Evaluation of the relatedness of Brucella spp. and Ochrobactrum anthropi and description of Ochrobactrum intermedium sp. nov., a new species with a closer relationship to Brucella spp

The relatedness of Brucella spp. and Ochrobactrum anthropi was studied by protein profiling, Western blot, immunoelectrophoresis and 16S rRNA analysis. Whole-cell and soluble proteins of brucellae and O. anthropi showed serological cross-reactivities quantitatively and qualitatively more intense than those existing with similar extracts of Agrobacterium spp. Numerical analysis of Western blot profiles of whole-cell extracts showed that O. anthropi LMG 3301 was closer to Brucella spp. than to O. anthropi LMG 3331T, a result not obtained by protein profiling. These differences were not observed by Western blot with soluble fractions, and immunoelectrophoretic analyses suggested that this was due to destruction of conformational epitopes in Western blot procedures with the subsequent simplification of antigenic profile. Analysis of the 16S rRNA sequences of strains previously used in the species definition confirmed that strain LMG 3301, and also LMG 3306, were closer to the brucellae, and that LMG 3331T was in a separate cluster. The LMG 3301 and the LMG 3331T clusters could also be separated by their different colistin sensitivity and by PCR with 16S rRNA Brucella primers, and both methods showed strains of both clusters among clinical isolates classified as O. anthropi by conventional tests. These results and those of previous DNA-DNA hybridization studies [Holmes, B., Popoff, M., Kiredjian, M. & Kersters, K. (1988). Int J Syst Bacteriol 38, 406-416] show that the LMG 3301 cluster and related clinical isolates should be given a new species status for which the name Ochrobactrum intermedium sp. nov. is proposed (type strain is LMG 3301T=NCTC 12171T = CNS 2-75T)

Antibody and delayed-type hypersensitivity responses to Ochrobactrum anthropi cytosolic and outer membrane antigens in infections by smooth and rough Brucella spp

Immunological cross-reactions between Brucella spp. and Ochrobactrum anthropi were investigated in animals and humans naturally infected by Brucella spp. and in experimentally infected rams (Brucella ovis infected), rabbits (Brucella melitensis infected), and mice (B. melitensis and Brucella abortus infected). In the animals tested, O. anthropi cytosolic proteins evoked a delayed-type hypersensitivity reaction of a frequency and intensity similar to that observed with B. melitensis brucellin. O. anthropi cytosolic proteins also reacted in gel precipitation tests with antibodies in sera from Brucella natural hosts with a frequency similar to that observed with B. melitensis proteins, and absorption experiments and immunoblotting showed antibodies to both Brucella-specific proteins and proteins common to Brucella and O. anthropi. No antibodies to O. anthropi cytosolic proteins were detected in the sera of Brucella-free hosts. Immunoblotting with sera of Brucella-infected sheep and goats showed immunoglobulin G (IgG) to Brucella group 3 outer membrane proteins and to O. anthropi proteins of similar molecular weight. No IgG to the O-specific polysaccharide of O. anthropi lipopolysaccharide was detected in the sera of Brucella-infected hosts. The sera of sheep, goats, and rabbits infected with B. melitensis contained IgG to O. anthropi rough lipopolysaccharide and lipid A, and B. ovis and O. anthropi rough lipopolysaccharides showed equal reactivities with IgG in the sera of B. ovis-infected rams. The findings show that the immunoresponse of Brucella-infected hosts to protein antigens is not necessarily specific for brucellae and suggest that the presence of O. anthropi or some related bacteria explains the previously described reactivities to Brucella rough lipopolysaccharide and outer membrane proteins in healthy animals

El valor de la recerca formativa per a la innovació docent i el desenvolupament competencial

2012PID-UB/117El projecte ha consistit en la introducció d’innovacions docents en dues assignatures del Grau de Pedagogia de la Facultat de Pedagogia ('Informàtica aplicada a la recerca educativa' i 'Orientació i Gènere') i una assignatura del Grau de Mestre en Educació Infantil de la Facultat de Formació del Professorat ('Observació i Innovació a l'aula) promovent la investigació formativa com a eina pedagògica. Conscients que la configuració de l'Espai Europeu d'Educació Superior planteja un gran repte per a l'aprofundiment de la investigació en el nou marc formatiu universitari, aquest projecte ha volgut validar mètodes d'ensenyament per al desenvolupament competencial (De Miguel, et al., 2006) que operativitzen la investigació formativa: l'Aprenentatge Basat en Problemes, l'Aprenentatge orientat a Projectes i l'ús de les narratives digitals (Rodríguez i Londoño, 2009) per fomentar l'autoaprenentatge i l'autogestió del coneixement. Els resultats obtinguts evidencien el valor d'aquestes estratègies pedagògiques instrumentalitzades per la investigació formativa per a l'assoliment de tres competències transversals comunes a la Universitat de Barcelona (Vicerrectorat de Política Docent, 2008): el compromís ètic, la capacitat d'aprenentatge i responsabilitat, i la capacitat comunicativa. A més també animen a avançar en el treball interdisciplinari per a l'avaluació de les mateixes, mitjançant l'elaboració de rúbriques específiques coherents amb les innovacions docents en les assignatures implicades.CONVOCATÒRIA D’AJUTS PER AL DESENVOLUPAMENT DE PROJECTES D’INNOVACIÓ DOCENT A LA UB. 2012PID-UB/11

Evaluation of allergic and serological tests for diagnosing Brucella melitensis infection in sheep

A total of 291 unvaccinated sheep from Brucella melitensis-infected flocks were examined for delayed-type hypersensitivity (DTH) responses with Brucellergene commercial allergen and with cold saline extract and cytosol from rough B. melitensis 115, and their sera were tested in the rose bengal test (RBT), complement fixation test (CFT), and enzyme-linked immunosorbent assay (ELISA) with lipopolysaccharide. DTH reactions were maximal after 72 h, with no intensity differences among allergens, inoculation sites (eyelid and tail), and doses tested. There were no differences in the results recorded by visual inspection and palpation of inoculation sites, by measuring skin thickness with a caliper, or by microscopic examination of samples taken at necropsy; Six days after DTH testing, anergy was observed in 100% of the animals, and 100% reactivity was recovered only after 24 days. All animals were necropsied, and thorough bacteriological searches were performed. The sensitivities found with the 140 animals from which B. melitensis was isolated were ELISA, 100%; DTH, 97.1%; RBT, 92.1%; and CFT, 88.6%. Those results put into question the value of RBT and CFT as screening and confirmatory tests for sheep brucellosis and at least indicate that their standardization should be modified. For 151 tested sheep from which B. melitensis was not isolated, the percentages of positive animals were ELISA, 100%; DTH, 94.0%; RBT, 57.6%; and CFT, 53.6%. All tests were negative for 100 tested sheep from Brucella-free flocks. The different results of bacteriological and immunological tests suggest the usefulness of developing indirect tests able to distinguish truly infected animals from those that have developed an immunological response

Brucella abortus and its closest phylogenetic relative, Ochrobactrum spp., differ in outer membrane permeability and cationic peptide resistance

The outer membrane (OM) of the intracellular parasite Brucella abortus is permeable to hydrophobic probes and resistant to destabilization by polycationic peptides and EDTA. The significance of these unusual properties was investigated in a comparative study with the opportunistic pathogens of the genus Ochrobactrum, the closest known Brucella relative. Ochrobactrum spp. OMs were impermeable to hydrophobic probes and sensitive to polymyxin B but resistant to EDTA. These properties were traced to lipopolysaccharide (LPS) because (i) insertion of B. abortus LPS, but not of Escherichia coli LPS, into Ochrobactrum OM increased its permeability; (ii) permeability and polymyxin B binding measured with LPS aggregates paralleled the results with live bacteria; and (iii) the predicted intermediate results were obtained with B. abortus-Ochrobactrum anthropi and E. coli-O. anthropi LPS hybrid aggregates. Although Ochrobactrum was sensitive to polymyxin, self-promoted uptake and bacterial lysis occurred without OM morphological changes, suggesting an unusual OM structural rigidity. Ochrobactrum and B. abortus LPSs showed no differences in phosphate, qualitative fatty acid composition, or acyl chain fluidity. However, Ochrobactrum LPS, but not B. abortus LPS, contained galacturonic acid. B. abortus and Ochrobactrum smooth LPS aggregates had similar size and zeta potential (-12 to -15 mV). Upon saturation with polymyxin, zeta potential became positive (1 mV) for Ochrobactrum smooth LPS while remaining negative (-5 mV) for B. abortus smooth LPS, suggesting hindered access to inner targets. These results show that although Ochrobactrum and Brucella share a basic OM pattern, subtle modifications in LPS core cause markedly different OM properties, possibly reflecting the adaptive evolution of B. abortus to pathogenicity

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Higher COVID-19 pneumonia risk associated with anti-IFN-α than with anti-IFN-ω auto-Abs in children

We found that 19 (10.4%) of 183 unvaccinated children hospitalized for COVID-19 pneumonia had autoantibodies (auto-Abs) neutralizing type I IFNs (IFN-alpha 2 in 10 patients: IFN-alpha 2 only in three, IFN-alpha 2 plus IFN-omega in five, and IFN-alpha 2, IFN-omega plus IFN-beta in two; IFN-omega only in nine patients). Seven children (3.8%) had Abs neutralizing at least 10 ng/ml of one IFN, whereas the other 12 (6.6%) had Abs neutralizing only 100 pg/ml. The auto-Abs neutralized both unglycosylated and glycosylated IFNs. We also detected auto-Abs neutralizing 100 pg/ml IFN-alpha 2 in 4 of 2,267 uninfected children (0.2%) and auto-Abs neutralizing IFN-omega in 45 children (2%). The odds ratios (ORs) for life-threatening COVID-19 pneumonia were, therefore, higher for auto-Abs neutralizing IFN-alpha 2 only (OR [95% CI] = 67.6 [5.7-9,196.6]) than for auto-Abs neutralizing IFN-. only (OR [95% CI] = 2.6 [1.2-5.3]). ORs were also higher for auto-Abs neutralizing high concentrations (OR [95% CI] = 12.9 [4.6-35.9]) than for those neutralizing low concentrations (OR [95% CI] = 5.5 [3.1-9.6]) of IFN-omega and/or IFN-alpha 2

Evaluation of the relatedness of Brucella spp. and Ochrobactrum anthropi and description of Ochrobactrum intermedium sp. nov., a new species with a closer relationship to Brucella spp

The relatedness of Brucella spp. and Ochrobactrum anthropi was studied by protein profiling, Western blot, immunoelectrophoresis and 16S rRNA analysis. Whole-cell and soluble proteins of brucellae and O. anthropi showed serological cross-reactivities quantitatively and qualitatively more intense than those existing with similar extracts of Agrobacterium spp. Numerical analysis of Western blot profiles of whole-cell extracts showed that O. anthropi LMG 3301 was closer to Brucella spp. than to O. anthropi LMG 3331T, a result not obtained by protein profiling. These differences were not observed by Western blot with soluble fractions, and immunoelectrophoretic analyses suggested that this was due to destruction of conformational epitopes in Western blot procedures with the subsequent simplification of antigenic profile. Analysis of the 16S rRNA sequences of strains previously used in the species definition confirmed that strain LMG 3301, and also LMG 3306, were closer to the brucellae, and that LMG 3331T was in a separate cluster. The LMG 3301 and the LMG 3331T clusters could also be separated by their different colistin sensitivity and by PCR with 16S rRNA Brucella primers, and both methods showed strains of both clusters among clinical isolates classified as O. anthropi by conventional tests. These results and those of previous DNA-DNA hybridization studies [Holmes, B., Popoff, M., Kiredjian, M. & Kersters, K. (1988). Int J Syst Bacteriol 38, 406-416] show that the LMG 3301 cluster and related clinical isolates should be given a new species status for which the name Ochrobactrum intermedium sp. nov. is proposed (type strain is LMG 3301T=NCTC 12171T = CNS 2-75T)

Antibody and delayed-type hypersensitivity responses to Ochrobactrum anthropi cytosolic and outer membrane antigens in infections by smooth and rough Brucella spp

Immunological cross-reactions between Brucella spp. and Ochrobactrum anthropi were investigated in animals and humans naturally infected by Brucella spp. and in experimentally infected rams (Brucella ovis infected), rabbits (Brucella melitensis infected), and mice (B. melitensis and Brucella abortus infected). In the animals tested, O. anthropi cytosolic proteins evoked a delayed-type hypersensitivity reaction of a frequency and intensity similar to that observed with B. melitensis brucellin. O. anthropi cytosolic proteins also reacted in gel precipitation tests with antibodies in sera from Brucella natural hosts with a frequency similar to that observed with B. melitensis proteins, and absorption experiments and immunoblotting showed antibodies to both Brucella-specific proteins and proteins common to Brucella and O. anthropi. No antibodies to O. anthropi cytosolic proteins were detected in the sera of Brucella-free hosts. Immunoblotting with sera of Brucella-infected sheep and goats showed immunoglobulin G (IgG) to Brucella group 3 outer membrane proteins and to O. anthropi proteins of similar molecular weight. No IgG to the O-specific polysaccharide of O. anthropi lipopolysaccharide was detected in the sera of Brucella-infected hosts. The sera of sheep, goats, and rabbits infected with B. melitensis contained IgG to O. anthropi rough lipopolysaccharide and lipid A, and B. ovis and O. anthropi rough lipopolysaccharides showed equal reactivities with IgG in the sera of B. ovis-infected rams. The findings show that the immunoresponse of Brucella-infected hosts to protein antigens is not necessarily specific for brucellae and suggest that the presence of O. anthropi or some related bacteria explains the previously described reactivities to Brucella rough lipopolysaccharide and outer membrane proteins in healthy animals