Evaluation of molecular protocols for the laboratory diagnosis of Salmonella infections in animals: in silico approach and analytical validation

• Grant number: 24/17611-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2025
• End date: March 31, 2026
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Preventive Veterinary Medicine
• Principal Investigator: Lara Borges Keid
• Grantee: Ariel Lima Dias
• Host Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil

Abstract

Salmonellosis is a disease caused by bacteria of the genus Salmonella, one of the most important diseases transmissible in humans, domestic and wild animals. It is associated with diarrheal conditions in humans and animals and reproductive problems in ruminants and horses. The diagnosis of the infection is mainly based on microbiological culture to isolate the bacterium and polymerase chain reaction (PCR) is an alternative in situations where it is not possible to properly collect and preserve samples in order to maintain bacterial viability, so that isolation in culture is successful. This proposal aims to review the molecular diagnostic protocols based on PCR for the detection of Salmonella spp. and the serovars Salmonella Typhimurium and Dublin to evaluate the primers using in silico approach and analytical validation. After the survey on the main genes and respective primers described for diagnosis, the search for DNA sequences of each gene and their multiple alignment will be carried out. The location of each pair of primers in the lineup will be done to determine the ability of the primers to amplify the greatest diversity of salmonella. The primers will then be evaluated for analytical specificity using the Primer-Blast program and for thermodynamic characteristics that favor amplification with the Primer3 and NetPrimer programs. Those who present the best performance in these analyses will be evaluated for analytical sensitivity using decreasing amounts of colony-forming units (CFU) of Salmonella submitted to the procedures of pre-enrichment, pre-enrichment and enrichment for bacterial isolation and without performing these procedures. The primers that present the best performances will be selected and used in future proposals aimed at the diagnosis of Salmonella in ruminants and wild fauna that will be developed by our research group.