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Research in Veterinary Science Jan 2023Salmonella Gallinarum greatly impacts commercial flocks and vaccination with S. Gallinarum 9R (SG9R) is one of the most effective control strategies in some countries....
Salmonella Gallinarum greatly impacts commercial flocks and vaccination with S. Gallinarum 9R (SG9R) is one of the most effective control strategies in some countries. However, mycotoxins can affect immunization success. Herein, we measured the cellular immune response in SG9R-vaccinated hens, quantified the impact of aflatoxins on the immune response, and determined whether the anti-mycotoxin additive (adsorbent) influences immunity after vaccination. One-day-old chicks of commercial laying hens were raised until 49 days of age and were assigned to six groups. T1 (control group): control diet (no detectable concentration of aflatoxin), no vaccine or adsorbent. T2: vaccine SG-9R at day 28, aflatoxins 2.5 ppm from day 1 to day 49, and adsorbent 2.5 Kg/ton. T3: control diet and vaccine. T4: aflatoxins and vaccine. T5: control diet and aflatoxins. T6: aflatoxins and adsorbent. Body weights were evaluated on days 1, 31, and 41. Cellular immune response was evaluated by flow cytometry at 31, 41, and 49 days of age. T lymphocytes, B lymphocytes, monocytes, phagocytic monocytes and heterophils were evaluated. Aflatoxins suppressed peripheral and mucosal helper T lymphocytes, and mucosal cytotoxic T lymphocytes in vaccinated birds (T2 and T4). However, inclusion of the adsorbent in the feed of vaccinated birds neutralized the effects of aflatoxin (T6). The concentration of immune cells may show differences after SG9R vaccination, particularly an increase in the monocyte concentration. The SG9R vaccine reduced the concentration of activated cytotoxic T lymphocytes, making this marker a good parameter to analyze before and three weeks after immunization.
Topics: Animals; Female; Chickens; Salmonella Vaccines; Aflatoxins; Poultry Diseases; Salmonella; Vaccination; Immunity, Cellular; Salmonella Infections, Animal
PubMed: 36434851
DOI: 10.1016/j.rvsc.2022.11.007 -
Acta Veterinaria Scandinavica May 2007Salmonella enterica serotype Gallinarum (S. Gallinarum) remains an important pathogen of poultry, especially in developing countries. There is a need to develop...
BACKGROUND
Salmonella enterica serotype Gallinarum (S. Gallinarum) remains an important pathogen of poultry, especially in developing countries. There is a need to develop effective and safe vaccines. In the current study, the effect of crp deletion was investigated with respect to virulence and biochemical properties and the possible use of a deletion mutant as vaccine candidate was preliminarily tested.
METHODS
Mutants were constructed in S. Gallinarum by P22 transduction from Salmonella Typhimurium (S. Typhimurium) with deletion of the crp gene. The effect was characterized by measuring biochemical properties and by testing of invasion in a chicken loop model and by challenge of six-day-old chickens. Further, birds were immunized with the deleted strain and challenged with the wild type isolate.
RESULTS
The crp deletions caused complete attenuation of S. Gallinarum. This was shown by ileal loop experiments not to be due to significantly reduced invasion. Strains with such deletions may have vaccine potential, since oral inoculatoin with S. Gallinarum Deltacrp completely protected against challenge with the same dose of wild type S. Gallinarum ten days post immunization. Interestingly, the mutations did not cause the same biochemical and growth changes to the two biotypes of S. Gallinarum. All biochemical effects but not virulence could be complemented by providing an intact crp-gene from S. Typhimurium on the plasmid pSD110.
CONCLUSION
Transduction of a Tn10 disrupted crp gene from S. Typhimurium caused attenuation in S. Gallinarum and mutated strains are possible candidates for live vaccines against fowl typhoid.
Topics: Amino Acid Sequence; Animals; Base Sequence; Biological Assay; Chickens; Cyclic AMP Receptor Protein; Female; Gene Deletion; Molecular Sequence Data; RNA, Bacterial; Reverse Transcriptase Polymerase Chain Reaction; Salmonella Infections, Animal; Salmonella Vaccines; Salmonella enterica; Salmonella typhimurium; Sequence Alignment; Transduction, Genetic; Vaccines, Attenuated; Virulence Factors
PubMed: 17488512
DOI: 10.1186/1751-0147-49-14 -
Parasites & Vectors Oct 2020The poultry red mite Dermanyssus gallinae (De Geer, 1778) is a major ectoparasite of poultry. Infestations are found in most laying hen farms in Europe, and breeder...
Evidence of vector borne transmission of Salmonella enterica enterica serovar Gallinarum and fowl typhoid disease mediated by the poultry red mite, Dermanyssus gallinae (De Geer, 1778).
BACKGROUND
The poultry red mite Dermanyssus gallinae (De Geer, 1778) is a major ectoparasite of poultry. Infestations are found in most laying hen farms in Europe, and breeder flocks have also been reported to be affected. Mite infestation has detrimental effects on animal welfare, it causes significant economic losses, and, additionally, D. gallinae is often considered as a vector for pathogens. Despite suspicion of a close relationship between the poultry red mite and Salmonella enterica enterica serovar Gallinarum biovar Gallinarum (serovar Gallinarum), the causative agent of fowl typhoid disease (FT), there has been no definitive proof of mite-mediated transmission. Therefore, an investigation was conducted to determine if D. gallinae-mediated transmission of serovar Gallinarum could be demonstrated among four different hen groups.
METHODS
Two groups of 8 hens (A and B) were experimentally infected with serovar Gallinarum in two isolators. After 7 days, when birds showed signs of FT, about 25,000 mites were introduced. After 3 days, mites were harvested and used to infest two other hen groups of 8 (C and D), in two separate isolators. The health status of hens was constantly monitored; detection and quantification of serovar Gallinarum were performed by PCR and qPCR from mites and organs of dead hens. The maximum likelihood estimation of the infection rate and mite vectorial capacity were calculated.
RESULTS
Clinical disease was observed in groups infected with serovar Gallinarum (A and B) and in hens of groups C and D infested with mites harvested from the isolators containing groups A and B. In all four groups, serovar Gallinarum was detected from liver, spleen, ovary, and cecum of hens, thus confirming the diagnosis of FT. Mite analysis demonstrated the presence of the pathogen, with an estimated infection rate ranging between 13.72 and 55.21 infected per thousand mites. Vectorial capacity was estimated to be 73.79.
CONCLUSIONS
Mites harvested from birds infected with serovar Gallinarum were shown to carry the mite, and then to transfer serovar Gallinarum to isolated groups of pathogen-free birds that subsequently showed signs of FT. Mite vectorial capacity was high, demonstrating that D. gallinae should be considered an effective vector of FT.
Topics: Animals; Arachnid Vectors; Chickens; Female; Mite Infestations; Mites; Poultry Diseases; Salmonella enterica; Serogroup; Typhoid Fever
PubMed: 33054854
DOI: 10.1186/s13071-020-04393-8 -
Avian Pathology : Journal of the W.V.P.A Apr 2004Salmonella enterica subsp. enterica serovar Gallinarum (S. gallinarum) is the causative organism of fowl typhoid, and an outbreak of fowl typhoid in Korea was confirmed...
Salmonella enterica subsp. enterica serovar Gallinarum (S. gallinarum) is the causative organism of fowl typhoid, and an outbreak of fowl typhoid in Korea was confirmed in 1992. The aim of this study was to investigate possible changes in fluoroquinolone susceptibility among S. gallinarum isolates from 1995 to 2001, and to analyse mutations of the gyrA gene in fluoroquinolone-resistant isolates. Among 258 S. gallinarum isolates tested by the disk diffusion method, isolates from 1995 (n=18) were susceptible to all fluoroquinolones tested, whereas a number of isolates from 2001 (n=46) showed reduced susceptibility to enrofloxacin (6.5%), ciprofloxacin (10.9%), norfloxacin (52.5%) and ofloxacin (82.6%). The minimum inhibitory concentration range of enrofloxacin, ciprofloxacin, norfloxacin, ofloxacin and danofloxacin increased from < or =0.06 approximately 0.25 microg/ml in 1995 to 2 approximately 8 microg/ml in 2001. When amino acid changes in the gyrA were analysed by DNA sequencing, 22.5% and 14.7% among 258 isolates had a mutation at the Ser-83 and Asp-87 codons, respectively, and the prevalence of these mutants increased from 5.6% in 1995 to 89.1% in 2001. These mutants contained a change from Ser to Phe or Tyr at codon 83, or a change from Asp to Gly, Tyr or Asn at codon 87, and showed a range of minimum inhibitory concentrations of enrofloxacin from 0.5 to 8 microg/ml, ciprofloxacin from 0.25 to 4 microg/ml, norfloxacin from 2 to 32 microg/ml, ofloxacin from 0.5 to 4 microg/ml, and danofloxacin from 0.5 to 4 microg/ml. These results suggested an important association between the gyrA mutations and fluoroquinolone resistance of S. gallinarum.
Topics: Amino Acid Sequence; Animals; Anti-Bacterial Agents; Base Sequence; Chickens; DNA Gyrase; Disease Outbreaks; Drug Resistance, Multiple, Bacterial; Fluoroquinolones; Korea; Molecular Sequence Data; Mutation; Poultry Diseases; Salmonella Infections, Animal; Salmonella enterica; Time Factors
PubMed: 15276996
DOI: 10.1080/0301945042000195759 -
Infection and Immunity Apr 2013Salmonella enterica serotype Gallinarum is the causative agent of fowl typhoid, a disease characterized by high morbidity and mortality that causes major economic losses...
Salmonella enterica serotype Gallinarum is the causative agent of fowl typhoid, a disease characterized by high morbidity and mortality that causes major economic losses in poultry production. We have reported that S. Gallinarum harbors a type VI secretion system (T6SS) encoded in Salmonella pathogenicity island 19 (SPI-19) that is required for efficient colonization of chicks. In the present study, we aimed to characterize the SPI-19 T6SS functionality and to investigate the mechanisms behind the phenotypes previously observed in vivo. Expression analyses revealed that SPI-19 T6SS core components are expressed and produced under in vitro bacterial growth conditions. However, secretion of the structural/secreted components Hcp1, Hcp2, and VgrG to the culture medium could not be determined, suggesting that additional signals are required for T6SS-dependent secretion of these proteins. In vitro bacterial competition assays failed to demonstrate a role for SPI-19 T6SS in interbacterial killing. In contrast, cell culture experiments with murine and avian macrophages (RAW264.7 and HD11, respectively) revealed production of a green fluorescent protein-tagged version of VgrG soon after Salmonella uptake. Furthermore, infection of RAW264.7 and HD11 macrophages with deletion mutants of SPI-19 or strains with genes encoding specific T6SS core components (clpV and vgrG) revealed that SPI-19 T6SS contributes to S. Gallinarum survival within macrophages at 20 h postuptake. SPI-19 T6SS function was not linked to Salmonella-induced cytotoxicity or cell death of infected macrophages, as has been described for other T6SS. Our data indicate that SPI-19 T6SS corresponds to a novel tool used by Salmonella to survive within host cells.
Topics: Animals; Bacterial Secretion Systems; Cell Line; Cell Survival; Chickens; Gene Deletion; Genomic Islands; Macrophages; Membrane Transport Proteins; Mice; Microbial Viability; Salmonella enterica; Time Factors; Virulence Factors
PubMed: 23357385
DOI: 10.1128/IAI.01165-12 -
Applied and Environmental Microbiology Jul 2011Fresh and processed poultry have been frequently implicated in cases of human salmonellosis. Furthermore, increased consumption of meat and poultry has increased the... (Review)
Review
Fresh and processed poultry have been frequently implicated in cases of human salmonellosis. Furthermore, increased consumption of meat and poultry has increased the potential for exposure to Salmonella enterica. While advances have been made in reducing the prevalence and frequency of Salmonella contamination in processed poultry, there is mounting pressure on commercial growers to prevent and/or eliminate these human pathogens in preharvest production facilities. Several factors contribute to Salmonella colonization in commercial poultry, including the serovar and the infectious dose. In the early 1900s, Salmonella enterica serovars Pullorum and Gallinarum caused widespread diseases in poultry, but vaccination and other voluntary programs helped eradicate pullorum disease and fowl typhoid from commercial flocks. However, the niche created by the eradication of these serovars was likely filled by S. Enteritidis, which proliferated in the bird populations. While this pathogen remains a significant problem in commercial egg and poultry production, its prevalence among poultry has been declining since the 1990s. Coinciding with the decrease of S. Enteritidis, S. Heidelberg and S. Kentucky have emerged as the predominant serovars in commercial broilers. In this review, we have highlighted bacterial genetic and host-related factors that may contribute to such shifts in Salmonella populations in commercial poultry and intervention strategies that could limit their colonization.
Topics: Animals; Ovum; Population Dynamics; Poultry; Salmonella Infections, Animal; Salmonella enterica; Serotyping
PubMed: 21571882
DOI: 10.1128/AEM.00598-11 -
Infection and Immunity Sep 2001Salmonella enterica serovar Gallinarum is a host-specific serotype that causes the severe systemic disease fowl typhoid in domestic poultry and a narrow range of other...
Salmonella enterica serovar Gallinarum requires the Salmonella pathogenicity island 2 type III secretion system but not the Salmonella pathogenicity island 1 type III secretion system for virulence in chickens.
Salmonella enterica serovar Gallinarum is a host-specific serotype that causes the severe systemic disease fowl typhoid in domestic poultry and a narrow range of other avian species but rarely causes disease in mammalian hosts. Specificity of the disease is primarily at the level of the reticuloendothelial system, but few virulence factors have been described other than the requirement for an 85-kb virulence plasmid. In this work, by making functional mutations in the type III secretion systems (TTSS) encoded by Salmonella pathogenicity island 1 (SPI-1) and SPI-2, we investigated the role of these pathogenicity islands in interactions between Salmonella serovar Gallinarum and avian cells in vitro and the role of these pathogenicity islands in virulence in chickens. The SPI-1 mutant showed decreased invasiveness into avian cells in vitro but was unaffected in its ability to persist within chicken macrophages. In contrast the SPI-2 mutant was fully invasive in nonphagocytic cells but failed to persist in macrophages. In chicken infections the SPI-2 mutant was attenuated while the SPI-1 mutant showed full virulence. In oral infections the SPI-2 mutant was not observed in the spleen or liver, and following intravenous inoculation it was cleared rapidly from these sites. SPI-2 function is required by Salmonella serovar Gallinarum for virulence, primarily through promoting survival within macrophages allowing multiplication within the reticuloendothelial system, but this does not preclude the involvement of SPI-2 in uptake from the gut to the spleen and liver. SPI-1 appears to have little effect on virulence and survival of Salmonella serovar Gallinarum in the host.
Topics: Animals; Bacterial Proteins; Cells, Cultured; Chickens; Macrophages; Mutation; Poultry Diseases; Salmonella Infections, Animal; Salmonella enterica; Virulence
PubMed: 11500419
DOI: 10.1128/IAI.69.9.5471-5476.2001 -
Brazilian Journal of Microbiology :... 2018Salmonella 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...
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.
Topics: Animals; Bacterial Proteins; Chickens; Female; Gene Silencing; Poultry Diseases; Salmonella Infections, Animal; Salmonella enterica; Spleen; Virulence
PubMed: 29426664
DOI: 10.1016/j.bjm.2017.09.006 -
Vaccine Feb 2013Salmonella enterica serovar Gallinarum is the causative agent of fowl typhoid, an important systemic disease of poultry with economic consequences in developing nations....
Salmonella enterica serovar Gallinarum is the causative agent of fowl typhoid, an important systemic disease of poultry with economic consequences in developing nations. A live attenuated orally applied S. Gallinarum vaccine could provide a low cost method for controlling this disease. We constructed S. Gallinarum strains in which the expression of the crp, rfc and rfaH genes, important for virulence of Salmonella Typhimurium in mice, were under the control of an arabinose-regulated promoter. We evaluated the virulence of these strains compared to wild-type S. Gallinarum and to mutants carrying deletions in these genes. We found that rfc mutants were fully virulent, indicating that, unlike the S. Typhimurium mouse model, the rfc gene is dispensable in S. Gallinarum for virulence in birds. In the case of rfaH, the deletion mutant was attenuated and protective, while the strain with arabinose-regulated rfaH expression retained full virulence. The strain exhibiting arabinose-regulated crp expression was attenuated. Its virulence was not affected by the inclusion of 0.2% arabinose in the drinking water. Birds immunized with this strain were protected against a lethal S. Gallinarum challenge and against colonization with the human pathogen Salmonella Enteritidis. This work shows that an arabinose-regulated crp strain provides a basis for further development of a fowl typhoid vaccine.
Topics: Animals; Chickens; Gene Deletion; Gene Expression Regulation, Bacterial; Poultry Diseases; Salmonella; Salmonella Infections, Animal; Salmonella Vaccines; Survival Analysis; Vaccines, Attenuated; Virulence; Virulence Factors
PubMed: 23261043
DOI: 10.1016/j.vaccine.2012.12.021 -
Developmental and Comparative Immunology Aug 2023In the present study, lipid-A gene mutants of Salmonella gallinarum (SG) were screened, and the arnT mutant exhibited optimal acidic and oxidative-stress and...
Screening of lipid-A related genes and development of low-endotoxicity live-attenuated Salmonella gallinarum by arnT deletion that elicits immune responses and protection against fowl typhoid in chickens.
In the present study, lipid-A gene mutants of Salmonella gallinarum (SG) were screened, and the arnT mutant exhibited optimal acidic and oxidative-stress and macrophage-survival. Modifying lipid-A by arnT-deletion resulted in significantly reduced endotoxicity, virulence, and mortality. Therefore, the arnT-deleted vaccine-candidate strain JOL2841 was constructed and demonstrated to be safe due to appropriate clearance by the chicken immune system. The reduced-endotoxicity of JOL2841 was evident from the downregulation of TNFα and IL-1β inflammatory cytokines, no inflammatory signs in organ gross-examination, and histopathological analysis. The IgY and IgA antibody titres, CD4, and CD8 T-cell population improvements, and IL-4, IL-2, and INFγ expression decipher the profound Th2 and Th1 immunogenicity. Consequently, JOL2841 exhibited prominent protection against wild-type SG challenge, as revealed by organ pathogen-load determination, organ gross-examination, and histopathological examination. Overall, the study represented the first report of arnT deficient SG resulted in negligible endotoxicity, low-virulence, safety and coordinated elicitation of humoral and cell-mediated immune response in chickens.
Topics: Animals; Chickens; Endotoxins; Typhoid Fever; Salmonella Vaccines; Poultry Diseases; Salmonella Infections, Animal; Salmonella; Immunity, Cellular; Lipids; Vaccines, Attenuated
PubMed: 37044268
DOI: 10.1016/j.dci.2023.104707