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A massive “infodemic” developed in parallel with the global COVID-19 pandemic and contributed to public misinformation at a time when access to quality information was crucial. This research aimed to analyze the science and health-related hoaxes that were spread during the pandemic with the objectives of (1) identifying the characteristics of the form and content of such false information, and the platforms used to spread them, and (2) formulating a typology that can be used to classify the different types of hoaxes according to their connection with scientific information. The study was conducted by analyzing the content of hoaxes which were debunked by the three main fact-checking organizations in Spain in the three months following WHO’s announcement of the pandemic (N = 533). The results indicated that science and health content played a prominent role in shaping the spread of these hoaxes during the pandemic. The most common hoaxes on science and health involved information on scientific research or health management, used text, were based on deception, used real sources, were international in scope, and were spread through social networks. Based on the analysis, we proposed a system for classifying science and health-related hoaxes, and identified four types according to their connection to scientific knowledge: “hasty” science, decontextualized science, badly interpreted science, and falsehood without a scientific basis. The rampant propagation and widespread availability of disinformation point to the need to foster media and scientific caution and literacy among the public and increase awareness of the importance of timing and substantiation of scientific research. The results can be useful in improving media literacy to face disinformation, and the typology we formulate can help develop future systems for automated detection of health and science-related hoaxes.

The brucellae are facultative intracellular bacteria that cause brucellosis, one of the major neglected zoonoses. In endemic areas, vaccination is the only effective way to control this disease. Brucella melitensis Rev 1 is a vaccine effective against the brucellosis of sheep and goat caused by B. melitensis, the commonest source of human infection. However, Rev 1 carries a smooth lipopolysaccharide with an O-polysaccharide that elicits antibodies interfering in serodiagnosis, a major problem in eradication campaigns. Because of this, rough Brucella mutants lacking the O-polysaccharide have been proposed as vaccines. To examine the possibilities of rough vaccines, we screened B. melitensis for lipopolysaccharide genes and obtained mutants representing all main rough phenotypes with regard to core oligosaccharide and O-polysaccharide synthesis and export. Using the mouse model, mutants were classified into four attenuation patterns according to their multiplication and persistence in spleens at different doses. In macrophages, mutants belonging to three of these attenuation patterns reached the Brucella characteristic intracellular niche and multiplied intracellularly, suggesting that they could be suitable vaccine candidates. Virulence patterns, intracellular behavior and lipopolysaccharide defects roughly correlated with the degree of protection afforded by the mutants upon intraperitoneal vaccination of mice. However, when vaccination was applied by the subcutaneous route, only two mutants matched the protection obtained with Rev 1 albeit at doses one thousand fold higher than this reference vaccine. These mutants, which were blocked in O-polysaccharide export and accumulated internal O-polysaccharides, stimulated weak anti-smooth lipopolysaccharide antibodies. The results demonstrate that no rough mutant is equal to Rev 1 in laboratory models and question the notion that rough vaccines are suitable for the control of brucellosis in endemic areas.

The two-component BvrR/BvrS system is essential for Brucella abortus virulence. It was shown previously that its dysfunction alters the expression of some major outer membrane proteins and the pattern of lipid A acylation. To determine the genes regulated by BvrR/BvrS, we performed a whole-genome microarray analysis using B. abortus RNA obtained from wild type and bvrR mutant cells grown in the same conditions. A total of 127 differentially expressed genes were found: 83 were over expressed and 44 were less expressed in the bvrR mutant. Two operons, the phosphotransferase system and the maltose transport system, were down-regulated. Several genes involved in cell envelope or outer membrane biogenesis were differentially expressed: genes for outer membrane proteins (omp25a, omp25d), lipoproteins, LPS and fatty acid biosynthesis, stress response proteins, chaperones, flagellar genes, and twelve genes encoding ABC transport systems. Ten genes related with carbon metabolism (pckA and fumB among others) were up-regulated in the bvrR mutant, and denitrification genes (nirK, norC and nosZ) were also regulated. Notably, seven transcriptional regulators were affected, including VjbR, ExoR and OmpR that were less expressed in the bvrR mutant. Finally, the expression of eleven genes which have been previously related with Brucella virulence was also altered. All these data corroborate the impact of BvrR/BvrS on cell envelope modulation, confirm that this system controls the carbon and nitrogen metabolism, and suggest a cross-talk among some regulators to adjust the Brucella physiology to the shift expected to occur during the transit from the extracellular to the intracellular niche.

Social networks have been used to teach and engage people about the importance of science. The integration of social networks in the daily routines of faculties and scientists is strongly recommended to increase their personal brand, improve their skills, enhance their visibility, share and communicate science to society, promote scientific culture, and even as a tool for teaching and learning. Here we review the use of Twitter in science and comment on our previous experience of using this social network as a platform for a Massive Online Open Course (MOOC) in Spain and Latin America. We propose to extend this strategy to a pan-European Microbiology MOOC in the near future.

Bacteria of the genus Brucella have the unusual capability to catabolize erythritol and this property has been associated with their virulence mainly because of the presence of erythritol in bovine foetal tissues and because the attenuated S19 vaccine strain is the only Brucella strain unable to oxydize erythritol. In this work we have analyzed the transcriptional changes produced in Brucella by erythritol by means of two high throughput approaches: RNA hybridization against a microarray containing most of Brucella ORF's constructed from the Brucella ORFeome and next generation sequencing of Brucella mRNA in an Illumina GAIIx platform. The results obtained showed the overexpression of a group of genes, many of them in a single cluster around the ery operon, able to co-ordinately mediate the transport and degradation of erythritol into three carbon atoms intermediates that will be then converted into fructose-6P (F6P) by gluconeogenesis. Other induced genes participating in the nonoxidative branch of the pentose phosphate shunt and the TCA may collaborate with the ery genes to conform an efficient degradation of sugars by this route. On the other hand, several routes of amino acid and nucleotide biosynthesis are up-regulated whilst amino acid transport and catabolism genes are down-regulated. These results corroborate previous descriptions indicating that in the presence of erythritol, this sugar was used preferentially over other compounds and provides a neat explanation of the the reported stimulation of growth induced by erythritol.

Se presenta un análisis de contenido de todos los bulos (N=292) relacionados con la pandemia Covid-19 identificados por las tres plataformas de verificación acreditadas en España, durante el primer mes del estado de alarma decretado por el Gobierno (14 marzo 2020-13 abril 2020). El estudio muestra que los bulos sobre el coronavirus fueron diseminados principalmente en las redes sociales y, entre ellas, sobre todo en las cerradas, como la aplicación móvil de mensajería WhatsApp. También detecta las particularidades formales y de contenido más frecuentes de los contenidos falsificados. Los resultados revelan que la pandemia, además de generar un gran número de bulos sobre salud y ciencia, casi un tercio de la muestra, también propició la difusión de numerosos contenidos falsos de tema político y gubernamental. El artículo explora los formatos, fuentes y territorios de procedencia de los bulos. Más allá de sus resultados empíricos, este estudio realiza contribuciones teóricas en el marco de los emergentes estudios sobre desórdenes informativos. En concreto, aporta una definición propia de bulo, así como una tipología en la que se identifican cuatro tipos de bulos: broma, exageración, descontextualización y engaño. A partir de esos cuatro tipos, se propone un 'diagrama de gravedad de los bulos'.

Background Brucellosis is a zoonosis caused by Brucella spp., a group of highly homogeneous bacteria. The insertion sequence IS 711 is characteristic of these bacteria, and occurs in variable numbers and positions, but always constant within a given species. This species-associated polymorphism is used in molecular typing and identification. Field isolates of B. abortus , the most common species infecting cattle, typically carry seven IS 711 copies (one truncated). Thus far, IS 711 transposition has only been shown in vitro and only for B. ovis and B. pinnipedialis , two species carrying a high number of IS 711 copies, but never in other Brucella species, neither in vitro nor in field strains. Results We found several B. abortus strains isolated from milk and aborted fetuses that carried additional IS 711 copies in two hitherto undescribed insertion sites: one in an intergenic region near to the 3' end of a putative lactate permease gene and the other interrupting the sequence of a marR transcriptional regulator gene. Interestingly, the second type of insertion was identified in isolates obtained repeatedly from the same herd after successive brucellosis outbreaks, an observation that proves the stability and virulence of the new genotype under natural conditions. Sequence analyses revealed that the new copies probably resulted from the transposition of a single IS 711 copy common to all Brucella species sequenced so far. Conclusions Our results show that the replicative transposition of IS 711 can occur under field conditions. Therefore, it represents an active mechanism for the emergence of genetic diversity in B. abortus thus contributing to intra-species genetic polymorphism.

Following the declaration, in March 2020, of the Covid-19 pandemic, there was an escalation of disinformation, involving multiple actors and reaching global dimensions. In this article, we analyze the possible causes and characteristics of the spread of disinformation on this issue. Disinformation about science can be explained by the distance that separates scientific knowledge from common knowledge and the difficult relationship between science and the media. The pandemic has multiplied the number of scientific publications and has accelerated publication rates, which has contributed to the dissemination of provisional, erroneous, or totally false information. A process of politicization has also developed, which has led to misinformation. In addition, the need to confront this health crisis has led society to demand accurate information from science, despite the fact that in many cases there is only uncertainty. The experience of this pandemic highlights the importance of providing citizens with accessible and rigorous knowledge that creates confidence in science. To achieve this, it is necessary to have specialized professionals capable of providing rigorous information, not only on the results but also on the research processes.

The assessment of the genetic stability is one of the essential elements to guarantee the biological quality of live anti-bacteria vaccines. Live attenuated Brucella melitensis Rev 1 is the most effective vaccine against brucellosis in small ruminants. Thirty-six B. melitensis Rev 1 vaccine strains isolated from human or animal sources from different geographic regions, from different commercial batches or laboratory collections were typed by the multiple-locus variable-number tandem repeat (VNTR) analysis (MLVA) recently described for Brucella spp. Our results demonstrated that B. melitensis Rev 1 group as assayed by MLVA is genetically very homogeneous. We believe that MLVA methodology could be an essential assay to guarantee the quality and stability of live anti-bacterial vaccines being produced worldwide and can be included as in vitro control.