Salmonella is often troublesome to some and can be dangerous or deadly for sensitive groups. Over 25,000 people are hospitalized for bacterial infection in the U.S., and over 400 people die every year.
In a step toward combatting Salmonella infections, UF/IFAS microbiology researchers published a study that they hope will lead to a vaccine against the disease.
Salmonella infections are often caused by consuming contaminated food or water or touching infected animals or livestock or their feces. This results in severe diarrhea and even arthritis post-infection.
The findings of the UF study will advance the development of a vaccine that protects against non-typhoidal strains of Salmonella, for which there are no current vaccines, said Mariola Ferraro, a study author and associate professor at the UF/IFAS microbiology and cell science department. And Ferraro said they also highlight how important it is to address solutions for antibiotic-resistant strains of Salmonella since resistant strains were found in Gainesville’s wastewater.
Antibiotic-resistant strains of Salmonella are especially dangerous and pose a distinct threat to children under 5, adults 65 and older, immunocompromised people, and people taking certain medications such as stomach acid reducers. And non-typhoidal Salmonella differs from typhoidal Salmonella, which causes typhoid fever and which has a vaccine.
The UF/IFAS study looks at a new method to deliver a Salmonella vaccine, which was tested in mice. Even though a previous study tested this vaccine with lab-derived strains of Salmonella, this time the researchers used Salmonella bacteria from the local environment (the wastewater system of Gainesville, Florida) and used those environmental, real-world strains to test the effectiveness of the vaccine they created, she said.
This study found that when tested with real-world strains of Salmonella, the vaccine created antibodies against this microbe in the mice – which equips the animals with a defense mechanism against Salmonella, according to Ferraro.
This vaccine, which was given to the mice through their noses, used an innovative approach of using small extracellular vesicles (sEVs) as a delivery method. And the sEVs are tiny particles created by cells and are one of the ways by which cells communicate with one another. For this study, researchers devised sEVs to carry bacterial proteins, allowing their transfer between cells and causing a long-lasting immune response. And since no live bacteria are given to mice, the risk for complications is lower.
She said this study not only found that the vaccine was causing immune response against real-world infections but highlighted the importance of these sEVs in regulating immunity – which is an important step toward understanding the immune system more fully.
These next steps will be to figure out sEVs’ role in the immune system and why these nano-sized vesicles could be safer and more effective at creating an immune response than introducing the bacteria into the body directly.
Lisa Emerson (the first author of the study) tragically passed away from natural causes in September at just 29 years old. And she was a driving force behind the success of this research.
Ferraro pointed out that Emerson had a deep dedication to integrating public health into microbiology research, and her passion for public health was clear to those who worked with her both at UF as a doctoral student and at the CDC, where she worked after graduation on studying emerging respiratory viruses.
UF now has a memorial scholarship in Emerson’s name for a student studying microbiology.
KEY QUOTE:
“Lisa truly cared. That’s why she chose to work at the CDC — because public health wasn’t just a field to her; it was a calling.”
– Study author Mariola Ferraro
