Recent study by scientists at Arizona State University's Biodesign Institute revealed that salmonella-based vaccine candidates can in help fighting infant pneumonia.

Roy Curtiss, an investigator of vaccines and infectious diseases said that the two vaccine strains draw on the properties of an unlikely vaccine carrierone generally associated with causing sickness rather than safeguarding the body against it.

Recent study has led to the development of two new vaccine candidates, labeled x9088 and x9558, under grants from the NIH and the Bill and Melinda Gates Foundation. The team said that the novel strains belong to a family known as recombinant attenuated Salmonella vaccines (RASVs). They say that the critical component boosting their effectiveness is a delayed mechanism of attenuation.

Researcher said that salmonella's notorious virulence is essentially short-circuited, but only after it has stimulated a robust systemic immune response to pneumococcal surface protein A (PspA), a vital bacterial pneumonia antigen.

The researchers have used genetic trickery to tame S. typhimurium, producing altered bacterial strains requiring mannose and/or arabinosesugars available in the lab, but absent in the human body. After roughly seven cell divisions, the bacterium exhausts its stores of specialized sugar. Unable to sustain the integrity of its cell wall, it bursts.

The researchers revealed that an initial version of the new vaccine is soon to begin the first pre-clinical trials in human subjects.