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The Journal of Veterinary Medical... Jul 2021Salmonella enterica serovar Gallinarum biovar Gallinarum (S. Gallinarum) is a host-specific pathogen causing systemic infection in poultry, which leads to significant...
Salmonella enterica serovar Gallinarum biovar Gallinarum (S. Gallinarum) is a host-specific pathogen causing systemic infection in poultry, which leads to significant economic losses due to high mortality. However, little is known about the dynamic process of systemic infection and pathogenic characteristics of S. Gallinarum in chickens. In the present study, we developed an oral infection model that reproduces the pathology of S. Gallinarum and clarified the host immune response of the infected chickens. Chickens at 20 days of age orally inoculated at a dose of 10 colony forming unit (CFU) showed typical clinical signs of fowl typhoid and died between 6 and 10 days post infection. The inoculated S. Gallinarum rapidly disseminated to multple organs and the bacterial counts increased in the liver and spleen at 3 days post infection. Pathological changes associated wirh inflammation in the liver and spleen became apparent at 4 days post infection, and increased expression of interferon (IFN)-γ and interleuikin (IL)-12 in the liver and spleen did not observed until 3 days post infection. These results indicate that S. Gallinarum rapidly spread to entire body through intestine, and the low-level of inflammatory responses in the liver during the early stage of infection may contribute to rapid, systemic dissemination of the bacteria. Our infection model and findings will contribute to the better understanding of the pathogenic mechanism of S. Gallinarum, and provide new insights into the prevention and control of fowl typhoid.
Topics: Animals; Chickens; Immunity; Poultry Diseases; Salmonella Infections, Animal; Salmonella enterica; Serogroup
PubMed: 34039786
DOI: 10.1292/jvms.21-0227 -
Vaccines Nov 2023Avian pathogenic (APEC) is one of the leading pathogens that cause devastating economic losses to the poultry industry. Type I fimbriae are essential adhesion factors...
Avian pathogenic (APEC) is one of the leading pathogens that cause devastating economic losses to the poultry industry. Type I fimbriae are essential adhesion factors of APEC, which can be targeted and developed as a vaccine candidate against multiple APEC serogroups due to their excellent immunogenicity and high homology. In this study, the recombinant strain SG102 was developed by expressing the APEC type I fimbriae gene cluster () on the cell surface of an avirulent () vector strain using a chromosome-plasmid-balanced lethal system. The expression of APEC type I fimbriae was verified by erythrocyte hemagglutination assays and antigen-antibody agglutination tests. In vitro, the level of the SG102 strain adhering to leghorn male hepatoma (LMH) cells was significantly higher than that of the empty plasmid control strain, SG101. At two weeks after oral immunization, the SG102 strain remained detectable in the livers, spleens, and ceca of SG102-immunized chickens, while the SG101 strain was eliminated in SG101-immunized chickens. At 14 days after the secondary immunization with 5 × 10 CFU of the SG102 strain orally, highly antigen-specific humoral and mucosal immune responses against APEC type I fimbriae protein were detected in SG102-immunized chickens, with IgG and secretory IgA (sIgA) concentrations of 221.50 μg/mL and 1.68 μg/mL, respectively. The survival rates of SG102-immunized chickens were 65% (13/20) and 60% (12/20) after challenge with 50 LD doses of APEC virulent strains O78 and O161 serogroups, respectively. By contrast, 95% (19/20) and 100% (20/20) of SG101-immunized chickens died in challenge studies involving APEC O78 and O161 infections, respectively. In addition, the SG102 strain effectively provided protection against lethal challenges from the virulent strain. These results demonstrate that the SG102 strain, which expresses APEC type I fimbriae, is a promising vaccine candidate against APEC O78 and O161 serogroups as well as infections.
PubMed: 38140181
DOI: 10.3390/vaccines11121778 -
Virology Journal Sep 2021The host-unrestricted, non-typhoidal Salmonella enterica serovar Enteritidis (S. Enteritidis) and the serovar Typhimurium (S. Typhimurium) are major causative agents...
BACKGROUND
The host-unrestricted, non-typhoidal Salmonella enterica serovar Enteritidis (S. Enteritidis) and the serovar Typhimurium (S. Typhimurium) are major causative agents of food-borne gastroenteritis, and the host-restricted Salmonella enterica serovar Gallinarum (S. Gallinarum) is responsible for fowl typhoid. Increasing drug resistance in Salmonella contributes to the reduction of effective therapeutic and/or preventive options. Bacteriophages appear to be promising antibacterial tools, able to combat infectious diseases caused by a wide range of Salmonella strains belonging to both host-unrestricted and host-restricted Salmonella serovars.
METHODS
In this study, five novel lytic Salmonella phages, named UPWr_S1-5, were isolated and characterized, including host range determination by plaque formation, morphology visualization with transmission electron microscopy, and establishment of physiological parameters. Moreover, phage genomes were sequenced, annotated and analyzed, and their genomes were compared with reference Salmonella phages by use of average nucleotide identity, phylogeny, dot plot, single nucleotide variation and protein function analysis.
RESULTS
It was found that UPWr_S1-5 phages belong to the genus Jerseyvirus within the Siphoviridae family. All UPWr_S phages were found to efficiently infect various Salmonella serovars. Host range determination revealed differences in host infection profiles and exhibited ability to infect Salmonella enterica serovars such as Enteritidis, Gallinarum, Senftenberg, Stanley and Chester. The lytic life cycle of UPWr_S phages was confirmed using the mitomycin C test assay. Genomic analysis revealed that genomes of UPWr_S phages are composed of 51 core and 19 accessory genes, with 33 of all predicted genes having assigned functions. UPWr_S genome organization comparison revealed 3 kinds of genomes and mosaic structure. UPWr_S phages showed very high sequence similarity to each other, with more than 95% average nucleotide identity.
CONCLUSIONS
Five novel UPWr_S1-5 bacteriophages were isolated and characterized. They exhibit host lysis range within 5 different serovars and are efficient in lysis of both host-unrestricted and host-restricted Salmonella serovars. Therefore, because of their ability to infect various Salmonella serovars and lytic life cycle, UPWr_S1-5 phages can be considered as useful tools in biological control of salmonellosis.
Topics: Genome, Viral; Genomics; Salmonella Phages; Salmonella enteritidis; Siphoviridae
PubMed: 34496915
DOI: 10.1186/s12985-021-01655-4 -
Frontiers in Veterinary Science 2022In order to prevent pullorum disease and fowl typhoid in breeders, the use of oregano essential oil (OEO) was tested for the prevention and treatment of infections of...
In order to prevent pullorum disease and fowl typhoid in breeders, the use of oregano essential oil (OEO) was tested for the prevention and treatment of infections of multidrug-resistant (SP) and (SG) in commercial Yellow-chicken breeders. In the challenge-protection experiment, commercial Hongguang-Black 1-day-old breeder chicks were randomly divided into four groups, including A (challenged, preventive dose), B (challenged, treatment dose), C (challenged, untreated), and D (unchallenged, untreated). Group A was supplemented with 200 μL/L OEO in the drinking water during the whole trial (1-35 days of age) and group B was supplemented with 400 μL/L OEO during 8-12 days of age, while groups C and D were kept as untreated controls. At 7 days of age, birds of groups A, B, and C were divided into two subgroups with equal number of birds (A-A, B-B, and C-C), and then subgroups A, B, and C were challenged with SP, while subgroups A, B, and C were challenged with SG. Clinical symptoms and death were observed and recorded daily. Every week during the experiment, serum antibodies against SP and SG of all the groups were detected by the plate agglutinate test (PAT). At the age of 35 days, all birds were weighed and necropsied, lesions were recorded and the challenging pathogens were isolated. The results showed that the positive rates of SP and SG isolation in groups A, A and B, B were significantly lower ( < 0.05) than those of groups C and C, respectively, while groups A and A were slightly lower ( > 0.05) than those of groups B and B. The average body weight (BW) of groups A and A were significantly higher ( < 0.05) than those of groups B, B and C, C, respectively, but there was no significant difference ( > 0.05) with that of group D. The -value between PAT positive and the recovery rates of was 0.99, which means they are highly positively correlated. The results of this study demonstrated that the prevention dose (200μL/L) and the treatment dose (400 μL/L) of OEO supplemented in the drinking water could all effectively decrease infections of SP and SG and that the effect of the prevention was greater than that of the treatment and finally that the prevention could also significantly reduce the BW decline of birds challenged with SP and SG.
PubMed: 36619954
DOI: 10.3389/fvets.2022.1058844 -
PloS One 2015The Salmonella enterica serovars Enteritidis, Dublin, and Gallinarum are closely related but differ in virulence and host range. To identify the genetic elements... (Comparative Study)
Comparative Study
The Salmonella enterica serovars Enteritidis, Dublin, and Gallinarum are closely related but differ in virulence and host range. To identify the genetic elements responsible for these differences and to better understand how these serovars are evolving, we sequenced the genomes of Enteritidis strain LK5 and Dublin strain SARB12 and compared these genomes to the publicly available Enteritidis P125109, Dublin CT 02021853 and Dublin SD3246 genome sequences. We also compared the publicly available Gallinarum genome sequences from biotype Gallinarum 287/91 and Pullorum RKS5078. Using bioinformatic approaches, we identified single nucleotide polymorphisms, insertions, deletions, and differences in prophage and pseudogene content between strains belonging to the same serovar. Through our analysis we also identified several prophage cargo genes and pseudogenes that affect virulence and may contribute to a host-specific, systemic lifestyle. These results strongly argue that the Enteritidis, Dublin and Gallinarum serovars of Salmonella enterica evolve by acquiring new genes through horizontal gene transfer, followed by the formation of pseudogenes. The loss of genes necessary for a gastrointestinal lifestyle ultimately leads to a systemic lifestyle and niche exclusion in the host-specific serovars.
Topics: Genome, Bacterial; Mutation; Polymorphism, Single Nucleotide; Salmonella enteritidis; Serogroup
PubMed: 26039056
DOI: 10.1371/journal.pone.0126883 -
The Journal of Poultry Science 2023Benefits chitosan-fermented feed additives (CFFAs) particularly in the regulation of the immune system and antimicrobial activity. Therefore, we investigated the...
Benefits chitosan-fermented feed additives (CFFAs) particularly in the regulation of the immune system and antimicrobial activity. Therefore, we investigated the immune-enhancing and bacterial clearance effects of CFFA (fermented by ) on broiler chickens Gallinarum challenge. We administered 2% or 4% CFFA evaluated its immune-enhancing effects using several immunological experiments, including examination of lysozyme activity, lymphocyte proliferation, and expression of cytokines. We also evaluated the bacterial clearance effects of CFFA against Gallinarum. CFFA administration markedly enhanced lysozyme activity, lymphocyte proliferation, and the expression of interleukin (IL)-2, IL-12, tumor necrosis factor alpha, and interferon gamma in the spleen. In broilers challenged with Gallinarum, the clinical signs of Gallinarum infection and the number of viable bacterial colonies in the feces and tissues decreased in both CFFA groups. Therefore, CFFAs could be good candidates for feed additive to improve nonspecific immune responses and bacterial clearance.
PubMed: 37426541
DOI: 10.2141/jpsa.2023016 -
Microbiology Spectrum Aug 2022Paratyphoid avian salmonellosis is considered one of the leading causes of poultry death, resulting in significant economic losses to poultry industries worldwide. In...
Genome-Based Assessment of Antimicrobial Resistance and Virulence Potential of Isolates of Non-Pullorum/Gallinarum Salmonella Serovars Recovered from Dead Poultry in China.
Paratyphoid avian salmonellosis is considered one of the leading causes of poultry death, resulting in significant economic losses to poultry industries worldwide. In China, especially in Shandong province, the leading producer of poultry products, several recurrent outbreaks of avian salmonellosis have been reported during the last decade where the precise causal agent remains unknown. Moreover, the establishment of earlier and more accurate recognition of pathogens is a key factor to prevent the further dissemination of resistant and/or hypervirulent clones. Here, we aim to use whole-genome sequencing combined with toolkits to provide the genomic features of the antimicrobial resistance and virulence potential of 105 regionally representative non-Pullorum/Gallinarum Salmonella isolates recovered from dead poultry between 2008 and 2019 in Shandong, China. Additionally, phenotypic susceptibility to a panel of 15 antibiotics representing 11 classes was assessed by the broth microdilution method. In this study, we identified eight serovars and nine multilocus sequence typing (MLST) types, with Salmonella enterica serovar Enteritidis sequence type 11 (ST11) being the most prevalent (84/105; 80%). Based on their phenotypic antimicrobial resistance, 77.14% of the isolates were defined as multidrug resistant (≥3 antimicrobial classes), with the detection of one S. Enteritidis isolate that was resistant to the 11 classes. The highest rates of resistance were observed against nalidixic acid (97.14%) and ciprofloxacin (91.43%), followed by ampicillin (71.43%), streptomycin (64.77%), and tetracycline (60%). Genomic characterization revealed the presence of 41 resistance genes, with an alarmingly high prevalence of (60%), in addition to genomic mutations affecting the DNA gyrase () and DNA topoisomerase IV () genes, conferring resistance to quinolones. The prediction of plasmid replicons detected 14 types, with a dominance of IncFIB(S)_1 and IncFII(S)_1 (87.62% for both), while the IncX1 plasmid type was considered the key carrier of antimicrobial resistance determinants. Moreover, we report the detection of critical virulence genes, including , , , , and , in addition to the typical determinants for Salmonella pathogenicity island 1 (SPI-1) and SPI-2. Furthermore, phylogenomic analysis revealed the detection of three intra-farm and five inter-farm transmission events. Overall, the detection of Salmonella isolates presenting high antimicrobial resistance and harboring different critical virulence genes is of major concern, which requires the urgent implementation of effective strategies to mitigate non-Pullorum/Gallinarum avian salmonellosis. Avian salmonellosis is one of the leading global causes of poultry death, resulting in substantial economic losses in China (constituting 9% of overall financial losses). In Shandong province, a top poultry producer (30% of the overall production in China, with 15% being exported to the world), extensive outbreaks of avian salmonellosis have been reported in the past decade where the causal agents or exact types remain rarely addressed. From approximately 2008 to 2019, over 2,000 Salmonella strains were isolated and identified from dead poultry during routine surveillance of 95 poultry farms covering all 17 cities in Shandong. Approximately 1,500 isolates were confirmed to be of non-Pullorum/Gallinarum Salmonella serovars. There is an urgent need to understand the mechanisms behind the implication of zoonotic Salmonella serovars in systemic infections of poultry. Here, we analyzed populations of clinically relevant isolates of non-Pullorum/Gallinarum Salmonella causing chicken death in China by a whole-genome sequencing approach and determined that antimicrobial-resistant Salmonella Enteritidis remained the major cause in the past decades.
Topics: Animals; Anti-Bacterial Agents; Chickens; Drug Resistance, Bacterial; Multilocus Sequence Typing; Poultry; Poultry Diseases; Salmonella; Salmonella Food Poisoning; Salmonella Infections, Animal; Salmonella enterica; Salmonella enteritidis; Serogroup; Virulence
PubMed: 35727054
DOI: 10.1128/spectrum.00965-22 -
Pathogens (Basel, Switzerland) Oct 2021One characteristic of the few serovars that produce typhoid-like infections is that disease-free persistent infection can occur for months or years in a small number of... (Review)
Review
One characteristic of the few serovars that produce typhoid-like infections is that disease-free persistent infection can occur for months or years in a small number of individuals post-convalescence. The bacteria continue to be shed intermittently which is a key component of the epidemiology of these infections. Persistent chronic infection occurs despite high levels of circulating specific IgG. We have reviewed the information on the basis for persistence in . Typhi, . Dublin, Gallinarum, . Pullorum, . Abortusovis and also . Typhimurium in mice as a model of persistence. Persistence appears to occur in macrophages in the spleen and liver with shedding either from the gall bladder and gut or the reproductive tract. The involvement of host genetic background in defining persistence is clear from studies with the mouse but less so with human and poultry infections. There is increasing evidence that the organisms (i) modulate the host response away from the typical Th1-type response normally associated with immune clearance of an acute infection to Th2-type or an anti-inflammatory response, and that (ii) the bacteria modulate transformation of macrophage from M1 to M2 type. The bacterial factors involved in this are not yet fully understood. There are early indications that it might be possible to remodulate the response back towards a Th1 response by using cytokine therapy.
PubMed: 34684248
DOI: 10.3390/pathogens10101299 -
Vaccines Jul 2022Worldwide, poultry infections by are the cause of significant economic losses, not only due to reduced production (due to fowl typhoid disease), but also considering...
The Efficacy of a Trivalent Inactivated Vaccine Combined with the Live Gallinarum 9R Vaccine in Young Layers after Experimental Infections with Enteritidis, Typhimurium, and Infantis.
Worldwide, poultry infections by are the cause of significant economic losses, not only due to reduced production (due to fowl typhoid disease), but also considering the efforts and control measures that must be constantly applied, especially due to zoonotic serovars. Poultry is a common reservoir of and its transmission into the food chain is a risk for humans. The vaccination of layers plays an important role in the overall efforts to prevent infections. An inactivated trivalent vaccine was prepared with Enteritidis, Typhimurium, and Infantis strains. Infection trials were performed to evaluate the efficacy of three vaccination schedules using inactivated and live Gallinarum 9R vaccines. For this purpose, at week 5 of life, one subcutaneous dose of live Gallinarum 9R vaccine (1-5 × 10 CFU) was given to Groups 1 and 2. At weeks 8 and 11 of life, chickens were also vaccinated with one (Group 1) or two (Groups 2 and 3) intramuscular doses of the inactivated oil-adjuvant trivalent vaccine (1 × 10 CFU/dose of each antigen). Group 4 consisted of chickens that remained unvaccinated (control). At week 14 of life, the efficacy of the vaccination plans was evaluated in three separate inoculation trials with Enteritidis, Typhimurium, or Infantis. After vaccination with the inactivated vaccine, homologous antibody production was observed, and after challenge, a significant reduction in the faecal shedding, invasion, and colonization of Typhimurium and Infantis was achieved by all vaccination schedules, while the vaccination with at least one dose of the live Gallinarum 9R vaccine was necessary to obtain such a significant protection against Enteritidis infection.
PubMed: 35891276
DOI: 10.3390/vaccines10071113 -
Frontiers in Microbiology 2018serovar Gallinarum biovars Pullorum ( Pullorum) and Gallinarum ( Gallinarum) can result in pullorum disease and fowl typhoid in avian species, respectively, and cause...
serovar Gallinarum biovars Pullorum ( Pullorum) and Gallinarum ( Gallinarum) can result in pullorum disease and fowl typhoid in avian species, respectively, and cause considerable economic losses in poultry in many developing countries. Conventional serotyping is a time-consuming, labor-intensive and expensive process, and the two biovars cannot be distinguished using the traditional serological method. In this study, we developed a rapid and reliable one-step multiplex polymerase chain reaction (PCR) assay to simultaneously identify and discriminate the biovars Pullorum and Gallinarum. The multiplex PCR method focused on three specific genes, , and . Based on bioinformatics analysis, we found that gene was present only in Pullorum and Gallinarum, and a region of difference in was deleted only in Pullorum after comparison with that of Gallinarum and other serovars. Three pairs of primers specific for the three genes were designed for the multiplex PCR system and their selectivity and sensitivity were determined. The multiplex PCR results showed that Pullorum and Gallinarum could be identified and discriminated accurately from all tested strains including 124 strains of various serovars and 42 strains of different non- pathogens. In addition, this multiplex PCR assay could detect a minimum genomic DNA concentration of 67.4 pg/μL, and 100 colony forming units. The efficiency of the multiplex PCR was evaluated by detecting natural-occurring isolates from a chicken farm. The results demonstrated that the established multiplex PCR was able to identify Gallinarum and Pullorum individually, with results being consistent with traditional serotyping and biochemical testing. These results demonstrated that a highly accurate and simple biovar-specific multiplex PCR assay could be performed for the rapid identification and discrimination of biovars Gallinarum and Pullorum, which will be useful, particularly under massive screening situations.
PubMed: 30108571
DOI: 10.3389/fmicb.2018.01718