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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 -
Frontiers in Cellular and Infection... 2021has been known as an important zoonotic pathogen that can cause a variety of diseases in both animals and humans. Poultry are the main reservoir for the serovars...
has been known as an important zoonotic pathogen that can cause a variety of diseases in both animals and humans. Poultry are the main reservoir for the serovars Pullorum (. Pullorum), Gallinarum (. Gallinarum), Enteritidis (. Enteritidis), and Typhimurium (. Typhimurium). The conventional serotyping methods for differentiating serovars are complicated, time-consuming, laborious, and expensive; therefore, rapid and accurate molecular diagnostic methods are needed for effective detection and prevention of contamination. This study developed and evaluated a TaqMan multiplex real-time PCR assay for simultaneous detection and differentiation of the . Pullorum, . Gallinarum, . Enteritidis, and Typhimurium. In results, the optimized multiplex real-time PCR assay was highly specific and reliable for all four target genes. The analytical sensitivity corresponded to three colony-forming units (CFUs) for these four serovars, respectively. The detection limit for the multiplex real-time PCR assay in artificially contaminated samples was 500 CFU/g without enrichment, while 10 CFU/g after pre-enrichment. Moreover, the multiplex real-time PCR was applied to the poultry clinical samples, which achieved comparable results to the traditional bacteriological examination. Taken together, these results indicated that the optimized TaqMan multiplex real-time PCR assay will be a promising tool for clinical diagnostics and epidemiologic study of in chicken farm and poultry products.
Topics: Animals; Chickens; Farms; Humans; Real-Time Polymerase Chain Reaction; Salmonella enteritidis; Sensitivity and Specificity; Serogroup
PubMed: 34660351
DOI: 10.3389/fcimb.2021.759965 -
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 -
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 -
Cancers Feb 2023Bacterial cancer therapy is a promising next-generation modality to treat cancer that often uses tumor-colonizing bacteria to deliver cytotoxic anticancer proteins....
Bacterial cancer therapy is a promising next-generation modality to treat cancer that often uses tumor-colonizing bacteria to deliver cytotoxic anticancer proteins. However, the expression of cytotoxic anticancer proteins in bacteria that accumulate in the nontumoral reticuloendothelial system (RES), mainly the liver and spleen, is considered detrimental. This study examined the fate of the strain MG1655 and an attenuated strain of serovar Gallinarum ( Gallinarum) with defective ppGpp synthesis after intravenous injection into tumor-bearing mice (~10 colony forming units/animal). Approximately 10% of the injected bacteria were detected initially in the RES, whereas approximately 0.01% were in tumor tissues. The bacteria in the tumor tissue proliferated vigorously to up to 10 colony forming units/g tissue, whereas those in the RES died off. RNA analysis revealed that tumor-associated activated rrnB operon genes encoding the rRNA building block of ribosome needed most during the exponential stage of growth, whereas those in the RES expressed substantially decreased levels of this gene and were cleared soon presumably by innate immune systems. Based on this finding, we engineered ΔppGpp Gallinarum to express constitutively a recombinant immunotoxin comprising TGFα and the exotoxin A (PE38) using a constitutive exponential phase promoter, the ribosomal RNA promoter rrnB P1. The construct exerted anticancer effects on mice grafted with mouse colon (CT26) or breast (4T1) tumor cells without any notable adverse effects, suggesting that constitutive expression of cytotoxic anticancer protein from rrnB P1 occurred only in tumor tissue.
PubMed: 36900277
DOI: 10.3390/cancers15051486 -
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 -
Microorganisms Jul 2020Foodborne diseases represent a major risk to public health worldwide. In this study, LPST153, a novel lytic phage with halo (indicative of potential depolymerase...
Foodborne diseases represent a major risk to public health worldwide. In this study, LPST153, a novel lytic phage with halo (indicative of potential depolymerase activity) was isolated by employing serovar Typhimurium ATCC 13311 as the host and had excellent lytic potential against . LPST153 is effectively able to lyse most prevalent tested serotypes of , including Typhimurium, Enteritidis, Pullorum and Gallinarum. Morphological analysis revealed that phage LPST153 belongs to family and order and could completely prevent host bacterial growth within 9 h at multiplicity of infection (MOI) of 0.1, 1, 10 and 100. LPST153 had a latent period of 10 min and a burst size of 113 ± 8 PFU/cell. Characterization of the phage LPST153 revealed that it would be active and stable in some harsh environments or in different conditions of food processing and storage. After genome sequencing and phylogenetic analysis, it is confirmed that LPST153 is a new member of the genus of subfamily. Further application experiments showed that this phage has potential in controlling in milk and sausage. LPST153 was also able to inhibit the formation of biofilms and it had the ability to reduce and kill bacteria from inside, including existing biofilms. Therefore, the phage LPST153 could be used as a potential antibacterial agent for control in the food industry.
PubMed: 32708328
DOI: 10.3390/microorganisms8071089 -
Polish Journal of Microbiology Jun 2023genus harbors five Type VI Secretion System (T6SS) gene clusters. The T6SS encoded in SPI-6 (T6SS) contributes to Typhimurium colonization of chickens and mice, while...
genus harbors five Type VI Secretion System (T6SS) gene clusters. The T6SS encoded in SPI-6 (T6SS) contributes to Typhimurium colonization of chickens and mice, while the T6SS encoded in SPI-19 (T6SS) of Gallinarum contributes to chicken colonization. Interestingly, the T6SS of Gallinarum complemented the defect in chicken colonization of a Typhimurium strain that lacks the T6SS, suggesting that both T6SSs are interchangeable. Here we show that the transfer of Gallinarum T6SS complemented the defect in mice colonization of a Typhimurium ΔT6SS strain, indicating that both T6SSs are functionally redundant during host colonization.
Topics: Animals; Mice; Salmonella typhimurium; Chickens; Multigene Family
PubMed: 37314360
DOI: 10.33073/pjm-2023-017 -
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 -
Pathogens (Basel, Switzerland) Oct 2020serovar Gallinarum (. Gallinarum) is the cause of typhoid in chickens but the immune factors that may facilitate the development of typhoid have not been fully...
serovar Gallinarum (. Gallinarum) is the cause of typhoid in chickens but the immune factors that may facilitate the development of typhoid have not been fully elucidated. We show that, in contrast to non-typhoid . Enteritidis infection, . Gallinarum significantly reduced nitrite ion production and expression of mRNA for heterophil granulocyte chemoattractants CXCLi2 and IL-6 in chicken monocyte-derived macrophages (chMDMs) ( < 0.05) at 6 h post-infection (pi). . Gallinarum also reduced IFN-γ and IL-17 expression by CD4 lymphocytes cultured with infected chMDMs for 5 days but did not induce a Th2 phenotype or anergy. In vivo, . Gallinarum also induced significantly lower expression of CXCLi1, CXCLi2, IL-1β, IL-6 and iNOS mRNA in the caecal tonsil by day 2 pi ( < 0.05-0.01) and consistently lower levels of IFN-γ, IL-18, IL-12, and IL-17. In the spleen, . Gallinarum induced significantly lower levels of iNOS and IFN-γ ( < 0.01 and 0.05 respectively) and consistently lower levels of IL-18 and IL-12 but significantly greater ( < 0.01) expression of anti-inflammatory IL-10 at day 4 and 5 pi when compared to . Enteritidis. This immune phenotype was associated with transit from the intestinal tissues to the liver by . Gallinarum, not observed following . Enteritidis infection. In conclusion, we report an immune mechanism that may facilitate typhoid disease in . Gallinarum-infected chickens. However, down-regulation of inflammatory mediators, upregulation of IL-10, and associated liver colonisation are also characteristic of human typhoid, suggesting that this may also be a useful model of typhoid in humans.
PubMed: 33076485
DOI: 10.3390/pathogens9100843