A novel vaccine strategy against Brucellosis using Brucella abortus multi-epitope OMPs vaccine based on Lactococcus lactis live bacterial vectors.

Brucella infections typically occur in mucosal membranes, emphasizing the need for mucosal vaccinations. This study evaluated the effectiveness of orally administering Lactococcus lactis (L. lactis) for producing the Brucella abortus multi-epitope OMPs peptide. A multi-epitope plasmid was generated through a reverse vaccinology method, and mice were administered the genetically modified L. lactis orally as a vaccine. The plasmid underwent digestion, synthesizing a 39 kDa-sized protein known as OMPs by the target group. The sera of mice that were administered the pNZ8124-OMPs-L. lactis vaccine exhibited a notable presence of IgG1 antibodies specific to outer membrane proteins (OMPs), heightened levels of interferon (IFN-λ) and tumor necrosis factor alpha (TNF-α), and enhanced transcription rates of interleukin 4 (IL-4) and interleukin 10 (IL-10). The spleen sections from the pNZ8124-OMPs-L. lactis and IRIBA group had less morphological damage associated with inflammation, infiltration of lymphocytes, and lesions to the spleen. The findings present a novel approach to utilizing the food-grade, non-pathogenic L. lactis as a protein cell factory to synthesize innovative immunological candidate OMPs. This approach offers a distinctive way to evaluate experimental medicinal items' practicality, safety, affordability, and long-term sustainability.

A subunit vaccine based on Brucella rBP26 induces Th1 immune responses and M1 macrophage activation.

Brucellosis is a global zoonotic infection caused by Brucella bacteria, which poses a significant burden on society. While transmission prevention is currently the most effective method, the absence of a licenced vaccine for humans necessitates the urgent development of a safe and effective vaccine. Recombinant protein-based subunit vaccines are considered promising options, and in this study, the Brucella BP26 protein is expressed using prokaryotic expression systems. The immune responses are evaluated using the well-established adjuvant CpG-ODN. The results demonstrate that rBP26 supplemented with a CpG adjuvant induces M1 macrophage polarization and stimulates cellular immune responses mediated by Th1 cells and CD8 + T cells. Additionally, it generates high levels of rBP26-specific antibodies in immunized mice. Furthermore, rBP26 immunization activates, proliferates, and produces cytokines in T lymphocytes while also maintaining immune memory for an extended period of time. These findings shed light on the potential biological function of rBP26, which is crucial for understanding brucellosis pathogenesis. Moreover, rBP26 holds promise as an effective subunit vaccine candidate for use in endemic areas.

What risk do Brucella vaccines pose to humans? A systematic review of the scientific literature on occupational exposure.

BACKGROUND: Currently, vaccination of livestock with attenuated strains of Brucella remains an essential measure for controlling brucellosis, although these vaccines may be dangerous to humans. The aim of this study was to review the risk posed to humans by occupational exposure to vaccine strains and the measures that should be implemented to minimize this risk. METHODS: This article reviewed the scientific literature indexed in PubMed up to September 30, 2023, following "the PRISMA guidelines". Special emphasis was placed on the vaccine strain used and the route of exposure. Non-occupational exposure to vaccine strains, intentional human inoculation, publications on exposure to wild strains, and secondary scientific sources were excluded from the study. RESULTS: Nineteen primary reports were found and classified in three subgroups: safety accidents in vaccine factories that led to an outbreak (n = 2), survellaince studies on vaccine manufacturing workers with a serologic diagnosis of Brucella infection (n = 3), and publications of infection by vaccine strains during their administration, including case reports, records of occupational accidents and investigations of outbreaks in vaccination campaigns (n = 14). Although accidental exposure during vaccine manufacturing were uncommon, they could provoke large outbreaks through airborne spread with risk of spread to the neighboring population. Besides, despite strict protection measures, a percentage of vaccine manufacturing workers developed positive Brucella serology without clinical infection. The most frequent type of exposure with symptomatic infection was needle injury during vaccine administration. Prolonged contact with the pathogen, lack of information and a low adherence to personal protective equipment (PPE) use in the work environment were commonly associated with infection. CONCLUSIONS: Brucella vaccines pose occupational risk of contagion to humans from their production to their administration to livestock, although morbidity is low and deaths were not reported. Recommended protective measures and active surveillance of exposed workers appeared to reduce this risk. It would be advisable to carry out observational studies and/or systematic registries using solid diagnostic criteria.

Protective Effects against Brucella abortus 544 Infection in a Murine Macrophage Cell Line and in a Mouse Model via Treatment with Sirtuin 1 Activators Resveratrol, Piceatannol and Ginsenoside Rg3.

Brucellosis is a contagious zoonotic disease that infects millions of people annually with hundreds of millions more being exposed. It is caused by Brucella, a highly infectious bacterial species capable of infecting humans with an estimated dose of 10-100 organisms. Sirtuin 1 (SIRT1) has been reported to contribute to prevention of viral diseases as well as a chronic infection caused by Mycobacterium bovis. Here, we investigated the role of SIRT1 in the establishment of Brucella abortus infection in both in vitro and in vivo systems using the reported SIRT1 activators resveratrol (RES), piceatannol (PIC), and ginsenoside Rg3 (Rg3). In RAW264.7 cells, SIRT1 activators did not alter the adherence of Brucella or Salmonella Typhimurium. However, reduced uptake of Brucella was observed in cells treated with PIC and Rg3, and survival of Brucella within the cells was only observed to decrease in cells that were treated with Rg3, while PIC treatment reduced the intracellular survival of Salmonella. SIRT1 treatment in mice via oral route resulted in augmented Brucella resistance for PIC and Rg3, but not RES. PIC treatment favors Th2 immune response despite reduced serum proinflammatory cytokine production, while Rg3-treated mice displayed high IL-12 and IFN-γ serum production. Overall, our findings encourage further investigation into the complete mechanisms of action of the different SIRT1 activators used as well as their potential benefit as an effective alternative approach against intracellular and extracellular pathogens.

Clearance of bacteria from lymph nodes in sheep immunized with Brucella suis S2 vaccine is associated with M1 macrophage activation.

Ovine brucellosis is a global zoonotic disease of sheep caused by Brucella melitensis, which inflicts a significant burden on human and animal health. Brucella suis strain S2 (B. suis S2) is a smooth live attenuated vaccine for the prevention of ovine brucellosis in China. However, no previous studies have assessed the immunogenicity of B. suis S2 vaccine after oral immunization in sheep. Here, we attempted to evaluate the ovine immune response over the course of B. suis S2 immunization and to identify in vivo predictors for vaccine development. Body temperature, serum Brucella antibodies, serum cytokines (IL-12p70 and interferon [IFN]-γ), and bacterial load in the mandibular lymph nodes (LN), superficial cervical LN, superficial inguinal LN, and spleen were investigated to determine the safety and efficacy of the vaccine. The abnormal body temperature of sheep occurred within 8 days post-infection (dpi). Brucella suis S2 persisted for a short time (< 21 dpi) in the mandibular LN. The highest level of IL-12p70 was observed at 9 dpi, whereas serum IFN-γ levels peaked at 12 dpi. Transcriptome analysis and quantitative reverse transcription PCR were performed to determine gene expression profiles in the mandibular LN of sheep. Antigen processing and presentation pathway was the dominant pathway related to the dataset. Our studies suggest that the immune response in ovine LN resembled type 1 immunity with the secretion of IL-12p70 and IFN-γ after B.suis S2 immunization and the vaccine may eliminate Brucella via stimulation of M1 macrophages through the course of Th cells.

Live mucosal vaccination stimulates potent protection via varied CD4+ and CD8+ T cell subsets against wild-type Brucella melitensis 16M challenge.

Re-emerging zoonotic pathogen Brucella spp. continues to impact developing countries and persists in expanding populations of wildlife species in the US, constantly threatening infection of our domestic herds. The development of improved animal and human vaccines remains a priority. In this study, immunity to a novel live attenuated B. melitensis strain, termed znBM-mC, was characterized. An oral prime, intranasal (IN) boost strategy conferred exquisite protection against pulmonary challenge, with wild-type (wt) B. melitensis providing nearly complete protection in the lungs and spleens from brucellae colonization. Vaccination with znBM-mC showed an IFN-γ+ CD8+ T-cell bias in the lungs as opposed to Rev 1-vaccinated mice showing IFN-γ+ CD4+ T-cell inclination. Lung CD4+ and CD8+ effector memory T cells (TEMs) increased over 200-fold; and lung CD4+ and CD8+ resident memory T cells (TRMs) increased more than 250- and 150-fold, respectively. These T cells served as the primary producers of IFN-γ in the lungs, which was essential for vaccine clearance and the predominant cytokine generated pre-and post-challenge with wt B. melitensis 16M; znBM-mC growth could not be arrested in IFN-γ-/- mice. Increases in lung TNF-α and IL-17 were also induced, with IL-17 being mostly derived from CD4+ T cells. Vaccination of CD4-/-, CD8-/-, and B6 mice with znBM-mC conferred full protection in the lungs and spleens post-pulmonary challenge with virulent B. melitensis; vaccination of IL-17-/- mice resulted in the protection of the lungs, but not the spleen. These data demonstrate the efficacy of mucosal vaccine administration for the generation of protective memory T cells against wt B. melitensis.

Ag85A, As an S2 Vaccine Carrier, Reduces the Toxicity of the S2 Vaccine and Enhances the Protective Ability of Mice against Brucella.

Brucella is a globally distributed zoonotic disease that can cause abortion and changes in immune function in humans and animals. At present, there is no good treatment plan for Brucella, and animals can only be treated harmlessly once they become ill, resulting in huge economic losses. Therefore, the prevention of Brucella infection is a very crucial step. Although a variety of Brucella vaccines have been widely used, they have varying degrees of shortcomings. For example, some Brucella vaccines have residual virulence, which leads to the emergence of Brucella in animals during the immunization process. Bacillus infection and other conditions occur. To further reduce the toxicity of the Brucella vaccine and enhance its protective effect on animals, this study used Antigen 85A (Ag85A) as a carrier of the Brucella vaccine to fuse with the Brucella S2 vaccine. The results of the study found that the S2-Ag85A oral Brucella vaccine could effectively reduce the toxicity residue of the S2 vaccine, stimulate the mice to produce a better immunogenic response, and effectively activate the expression levels of Brucella heterozygous IgG1 and IgG2a. Experiments have shown that the expression of IFN-γ in the peripheral blood serum and spleen of mice is significantly increased, and the expression levels of IL-1ß, TNF-α, and IL-6 are significantly reduced, which may indicate that S2-Ag85A oral Brucella vaccine could induce the expression of IFN-γ, thus downregulating the expression levels of IL-6 and TNF-α in the spleen tissue. The above results indicate that the S2-Ag85A oral vaccine is an effective attenuated vaccine for preventing Brucella infection.

Formyl peptide receptor 2 (FPR2) antagonism is a potential target for the prevention of Brucella abortus 544 infection.

Here, we explore the potential role of formyl peptide receptor 2 (FPR2) during Brucella abortus infection. FPR2 manipulation affected B. abortus internalization but not its growth within macrophages. During the activation of FPR2 induced by its agonist AGP-8694, a high level of Brucella uptake was accompanied by an increase in ERK phosphorylation, while intracellular survival at 24 h postincubation was observed to be associated with slightly reduced nitrite accumulation but augmented superoxide anion production. Attenuated secretion of IL-6 and IL-10 were observed 48 h postincubation in the bone marrow-derived macrophages (BMDMs) treated with the FPR2 antagonist WRW4. An opposite pattern of bacterial uptake was observed upon treatment with the FPR2 antagonist, but no significant changes in the activation of MAPKs or the production of nitrite or superoxide anion were observed. Interestingly, AGP-8694 treatment of mice did not lead to differences in spleen or liver weight but slightly enhanced bacterial proliferation was observed in the spleen. Although the weights of the spleen or liver did not differ, WRW4 treatment led to reduced bacterial proliferation in the spleen. Furthermore, FPR2 antagonist treatment was associated with high serum levels of the proinflammatory cytokines IL-12, TNF-α, IFN-γ and MCP-1, while the production of TNF-α was inhibited in AGP-8694-treated mice. IL-6 and IL-10 levels were slightly increased in AGP-8694-treated mice at 24 h postinfection. Our findings demonstrated the contribution of FPR2 via manipulating this receptor using its reported agonist AGP-8694 and antagonist WRW4 in both in vitro and in vivo systems. Although activation of the receptor did not consistently induced Brucella infection, FPR2 inhibition may be a promising strategy to treat brucellosis in animals which encourages further investigation.

Characteristics of Brucella abortus vaccine strain A19 reveals its potential mechanism of attenuated virulence.

Brucella vaccination is one of the most important strategies for controlling brucellosis in livestock. The A19 strain was the effective vaccine used to control brucellosis in China. However, the characteristics of physiological and attenuated virulence of the A19 strain are not investigated in detail. In this study, we compared the phenotypic characteristics of the A19 to the wild-type strain S2308. Virulence test showed that the A19 was significantly attenuated at chronic infection stage in infected mouse model. In growth analysis, the A19 exhibited a quick growth at exponential phase and premature at stationary phase. The inflammatory response of macrophages infected by the A19 was detected using TaqMan qPCR assay, indicating that the inflammatory level of the A19-infected macrophages was higher than that of the S2308 infection. Cell death analysis showed that the A19 was not cytotoxic for macrophages. Cell infection showed that the A19 reduced its ability to invade, survive and traffic within host cells, and the intracellular A19 hardly excludes lysosome-associated marker LAMP-1, suggesting that the A19 can't escape the lysosome degradation within host cells. In further study, the sensitivity test exhibited that the A19 is more sensitive to stress and bactericidal factors than the S2308 strain, Western blot and silver staining analysis exhibited that the A19 has a different expression pattern of OMPs and reduces LPS O-antigen expression relative to the S2308 strain. Those data give us a more detailed understanding about the A19 vaccine strain, which will be beneficial for improvement of current Brucella vaccine and overcoming its defects.

Epitope-Based Vaccine of a Brucella abortus Putative Small RNA Target Induces Protection and Less Tissue Damage in Mice.

Brucella spp. are Gram-negative, facultative intracellular bacteria that cause brucellosis in humans and animals. Currently available live attenuated vaccines against brucellosis still have drawbacks. Therefore, subunit vaccines, produced using epitope-based antigens, have the advantage of being safe, cost-effective and efficacious. Here, we identified B. abortus small RNAs expressed during early infection with bone marrow-derived macrophages (BMDMs) and an apolipoprotein N-acyltransferase (Int) was identified as the putative target of the greatest expressed small RNA. Decreased expression of Int was observed during BMDM infection and the protein sequence was evaluated to rationally select a putative immunogenic epitope by immunoinformatic, which was explored as a vaccinal candidate. C57BL/6 mice were immunized and challenged with B. abortus, showing lower recovery in the number of viable bacteria in the liver, spleen, and axillary lymph node and greater production of IgG and fractions when compared to non-vaccinated mice. The vaccinated and infected mice showed the increased expression of TNF-α, IFN-γ, and IL-6 following expression of the anti-inflammatory genes IL-10 and TGF-ß in the liver, justifying the reduction in the number and size of the observed granulomas. BMDMs stimulated with splenocyte supernatants from vaccinated and infected mice increase the CD86+ marker, as well as expressing greater amounts of iNOS and the consequent increase in NO production, suggesting an increase in the phagocytic and microbicidal capacity of these cells to eliminate the bacteria.

Administration of Exogenous Progesterone Protects Against Brucella abortus Infection-Induced Inflammation in Pregnant Mice.

Progesterone has been recognized as essential for the establishment and maintenance of pregnancy, and is typically known as an immunosuppressive agent. However, its effects on mediating Brucella infection-induced inflammation have not been evaluated. Here we demonstrated that Brucella abortus infection inhibits progesterone levels in the pregnant mouse by suppressing the production of progesterone by placenta. Progesterone treatment significantly reduced the secretion of inflammatory cytokines in serum, macrophages, and trophoblasts of B. abortus-infected mice, leading to decreased placentitis and enhancing the pup viability. Mechanistically, this decreased inflammatory response results from inhibition of NF-kB activation by progesterone. Moreover, progesterone treatment suppresses B. abortus growth within trophoblasts associated with an inability of bacteria to escape the late endosome compartment in vitro. Collectively, our data illustrate that progesterone treatment might be useful therapeutically in protection against placentitis or abortion caused by B. abortus infection.

Meta-analysis of brucellosis vaccinology in natural hosts / Meta-análise da vacinologia de brucelose em hospedeiros naturais

Brucellosis is a relevant zoonotic disease for which the most important tool for control is vaccination of susceptible animals. Assessment of vaccine efficacy in natural hosts is based on prevention of abortion and Brucella infection in organs of immunized animals. A meta-analysis of experimental vaccination of Brucella spp. natural hosts was performed, including 45 PubMed and/or Scopus-indexed publications, representing 116 individual experiments. Difference of risk was calculated as an indicator of protection, and a temporal analysis (1980-2016) demonstrated that experimental vaccines tested on natural hosts provided levels of protection that were stable over the past decades. The meta-regression model developed in this study included different vaccine categories (attenuated, inactivated, mutant, subunit, and vectored) considering the difference of risk as the dependent variable. The subcutaneous route of vaccination provided better protection when compared to the intramuscular and oral routes of vaccination. Surprisingly, inactivated vaccines provided better protection than live naturally attenuated vaccine strains (spontaneous mutations) that were considered the reference, whereas subunit vaccines provided lower levels of protection. This is the first meta-analysis of Brucella vaccinology in the natural hosts. These results are useful for the development of new vaccination protocols for controlling animal brucellosis.(AU)

Brucelose é uma doença zoonótica relevante, para a qual a vacinação de animais susceptíveis é a ferramenta mais importante de controle. Avaliação da eficácia vacinal em hospedeiros naturais é baseada na prevenção de aborto e da colonização de órgãos pela Brucella spp. em animais imunizados. Foi realizada meta-análise de estudos de vacinação experimental de Brucella spp. em hospedeiros naturais, incluindo 45 publicações indexadas pela PubMed e/ou Scopus, representando 116 experimentos individuais. Diferença de risco foi calculada como indicador de proteção e uma análise temporal (1980-2016) demonstrou que vacinas experimentais testadas em hospedeiros naturais promoveram níveis de proteção que foram estáveis ao longo das últimas décadas. O modelo de meta-regressão desenvolvido neste estudo incluiu diferentes categorias de vacinas (atenuada, inativada, mutante, subunidade e vetorial) considerando a diferença de risco como variável dependente. A via de vacinação subcutânea promoveu melhor proteção quando comparada às vias intramuscular e oral. Surpreendentemente, vacinas inativadas promoveram melhor proteção que vacinas vivas atenuadas (com mutações espontâneas) que foram consideradas como referência, enquanto vacinas de subunidades promoveram menor proteção. Este é o primeiro estudo de meta-análise da vacinologia de Brucella em hospedeiros naturais. Estes resultados são úteis para o desenvolvimento de novos protocolos vacinais para controle de brucelose animal.(AU)

Brucella ovis mutant in ABC transporter protects against Brucella canis infection in mice and it is safe for dogs.

BACKGROUND/OBJECTIVES: Vaccination is the most important tool for controlling brucellosis, but currently there is no vaccine available for canine brucellosis, which is a zoonotic disease of worldwide distribution caused by Brucella canis. This study aimed to evaluate protection and immune response induced by Brucella ovis ΔabcBA (BoΔabcBA) encapsulated with alginate against the challenge with Brucella canis in mice and to assess the safety of this strain for dogs. METHODS: Intracellular growth of the vaccine strain BoΔabcBA was assessed in canine and ovine macrophages. Protection induced by BoΔabcBA against virulent Brucella canis was evaluated in the mouse model. Safety of the vaccine strain BoΔabcBA was assessed in experimentally inoculated dogs. RESULTS: Wild type B. ovis and B. canis had similar internalization and intracellular multiplication profiles in both canine and ovine macrophages. The BoΔabcBA strain had an attenuated phenotype in both canine and ovine macrophages. Immunization of BALB/c mice with alginate-encapsulated BoΔabcBA (108 CFU) induced lymphocyte proliferation, production of IL-10 and IFN-γ, and protected against experimental challenge with B. canis. Dogs immunized with alginate-encapsulated BoΔabcBA (109 CFU) seroconverted, and had no hematologic, biochemical or clinical changes. Furthermore, BoΔabcBA was not detected by isolation or PCR performed using blood, semen, urine samples or vaginal swabs at any time point over the course of this study. BoΔabcBA was isolated from lymph nodes near to the site of inoculation in two dogs at 22 weeks post immunization. CONCLUSION: Encapsulated BoΔabcBA protected mice against experimental B. canis infection, and it is safe for dogs. Therefore, B. ovis ΔabcBA has potential as a vaccine candidate for canine brucellosis prevention.

Insights into irr and rirA gene regulation on the virulence of Brucella melitensis M5-90.

Iron is a fundamental element required by most organisms, including Brucella. Several researchers have suggested that the iron response regulator (irr) and rhizobial iron regulator (rirA) genes regulate iron acquisition by Brucella abortus, influencing heme synthesis by and virulence of this pathogen. However, little is known about another Brucella species, Brucella melitensis. In this research, we successfully constructed two mutants: M5-90Δirr and M5-90ΔrirA. The adhesion, invasion, and intracellular survivability of these two mutants were evaluated in RAW264.7 cells infected with 1 × 106 CFU of M5-90Δirr, M5-90ΔrirA, or M5-90. We also tested the sensitivity of cells to hydrogen peroxide and their ability to grow. In addition, the virulence of these two mutants was evaluated in BALB/c mice. The results showed that the ability of these two mutants to invade and adhere inside the murine macrophages RAW264.7 was attenuated but their ability to replicate intracellularly was strengthened, enhancing the resistance to hydrogen peroxide. The M5-90Δirr mutant showed stronger growth ability than the parental strain under iron-limiting conditions. No differences were observed in the number of bacteria in spleen between M5-90 and M5-90Δirr at 7 or 15 days postinfection. However, the number of M5-90ΔrirA in spleen reduced significantly at 15 days postinfection. The splenic index of the M5-90Δirr group is evidently lower than that of M5-90. This is the first report that irr and rirA genes of B. melitensis are associated not only with virulence but also with growth ability. Together, our data suggest that M5-90Δirr is a promising Brucella vaccine candidate.

Mannosylated chitosan nanoparticles loaded with FliC antigen as a novel vaccine candidate against Brucella melitensis and Brucella abortus infection.

Brucellosis is a worldwide bacterial zoonosis disease. Live attenuated Brucella vaccines have several drawbacks. Thus development of a safe and effective vaccine for brucellosis is a concern of many scientists. FliC protein contributes in virulence of Brucella; hence, it is a promising target for brucellosis vaccine. In this study, Mannosylated Chitosan Nanoparticles (MCN) loaded with FliC protein were synthesized as a targeted vaccine delivery system. The immunogenicity and protective efficacy of FliC and FliC-MCN against Brucella infection were evaluated in BALB/c mice. After cloning, expression and purification, FliC protein was loaded on MCN. The particle size, loading efficiency and in vitro release of the NPs were determined. Our investigation revealed that FliC and FliC-MCN could significantly increase specific IgG response (higher IgG2a titers). Besides, spleen cells from immunized mice produced high level of IFN-γ and IL-2 and low level IL-10 cytokines. Immunization with FliC and FliC-MCN conferred significant degree of protection against B. melitensis 16 M and B. abortus 544 infections. Overall these results indicate that FliC protein would be a novel potential antigen candidate for the development of a subunit vaccine against B. melitensis and B. abortus. Moreover, MCN could be used as an adjuvant and targeted vaccine delivery system.

Pathogenic potential of Brucella ovis field isolates with different genotypic profile and protection provided by the vaccine strain B. ovis ΔabcBA against B. ovis field isolates in mice / Vacina viva atenuada Brucella ovis Δ abcBA encapsulada protege camundongos frente a desafios de B. ovis isoladas de campo

Brucella ovis causes economic and reproductive losses in sheep herds. The goal of this study was to characterize infection with B. ovis field isolates in a murine model, and to evaluate protection induced by the candidate vaccine strain B. ovis ΔabcBA in mice challenged with these field isolates. B. ovis field strains were able to colonize and cause lesions in the liver and spleen of infected mice. After an initial screening, two strains were selected for further characterization (B. ovis 94 AV and B. ovis 266 L). Both strains had in vitro growth kinetics that was similar to that of the reference strain B. ovis ATCC 25840. Vaccination with B. ovis ΔabcBA encapsulated with 1% alginate was protective against the challenge with field strains, with the following protection indexes: 0.751, 1.736, and 2.746, for mice challenged with B. ovis ATCC25840, B. ovis 94 AV, and B. ovis 266 L, respectively. In conclusion, these results demonstrated that B. ovis field strains were capable of infecting and inducing lesions in experimentally infected mice. The attenuated vaccine strain B. ovis ΔabcBA induced protection in mice challenged with different B. ovis field isolates, resulting in higher protection indexes against more pathogenic strains.(AU)

Brucella ovis é responsável por perdas econômicas e reprodutivas em rebanhos ovinos. O objetivo deste trabalho foi caracterizar a infecção com as cepas isoladas de campo de B. ovis em modelo murino e avaliar a eficiência vacinal da mutante B. ovis ΔabcAB para proteção contra desafio com as cepas isoladas de campo. Foram utilizadas sete cepas isoladas de campo foram capazes de colonizar e provocar lesões no fígado e no baço de camundongos após sete dias pós-infecção. Após triagem, duas cepas foram selecionadas para a melhor caracterização (B. ovis 94 AV and B. ovis 266L). Ambas apresentaram crescimento em placa de cultivo semelhante ao da cepa de referência B. ovis ATCC 25840. A vacinação com a cepa de Brucella ovis ΔabcBA encapsulada com alginato a 1% foi capaz de proteger camundongos desafiados com as cepas isoladas de campo, com os seguintes índices de proteção: 0,751, 1,736 e 2,746, para camundongos desafiados com B. ovis ATCC 25840, B. ovis 94 AV e B. ovis 266 L, respectivamente. Estes resultados demonstraram que as cepas isoladas de campo de B. ovis são capazes de infectar e induzir lesão em camundongos experimentalmente infectados. O uso da cepa mutante atenuada B. ovis ΔabcBA para vacinação de fêmeas C57BL/6 desafiados com diferentes cepas de B. ovis induziu proteção nos camundongos desafiados com diferentes cepas de B. ovis. Deste modo, mostrando-se eficiente na proteção das cepas de campo de B. ovis.(AU)

ß-Sitosterol Contributes in the Resistance to Invasion and Survival of Brucella abortus 544 within RAW264.7 Cells, and Cytokine Production with Reduced Susceptibility to Infection in BALB/c Mice.

We previously identified ß-sitosterol (BS) as one of the most abundant compounds found in Korean red ginseng oil. BS is a widely prevalent vegetable-derived phytosterol with many known health benefits. Here, we investigated the efficacy of BS against Brucella (B.) abortus infection. BS showed no effect on bacterial growth but attenuated internalization, intracellular survival and MAPKs-linked intracellular signaling in RAW264.7 cells. BS treatment in cells is also associated with increased nitrite concentration during infection at 24 h. Slightly enhanced resistance to B. abortus infection was observed in mice orally given BS, which could be mediated by induced production of proinflammatory cytokines. Taken together, our study demonstrates the contribution of BS treatment against B. abortus infection although further investigation is encouraged to maximize its beneficial effects against intracellular infection.

Deletion of the LuxR-type regulator VjbR in Brucella canis affects expression of type IV secretion system and bacterial virulence, and the mutant strain confers protection against Brucella canis challenge in mice.

Brucella spp. are facultative intracellular pathogens and zoonotic agents which pose a huge threat to human health and animal husbandry. The B. melitensis, B. abortus, and B. suis cause undulant fever and influenza-like symptoms in humans. However, the effects of B. canis have not been extensively studied. The quorum sensing-dependent transcriptional regulator VjbR influences the Brucella virulence in smooth type Brucella strains, such as B. melitensis, B. abortus and rough type Brucella ovis. However, the function of VjbR in the rough-type B. canis is unknown. In the present study, we discovered that deletion of this regulator significantly affected Brucella virulence in macrophage and mice infection models. The expression levels of virB operon and the ftcR gene were significantly altered in the vjbR mutant strain. We further investigated the protective effect of different doses of the vjbR mutant in mice and the results indicated that VjbR conferred protection against the virulent B. canis strain. This study presents the first evidence that the transcriptional regulator VjbR has important function in B. canis. In addition, according to its reduced virulence and the protective immunity it induces in mice, it can be a potential live attenuated vaccine against B. canis.

Zoonosis and veterinary waste disposal in rural practice / Zoonosis y disposición de desperdicios veterinarios en la práctica rural

The objectives of this study were to estimate: (a) the frequency of zoonoses in large animal veterinarians from rural areas of the province of Buenos Aires, Argentina, and (b) to describe the use and disposal of personal protective equipment (PPE) and selective veterinary clinical waste. A cross-sectional study was carried out on large animal veterinary practitioners in the Province of Buenos Aires (n = 106). One third (29.2%) of them had been diagnosed with a zoonosis by laboratory-methods, being brucellosis the most frequent (22.6%). The more years passed since their graduation, the greater the chances of becoming ill (p < 0.001). Gloves were the most adopted PPE; however, other elements had little or no use at all. Older and experienced professionals used PPE less frequently than young inexperienced practitioners. Some PPE was frequently reused and the final disposal of veterinary waste was often inappropriate. A change in behavior is an urgent need to preserve not only the veterinarians' health but also their families' wellbeing and to ensure proper disposal of potentially hazardous waste.

Los objetivos de este trabajo fueron los siguientes: a) estimar la frecuencia de zoonosis en veterinarios de grandes animales que desarrollan su labor en la provincia de Buenos Aires; b) describir el uso y la disposición de los elementos de protección personal (EPP) y otros residuos generados durante el trabajo de estos veterinarios. Para ello se realizó un estudio transversal en una muestra de 106 profesionales. En un tercio de ellos (29,2%) se había sido diagnosticado por métodos de laboratorio alguna zoonosis; la brucelosis fue la más frecuente (22,6%). Se encontró que a mayor tiempo transcurrido desde la graduación, mayor era la probabilidad de enfermarse (p< 0,001). Sobre la base de las respuestas obtenidas en cuestionarios estructurados, se determinó lo siguiente: que los guantes fueron el EPP más adoptado, mientras que otros elementos tuvieron escasa o nula adopción; que los profesionales de mayor edad y experiencia usaron EPP con menos frecuencia que los practicantes más jóvenes e inexpertos; y que algunos EPP se reutilizaban con frecuencia y que la eliminación final de los desechos veterinarios fue a menudo inapropiada. Considerando estos hallazgos, es claro que se requiere un cambio de comportamiento para preservar no solo la salud de los veterinarios, sino también para asegurar el bienestar de sus familias y garantizar la eliminación adecuada de los residuos potencialmente peligrosos.

Interplay of oxidative stress and antioxidant bio markers in oil adjuvant Brucella melitensis vaccinated and challenged mice.

The intracellular nature of Brucella leads to rise in oxidative stress due to bacterial invasion, particularly at the site of predilection spleen and lymph nodes. The present study aimed to evaluate the erythrocytic and tissue specific oxidative stress responses induced during oil adjuvant killed Brucella melitensis vaccination. The results of the study clearly implicated a significant increase in level of catalase, and superoxide dismutase (SOD) activity and lipid peroxidation (LPO), and total protein content in erythrocytes after vaccination. The activity of glutathione-S-transferase (GST) was unaltered during the period of experiment. The catalase activity and GSH content was significantly increased in lung and spleen tissues. The tissues GST levels increased significantly in all tissues, while tissue SOD level increased significantly only in lung tissues. Thus, it can be inferred that oil adjuvant based Brucella vaccine induces negligible signs of inflammatory pathophysiology and supports the development of significant level of protection against virulent Brucella challenge.