Researchers develop oral Salmonella vaccine

Salmonella is responsible for one of the most common foodborne illnesses in the world. In the US alone, it is estimated that there are about 1.4 million cases, with 15,000 hospitalisations and 400 deaths, each year.

Researchers from The University of Texas Medical Branch have developed an oral vaccine against Salmonella poisoning. In earlier studies, the UTMB researchers developed potential vaccines from three genetically mutated versions of the bacteria, Salmonella typhimurium, that were shown to protect mice against a lethal dose of Salmonella. In these studies, the vaccines were given as an injection.

However, oral vaccination is the simplest and least invasive way to protect people against Salmonella infection. Taking the vaccine by mouth has the added advantage of using the same pathway that Salmonella uses to wreak havoc on the digestive system.

“In the current study, we analysed the immune responses of mice that received the vaccination by mouth as well as how they responded to a lethal dose of Salmonella,” said Ashok Chopra, UTMB professor of microbiology and immunology. “We found that the orally administered vaccines produced strong immunity against Salmonella, showing their potential for future use in people.”

There is no vaccine currently available for Salmonella poisoning. Antibiotics are the first choice, but some strains are developing antibiotic resistance. Another dangerous aspect of Salmonella is that it can be used as a bioweapon — this happened in Oregon when a religious cult intentionally contaminated restaurant salad bars and sickened 1000 people.

People with compromised immune systems and children under the age of three are at increased risk of invasive non-typhoidal salmonellosis, which causes systemic infection. There are about 1 million cases globally per year, with a 25% fatality rate.

The study’s findings have been published in Frontiers in Cellular and Infection Microbiology.