RESUMO
OBJECTIVES: The pathogenic microorganisms that cause intestinal diseases can significantly jeopardize people's health. Currently, there are no authorized treatments or vaccinations available to combat the germs responsible for intestinal disease. METHODS: Using immunoinformatics, we developed a potent multi-epitope Combination (combo) vaccine versus Salmonella and enterohemorrhagic E. coli. The B and T cell epitopes were identified by performing a conservancy assessment, population coverage analysis, physicochemical attributes assessment, and secondary and tertiary structure assessment of the chosen antigenic polypeptide. The selection process for vaccine development included using several bioinformatics tools and approaches to finally choose two linear B-cell epitopes, five CTL epitopes, and two HTL epitopes. RESULTS: The vaccine had strong immunogenicity, cytokine production, immunological properties, non-toxicity, non-allergenicity, stability, and potential efficacy against infections. Disulfide bonding, codon modification, and computational cloning were also used to enhance the stability and efficacy of expression in the host E. coli. The vaccine's structure has a strong affinity for the TLR4 ligand and is very durable, as shown by molecular docking and molecular modeling. The results of the immunological simulation demonstrated that both B and T cells had a heightened response to the vaccination component. CONCLUSIONS: The comprehensive in silico analysis reveals that the proposed vaccine will likely elicit a robust immune response against pathogenic bacteria that cause intestinal diseases. Therefore, it is a promising option for further experimental testing.
Assuntos
Epitopos de Linfócito B , Epitopos de Linfócito T , Vacinologia , Humanos , Epitopos de Linfócito T/imunologia , Vacinologia/métodos , Epitopos de Linfócito B/imunologia , Vacinas Combinadas/imunologia , Genômica/métodos , Escherichia coli Êntero-Hemorrágica/imunologia , Salmonella/imunologia , Animais , Biologia Computacional/métodos , Simulação de Acoplamento Molecular , Vacinas contra Escherichia coli/imunologia , Infecções por Escherichia coli/prevenção & controle , Infecções por Escherichia coli/imunologia , Infecções por Salmonella/imunologia , Infecções por Salmonella/prevenção & controle , Antígenos de Bactérias/imunologia , Desenvolvimento de Vacinas/métodos , Vacinas Bacterianas/imunologiaRESUMO
Engineered Salmonella has emerged as a promising microbial immunotherapy against tumors; however, its clinical effectiveness has encountered limitations. In our investigation, we unveil a non-dose-dependent type of behavior regarding Salmonella's therapeutic impact and reveal the regulatory role of neutrophils in diminishing the efficacy of this. While Salmonella colonization within tumors recruits a substantial neutrophil population, these neutrophils predominantly polarize into the pro-tumor N2 phenotype, elevating PD-L1 expression and fostering an immunosuppressive milieu within the tumor microenvironment. In order to bypass this challenge, we introduce MnO2 nanoparticles engineered to activate the STING pathway. Harnessing the STING pathway to stimulate IFN-ß secretion prompts a shift in neutrophil polarization from the N2 to the N1 phenotype. This strategic repolarization remodels the tumor immune microenvironment, making the infiltration and activation of CD8+ T cells possible. Through these orchestrated mechanisms, the combined employment of Salmonella and MnO2 attains the synergistic enhancement of anti-tumor efficacy, achieving the complete inhibition of tumor growth within 20 days and an impressive 80% survival rate within 40 days, with no discernible signs of significant adverse effects. Our study not only unveils the crucial in vivo constraints obstructing microbial immune therapy but also sets out an innovative strategy to augment its efficacy. These findings pave the way for advancements in cell-based immunotherapy centered on leveraging the potential of neutrophils.
Assuntos
Imunoterapia , Compostos de Manganês , Proteínas de Membrana , Camundongos Endogâmicos C57BL , Nanopartículas , Neutrófilos , Óxidos , Salmonella , Microambiente Tumoral , Compostos de Manganês/química , Animais , Neutrófilos/imunologia , Neutrófilos/metabolismo , Imunoterapia/métodos , Camundongos , Proteínas de Membrana/metabolismo , Salmonella/imunologia , Nanopartículas/química , Linfócitos T CD8-Positivos/imunologia , Linhagem Celular Tumoral , Feminino , Neoplasias/terapia , Neoplasias/imunologia , Transdução de Sinais , HumanosRESUMO
Immunotherapies have revolutionized cancer treatment. These treatments rely on immune cell activation in tumours, which limits the number of patients that respond. Inflammatory molecules, like lipopolysaccharides (LPS), can activate innate immune cells, which convert tumour microenvironments from cold to hot, and increase therapeutic efficacy. However, systemic delivery of lipopolysaccharides (LPS) can induce cytokine storm. In this work, we developed immune-controlling Salmonella (ICS) that only produce LPS in tumours after colonization and systemic clearance. We tuned the expression of msbB, which controls production of immunogenic LPS, by optimizing its ribosomal binding sites and protein degradation tags. This genetic system induced a controllable inflammatory response and increased dendritic cell cross-presentation in vitro. The strong off state did not induce TNFα production and prevented adverse events when injected into mice. The accumulation of ICS in tumours after intravenous injection focused immune responses specifically to tumours. Tumour-specific expression of msbB increased infiltration of immune cells, activated monocytes and neutrophils, increased tumour levels of IL-6, and activated CD8 T cells in draining lymph nodes. These immune responses reduced tumour growth and increased mouse survival. By increasing the efficacy of bacterial anti-cancer therapy, localized production of LPS could provide increased options to patients with immune-resistant cancers.
Assuntos
Lipopolissacarídeos , Neoplasias , Animais , Lipopolissacarídeos/imunologia , Neoplasias/terapia , Neoplasias/imunologia , Camundongos , Salmonella/imunologia , Salmonella/genética , Camundongos Endogâmicos C57BL , Modelos Animais de Doenças , Células Dendríticas/imunologia , Imunoterapia/métodos , HumanosRESUMO
BACKGROUND: Consumption of pork and pork products is a major source of human infection with Salmonella. Salmonella is typically subclinical in pigs, making it difficult to identify infected pigs. Therefore, effective surveillance of Salmonella in pigs critically relies on good knowledge on how well the diagnostic tests used perform. A test that has been used in several countries for Salmonella monitoring is serological testing of meat juice using an ELISA (MJ ELISA) to detect antibodies against Salmonella. This MJ ELISA data could be used to estimate infection prevalence and trends. However, as the MJ ELISA output is a sample-to-positive (S/P) ratio, which is a continuous outcome rather than a binary (positive/negative) result, the interpretation of this data depends upon a chosen cut-off. AIM: To apply Bayesian latent class models (BLCMs) to estimate diagnostic accuracy of the MJ ELISA test values in the absence of a gold standard without needing to apply a cut-off. METHODS AND RESULTS: BLCMs were fitted to data from a UK abattoir survey carried out in 2006 in order to estimate the diagnostic accuracy of MJ ELISA with respect to the prevalence of active Salmonella infection. This survey consisted of a MJ ELISA applied in parallel with the bacteriological testing of caecal contents, carcass swabs and lymph nodes (n = 625). A BLCM was also fitted to the same data but with dichotomisation of the MJ ELISA results, in order to compare with the model using continuous outcomes. Estimates were obtained for sensitivity and specificity of the ELISA over a range of S/P values and for the bacteriological tests and were found to be similar between the models using continuous and dichotomous ELISA outcomes. CONCLUSION: The Bayesian method without specifying a cut-off does allow prevalence to be inferred without specifying a cut-off for the ELISA. The study results will be useful for estimating infection prevalence from serological surveillance data.
Assuntos
Teorema de Bayes , Ensaio de Imunoadsorção Enzimática , Salmonelose Animal , Salmonella , Doenças dos Suínos , Animais , Suínos , Ensaio de Imunoadsorção Enzimática/veterinária , Ensaio de Imunoadsorção Enzimática/métodos , Doenças dos Suínos/diagnóstico , Doenças dos Suínos/microbiologia , Doenças dos Suínos/epidemiologia , Salmonella/isolamento & purificação , Salmonella/imunologia , Salmonelose Animal/diagnóstico , Salmonelose Animal/epidemiologia , Salmonelose Animal/microbiologia , Matadouros , Carne/microbiologia , Sensibilidade e Especificidade , Anticorpos Antibacterianos/sangueRESUMO
Salmonella infections pose a significant global public health concern due to the substantial expenses associated with monitoring, preventing, and treating the infection. In this study, we explored the core proteome of Salmonella to design a multi-epitope vaccine through Subtractive Proteomics and immunoinformatics approaches. A total of 2395 core proteins were curated from 30 different isolates of Salmonella (strain NZ CP014051 was taken as reference). Utilizing the subtractive proteomics approach on the Salmonella core proteome, Curlin major subunit A (CsgA) was selected as the vaccine candidate. csgA is a conserved gene that is related to biofilm formation. Immunodominant B and T cell epitopes from CsgA were predicted using numerous immunoinformatics tools. T lymphocyte epitopes had adequate population coverage and their corresponding MHC alleles showed significant binding scores after peptide-protein based molecular docking. Afterward, a multi-epitope vaccine was constructed with peptide linkers and Human Beta Defensin-2 (as an adjuvant). The vaccine could be highly antigenic, non-toxic, non-allergic, and have suitable physicochemical properties. Additionally, Molecular Dynamics Simulation and Immune Simulation demonstrated that the vaccine can bind with Toll Like Receptor 4 and elicit a robust immune response. Using in vitro, in vivo, and clinical trials, our findings could yield a Pan-Salmonella vaccine that might provide protection against various Salmonella species.
Assuntos
Biologia Computacional , Epitopos de Linfócito T , Proteômica , Salmonella , Proteômica/métodos , Epitopos de Linfócito T/imunologia , Salmonella/imunologia , Salmonella/genética , Biologia Computacional/métodos , Humanos , Genômica/métodos , Simulação de Acoplamento Molecular , Vacinas contra Salmonella/imunologia , Animais , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/química , Simulação de Dinâmica Molecular , Infecções por Salmonella/prevenção & controle , Infecções por Salmonella/imunologia , Infecções por Salmonella/microbiologia , Epitopos de Linfócito B/imunologia , ImunoinformáticaRESUMO
Type 1 diabetes (T1D)-associated hyperglycemia develops, in part, from loss of insulin-secreting beta cells. The degree of glycemic dysregulation and the age at onset of disease can serve as indicators of the aggressiveness of the disease. Tracking blood glucose levels in prediabetic mice may demonstrate the onset of diabetes and, along with animal age, also presage disease severity. In this study, an analysis of blood glucose levels obtained from female NOD mice starting at 4 weeks until diabetes onset was undertaken. New onset diabetic mice were orally vaccinated with a Salmonella-based vaccine towards T1D-associated preproinsulin combined with TGFß and IL10 along with anti-CD3 antibody. Blood glucose levels were obtained before and after development of disease and vaccination. Animals were classified as acute disease if hyperglycemia was confirmed at a young age, while other animals were classified as progressive disease. The effectiveness of the oral T1D vaccine was greater in mice with progressive disease that had less glucose excursion compared to acute disease mice. Overall, the Salmonella-based vaccine reversed disease in 60% of the diabetic mice due, in part, to lessening of islet inflammation, improving residual beta cell health, and promoting tolerance. In summary, the age of disease onset and severity of glucose dysregulation in NOD mice predicted response to vaccine therapy. This suggests a similar disease categorization in the clinic may predict therapeutic response.
Assuntos
Glicemia , Diabetes Mellitus Tipo 1 , Camundongos Endogâmicos NOD , Animais , Feminino , Diabetes Mellitus Tipo 1/imunologia , Diabetes Mellitus Tipo 1/microbiologia , Camundongos , Administração Oral , Glicemia/metabolismo , Vacinas contra Salmonella/imunologia , Vacinas contra Salmonella/administração & dosagem , Salmonella/imunologia , Insulina/imunologia , Progressão da Doença , Doença Aguda , Precursores de ProteínasRESUMO
Due to inherent differences in cellular composition and metabolic behavior with host cells, tumor-harbored bacteria can discriminatorily affect tumor immune landscape. However, the mechanisms by which intracellular bacteria affect antigen presentation process between tumor cells and antigen-presenting cells (APCs) are largely unknown. The invasion behavior of attenuated Salmonella VNP20009 (VNP) into tumor cells is investigated and an attempt is made to modulate this behavior by modifying positively charged polymers on the surface of VNP. It is found that non-toxic chitosan oligosaccharide (COS) modified VNP (VNP@COS) bolsters the formation of gap junction between tumor cells and APCs by enhancing the ability of VNP to infect tumor cells. On this basis, a bacterial biohybrid is designed to promote in situ antigen cross-presentation through intracellular bacteria induced gap junction. This bacterial biohybrid also enhances the expression of major histocompatibility complex class I molecules on the surface of tumor cells through the incorporation of Mdivi-1 coupled with VNP@COS. This strategic integration serves to heighten the immunogenic exposure of tumor antigens; while, preserving the cytotoxic potency of T cells. A strategy is proposed to precisely controlling the function and local effects of microorganisms within tumors.
Assuntos
Apresentação de Antígeno , Quitosana , Junções Comunicantes , Salmonella , Humanos , Quitosana/química , Linhagem Celular Tumoral , Junções Comunicantes/metabolismo , Salmonella/imunologia , Animais , Apresentação Cruzada , Camundongos , Oligossacarídeos/química , Neoplasias/imunologia , Neoplasias/patologia , Células Apresentadoras de Antígenos/imunologia , Antígenos de Histocompatibilidade Classe I/metabolismo , Antígenos de Histocompatibilidade Classe I/imunologiaRESUMO
Outer membrane vesicles (OMVs) are membranous structures frequently observed in Gram-negative bacteria that contain bioactive substances. These vesicles are rich in bacterial antigens that can activate the host's immune system, making them a promising candidate vaccine to prevent and manage bacterial infections. The aim of this study was to assess the immunogenicity and protective efficacy of OMVs derived from Salmonella enterica serovar Typhimurium and S. Choleraesuis, while also focusing on enhancing OMV production. Initial experiments showed that OMVs from wild-type strains did not provide complete protection against homologous Salmonella challenge, possible due to the presence of flagella in the purified OMVs samples, which may elicit an unnecessary immune response. To address this, flagellin-deficient mutants of S. Typhimurium and S. Choleraesuis were constructed, designated rSC0196 and rSC0199, respectively. These mutants exhibited reduced cell motility and their OMVs were found to be flagellin-free. Immunization with non-flagellin OMVs derived from rSC0196 induced robust antibody responses and improved survival rates in mice, as compared to the OMVs derived from the wild-type UK-1. In order to enhance OMV production, deletions of ompA or tolR were introduced into rSC0196. The deletion of tolR not only increase the yield of OMVs, but also conferred complete protection against homologous S. Typhimurium challenge in mice. Collectively, these findings indicate that the flagellin-deficient OMVs with a tolR mutation have the potential to serve as a versatile vaccine platform, capable of inducing broad-spectrum protection against significant pathogens.
Assuntos
Proteínas da Membrana Bacteriana Externa , Camundongos Endogâmicos BALB C , Vacinas contra Salmonella , Salmonella typhimurium , Animais , Salmonella typhimurium/imunologia , Salmonella typhimurium/genética , Camundongos , Vacinas contra Salmonella/imunologia , Proteínas da Membrana Bacteriana Externa/imunologia , Proteínas da Membrana Bacteriana Externa/genética , Feminino , Flagelina/imunologia , Flagelina/genética , Salmonelose Animal/prevenção & controle , Salmonelose Animal/microbiologia , Salmonelose Animal/imunologia , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/imunologia , Membrana Externa Bacteriana/imunologia , Salmonella/imunologia , Salmonella/genética , Imunogenicidade da Vacina , Antígenos de Bactérias/imunologiaRESUMO
Nanobodies (Nbs) serve as powerful tools in immunoassays. However, their small size and monovalent properties pose challenges for practical application. Multimerization emerges as a significant strategy to address these limitations, enhancing the utilization of nanobodies in immunoassays. Herein, we report the construction of a Salmonella-specific fenobody (Fb) through the fusion of a nanobody to ferritin, resulting in a self-assembled 24-valent nanocage-like structure. The fenobody exhibits a 35-fold increase in avidity compared to the conventional nanobody while retaining good thermostability and specificity. Leveraging this advancement, three ELISA modes were designed using Fb as the capture antibody, along with unmodified Nb422 (FbNb-ELISA), biotinylated Nb422 (FbBio-ELISA), and phage-displayed Nb422 (FbP-ELISA) as the detection antibody, respectively. Notably, the FbNb-ELISA demonstrates a detection limit (LOD) of 3.56 × 104 CFU/mL, which is 16-fold lower than that of FbBio-ELISA and similar to FbP-ELISA. Moreover, a fenobody and nanobody sandwich chemiluminescent enzyme immunoassay (FbNb-CLISA) was developed by replacing the TMB chromogenic substrate with luminal, resulting in a 12-fold reduction in the LOD. Overall, the ferritin-displayed technology represents a promising methodology for enhancing the detection performance of nanobody-based sandwich ELISAs, thereby expanding the applicability of Nbs in food detection and other fields requiring multivalent modification.
Assuntos
Ensaio de Imunoadsorção Enzimática , Ferritinas , Salmonella , Anticorpos de Domínio Único , Ferritinas/imunologia , Ferritinas/química , Ferritinas/genética , Anticorpos de Domínio Único/química , Anticorpos de Domínio Único/genética , Anticorpos de Domínio Único/imunologia , Salmonella/imunologia , Salmonella/genética , Ensaio de Imunoadsorção Enzimática/métodos , Limite de Detecção , Afinidade de Anticorpos , Anticorpos Antibacterianos/imunologia , Imunoensaio/métodosRESUMO
BACKGROUND: Salmonella, a foodborne pathogen poses significant threats to food safety and human health. Immunochromatographic (ICTS) sensors have gained popularity in the field of food safety due to their convenience, speed, and cost-effectiveness. However, most existing ICTS sensors rely on antibody sandwich structures which are limited by their dependence on high-quality paired antibodies and restricted sensitivity. For the first time, we combined multi-line ICTS strips with fluorescent bacterial probes to develop a label-free multi-line immunochromatographic sensor capable of detecting broad-spectrum Salmonella. Salmonella was labeled with the aggregation-induced luminescence material TCBPE, resulting in its transformation into a green fluorescent probe. RESULTS: Using this sensor, we successfully detected Salmonella typhimurium within the concentration range of 104-108 CFU/mL with a visual detection limit of 6.0 × 104 CFU/mL. Compared to single-line sensors, our multi-line sensor exhibited significantly improved fluorescence intensity resulting in enhanced detection sensitivity by 50 %. Furthermore, our developed multi-line ICTS sensor demonstrated successful detection of 18 different strains of Salmonella without any cross-reaction observed with 5 common foodborne pathogens tested. The applicability and reliability were validated using milk samples, cabbage juice samples as well and drinking water samples suggesting its potential for rapid and accurate detection of Salmonella in real-world scenarios across both the food industry and clinical settings. SIGNIFICANCE: In this experiment, we developed a TCBPE-based multiline immunochromatographic sensor. Specifically, Salmonella was labeled with the aggregation-induced luminescence material TCBPE, resulting in its transformation into a green fluorescent probe. Through the multi-line analysis system, the detection sensitivity and accuracy of the sensor are improved. In brief, the sensor does not require complex antibody labeling and paired antibodies, and only one antibody is needed to complete the detection process.
Assuntos
Cromatografia de Afinidade , Cromatografia de Afinidade/métodos , Cromatografia de Afinidade/instrumentação , Leite/microbiologia , Leite/química , Microbiologia de Alimentos , Animais , Corantes Fluorescentes/química , Salmonella/isolamento & purificação , Salmonella/imunologia , Contaminação de Alimentos/análise , Limite de Detecção , Salmonella typhimurium/isolamento & purificação , Salmonella typhimurium/imunologia , Brassica/química , Brassica/microbiologiaRESUMO
Immune-checkpoint blockade (ICB) reinvigorates T cells from exhaustion and potentiates T-cell responses to tumors. However, most patients do not respond to ICB therapy, and only a limited response can be achieved in a "cold" tumor with few infiltrated lymphocytes. Synthetic biology can be used to engineer bacteria as controllable bioreactors to synthesize biotherapeutics in situ. We engineered attenuated Salmonella VNP20009 with synthetic gene circuits to produce PD-1 and Tim-3 scFv to block immunosuppressive receptors on exhausted T cells to reinvigorate their antitumor response. Secreted PD-1 and Tim-3 scFv bound PD-1+ Tim-3+ T cells through their targeting receptors in vitro and potentiated the T-cell secretion of IFN-γ. Engineered bacteria colonized the hypoxic core of the tumor and synthesized PD-1 and Tim-3 scFv in situ, reviving CD4+ T cells and CD8+ T cells to execute an antitumor response. The bacteria also triggered a strong innate immune response, which stimulated the expansion of IFN-γ+ CD4+ T cells within the tumors to induce direct and indirect antitumor immunity.
Assuntos
Inibidores de Checkpoint Imunológico , Receptor de Morte Celular Programada 1 , Salmonella , Inibidores de Checkpoint Imunológico/farmacologia , Animais , Receptor de Morte Celular Programada 1/metabolismo , Receptor de Morte Celular Programada 1/imunologia , Camundongos , Salmonella/imunologia , Salmonella/genética , Receptor Celular 2 do Vírus da Hepatite A/metabolismo , Receptor Celular 2 do Vírus da Hepatite A/genética , Linhagem Celular Tumoral , Linfócitos T CD8-Positivos/imunologia , Humanos , Interferon gama/metabolismo , Interferon gama/imunologia , Anticorpos de Cadeia Única/imunologia , Anticorpos de Cadeia Única/genética , Anticorpos de Cadeia Única/farmacologia , Camundongos Endogâmicos C57BL , Biologia Sintética/métodos , Linfócitos T CD4-Positivos/imunologia , Imunoterapia/métodosRESUMO
Antimicrobial resistance (AMR) poses a significant threat to human health. Although vaccines have been developed to combat AMR, it has proven challenging to associate specific vaccine antigens with AMR. Bacterial plasmids play a crucial role in the transmission of AMR. Our recent research has identified a group of bacterial plasmids (specifically, IncHI plasmids) that encode large molecular mass proteins containing bacterial immunoglobulin-like domains. These proteins are found on the external surface of the bacterial cells, such as in the flagella or conjugative pili. In this study, we show that these proteins are antigenic and can protect mice from infection caused by an AMR Salmonella strain harboring one of these plasmids. Furthermore, we successfully generated nanobodies targeting these proteins, that were shown to interfere with the conjugative transfer of IncHI plasmids. Considering that these proteins are also encoded in other groups of plasmids, such as IncA/C and IncP2, targeting them could be a valuable strategy in combating AMR infections caused by bacteria harboring different groups of AMR plasmids. Since the selected antigens are directly linked to AMR itself, the protective effect extends beyond specific microorganisms to include all those carrying the corresponding resistance plasmids.
Assuntos
Farmacorresistência Bacteriana , Plasmídeos , Animais , Plasmídeos/genética , Camundongos , Farmacorresistência Bacteriana/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/metabolismo , Antibacterianos/farmacologia , Anticorpos de Domínio Único/imunologia , Anticorpos de Domínio Único/genética , Anticorpos de Domínio Único/farmacologia , Antígenos de Bactérias/imunologia , Antígenos de Bactérias/genética , Feminino , Salmonella/genética , Salmonella/imunologia , Salmonella/efeitos dos fármacos , Imunoglobulinas/genética , Imunoglobulinas/imunologia , Camundongos Endogâmicos BALB CRESUMO
Coturniculture has increased significantly in the last decades. There are several pathogens that can affect these birds. Among the diseases, fowl typhoid stands out as a disease with a potentially great impact to the poultry industry. The objective of this the study was to evaluate the effect of doses and administration routes of live 9R vaccine on protection of Japanese quails against experimental infection with Salmonella Gallinarum (SG). Two hundred and fifty birds were used, divided into five groups: G1, oral vaccination with one dose; G2, oral vaccination with 2 doses; G3, subcutaneous vaccination with one dose; G4, subcutaneous vaccination with two doses and G5 not vaccinated. All birds from all five groups were challenged with SG at an age of 45 days. SG was quantified in the periods of one, four, seven and twelve days after the challenge. The presence of clinical signs and macroscopic lesions of the disease were observed. The groups vaccinated by subcutaneous route had a higher egg production and lower mortality rate. Birds receiving a dose of the vaccine by subcutaneous route also showed lower amount of SG in the liver and spleen seven days after the challenge.(AU)
A coturnicultura tem aumentado significativamente nas últimas décadas. Existem vários patógenos que podem afetar essas aves. Entre as doenças, o tifo aviário se destaca como uma doença de grande impacto para a indústria avícola. O objetivo deste estudo foi avaliar o efeito de doses e vias de administração da vacina viva 9R na proteção de codornas japonesas contra infecção experimental por Salmonella Gallinarum (SG). Foram utilizadas duzentos e cinquenta aves, divididas em cinco grupos: G1, vacinação oral com uma dose; G2, vacinação oral com 2 doses; G3, vacinação subcutânea com uma dose; G4, vacinação subcutânea com duas doses e G5 não vacinado. Todas as aves dos cinco grupos foram desafiadas com SG aos 45 dias de idade. A SG foi quantificada nos períodos de um, quatro, sete e doze dias após o desafio. Foi observada a presença de sinais clínicos e lesões macroscópicas da doença. Os grupos vacinados por via subcutânea apresentaram maior produção de ovos e menor taxa de mortalidade. Aves recebendo uma dose da vacina por via subcutânea também apresentaram menor quantidade de SG no fígado e baço sete dias após o desafio.(AU)
Assuntos
Animais , Salmonella/imunologia , Vacinas/administração & dosagem , Vias de Administração de Medicamentos/veterinária , Coturnix/imunologiaRESUMO
A diversificação da produção industrial de alimentos de origem suína e o intercâmbio comercial de animais e seus derivados destinados ao consumo humano podem ser importantes disseminadores de sorovares de Salmonella spp. na cadeia alimentar. Objetivou-se avaliar em 86 cepas de Salmonella spp., isoladas em granja de terminação e no abate de suínos, a ocorrência de três genes de virulência (invA, agfA e lpfA), bem como a similaridade genética entre elas. A ocorrência do gene invA foi verificada em 100% das amostras. O gene lpfA foi detectado em 80,23% (69/86) das cepas, não foi detectado em S. Panama e estava presente em todas as cepas de S. Infantis. O gene agfA foi detectado em 63,95% (55/86) das amostras. S. Agona apresentou positividade para todos os genes de virulência estudados. A análise de homologia entre as cepas agrupou os diferentes sorovares em clusters. A similaridade foi independente do local de isolamento, o que demonstra a presença de clones ao longo da cadeia de produção e a existência de multiplicidade de fontes para a infecção dos animais, como a ração, e a contaminação cruzada das carcaças. A pesquisa de genes de virulência e a avaliação da proximidade gênica permitem a caracterização e um maior entendimento sobre cepas de Salmonella circulantes na cadeia produtiva de suínos e, assim, podem subsidiar medidas de controle durante o processo produtivo com o objetivo de garantir a saúde do consumidor...
The diversification of industrial food production of swine origin and trade of animals and their derivatives for human consumption may be important disseminators of serovars of Salmonella spp. in the food chain. This study aimed to evaluate 86 strains of Salmonella spp. isolated form in the finishing and slaughter of pigs, the occurrence of three virulence genes (invA, agfa and lpfA), as well as the genetic similarity between them. The occurrence of gene invA was observed in 100% of the samples. The gene lpfA was detected in 80.23% (69/86) strains and is not detected in S. Panama, but present in all strains of S. Infantis. The gene agfA was detected in 63.95% (55/86). S. Agona was positive for all virulence genes studied. The analysis of homology between the different serovars grouped the isolates in clusters. The similarity was regardless of the location of isolation, demonstrating the presence of clones along the production chain and that there are multiple sources for the infection of animals, such as feed, and cross-contamination of carcasses. A survey of virulence genes and evaluation of gene proximity allow characterization and better understanding of Salmonella strains circulating in the pig production chain, thus being able to support control measures during the production process in order to ensure consumer health...
Assuntos
Animais , Homologia de Genes , Suínos , Salmonella/imunologia , Salmonella/virologia , Indicadores de Contaminação/prevenção & controle , Indústria da Carne , Virulência , Fatores de VirulênciaRESUMO
O desenvolvimento dos imunoensaios enzimáticos (ELISA) aplicados à detecçäo de Salmonella em alimentos foi revisto, com ênfase sobre os pontos críticos que podem afetar o desempenho e aceitaçäo do método, tais como: produçäo de anti-soros policlonais e monoclonais anti-Salmonella, tipos de ELISA aplicados à detecçäo de Salmonella, sensibilidade e técnica de elevaçäo, Kits disponíveis e situaçäo oficial do método atualmente
Assuntos
Antígenos de Bactérias/imunologia , Ensaio de Imunoadsorção Enzimática , Microbiologia de Alimentos , Salmonella/imunologia , Complexo Antígeno-Anticorpo , Técnicas Imunoenzimáticas , Sensibilidade e EspecificidadeRESUMO
Cinquenta amostras de misturas prontas destinadas ao tempero de alimentos, denominadas "Tempero pronto", a venda nos supermercados da cidade de Säo Paulo, foram submetidas a análise microbiológica para verificaçäo da presença de bactérias causadoras de toxinfecçöes alimentares e para determinaçäo dos níveis de contaminaçäo por microrganismos deteriorantes. Estes produtos säo compostos principalmente de cebola, alho, tomate, óleo, salsinha, pimentäo e diversos condimentos (sal, pimenta do reino, orégano, entre outros). Em nenhuma das amostras foi detectada a presença de Salmonella sp, Staphylococcus aureus, Escherichia coli (como também coliformes fecais) e clostrídios sulfito-redutores. Bacillus cereus e bolores e leveduras foram detectados em 5 amostras, em níveis inferiores a 300 UFC/g. Bactérias esporulantes anaeróbias também näo foram observadas. As bactérias esporulantes anaeróbias também näo foram observadas. As bactérias aeróbias mesófilas variaram entre 10**1 e 10**5 UFC/g, as bactérias aeróbias termófilas e as bactérias esporulantes aeróbias mesófilas entre 10**1 e 10**4UFC/g
Assuntos
Salmonella/imunologia , Staphylococcus aureus/imunologia , Bacillus cereus/imunologia , Enterobacteriaceae/imunologia , Escherichia coli/imunologia , Análise de Alimentos , Conservação de Alimentos , Leveduras , Brasil , Microbiologia de Alimentos , Contaminação de AlimentosRESUMO
Se realizó un estudio comparativo para la identificación de antígenos flagelares de Salmonella empleando el método de aglutinación en tubo con sueros de Spicer-Edwards y la reacción de coaglutinación utilizando proteína A de Staphylococcus aureus Cowan 1 (NCTC 8530). Se tipificaron por ambos métodos 39 serotipos de Salmonella pertenecientes a ocho serogrupos del esquema antigénico de Kauffman-White. Cada uno de los serogrupos incluía salmonelas de los diferentes serotipos monofásicos y bifásicos. El análisis estadístico de los resultados demostró que la reacción de coaglutinación tuvo mayor sensibilidad y especificidad para la detección de antígenos flagelares que la reacción clásica de aglutinación en tubo. El uso de menor cantidad de antisueros para detectar antígenos de Salmonella sin pérdida de sensibilidad y/o especificidad en la prueba de coaglutinación representa un ahorro importante para laboratorios clínios y de investigación epidemiológica que requieren de la identificación de estos microorganismos
Assuntos
Aglutinação , Soros Imunes/administração & dosagem , Proteínas de Bactérias/isolamento & purificação , Salmonella/classificação , Soros Imunes/classificação , Soros Imunes/imunologia , Proteínas de Bactérias/imunologia , Proteínas de Bactérias , Salmonella/imunologia , Salmonella/patogenicidadeRESUMO
Salmonella spp é um dos microrganismos patogênicos de relevância em alimentos. Sua detecção em alimentos por metodologia de cultura é trabalhosa e demorada, o que explica a grande variedade de sistemas automatizados e kits para detecção rápida desse patógeno existentes no mercado. Muitos desses métodos alternativos são validados por organizações internacionalmente reconhecidas, mas tais validações têm sido efetuadas em condições laboratoriais artificiais e com matrizes alimentares experimentalmente contaminadas, dificilmente refletindo a realidade de um laboratório de rotina de análises microbiológicas de alimentos. Nesse trabalho, avaliou-se o desempenho de sete métodos rápidos alternativos genotípicos e imunológicos, usados simultaneamente para detecção de Salmonella spp em 244 amostras de alimentos sem contaminação experimental, empregando o método de cultura ISO 6579:2002 como método de referência. Os métodos avaliados foram BAX Salmonella, VIDAS Salmonella, Transia Plate Salmonella Gold, VIP Salmonella, TECRA UNQUIQUE SALMONELLA, Singlepath Salmonella e 1-2 Test. O nível de detecção para cada método também foi-determinado. O método de referência detectou 50 amostras (20,5%) positivas para Salmonella spp. Nas condições em que o trabalho foi realizado, a porcentagem de concordância dos resultados positivos obtidos pelos métodos alternativos avaliados, em relação aos obtidos pelo método ISO 6579:2002 variou de 42,3% a 100%, dependendo do método avaliado e da matriz alimentar analisada...