Membrane anchoring stabilizes and favors secretion of New Delhi metallo-β-lactamase

Carbapenems, 'last-resort' β-lactam antibiotics, are inactivated by zinc-dependent metallo-β-lactamases (MBLs). The host innate immune response withholds nutrient metal ions from microbial pathogens by releasing metal-chelating proteins such as calprotectin. We show that metal sequestration is detrimental for the accumulation of MBLs in the bacterial periplasm, because those enzymes are readily degraded in their nonmetallated form. However, the New Delhi metallo-β-lactamase (NDM-1) can persist under conditions of metal depletion. NDM-1 is a lipidated protein that anchors to the outer membrane of Gram-negative bacteria. Membrane anchoring contributes to the unusual stability of NDM-1 and favors secretion of this enzyme in outer-membrane vesicles (OMVs). OMVs containing NDM-1 can protect nearby populations of bacteria from otherwise lethal antibiotic levels, and OMVs from clinical pathogens expressing NDM-1 can carry this MBL and the bla[subscript NDM] gene. We show that protein export into OMVs can be targeted, providing possibilities of new antibacterial therapeutic strategies.Kinship Foundation. Searle Scholars ProgramMassachusetts Institute of Technology. Department of Chemistr

Estudio socioeconómico sobre desarrollo local y empleo juvenil del municipio de Oviedo

Definir la realidad socioeconómica del municipio de Oviedo lo que, junto al estudio realizado en otros municipios, constituirá una primera fase. El municipio de Oviedo, que representa el centro de la región e incluye su capitalidad. Más amplio de dinamización y promoción territorial. El proceso se realizó a través de la combinación de consulta de fuentes secundarias, análisis directo mediante encuestas y entrevistas con agentes sociales del municipio. Se obtiene un estudio exhaustivo del municipio de Oviedo en cada uno de los apartados señalados. La actividad predominante está en el sector servicios. En el mercado de trabajo las cifras de empleo manifiestan un alto grado de terciarización muy por encima del conjunto de la región. La evolución de los empleos varía según sectores, destaca la dificultad que supone para muchas empresas el cuantificar sus necesidades futuras de recursos humanos, aunque sí se señalan los distintos perfiles ocupacionales demandados. Los procedimientos para reclutar personal son, básicamente, procesos informales y no reglados. Se contempla con optimismo la evolución de los distintos sectores. Los jóvenes entre 16 y 29 años permanecen en el Sistema Educativo reglado, aumentando la escolarización en las Enseñanzas Medias y Universidad, demorándose así la incorporación al mercado de trabajo. Los itinerarios formativos presentan una distribución territorial y social claramente diferenciada, siendo coherente con estos resultados los obtenidos al relacionar el itinerario formativo y el status social de la familia de origen del sujeto. El estudio de la oferta formativa está muy relacionada con este análisis de los jóvenes. La oferta formativa ocupacional no reglada está centrada prácticamente en el plan FIP del Instituto Nacional de Empleo. Destaca, además, la importancia creciente de especialidades relacionadas con la construcción, transporte, servicios a empresas, mecánica, sanidad y hostelería.AsturiasES

Crystal Structure of the Metallo-β-Lactamase GOB in the Periplasmic Dizinc Form Reveals an Unusual Metal Site.

International audienceMetallo-beta-lactamases (MBLs) are broad-spectrum, Zn(II)-dependent lactamases able to confer resistance to virtually every β-lactam antibiotic currently available. The large diversity of active-site structures and metal content among MBLs from different sources has limited the design of a pan-MBL inhibitor. GOB-18 is a divergent MBL from subclass B3 that is expressed by the opportunistic Gram-negative pathogen Elizabethkingia meningoseptica This MBL is atypical, since several residues conserved in B3 enzymes (such as a metal ligand His) are substituted in GOB enzymes. Here, we report the crystal structure of the periplasmic di-Zn(II) form of GOB-18. This enzyme displays a unique active-site structure, with residue Gln116 coordinating the Zn1 ion through its terminal amide moiety, replacing a ubiquitous His residue. This situation contrasts with that of B2 MBLs, where an equivalent His116Asn substitution leads to a di-Zn(II) inactive species. Instead, both the mono- and di-Zn(II) forms of GOB-18 are active against penicillins, cephalosporins, and carbapenems. In silico docking and molecular dynamics simulations indicate that residue Met221 is not involved in substrate binding, in contrast to Ser221, which otherwise is conserved in most B3 enzymes. These distinctive features are conserved in recently reported GOB orthologues in environmental bacteria. These findings provide valuable information for inhibitor design and also posit that GOB enzymes have alternative functions

Virulence role of the outer membrane protein CarO in carbapenem-resistant Acinetobacter baumannii

© 2020 The Author(s)Novel approaches to treat carbapenem-resistant Acinetobacter baumannii (CRAB) infections are urgently needed and anti-virulence drugs represent promising alternatives, but our knowledge on potential targets is scarce. We searched for potential A. baumannii virulence factors by whole-genome sequencing-based comparisons of CRAB clinical isolates causing bloodstream infections secondary to ventilator-associated pneumonia from demographics and clinically homogeneous patients, who received optimal treatment but with different clinical outcomes. Thus, the carO gene was interrupted in CRAB isolates from surviving patients, while it was intact in isolates from non-surviving patients, and proteomic/immunoblot techniques corroborated it. When the virulence role of A. baumannii CarO was analyzed in model systems, isogenic ΔcarO mutants and a CRAB clinical isolate with truncated CarO, showed lower ability to adhere and invade A549 cells and in vivo virulence. This unnoticed virulence role for CarO postulate this A. baumannii outer membrane protein as a potential target for new therapies against CRAB infections.This work was supported by the Instituto de Salud Carlos III, Proyectos de Investigación en Salud under grant [PI12/0255]; Plan Nacional de I+D+i 2013-2016 and Instituto de Salud Carlos III, Subdirección General de Redes y Centros de Investigación Cooperativa, Ministerio de Ciencia, Innovación y Universidades under grant [BFU2016-77297-P]; Plan Nacional de I+D+i 2013-2016 and Instituto de Salud Carlos III, Subdirección General de Redes y Centros de Investigación Cooperativa, Ministerio de Ciencia, Innovación y Universidades, Spanish Network for Research in Infectious Diseases under grant [REIPI RD16/0016/0009] - co-financed by European Development Regional Fund “A way to achieve Europe,” Operative program Intelligent Growth 2014-2020; and Agencia Nacional de Promoción Científica y Tecnológica, ANPCyT, Argentina, under grants [PICT-2015-1072 and PICT-2017-3536]. G.L.H. was supported by the program i-PFIS (Doctorados IIS-Empresa en Ciencias y Tecnologías de la Salud), Instituto de Salud Carlos III, Subdirección General de Redes y Centros de Investigación Cooperativa, Ministerio de Ciencia, Innovación y Universidades under grant [IFI15/ 00128]. T.C.C. is supported by the V Plan Propio of the University of Seville with a postdoctoral contract. M.E.P. I. is a postdoctoral researcher belonging to the program “Nicolás Monardes” (C1-0038-2019), Servicio Andaluz de Salud, Junta de Andalucía, Spain