Comparative proteomic analysis of outer membrane vesicles from Brucella suis, Brucella ovis, Brucella canis and Brucella neotomae.

Gram-negative bacteria release nanovesicles, called outer membrane vesicles (OMVs), from their outer membrane. Proteomics has been used to determine their composition. OMVs contain proteins able to elicit an immune response, so they have been proposed as a model to develop acellular vaccines. In this study, OMVs of Brucella suis, B. ovis, B. canis, and B. neotomae were purified and analyzed by SDS-PAGE, transmission electron microscopy and liquid chromatography coupled to mass spectrometry to determine the pan-proteome of these vesicles. In addition, antigenic proteins were detected by western blot with anti-Brucella sera. The in silico analysis of the pan-proteome revealed many homologous proteins, such as Omp16, Omp25, Omp31, SodC, Omp2a, and BhuA. Proteins contained in the vesicles from different Brucella species were detected by anti-Brucella sera. The occurrence of previously described immunogenic proteins derived from OMVs supports the use of these vesicles as candidates to be evaluated as an acellular brucellosis vaccine.

Outer Membrane Vesicles From Brucella melitensis Modulate Immune Response and Induce Cytoskeleton Rearrangement in Peripheral Blood Mononuclear Cells.

Similar to what has been described in other Gram-negative bacteria, Brucella melitensis releases outer membrane vesicles (OMVs). OMVs from B. melitensis 16M and the rough-mutant B. melitensis VTRM1 were able to induce a protective immune response against virulent B. melitensis in mice models. The presence of some proteins which had previously been reported to induce protection against Brucella were found in the proteome of OMVs from B. melitensis 16M. However, the proteome of OMVs from B. melitensis VTRM1 had not previously been determined. In order to be better understand the role of OMVs in host-cell interactions, the aim of this work was to compare the proteomes of OMVs from B. melitensis 16M and the derived rough-mutant B. melitensis VTRM1, as well as to characterize the immune response induced by vesicles on host cells. Additionally, the effect of SDS and proteinase K on the stability of OMVs was analyzed. OMVs from B. melitensis 16M (smooth strain) and the B. melitensis VTRM1 rough mutant (lacking the O-polysaccharide side chain) were analyzed through liquid chromatography-mass spectrometry (LC-MS/MS). OMVs were treated with proteinase K, sodium deoxycholate, and SDS, and then their protein profile was determined using SDS-PAGE. Furthermore, PBMCs were treated with OMVs in order to measure their effect on cytoskeleton, surface molecules, apoptosis, DNA damage, proliferation, and cytokine-induction. A total of 131 proteins were identified in OMVs from B. melitensis16M, and 43 in OMVs from B. melitensis VTRM1. Proteome comparison showed that 22 orthologous proteins were common in vesicles from both strains, and their core proteome contained Omp31, Omp25, GroL, and Omp16. After a subsequent detergent and enzyme treatment, OMVs from B. melitensis VTRM1 exhibited higher sensitive compared to OMVs from the B. melitensis 16M strain. Neither OMVs induced IL-17, proliferation, apoptosis or DNA damage. Nonetheless, OMVs from the smooth and rough strains induced overproduction of TNFα and IL-6, as well as actin and tubulin rearrangements in the cytoskeleton. Moreover, OMVs from both strains inhibited PD-L1 expression in T-cells. These data revealed significant differences in OMVs derived from the rough and smooth Brucella strains, among which, the presence or absence of complete LPS appeared to be crucial to protect proteins contained within vesicles and to drive the immune response.

Mexican unpasteurised fresh cheeses are contaminated with Salmonella spp., non-O157 Shiga toxin producing Escherichia coli and potential uropathogenic E. coli strains: A public health risk.

Fresh cheeses are a main garnish of Mexican food. Consumption of artisanal fresh cheeses is very common and most of them are made from unpasteurised cow milk. A total of 52 fresh unpasteurised cheeses of five different types were purchased from a variety of suppliers from Tabasco, Mexico. Using the most probable number method, 67% and 63% of samples were positive for faecal coliforms and E. coli, respectively; revealing their low microbiological quality. General hygienic conditions and practices of traditional cheese manufacturers were poor; most establishments had unclean cement floors, all lacked windows and doors screens, and none of the food-handlers wore aprons, surgical masks or bouffant caps. After analysing all E. coli isolates (121 strains) for the presence of 26 virulence genes, results showed that 9 (17%) samples were contaminated with diarrheagenic E. coli strains, 8 harboured non-O157 Shiga toxin producing E. coli (STEC), and one sample contained both STEC and diffusely adherent E. coli strains. All STEC strains carried the stx1 gene. Potential uropathogenic E. coli (UPEC) strains were isolated from 15 (29%) samples; the most frequent gene combination was fimA-agn43. Two samples were contaminated with Salmonella. The results demonstrated that unpasteurised fresh cheeses produced in Tabasco are of poor microbiological quality and may frequently harbour foodborne pathogens. Food safety authorities in Mexico need to conduct more rigorous surveillance of fresh cheeses. Furthermore, simple and inexpensive measures as establishing programs emphasizing good hand milking practices and hygienic manufacturing procedures may have a major effect on improving the microbiological quality of these food items.

Partial Characterization of Bacteriocin Produced by Halotolerant Pediococcus acidilactici Strain QC38 Isolated from Traditional Cotija Cheese.

During a screening of lactic acid bacteria producing bacteriocin from Cotija cheese, the strain QC38 was isolated. Based on the 16S rRNA gene nucleotide sequencing (516 pb accession no KJ210322) and phylogenetic analysis, the isolate was identified as Pediococcus acidilactici. Neutralized cell-free supernatant was tested for antimicrobial activity against 17 Gram-negative and Gram-positive pathogens. Growth inhibition was achieved against Listeria monocytogenes (supplier or indication or source), Staphylococcus aureus, Vibrio vulnificus, Vibrio cholerae O1 Ogawa, Vibrio cholerae NO 01 and Salmonella enterica subsp. Enterica serovar Typhimurium. Bacteriocin-like substance, after heating at 121°C for 15 min it remained stable and its antimicrobial activity was observed at pH ranging from 1.0 to 10.0 but inactivated by α-chymotrypsin and proteinase K. Strain QC38 was able to grow in 1-9% NaCl concentration. The plate overlay assay showed an approximate size of bacteriocin-like substance between 3.4 and 6.5 kDa. P. acidilactici QC38 harboured a plasmid that contains a gene for a pediocin (PA-1).

[Comparison of the tests polymerase chain reaction, serology, and blood culture with respect to sensitivity and specificity for detection of Brucella spp in human samples]. / Comparación de las pruebas: reacción en cadena de la polimerasa (PCR), serología y hemocultivo con respecto a sensibilidad y especificidad, para la detección de Brucella spp en muestras humanas.

OBJECTIVE: The aim of this study was to evaluate the sensitivity and specificity of polymerase chain reaction for detection of Brucella spp in human blood samples compared with the serological tests and blood culture. MATERIAL AND METHODS: In 2005, a total of 92 people were sampled from the towns of Anahuac and Sabinas Hidalgo, Nuevo Leon, where an outbreak of human cases had taken place in the same year as this study. The sera collected were analyzed by serological tests according to the NOM 022-SS2-1994. DNA was obtained using CTAB extraction method and it was used to amplify a fragment of 223 bp of the coding sequence for a protein of 31 kDa present in all Brucella species. RESULTS: The polymerase chain reaction test detected 23 positive samples. The sensitivity and specificity compared with RB was 44.68 and 95.56%, respectively. Compared with mouse antibody production, it was 51.61 and 88.52%, and 2-mercaptoethanol was 53.57 and 87.50%. When isolation (positives cultures) was compared with polymerase chain reaction, we obtained 100.0% sensitivity and 80.23% specificity, taking into account people with positive and negative serology. CONCLUSIONS: The polymerase chain reaction test can be an alternative tool to bacterial culture in human brucellosis diagnosis.

Brucellosis outbreak in a rural endemic region of Mexico - a comprehensive investigation.

Brucellosis is a worldwide zoonotic disease. Generally, humans can be infected by either the consumption of raw milk and fresh cheeses made from unpasteurised milk or by contact with infected animals, mainly in endemic regions. In this study, we investigated a brucellosis outbreak in State of Guanajuato, an endemic region of Mexico. Microbiological culture of human blood, raw milk from cows and goats, and fresh cheeses was performed to isolate Brucella. Identification of the bacteria was done by bacteriological procedures and by multiplex Bruce-ladder polymerase chain reaction (PCR). Brucella melitensis was isolated from patients, infected goats, and fresh goat cheeses; while Brucella abortus was isolated from cows. All patients had eaten fresh cheese, but no occupational exposure to animals was reported. The results of molecular typing did not show any Brucella vaccine strains. The isolation, identification, and molecular characterisation of Brucella spp. in both human brucellosis cases and infected animals are very important to identify the source of infection and to take control measures in endemic regions.

A history of the development of Brucella vaccines.

Brucellosis is a worldwide zoonosis affecting animal and human health. In the last several decades, much research has been performed to develop safer Brucella vaccines to control the disease mainly in animals. Till now, no effective human vaccine is available. The aim of this paper is to review and discuss the importance of methodologies used to develop Brucella vaccines in pursuing this challenge.

Comparative genomic analysis of two brucellaphages of distant origins.

Here, we present the first complete genome sequence of brucellaphage Tbilisi (Tb) and compared it with that of Pr, a broad host-range brucellaphage recently isolated in Mexico. The genomes consist of 41,148 bp (Tb) and 38,253 bp (Pr), they differ mainly in the region encoding structural proteins, in which the genome of Tb shows two major insertions. Both genomes share 99.87% nucleotide identity, a high percentage of identity among phages isolated at so globally distant locations and temporally different occasions. Sequence analysis revealed 57 conserved ORFs, three transcriptional terminators and four putative transcriptional promoters. The co-occurrence of an ORF encoding a putative DnaA-like protein and a putative oriC-like origin of replication was found in both brucellaphages genomes, a feature not described in any other phage genome. These elements suggest that DNA replication in brucellaphages differs from other phages, and might resemble that of bacterial chromosomes.

Characterization of outer membrane vesicles from Brucella melitensis and protection induced in mice.

The outer membrane vesicles (OMVs) from smooth B. melitensis 16 M and a derived rough mutant, VTRM1 strain, were purified and characterized with respect to protein content and induction of immune responses in mice. Proteomic analysis showed 29 proteins present in OMVs from B. melitensis 16 M; some of them are well-known Brucella immunogens such as SOD, GroES, Omp31, Omp25, Omp19, bp26, and Omp16. OMVs from a rough VTRM1 induced significantly higher expression of IL-12, TNFα, and IFNγ genes in bone marrow dendritic cells than OMVs from smooth strain 16 M. Relative to saline control group, mice immunized intramuscularly with rough and smooth OMVs were protected from challenge with virulent strain B. melitensis 16 M just as well as the group immunized with live strain B. melitensis Rev1 (P < 0.005). Additionally, the levels of serum IgG2a increased in mice vaccinated with OMVs from rough strain VTRM1 consistent with the induction of cell-mediated immunity.

Brucella melitensis survival during manufacture of ripened goat cheese at two temperatures.

The aim of the current work was to assess the influence of two temperatures, 4°C and 24°C, on pH and water activity and their association with Brucella melitensis survival during the traditional manufacture of ripened goat cheese. Raw milk from a brucellosis-free goat herd was used for the manufacture of ripened cheese. The cheese was inoculated with 5×10(9) of the B. melitensis 16M strain during the tempering stage. The cheeses were matured for 5, 20, and 50 days at both temperatures. To assess Brucella survival, the pH and a(w) were recorded at each stage of the process (curd cutting, draining whey, immersion in brine, ripening I, ripening II, and ripening III). B. melitensis was detected at ripening stage III (1×10(3) colony-forming unit [CFU]/mL) from cheeses matured at 4°C with a pH of 5.0 and a(w) of 0.90, and at a ripening stage II (1×10(4) CFU/mL) from cheeses ripened at 24°C with a pH of 4.0 and a(w) of 0.89. The remaining stages were free from the inoculated pathogen. In addition, viable B. melitensis was recovered in significant amounts (1-2×10(6) CFU/mL) from the whey fractions of both types of cheese ripened at 24°C and 4°C. These results revealed the effects of high temperature (24°C vs. 4°C) on the low pH (4) and a(w) (0.89) that appeared to be associated with the suppression of B. melitensis at the early stages of cheese ripening. In the ripened goat cheeses, B. melitensis survived under a precise combination of temperature during maturation, ripening time, and a(w) in the manufacturing process.

Isolation of Brucella melitensis from an abscess on the left foot of a 3-year-old infant.

An unusual case of a 3-year-old girl with a brucellar foot abscess is reported. Although direct microscopic examination of samples from the lesion did not reveal micro-organisms of any kind, a 7 day culture of caseous material yielded small colonies of Gram-negative cocobacilli in Löwenstein-Jensen medium. These were biochemically and molecularly identified as Brucella melitensis. The possibility of foot abscess being caused by Brucella should be considered in countries where brucellosis is endemic.

Enzymatic, immunological and phylogenetic characterization of Brucella suis urease.

BACKGROUND: The sequenced genomes of the Brucella spp. have two urease operons, ure-1 and ure-2, but there is evidence that only one is responsible for encoding an active urease. The present work describes the purification and the enzymatic and phylogenomic characterization of urease from Brucella suis strain 1330. Additionally, the urease reactivity of sera from patients diagnosed with brucellosis was examined. RESULTS: Urease encoded by the ure-1 operon of Brucella suis strain 1330 was purified to homogeneity using ion exchange and hydrophobic interaction chromatographies. The urease was purified 51-fold with a recovery of 12% of the enzyme activity and 0.24% of the total protein. The enzyme had an isoelectric point of 5, and showed optimal activity at pH 7.0 and 28-35 degrees C. The purified enzyme exhibited a Michaelis-Menten saturation kinetics with a Km of 5.60 +/- 0.69 mM. Hydroxyurea and thiourea are competitive inhibitors of the enzyme with Ki of 1.04 +/- 0.31 mM and 26.12 +/- 2.30 mM, respectively. Acetohydroxamic acid also inhibits the enzyme in a competitive way. The molecular weight estimated for the native enzyme was between 130-135 kDa by gel filtration chromatography and 157 +/- 7 kDa using 5-10% polyacrylamide gradient non-denaturing gel. Only three subunits in SDS-PAGE were identified: two small subunits of 14,000 Da and 15,500 Da, and a major subunit of 66,000 Da. The amino terminal sequence of the purified large subunit corresponded to the predicted amino acid sequence encoded by ureC1. The UreC1 subunit was recognized by sera from patients with acute and chronic brucellosis. By phylogenetic and cluster structure analyses, ureC1 was related to the ureC typically present in the Rhizobiales; in contrast, the ureC2 encoded in the ure-2 operon is more related to distant species. CONCLUSION: We have for the first time purified and characterized an active urease from B. suis. The enzyme was characterized at the kinetic, immunological and phylogenetic levels. Our results confirm that the active urease of B. suis is a product of ure-1 operon.

Cloning, expression and characterization of immunogenic aminopeptidase N from Brucella melitensis.

A 97-kDa purified aminopeptidase N (PepN) of Brucella melitensis was previously identified to be immunogenic in humans. The B. melitensis pepN gene was cloned, expressed in Escherichia coli and purified by affinity chromatography. The recombinant PepN (rPepN) exhibited the same biochemical properties, specificity and susceptibility to inhibitors as the native PepN. rPepN was evaluated as a diagnostic antigen in an indirect enzyme-linked immunosorbent assay (ELISA) using sera from patients with acute and chronic brucellosis. The specificity of the ELISA was determined with sera from healthy donors. The ELISA had a cutoff value of 0.156 with 100% specificity and 100% sensitivity. Higher sensitivity was obtained using rPepN compared with crude extract from B. melitensis. Anti-PepN sera did not exhibit serological cross-reaction to crude extracts from Rhizobium tropici, Ochrobactrum anthropi, Yersinia enterocolitica 09 or E. coli O157H7.

Survival of Brucella abortus in milk fermented with a yoghurt starter culture.

In countries such as Mexico, brucellosis is still an important public health problem due to the consumption of non-pasteurized milk and dairy products, contaminated with Brucella spp. The aim of this study was to look into the survival of Brucella abortus during fermentation of milk with a yoghurt starter culture and storage at refrigeration temperature. Sterile skim milk was inoculated with B. abortus at two concentrations, 10(5) and 10(8) CFU/ml simultaneously with a yoghurt starter culture of lactic acid bacteria (Streptococcus thermophilus and Lactobacillus delbrueckii subspecie bulgaricus). Inoculated flasks were incubated at 42 degrees C, followed by refrigeration at 4 degrees C. Samples were taken during fermentation and during storage and viable count of B. abortus and lactic acid bacteria and pH were determined. Results showed that after 10 days of storage at 4 degrees C, B. abortus was recovered in fermented milk at a level of 10(5) CFU/ml, despite the low pH below 4.0. Therefore B. abortus is able to survive in fermented milk. This finding may imply that non-pasteurized fermented milk contaminated with Brucella abortus could be a means of transmission of these bacteria.

[Anti-Brucella antibody seroprevalence in blood donors for therapeutic ends at three blood banks of the Mexican Institute of Social Security]. / Seroprevalencia de anticuerpos anti-Brucella en disponentes de sangre con fines terapéuticos en tres bancos de sangre del Instituto Mexicano del Seguro Social.

INTRODUCTION: To determine seroprevalence for Brucella sp. in blood donors, a serologic study was carried out at three blood banks of the Instituto Mexicano del Seguro Social (IMSS). METHODS: 500 blood samples were taken from selected blood donors. Laboratory tests were used, such as Bengal rose (BR), Standard agglutination in microplate (SAM) and in presence of 2-Mercaptoethanol agglutination in microplate (2ME), which were applied to 500 blood sera from selected effective blood donors. The sample was representative according to the statistical analysis developed. RESULTS: 18 of 500 analyzed sera were positive, with seroprevalence of 3.6%, male sex (83.4%), predominating, as secondary activity group (72.2%). According to academic archivement, blood donors with secondary school had highest seropositivity (55.6%). CONCLUSION: In this study, we conclude that brucellosis has peculiar epidemiologic characteristics in blood banks that participated in this research; therefore it is highly recommended to perform screening tests such as BR, SAM, and 2ME to identified anti-Brucella antibodies in the sera of effective blood donors.

Susceptibility of Mexican brucella isolates to moxifloxacin, ciprofloxacin and other antimicrobials used in the treatment of human brucellosis.

Brucellosis is a disease of domestic and wild animals that is transmitted to humans and exists worldwide. We assessed the in vitro activity of moxifloxacin, ciprofloxacin, tetracycline, doxicycline, rifampin, streptomycin and trimethoprim-sulfamethoxazole (TMP/SMX) against 97 Brucella strains isolated from clinical samples, animals and dairy products in Mexico. Fluoroquinolones showed an antibacterial activity similar to that of tetracyclines (MIC(90) 0.5). Other drugs commonly used against brucellosis were less active, such as rifampin (MIC(90) 2.0 microg/ml) and streptomycin (MIC(90) 4.0 microg/ml). TMP/SMX showed the poorest activity (MIC(90) 8.0 microg/ml). Fluoroquinolones, either first-generation or the newer 8-methoxi derivatives, might be useful in the therapy of brucellosis, which remains to be assessed in clinical trials.

Seroprevalencia de anticuerpos anti-Brucella en disponentes de sangre con fines terapéuticos en tres bancos de sangre del Instituto Mexicano del Seguro Social / Anti-Brucella Antibody Seroprevalence in Blood Donors for Therapeutic Ends at Three Blood Banks of the Mexican Institute of Social Security

Introducción: la brucelosis es una zoonosis, que causa grandes pérdidas económicas en las zonas conurbanas de la Ciudad de México y es un problema importante de salud pública en los habitantes circunvecinos al Distrito Federal. El objetivo fue detectar anticuerpos anti-Brucella y según los resultados que proporcionó esta investigación, se propone como prueba de laboratorio de escrutinio en los donadores de sangre. Material y métodos: se analizaron 500 sueros sanguíneos de disponentes efectivos seleccionados y cuya muestra fue representativa de acuerdo al análisis estadístico elaborado. Las pruebas de laboratorio incluyeron Rosa de Bengala, Aglutinación Estándar en Microplaca y 2 Mercaptoetanol. Resultados: de los 500 sueros analizados 18 mostraron seropositividad con una tasa de seroprevalencia de 3.6%, predominando el sexo masculino (83.4%), por grupo de actividad las secundarias (72.2%), por grado de estudios académicos los de secundaria fueron los de mayor positividad (55.6%). Conclusión: la brucelosis posee características epidemiológicas peculiares en los bancos de sangre participantes en esta investigación, por lo que es importante incluir pruebas de escrutinio en búsqueda de anticuerpos anti-Brucella en los disponentes de sangre efectivos.

Introduction: to determine seroprevalence for Brucella sp. in blood donors, a serologic study was carried out at three blood banks of the Instituto Mexicano del Seguro Social (IMSS). Methods: 500 blood samples were taken from selected blood donors. Laboratory tests were used, such as Bengal rose (BR), Standard agglutination in microplate (SAM) and in presence of 2-Mercaptoethanol agglutination in microplate (2ME), which were applied to 500 blood sera from selected effective blood donors. The sample was representative according to the statistical analysis developed. Results: 18 of 500 analyzed sera were positive, with seroprevalence of 3.6%, male sex (83.4%), predominating, as secondary activity group (72.2%). According to academic archivement, blood donors with secondary school had highest seropositivity (55.6%). Conclusion: In this study, we conclude that brucellosis has peculiar epidemiologic characteristics in blood banks that participated in this research; therefore it is highly recommended to perform screening tests such as BR, SAM, and 2ME to identified anti-Brucella antibodies in the sera of effective blood donors.

Purification and characterization of an immunogenic aminopeptidase of Brucella melitensis.

An immunogenic aminopeptidase was purified from Brucella melitensis strain VTRM1. The purification procedure consisted of ammonium sulfate fractionation and three chromatographic steps. This procedure resulted in a yield of 29% and a 144-fold increase in specific activity. The aminopeptidase appeared to be a monomeric enzyme with a molecular mass of 96 kDa and an isoelectric point of 4.8. Its activity was optimal at pH 7.0 at 40 degrees C. The enzyme was strongly inhibited by EDTA, 1,10-phenathroline, and divalent cations (Zn(2+) and Hg(2+)), suggesting that this protein was a metalloaminopeptidase. The enzyme showed preference for alanine at the N termini of aminoacyl derivatives. The K(m) values for L-alanine-p-nitroanilide (Ala-pNA) and Lys-pNA were 0.35 and 0.18 mM, respectively. The N-terminal sequence of aminopeptidase was used for a homologous search in the genomes of B. melitensis 16M and Brucella suis 1330. The analysis revealed an exact match of the probe sequence (36 bp) with an open reading frame of 2,652 bp encoding a protein predicted to be alanyl aminopeptidase (aminopeptidase N). Collectively, these data suggest designation of the B. melitensis enzyme as an aminopeptidase N. The aminopeptidase was recognized by sera from patients with acute and chronic brucellosis, suggesting that the enzyme may have important diagnostic implications.

Antigen-specific activation and proliferation of CD4+ and CD8+ T lymphocytes from brucellosis patients.

Salt-extractable antigen from Brucella melitensis 16M (RCM-BM) was used to evaluate the immune response from acute and chronic patients suffering from Brucella infections (in Mexico); their responses were compared with those of healthy controls. As a readout we used upregulation of CD69 (a well-established early activation marker for lymphocytes), lymphocyte proliferation by 3[H]thymidine or 5-bromo-2-deoxyuridine (BrdU) incorporation measured by liquid scintillation or flow cytometry, respectively, and production of gamma interferon (IFN gamma). We compared the antigen-specific response with the response induced by phytohaemagglutinin (PHA) as a positive control. There was no difference between acute patients and the healthy controls in the percentages of CD3+, CD4+ or CD8+ lymphocytes. However, we found that chronic patients had a significant (P < 0.05) increase in the CD8+ T cells, in line with previous studies. Antigen-specific responses to RCM-BM showed a significant (P < 0.05) upregulation of CD69 in both CD4+ and CD8+ T lymphocytes in acute brucellosis patients and in CD8+ T lymphocytes in chronic patients, indicating that both populations became activated by this antigen preparation. Moreover, lymphocyte proliferation from both acute and chronic patients in response to RCM-BM was highly significant (P < 0.001) when compared with healthy controls. However, there were no apparent differences between acute and chronic patients. Although the incorporation of BrdU showed similar results it provided additional information, since we demonstrated that both CD4+ and CD8+ T lymphocytes from acute and chronic patients proliferated equally well in response to RCM-BM. Similar results were observed with intracellular IFN gamma determination. As a whole, our data suggest an important role for both CD4+ and CD8+ T lymphocytes in Brucella infection in humans. As has been reported in mice, it is feasible that activated CD8+ T cells participate in protection against Brucella in humans through cytotoxicity or/and by the production of factors such as interferon and granulysin. The role of these cells should be carefully analysed to understand better their participation in human infection by Brucella.

Vacunas en la brucelosis humana / Vaccines in human brucellosis

Hace casi 100 años la brucelosis humana fue considerada por Zammit y Horrocks como una zoonosis, sólo 18 años después que Bruce identificó el agente etiológico de la fiebre de Malta. A lo largo de los años, el avance científico se ha visto encaminado primordialmente al control de la brucelosis animal en los aspectos de diagnóstico y vacunación. En cuanto a la enfermedad en el humano, el progreso más importante ha sido la quimioterapia, aunque en la última década el diagnóstico correcto ha sido un asunto de preocupación general. Las estrategias de erradicación de la brucelosis se divide en tres categorías: 1) Erradicación de la brucelosis animal; 2) Mejoramiento de las medidas de higiene individual y saneamiento y 3) Inmunización. Las vacunas contra la brucelosis han sido desarrolladas a lo largo de tres líneas: 1) vacunas vivas preparadas con cepas atenuadas como B. abortus cepa 19 y B. melitensis cepa Rev.1; 2) células completas inactivadas, como B. abortus cepa 45/20 y B. melitensis H-38 que se administran con adyuvante oleoso y 3) vacunas preparadas con fracciones celulares. Todas ellas han sido usadas ampliamente en el control de la brucelosis en animales y sólo en algunos casos muy particulares en humanos