Desarrollo de vacunas contra infecciones nosocomiales

El descubrimiento de los antibióticos y el desarrollo para su uso clínico puede ser considerado uno de los logros biomédicos más importantes del siglo pasado. Desafortunadamente, muchas especies de bacterias patógenas han desarrollado y/o adquirido múltiples tipos de mecanismos de resistencia que pueden limitar severamente la eficacia terapéutica de la terapia antimicrobiana. La vacunación es un método eficaz para prevenir infecciones bacterianas, sin embargo, no se ha aplicado con éxito en las infecciones causadas por algunos de los más problemáticos patógenos multirresistentes. Nuestra investigación desarrollada en el Centro Nacional de Microbiología, Madrid, España, se centra en estudiar el potencial de las vacunas para contribuir a reducir la carga de enfermedades infecciosas causadas por bacterias Gram-negativas multirresistentes. Los obstáculos técnicos, logísticos y sociales que han limitado el desarrollo exitoso de vacunas para estas infecciones en el pasado serán presentados, así como los avances recientes en el desarrollo de vacunas que pueden contribuir a superar estos desafíos. Así mismo, se presentará una síntesis de las tecnologías de vacunas que se han empleado en el desarrollo de vacunas para bacterias Gram-negativas multirresistentes clave, y tecnologías emergentes que pueden contribuir a futuros éxitos. Finalmente, se presentará el desarrollo de una vacuna en contra de los tres patógenos Gram-negativos resistentes a múltiples fármacos más preocupantes, Acinetobacter baumannii, Klebsiella pneumoniae y Pseudomonas aeruginosa, centrándose en estudios recientes realizados en nuestro laboratorio, así como una revisión exhaustiva de los esfuerzos de desarrollo de vacunas durante los últimos 40 años

Effect of Subinhibitory Concentrations of Antibiotics and Disinfectants on ISAba-Mediated Inactivation of Lipooligosaccharide Biosynthesis Genes in Acinetobacter baumannii

Inactivation of the lipooligosaccharide (LOS) biosynthesis genes lpxA, lpxC and lpxD by ISAba insertion elements results in high-level resistance to colistin in A. baumannii. In the present study, we quantify the rate of spontaneous insertional inactivation of LOS biosynthesis genes by ISAba elements in the ATCC 19606-type strain and two multidrug clinical isolates. Using insertional inactivation of lpxC by ISAba11 in the ATCC 19606 strain as a model, we determine the effect of several subinhibitory concentrations of the antibiotics, namely tetracycline, ciprofloxacin, meropenem, kanamycin and rifampicin, as well as the disinfectants ethanol and chlorhexidine on ISAba11 insertion frequencies. Notably, subinhibitory concentrations of tetracycline significantly increased ISAba11 insertion, and rifampicin completely inhibited the emergence of colistin resistance due to ISAba11 inactivation of lpxC. Sequencing of ISAba11 insertion sites within the lpxC gene demonstrated that insertions clustered between nucleotides 382 and 618 (58.3% of unique insertions detected), indicating that this may be a hotspot for ISAba11 insertion. The alignment of insertion sites revealed a semi-conserved AT-rich consensus sequence upstream of the ISAba11 insertion site, suggesting that ISAba11 insertion sites may be sequence-dependent. This study explores previously uncharacterized aspects regarding the acquisition of colistin resistance through insertional activation in LOS biosynthesis genes in A. baumannii.This research was supported by grants MPY 380/18 from the Instituto de Salud Carlos III (ISCIII) awarded to M.J.M. A.C.L. is supported by the Atracción de Talento Program of the Community of Madrid.S

Mutation Analysis in Regulator DNA-Binding Regions for Antimicrobial Efflux Pumps in 17,000 Pseudomonas aeruginosa Genomes

Mutations leading to upregulation of efflux pumps can produce multiple drug resistance in the pathogen Pseudomonas aeruginosa. Changes in their DNA binding regions, i.e., palindromic operators, can compromise pump depression and subsequently enhance resistance against several antibacterials and biocides. Here, we have identified (pseudo)palindromic repeats close to promoters of genes encoding 13 core drug-efflux pumps of P. aeruginosa. This framework was applied to detect mutations in these repeats in 17,292 genomes. Eighty-nine percent of isolates carried at least one mutation. Eight binary genetic properties potentially related to expression were calculated for mutations. These included palindromicity reduction, mutation type, positioning within the repeat and DNA-bending shift. High-risk ST298, ST308 and ST357 clones commonly carried four conserved mutations while ST175 and the cystic fibrosis-linked ST649 clones showed none. Remarkably, a T-to-C transition in the fourth position of the upstream repeat for mexEF-oprN was nearly exclusive of the high-risk ST111 clone. Other mutations were associated with high-risk sublineages using sample geotemporal metadata. Moreover, 1.5% of isolates carried five or more mutations suggesting they undergo an alternative program for regulation of their effluxome. Overall, P. aeruginosa shows a wide range of operator mutations with a potential effect on efflux pump expression and antibiotic resistance.This research was funded by Acción Estratégica en Salud from the ISCIII, grant MPY 509/19. This research was also supported by Personalized and Precision Medicine grant from the Instituto de Salud Carlos III (MePRAM Project, PMP22/00092), Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación and Unión Europea-NextGenerationEU.S

High-affinity chemotaxis to histamine of the human pathogen Pseudomonas aeruginosa

FEMS 2019: 8th congress of European Microbiologists, in Glasgow, Scotland, 7-11 July 201

elaboracion de papel vegetal que cumpla las normas tappi para el diseno e impresion a partir de la fibra de la cascara del platano verde

En la presente investigación se elaborará un manual para la elaboración de papel vegetal que cumpla las normas TAPPI para el diseño e impresión a partir de la fibra de la cascara del plátano verde ya que estas técnicas antiguas que inusualmente se usan para la elaboración de papel artesanal han funcionado bien debido a que ha sido destinado para impresión serigrafía o manual que no demanden mayor calidad ni parámetros técnicos de su constitución. Hay que tener en ceunta que la fabricación del papel a mano es una técnica que a pesar de tener miles de años de antigüedad no ha sido explotada adecuadamente y no se consigue papel de buena calidad que pueda reemplazar a los que usamos normalmente. Muchos artesanos hacen papel a mano sin una técnica científica que permita conocer las propiedades de las fibras a utilizar para elaborar papel para imprenta o impresoras comunes. En nuestro caso elaboraremos papel vegetal a partir de la fibra de la cascara del plátano verde que presente las mejores propiedades de formación física y óptica.</p

Anti-Inflammatory Activity and Changes in Antioxidant Properties of Leaf and Stem Extracts from Vitex mollis

Vitex mollis is used in traditional Mexican medicine for the treatment of some ailments. However, there are no studies on what happens to the anti-inflammatory activity or antioxidant properties and total phenolic content of leaves and stem extracts of Vitex mollis during the digestion process; hence, this is the aim of this work. Methanolic, acetonic, and hexanic extracts were obtained from both parts of the plant. Extract yields and anti-inflammatory activity (elastase inhibition) were measured. Additionally, changes in antioxidant activity (DPPH and ABTS) and total phenols content of plant extracts before and after in vitro digestion were determined. The highest elastase inhibition to prevent inflammation was presented by hexanic extracts (leaf = 94.63% and stem = 98.30%). On the other hand, the major extract yield (16.14%), antioxidant properties (ABTS = 98.51% and DPPH = 94.47% of inhibition), and total phenols (33.70 mg GAE/g of dried sample) were showed by leaf methanolic extract. Finally, leaf and stem methanolic extracts presented an antioxidant activity increase of 35.25% and 27.22%, respectively, in comparison to their initial values after in vitro digestion process. All samples showed a decrease in total phenols at the end of the digestion. These results could be the basis to search for new therapeutic agents from Vitex mollis

Towards Control and Oversight of SARS-CoV-2 Diagnosis and Monitoring through Multiplexed Quantitative Electroanalytical Immune Response Biosensors

The development of versatile and sensitive biotools to quantify specific SARS-CoV-2 immunoglobulins in SARS-CoV-2 infected and non-infected individuals, built-on the surface of magnetic microbeads functionalized with nucleocapsid (N) and inhouse expressed recombinant spike (S) proteins is reported. Amperometric interrogation of captured N- and S-specific circulating total or individual immunoglobulin (Ig) isotypes (IgG, IgM, and IgA), subsequently labelled with HRP-conjugated secondary antibodies, was performed at disposable single or multiplexed (8) screen-printed electrodes using the HQ/HRP/H2O2 system. The obtained results using N and in-house expressed S ectodomains of five SARS-CoV-2 variants of concern (including the latest Delta and Omicron) allow identification of vulnerable populations from those with natural or acquired immunity, monitoring of infection, evaluation of vaccine efficiency and even identification of the variant responsible for the infection

Chemoperception of Specific Amino Acids Controls Phytopathogenicity in Pseudomonas syringae pv. tomato

IMPORTANCE There is substantive evidence that chemotaxis is a key requisite for efficient pathogenesis in plant pathogens. However, information regarding particular bacterial chemoreceptors and the specific plant signal that they sense is scarce. Our work shows that the phytopathogenic bacterium Pseudomonas syringae pv. tomato mediates not only chemotaxis but also the control of pathogenicity through the perception of the plant abundant amino acids Asp and Glu. We describe the specificity of the perception of L- and D-Asp and L-Glu by the PsPto-PscA chemoreceptor and the involvement of this perception in the regulation of pathogenicity-related traits. Moreover, a saturating concentration of D-Asp reduces bacterial virulence, and we therefore propose that ligand-mediated interference of key chemoreceptors may be an alternative strategy to control virulence.Supplemental material for this article may be found at https://doi.org/10.1128/mBio .01868-19.We acknowledge M. Trini Gallegos for kindly provide plasmid pCdrA::gfpS and S. Nebreda for technical assistance.Chemotaxis has been associated with the pathogenicity of bacteria in plants and was found to facilitate bacterial entry through stomata and wounds. However, knowledge regarding the plant signals involved in this process is scarce. We have addressed this issue using Pseudomonas syringae pv. tomato, which is a foliar pathogen that causes bacterial speck in tomato. We show that the chemoreceptor P. syringae pv. tomato PscA (PsPto-PscA) recognizes specifically and with high affinity L-Asp, L-Glu, and D-Asp. The mutation of the chemoreceptor gene largely reduced chemotaxis to these ligands but also altered cyclic di-GMP (c-di-GMP) levels, biofilm formation, and motility, pointing to cross talk between different chemosensory pathways. Furthermore, the PsPto-PscA mutant strain showed reduced virulence in tomato. Asp and Glu are the most abundant amino acids in plants and in particular in tomato apoplasts, and we hypothesize that this receptor may have evolved to specifically recognize these compounds to facilitate bacterial entry into the plant. Infection assays with the wild-type strain showed that the presence of saturating concentrations of D-Asp also reduced bacterial virulence.This work was supported by grants AGL2015-63851-R and RTI2018-095222-B100 (to E.L.-S.) and BIO2016-76779-P (to T.K.) from the Ministerio de Economía y Competitividad, Spain. J.P.C.-V. was supported by the FPI program (BES-2016-076452, MINECOSpain)

Crying out for help with root exudates : adaptive mechanisms by which stressed plants assemble health-promoting soil microbiomes

Plants employ immunological and ecological strategies to resist biotic stress. Recent evidence suggests that plants adapt to biotic stress by changing their root exudation chemistry to assemble health-promoting microbiomes. This so-called ‘cry-for-help’ hypothesis provides a mechanistic explanation for previously characterized soil feedback responses to plant disease, such as the development of disease-suppressing soils upon successive cultivations of take all-infected wheat. Here, we divide the hypothesis into individual stages and evaluate the evidence for each component. We review how plant immune responses modify root exudation chemistry, as well as what impact this has on microbial activities, and the subsequent plant responses to these activities. Finally, we review the ecological relevance of the interaction, along with its translational potential for future crop protection strategies