Comparative genome analysis of Salmonella enterica serovar Gallinarum biovars Pullorum and Gallinarum decodes strain specific genes

Abstract

Salmonella enterica serovar Gallinarum biovar Pullorum (bvP) and biovar Gallinarum (bvG) are the etiological agents of pullorum disease (PD) and fowl typhoid (FT) respectively, which cause huge economic losses to poultry industry especially in developing countries including India. Vaccination and biosecurity measures are currently being employed to control and reduce the S. Gallinarum infections. High endemicity, poor implementation of hygiene and lack of effective vaccines pose challenges in prevention and control of disease in intensively maintained poultry flocks. Comparative genome analysis unravels similarities and dissimilarities thus facilitating identification of genomic features that aids in pathogenesis, niche adaptation and in tracing of evolutionary history. The present investigation was carried out to assess the genotypic differences amongst S. enterica serovar Gallinarum strains including Indian strain S. Gallinarum Sal40 VTCCBAA614 with a focus on identification of candidate virulence factors. The comparative genome analysis revealed an open pan-genome consisting of 5091 coding sequence (CDS) with 3270 CDS belonging to core-genome, 1254 CDS to dispensable genome and strain specific genes i.e. singletons ranging from 3 to 102 amongst the analyzed strains. Moreover, the investigated strains exhibited diversity in genomic features such as genomic islands, prophage regions, toxin-antitoxin cassettes, and acquired antimicrobial resistance genes. The identified genetic differences among the S. enterica serovar Gallinarum strains could be used for bacterial typing, design of rapid and reliable diagnostics, structure based inhibitor development and vaccine design for effective infection control as well as eradication and will also form basis for future experimental investigations.

Non-Antibiotics Strategies to Control Salmonella Infection in Poultry

“…On the other hand, a comparative genomics analysis allowed evaluating the genotypic differences between Salmonella enterica serovar Gallinarum, revealing an open pangenome, where virulence factors, genomic islands, and antimicrobial resistance genes were identified. The information of this genome could help the identification of Salmonella strains and with this have fast and reliable diagnoses, in addition to the design of vaccines for the effective control against this pathogen [ 22 ].…”

“…On the other hand, bacteriophages [ 15 , 16 ], in ovo applications [ 17 , 18 ], and vaccines [ 19 , 20 , 21 ] are viable and technological non-feeding-based strategies extensively proved and implemented to reduce or control Salmonella infection in poultry. Currently, -omic technologies can be used as complementary tools in poultry to obtain information that can result in the formulation of therapeutic strategies and for detecting patterns of resistance to antibiotics, reducing the presence of Salmonella and production costs [ 22 ].…”

Salmonella in Poultry; An Overview

“…These methods can minimize or control Salmonella infection in poultry. Currently, -omic technologies can be utilized in poultry as supplemental tools to gather data that can lead to the development of therapeutic strategies and the detection of patterns of antibiotic resistance, reducing the presence of Salmonella and production costs [22]. As we know that bacterial disease are mainly treated by antibiotics but these are causing antibiotic resistivity in poultry [23,24].…”

In vitro antibacterial effect of enrofloxacin combined with lavender essential oil on selected Salmonella serotypes isolated most commonly poultry

“…The genus Salmonella includes two species: Salmonella enterica (divided into six subspecies) and Salmonella bongori (within which 20 serotypes are distinguished) (8). Non-motile Salmonella Gallinarum, comprising Salmonella Gallinarum biovar Gallinarum and Salmonella Gallinarum biovar Pullorum responsible for fowl typhoid and pullorum disease, respectively, is a specific invasive serotype occurring in farmed poultry (25). The non-specific though equally invasive serotypes include Salmonella Typhimurium, Salmonella Enteritidis and Salmonella Infantis (17).…”