Characterization of Two-Component System CitB Family in Salmonella Pullorum

Abstract

Salmonella enterica, serovar Gallinarum, biovar Pullorum, is an avian-specific pathogen which has caused considerable economic losses to the poultry industry worldwide. Two-component systems (TCSs) play an essential role in obtaining nutrients, detecting the presence of neighboring bacteria and regulating the expression of virulence factors. The genome analysis of S. Pullorum strain S06004 suggesting the carriage of 22 pairs of TCSs, which belong to five families named CitB, OmpR, NarL, Chemotaxis and LuxR. In the CitB family, three pairs of TCSs, namely CitA-CitB, DcuS-DcuR and DpiB-DpiA, remain unaddressed in S. Pullorum. To systematically investigate the function of the CitB family in S. Pullorum, four mutants, ΔcitAB (abbreviated as Δcit), ΔdcuSR (Δdcu), ΔdpiBA (Δdpi) and ΔcitABΔdcuSRΔdpiBA (Δ3), were made using the CRISPR/Cas9 system. The results demonstrated that the CitB family did not affect the growth of bacteria, the results of biochemical tests, invasion and proliferation in chicken macrophage HD-11 cells and the expression of fimbrial protein. But the mutants showed thicker biofilm formation, higher resistance to antimicrobial agents, enhanced tolerance to inhibition by egg albumen and increased virulence in chicken embryos. Moreover, the deletion of Dpi TCS was detrimental to survival after exposure to hyperosmotic and oxidative environments, as well as the long-term colonization of the small intestine of chickens. Collectively, we provided new knowledge regarding the possible role of the CitB family involved in the pathogenic processes of S. Pullorum.

A new Salmonella enterica serovar that was isolated from a wild sparrow presents a distinct genetic, metabolic and virulence profile

“…S3)] and its possible association with an avian host, we were interested in characterizing environmentally-relevant phenotypes of this serovar. Specifically, we were interested in studying the motility and biofilm formation of S. Tirat-Zvi, as previous reports have shown that the poultryassociated serovars, S. Gallinarum and S. Pullorum are not motile and weak biofilm producers [34,35]. Additionally, we sought out to test the resistance of S. Tirat-Zvi to arsenic compounds, due to the uncommon presence of the of the ars cluster (see below).…”

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“…X. Kang et al (2022) demonstrated that some host-adapted Salmonella serovars can suppress the innate immune response and create an infection-friendly environment for long-term survival in host cells, such as S. Pullorum. SteE has been reported to be closely associated with colonisation of bacterial invasion in mice (Jaslow et al, 2018).…”

Identification and Evaluation of Novel Antigen Candidates against Salmonella Pullorum Infection Using Reverse Vaccinology

“…In adult birds, S. Pullorum infection can result in weight loss, decreased fertility and laying, diarrhea, and reproductive tract abnormalities with a chronic carrier state [5]. S. Pullorum is challenging to control due to its vertical and horizontal transmission capabilities [6][7][8]. It has become more prevalent recently and poses a severe threat in many developing countries [9].…”