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Poultry Science May 2024An effective vaccine strategy is indispensable against infectious bronchitis virus (IBV) and fowl typhoid (FT), both of which threaten the poultry industry. This study...
A low-endotoxic Salmonella enterica Gallinarum serovar delivers infectious bronchitis virus immunogens via a dual-promoter vector system that drives protective immune responses through MHC class-I and -II activation in chickens.
An effective vaccine strategy is indispensable against infectious bronchitis virus (IBV) and fowl typhoid (FT), both of which threaten the poultry industry. This study demonstrates a vector system, pJHL270, designed to express antigens in prokaryotic and eukaryotic cells. The vector system stimulates immune responses via synchronized antigen presentation to MHC class-I and -II molecules to produce balanced Th1/Th2 responses. The vaccine antigens were crafted by selecting the consensus sequence of the N-terminal domain of the spike protein (S1-NTD) and a conserved immunogenic region of the nucleocapsid protein (N-) from IBV strains circulating in South Korea. The vaccine antigen was cloned and transformed into a live-attenuated Salmonella Gallinarum (SG) strain, JOL2854 (∆lon, ∆cpxR, ∆rfaL, ∆pagL, ∆asd). Western blot analysis confirmed concurrent antigen expression in Salmonella and eukaryotic cells. Oral immunization with the SG-based IBV vaccine construct JOL2918 induced IBV antigen and Salmonella-specific humoral and cell-mediated immune responses in chickens. PBMCs collected from immunized chickens revealed that MHC class-I and -II expression had increased 3.3-fold and 2.5-fold, respectively, confirming MHC activation via bilateral antigen expression and presentation. Immunization induced neutralizing antibodies (NAbs) and reduced the viral load by 2-fold and 2.5-fold in the trachea and lungs, respectively. The immunized chickens exhibited multifaceted humoral, mucosal, and cell-mediated responses via parallel MHC class-I and -II activation as proof of a balanced Th1/Th2 immune response. The level of NAbs, viral load, and gross and histological analyses provide clear evidence that the construct provides protection against IBV and FT.
PubMed: 38795516
DOI: 10.1016/j.psj.2024.103844 -
Open Veterinary Journal Feb 2024Presently, there exists a growing interest in mitigating the utilization of antibiotics in response to the challenges emanating from their usage in livestock. A viable...
BACKGROUND
Presently, there exists a growing interest in mitigating the utilization of antibiotics in response to the challenges emanating from their usage in livestock. A viable alternative strategy encompasses the introduction of live microorganisms recognized as probiotics, exerting advantageous impacts on the immune system and nutritional aspects of the host animals. Native lactic acid bacteria, inherently possessing specific properties and adaptive capabilities tailored to each animal, are deemed optimal contenders for probiotic advancement.
AIM
In the current investigation, microorganisms exhibiting probiotic potential were isolated, characterized, and identified from the fecal samples of guinea pigs () belonging to the Peruvian breed.
METHODS
The lactic acid bacteria isolated on Man, Rogosa, and Sharpe agar underwent Gram staining, catalase testing, proteolytic, amylolytic, and cellulolytic activity assays, low pH tolerance assessment, hemolytic evaluation, antagonism against ., determination of autoaggregation and coaggregation capacity, and genotypic characterization through sequencing of the 16S rRNA gene.
RESULTS
A total of 33 lactic acid bacteria were isolated from the feces of 30 guinea pigs, also 10 isolates were selected based on Gram staining and catalase testing. All strains exhibited proteolytic activity, while only one demonstrated amylolytic capability, and none displayed cellulase activity. These bacteria showed higher tolerance to pH 5.0 and, to a lesser extent, to pH 4.0. Furthermore, they exhibited antagonistic activity against . Only two bacteria demonstrated hemolytic activity, and were subsequently excluded from further evaluations. Subsequent assessments revealed autoaggregation capacities ranging from 4.55% to 23.19%, with a lesser degree of coaggregation with . ranging from 3.53% to 8.94% for the remaining eight bacterial isolates. Based on these comprehensive tests, five bacteria with notable probiotic potential were identified by molecular assays as Leuconostoc citreum, and
CONCLUSION
The identified bacteria stand out as promising probiotic candidates, deserving further assessment in Peruvian breed guinea pigs. This exploration aims to enhance production outcomes while mitigating the adverse effects induced by pathogenic microorganisms.
Topics: Humans; Guinea Pigs; Animals; Lactobacillales; RNA, Ribosomal, 16S; Catalase; Feces; Genomics; Probiotics
PubMed: 38549567
DOI: 10.5455/OVJ.2024.v14.i2.12 -
Frontiers in Microbiology 2024Strawberry ( × ) fruits are vulnerable to bacterial contamination; some species are pathogenic and can affect human health. Comprehending the bacterial composition and...
BACKGROUND
Strawberry ( × ) fruits are vulnerable to bacterial contamination; some species are pathogenic and can affect human health. Comprehending the bacterial composition and diversity at different ripe stages is a key determinant of the fruit health, productivity, and quality.
METHODOLOGY
An amplicon metagenomic approach on the 16S rRNA region was used to identify the bacterial diversity in exocarp of fruits collected from a farm field at two ripe stages: breaking (white, phase two) and ripe (red, phase four) and purchased from different retail market stands at ripe (red, phase four, ready-to-eat) stage. Besides, the fruit quality was assessed.
RESULTS
Strawberries carries a high microorganisms diversity, with , and being the most abundant families across the samples. Among the groups, and were the most abundant families at breaking (phase two) and ripe (phase four), whereas , and were the most abundant families in the market group. Although samples from group four-field and market were at the same ripe stage, the bacterial species composition was divergent. spp. were prevalent (above 60%) in samples collected from the market group, and (above 70%) species were mostly found in the samples collected from the field settings regardless of the phase. Besides, and were detected in the ready-to-eat samples from both the field and the market, while was detected in the samples that originated from the market. Interestingly, and , two human opportunistic pathogens, were detected in the fruits from the market only. According to alpha and beta diversity analyses, strawberry fruits displayed significant differences ( < 0.05) in bacterial communities within the ripe group, with the samples from the market showing the most bacterial diversity. Although we do not directly correlate the quality attributes with bacterial diversity, the results indicated a clear separation between groups according with their ripe stage and origin.
CONCLUSION
This study provides a comprehensive framework of the bacterial diversity throughout the transition from unripe to ripe strawberries which may aid in the development of preventative measures to manage the postharvest contamination.
PubMed: 38435684
DOI: 10.3389/fmicb.2024.1348316 -
Microorganisms Jan 2024Fowl typhoid is a septicemic disease caused by subsp. serovar Gallinarum biovar Gallinarum. It is a host-specific disease primarily affecting chickens and turkeys,...
Fowl typhoid is a septicemic disease caused by subsp. serovar Gallinarum biovar Gallinarum. It is a host-specific disease primarily affecting chickens and turkeys, although it has been reported in various animal species and sporadically in humans. Here, we present a case of a fowl typhoid outbreak on a turkey poult farm where the source of infection was the hatchery. The birds started showing symptoms of growth retardation at 21 days of age, after which the mortality rates gradually started to increase. Post mortem examination revealed that the main lesions were granulomatous proliferations in the small intestines. The results of the histopathological examination indicate that the severity of the infection was alleviated by the application of phytogenic mixtures and probiotics as a supportive treatment, even though the affected flock was eventually culled at 60 days of age. The farmer was advised to apply more strict biosecurity measures to prevent the spread of the disease on the farm and try to eradicate the pathogen from the barn. Since the outbreak, there have been no recurrent infections.
PubMed: 38257990
DOI: 10.3390/microorganisms12010165 -
Antibiotics (Basel, Switzerland) Dec 2023subsp. serovar Gallinarum (G) has two distinct biovars, Pullorum and Gallinarum. They are bacterial pathogens that exhibit host specificity for poultry and aquatic... (Review)
Review
subsp. serovar Gallinarum (G) has two distinct biovars, Pullorum and Gallinarum. They are bacterial pathogens that exhibit host specificity for poultry and aquatic birds, causing severe systemic diseases known as fowl typhoid (FT) and Pullorum disease (PD), respectively. The virulence mechanisms of biovars Gallinarum and Pullorum are multifactorial, involving a variety of genes and pathways that contribute to their pathogenicity. In addition, these serovars have developed resistance to various antimicrobial agents, leading to the emergence of multidrug-resistant strains. Due to their economic and public health significance, rapid and accurate diagnosis is crucial for effective control and prevention of these diseases. Conventional methods, such as bacterial culture and serological tests, have been used for screening and diagnosis. However, molecular-based methods are becoming increasingly important due to their rapidity, high sensitivity, and specificity, opening new horizons for the development of innovative approaches to control FT and PD. The aim of this review is to highlight the current state of knowledge on biovars Gallinarum and Pullorum, emphasizing the importance of continued research into their pathogenesis, drug resistance and diagnosis to better understand and control these pathogens in poultry farms.
PubMed: 38247582
DOI: 10.3390/antibiotics13010023 -
Animals : An Open Access Journal From... Dec 2023This study investigates the potential role of Cold-pressed Valencia Terpeneless citrus oil (CO), as a natural antimicrobial, in controlling causative agents of pullorum...
This study investigates the potential role of Cold-pressed Valencia Terpeneless citrus oil (CO), as a natural antimicrobial, in controlling causative agents of pullorum disease and fowl typhoid in floor materials for poultry farming, specifically wooden chips. The study addresses the issues that have arisen as a result of the reduction in antibiotic use in poultry farming, which has resulted in the re-emergence of bacterial diseases including salmonellosis. CO efficiently inhibits the growth of pathogens including various serovars of (SE), including SE serovar Gallinarum () and SE serovar Pullorum (), in a dose-dependent manner. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of CO showed potential for controlling diverse and isolates. Growth inhibition assays demonstrated that 0.4% (/) CO eliminated and from 24 h onwards, also impacting poultry gut microbiota and probiotic strains. Floor material simulation, specifically wooden chips treated with 0.4% CO, confirmed CO's effectiveness in preventing and growth on poultry house floors. This study also investigated the effect of CO on the expression of virulence genes in and . Specifically, the study revealed that the application of CO resulted in a downregulation trend in virulence genes, including , , , , and , in both and , implying that CO may alter the pathogenicity of these bacterial pathogens. Overall, this study reveals that CO has the potential to be used as a natural antimicrobial in the prevention and management of -related infections in chicken production, offering a viable alternative to control these re-emerging diseases.
PubMed: 38200754
DOI: 10.3390/ani14010023 -
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 -
Microorganisms Dec 2023subsp. serovar Gallinarum biovar pullorum ( pullorum) is an avian-specific pathogen that has caused considerable economic losses to the poultry industry. High...
subsp. serovar Gallinarum biovar pullorum ( pullorum) is an avian-specific pathogen that has caused considerable economic losses to the poultry industry. High endemicity, poor implementation of hygiene measures, and lack of effective vaccines hinder the prevention and control of this disease in intensively maintained poultry flocks. In recent years, the incidence of arthritis in chicks caused by pullorum infection has increased. In this study, four pullorum strains were identified from the livers, spleens, and joint fluids of Qingjiaoma chicken breeders with arthritis clinical signs, and an arthritis model of chicks was successfully established using SP206-2. Whole genome sequencing of the SP206-2 strain showed that the genome was 4,730,579 bp, 52.16% GC content, and contained 5007 genes, including 4729 protein-coding regions. The genomic analysis of four arthritis-causing isolates and three diarrhea-causing isolates showed that the genome of arthritis-causing isolates was subject to nonsynonymous mutations, shift mutations, and gene copy deletions. An SNP phylogenetic tree analysis showed that arthritis-causing isolates are located in a different evolutionary branch from diarrhea-causing isolates. Further differential genes analysis showed that the genome of arthritis-causing isolates had missense mutations in genes related to substance metabolism and substance transport, as a result of adaptive evolution.
PubMed: 38138130
DOI: 10.3390/microorganisms11122986 -
Molecular Therapy Oncolytics Dec 2023We report here a novel anti-cancer therapy based on an avian-host-specific serotype serovar Gallinarum () deficient in ppGpp synthesis. To monitor the tumor targeting,...
We report here a novel anti-cancer therapy based on an avian-host-specific serotype serovar Gallinarum () deficient in ppGpp synthesis. To monitor the tumor targeting, a bioluminescent ΔppGpp was constructed and injected intravenously into mice bearing syngeneic and human xenograft tumors. Strong bioluminescent signals were detected specifically in all grafted tumors at 2 days post-injection (dpi). The bacterial counts in normal and tumor tissue at 1 dpi revealed that ΔppGpp reached >10 CFU/g in tumor tissue and 10-10 CFU/g in endothelial organs; counts were much lower in other organs. At 16 dpi, ΔppGpp counts in tumor tissue decreased to ∼10 CFU/g, while those in the other organs became undetectable. A strong anti-cancer effect was observed after the injection of ΔppGpp into BALB/c mice grafted with CT26 colon cancer cells. This could be attributed to reduced virulence, which allowed the administration of at least a 10-fold greater dose (10 CFU) of ΔppGpp than other attenuated strains of serovar Typhimurium (≤10 CFU). An advantage of the avian-specific as a cancer therapeutic should be a reduced capacity to cause infections or harm in humans.
PubMed: 38053546
DOI: 10.1016/j.omto.2023.100745 -
Iranian Journal of Microbiology Oct 2023Antibiotic resistance is an indicator of the passively acquired and circulating resistance genes. Gallinarum significantly affects the poultry food industry. The...
BACKGROUND AND OBJECTIVES
Antibiotic resistance is an indicator of the passively acquired and circulating resistance genes. Gallinarum significantly affects the poultry food industry. The present study is the first study of the Gallinarum biofilm in Iran, which is focused on the characterization of the Gallinarum serovars and their acquired antibiotic resistance genes circulating in poultry fields in central and northwestern Iran.
MATERIALS AND METHODS
Sixty isolates of . Gallinarum serovar were collected from feces of live poultry. The bacteria were isolated using biochemical tests and confirmed by Multiplex PCR. Biofilm formation ability and the antibacterial resistance were evaluated using both phenotypic and genotypic methods. The data were analyzed using SPSS software.
RESULTS
According to Multiplex PCR for , and genes, all 60 . Gallinarum serovars were Gallinarum biovars. In our study, the antibiotic resistance rate among isolated strains was as follows: Penicillin (100%), nitrofurantoin (80%), nalidixic acid (45%), cefoxitin (35%), neomycin sulfate (30%), chloramphenicol (20%), and ciprofloxacin (5%). All isolates were susceptible to imipenem, ertapenem, ceftriaxone, ceftazidime, and ceftazidime+clavulanic acid. All sixty isolates did not express the resistance genes , , and . On the other hand, they expressed (85%), (75%), (70%), (60%), (20%), (15%), (10%), (5%), and (5%). All Gallinarum isolates formed biofilm and expressed gene.
CONCLUSION
Considering that the presence of this bacteria is equal to the death penalty to the herd, the distribution of resistance genes could be a critical alarm for pathogen monitoring programs in the region. This study showed a positive correlation between biofilm formation and 50% of tested resistance genes. Also, it was found that the most common circulating biovars are multidrug-resistant.
PubMed: 37941876
DOI: 10.18502/ijm.v15i5.13869