In order to better understand the mechanisms that encourage colonization of chickens’ intestinal tracts by these dangerous bacteria and find strategies to treat the infection they cause, a team of researchers in Brazil working with funding from FAPESP developed mutant versions of Salmonella.

Scientific Reports has released an article about the findings. Contrary to predictions, the mutant strains produced more serious infections than wild-type bacteria, the researchers observe in the study.

The pduA and ttrA genes were eliminated in the mutant strains. Both genes had been demonstrated in earlier studies using mice to account for Salmonella’s capacity to survive in an environment devoid of oxygen, favoring intestine colonization and dissemination in a production environment.She received a FAPESP technical training scholarship, and she is engaged in doctoral research at the School of Agricultural and Veterinary Sciences (FCAV-UNESP) of So Paulo State University in Jaboticabal.

“Salmonella’s genetic machinery is sufficient to allow it to alter behavior in response to hosts [commercial poultry] as well as other bacteria that coexist in the same environment as it and compete with it. Mauro Saraiva, the second author of the article and the study’s principal investigator during a postdoctoral fellowship at FCAV-UNESP, explained that when these two genes were removed, the organism discovered new survival mechanisms and grew even more deadly to birds.

The findings highlight the significance of taking animal health precautions as soon as chicks hatch and up to slaughter, along with care throughout meat transit and preservation. A vaccination to stop chickens’ intestinal worms from strains of Salmonella responsible for food-borne outbreaks of human salmonellosis lies beyond the horizon for now.

The study is part of a project supported by FAPESP and led by Angelo Berchieri Junior, a professor at FCAV-UNESP (read more at: to Berchieri Junior, few food-borne human infections have been detected in Brazil, but consumers should not neglect proper food conservation and hygiene. “The Salmonella serotypes known to cause food-borne diseases don’t always make a person sick. Although there are other important routes for these bacteria to be introduced into poultry farms, the greatest danger occurs when very young chicks are exposed, as their immune system isn’t fully formed,” he said.

In these cases, fecal excretion lasts longer and causes more extensive contamination of the chicken shed. As a result, more infected birds are transported to the slaughterhouse. Most contamination of carcasses (chickens ready for sale) occurs during this stage.