Inactivation of phoPQ genes attenuates Salmonella Gallinarum biovar Gallinarum to susceptible chickens

Author(s)

Rodrigues Alves, Lucas Bocchini ^[1] ; de Freitas Neto, Oliveiro Caetano ^[2] ; Alves Batista, Diego Felipe ^[1] ; Barbos, Fernanda de Oliveira ^[1] ; Rubio, Marcela da Silva ^[1] ; Secundo de Souza, Andrei Itajahy ^[1] ; de Almeida, Adriana Maria ^[1] ; Barrow, Paul Andrew ^[3] ; Berchieri Junior, Angelo ^[1]

Affiliation

^[1] Sao Paulo State Univ Unesp, Sch Agr & Vet Sci, Post Grad Program Agr & Livestock Microbiol, Jaboticabal, SP - Brazil

^[2] Univ Fed Paraiba, Dept Vet Sci, POB 58397-000, Areia, MG - Brazil

^[3] Univ Nottingham, Sch Vet Med & Sci, Loughborough, Leics - England

• Document type: Journal article
• Source: Brazilian Journal of Microbiology; v. 49, n. 3, p. 601-606, JUL-SEP 2018.
• Web of Science Citations: 0

Abstract

Abstract Salmonella Gallinarum is a host-restrict pathogen that causes fowl typhoid, a severe systemic disease that is one of the major concerns to the poultry industry worldwide. When infecting the bird, SG makes use of evasion mechanisms to survive and to replicate within macrophages. In this context, phoPQ genes encode a two-component regulatory system (PhoPQ) that regulates virulence genes responsible for adaptation of Salmonella spp. to antimicrobial factors such as low pH, antimicrobial peptides and deprivation of bivalent cations. The role of the mentioned genes to SG remains to be investigated. In the present study a phoPQ-depleted SG strain (SG ΔphoPQ) was constructed and its virulence assessed in twenty-day-old laying hens susceptible to fowl typhoid. SG ΔphoPQ did cause neither clinical signs nor mortality in birds orally challenged, being non-pathogenic. Furthermore, this strain was not recovered from livers or spleens. On the other hand, chickens challenged subcutaneously with the mutant strain had discreet to moderate pathological changes and also low bacterial counts in liver and spleen tissues. These findings show that SG ΔphoPQ is attenuated to susceptible chickens and suggest that these genes are important during chicken infection by SG. (AU)

• FAPESP's process: 16/10369-0 - Pathogenicity of Salmonella spp. with deletions in the genes phoPQ, fliD e clpP in comercial poultry
• Grantee: Angelo Berchieri Junior
• Support Opportunities: Regular Research Grants