team discovered that Salmonella extracts energy from two proteins—tyramine, a monoamine, and D-glucuronic acid (DGA), a sugar acid—both present in the mammalian gut, including humans and chickens. The study aimed to understand how Salmonella acquires energy from these sources and identified specific genes responsible for this process.
To target Salmonella’s growth, the researchers explored inhibiting the consumption of tyramine and DGA. In lab tests, a monoamine oxidase (MAO) inhibitor, commonly used as an antidepressant, effectively halted Salmonella’s ability to use tyramine as a food source. The inhibitor demonstrated efficacy against various Salmonella serotypes.
Similarly, researchers found that a drug used in human cancer patients to reduce side effects could block the production of DGA, essentially starving Salmonella. Although cautioning against using antidepressants in chickens, Shah expressed optimism about anti-nutritional strategies as potential solutions.
The findings suggest promising avenues for developing novel nutritional approaches to reduce Salmonella infections in chickens. Shah highlighted the importance of understanding Salmonella’s genetic makeup to devise effective strategies, emphasizing the potential impact on food safety efforts through a realistic reduction in Salmonella counts.