A few new Salmonella Typhi vaccines use live attenuated strains of the bacteria, but such methods can mean the salmonella is shed into the environment through excrement. Researchers at Arizona State University's Biodesign Institute have been researching ways to detect S. Typhi--the cause of typhoid fever--in feces after use of the vaccine.
A test, known as RapidChek Select Salmonella, enriches bacterium in stool and reduces competitor microbes to detect the presence of salmonella. The idea here is to ensure that vaccinated patients are not excreting live vaccine microbes, which could then find their way into other humans.
"This technology is of critical value to help us assess the degree and duration of shedding that occurs after immunization with any live vaccine," the institute's Karen Brenneman says in a release. "We have an ethical responsibility to make sure we understand the effects of vaccination not only on the individual that receives the vaccine, but also on those around him/her in the community."
Patients will often excrete salmonella for three to 5 weeks after infection, the institute says. Typhoid fever infection, though, can result in shedding the bacteria for up to three months.
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