Estructura cristalográfica de la B-lactamasa oxa-24: bases estructurales que determinan su actividad carbapenemasa

146 p.-77 fig.-18 tab.OXA-24 is a class D carbapenem-hydrolyzing oxacillinase extracted from a clinically epidemic multidrug-resistant Acinetobacter baumannii strain. In contrast to other oxacillinases, most of these OXA-type carbapenemases do not present hydrolytic activity against oxacillin, cloxacillin, and methicillin, and they display activity against carbapenems. Moreover, these enzymes are widely dispersed in clinically relevant species, such as A. baumannii and Pseudomonas aeruginosa. Carbapenems are the remaining drug of choice to treat these multiresistant pathogens responsible for severe nosocomial infections. Thus, the emergence of OXA-type carbapenemases represents a particularly disturbing problem. The native form of OXA-24 is a monomer with 275 residues. OXA-24 folds into an α/β structure composed by two domains, one helical and one mixed α/β containing a six stranded antiparallel β-sheet covered by the N- and C-terminal α- helices. The active site of OXA-24 lies in a cleft at the interface of the β-sheet and the helical domain and is composed of three highly conserved motifs in all Class D β- lactamases, which are referred to as the active site elements 1 (S81-T82-F83-K84), 2 (S128-A129-V130) and 3 (K218-S219-G220). The first element is located at the N-terminal end of the 310 helix 3 and contains the catalytic serine (S81) and the carboxylated lysine (K84), which plays a regulatory role in the acylation- deacylation process. The second motif is located at the loop connecting helices 4 and 5 and the third active site element is made up by residues from the β4 strand. The interaction between Y112 and M223 is essential for the carbapenem specificity in OXA-24. The interaction between these residues creates a hydrophobic barrier that limits the access to the catalytic site, defining a tunnel- like entrance to the active site. The substrate is anchored into the tunnel-like cavity of the binding site through the Y112 that binds the 6-hydroxyethyl group of the carbapenemic antibiotics, playing an important role in the catalytic efficiency of OXA-24 for carbapenems. The key role of the Y112 and the M223 has been confirmed by mutagenesis studies. The substitution of the residues Y112 and M223 by alanine eliminates the hydrophobic barrier essential for the carbapenem specificity and decreased significantly the hydrolytic activity of OXA-24 against carbapenems. When both amino acids are mutated, the MIC for imipenem and meropenem decreased and reached basal levels, respectively. Biochemical experiments also confirm the lower catalytic efficiency of the mutants for carbapenems.Class D carbapenemases are usually resistant to commercial β-lactamase inhibitors, so new effective inhibitors are urgently needed. Three unique 6- alkylidene-2 ́- substituted penicillanic acid sulfones were synthesized and tested against OXA-24. The X-ray structures of OXA-24 in complex with these compounds reveal the formation of stable bicyclic aromatic intermediates with their carbonyl oxygen in the oxyanion hole. The position of the inhibitors was clearly defined in the active site through its conjugated acyl group covalently attached to the catalytic serine (S81). The conformation of the active site is very similar to that of the native enzyme, but several conformational changes can be observed in some residues involved directly in the accommodation of the inhibitor. A network of interactions contributes to stabilize the intermediate state. The stable acyl-enzyme complexes from the 6- alkylidene-2′-substituted penicillin sulfone inhibitors are formed by a sequence of events in which the initial nucleophilic attack of S81 Oγ on the carbonyl of the penicillin ring releases the β-lactam nitrogen lone pair, thus enabling the opening of the neighboring sulfone ring. Another rearrangement provided by the pyridyl nitrogen bonded to the former C5 of the resultant imine leads to the formation of the crystallographically observed indolizine system. These data provide us with the first structural evidence that 6-alkylidene-2 ́- substituted penicillin sulfones are effective mechanism-based inactivators of class D β-lactamases.Peer reviewe

Estructura cristalográfica de la β-lactamasa OXA-24: bases estructurales que determinan su actividad carbapenemasa

Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 26-03-201

Structural characterization of TssL from Acinetobacter baumannii: A key component of the type VI secretion system

The type VI secretion system (T6SS) is a complex molecular nanomachine used by Gram-negative bacteria to deliver diverse effectors into adjacent cells. A membrane complex (MC) anchors this transport system to the bacterial cell wall. One of the proteins forming the MC is TssL, a cytoplasmic protein bound to the inner membrane through a single transmembrane helix. Here, we report the structure of the cytoplasmic N-terminal region of TssL fro

Asociación entre los trastornos temporomandibulares y el tipo de bruxismo, evaluados radiográficamente.

Introducción Los Trastornos Temporomandibulares (TTM) constituyen un grupo de condiciones dolorosas que afectan a la Articulación Temporomandibular y/o a los músculos de la masticación cuya etiología es multifactorial. Diversos autores han estudiado el papel etiológico de las parafunciones como el bruxismo; caracterizado por el apretar y/o rechinar los dientes

Near real-time surveillance of the SARS-CoV-2 epidemic with incomplete data

When responding to infectious disease outbreaks, rapid and accurate estimation of the epidemic trajectory is critical. However, two common data collection problems affect the reliability of the epidemiological data in real time: missing information on the time of first symptoms, and retrospective revision of historical information, including right censoring. Here, we propose an approach to construct epidemic curves in near real time that addresses these two challenges by 1) imputation of dates of symptom onset for reported cases using a dynamically-estimated "backward" reporting delay conditional distribution, and 2) adjustment for right censoring using the NobBS software package to nowcast cases by date of symptom onset. This process allows us to obtain an approximation of the time-varying reproduction number (Rt) in real time. We apply this approach to characterize the early SARS-CoV-2 outbreak in two Spanish regions between March and April 2020. We evaluate how these real-time estimates compare with more complete epidemiological data that became available later. We explore the impact of the different assumptions on the estimates, and compare our estimates with those obtained from commonly used surveillance approaches. Our framework can help improve accuracy, quantify uncertainty, and evaluate frequently unstated assumptions when recovering the epidemic curves from limited data obtained from public health systems in other locations.PMD was supported by the fellowship Ramón Areces Foundation. JAH was funded by the National Institute of General Medical Sciences, Award U54GM088558, and the National Institutes of Health Director’s Early Independence, Award DP5-OD028145. ML was supported by the Morris-Singer Fund and by a subcontract from the Carnegie Mellon University under an award from the US Centers for Disease Control and Prevention, Award U01IP001121). MS was supported by the National Institute Of General Medical Sciences, Award R01GM130668-02. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.S

Peptidyl Nitroalkene Inhibitors of Main Protease (Mpro) rationalized by Computational/1 Crystallographic 2 Investigations as Antivirals against SARS-CoV-2

34 p.-10 fig.-2 tab.-2 schem.The coronavirus disease 2019 (COVID-19) pandemic continues to represent a global public health issue. The viral main protease (Mpro) represents one of the most attractive targets for the development of antiviral drugs. Herein we report peptidyl nitroalkenes exhibited enzyme inhibitory activity against Mpro (Ki: 1-10 μM) and three of them good anti-SARS-CoV-2 infection activity in the low micromolar range (EC50: 1-12 μM) without significant toxicity. Additional kinetic studies of compounds FGA145, FGA146 and FGA147 show that all three compounds inhibit Cathepsin L, denoting a possible multitarget effect of these compounds in the antiviral activity. QM/MM computer simulations assisted in the design and in elucidating the way of action. Finally, structural analysis shows, in agreement with the computer predictions, the binding mode of FGA146 and FGA147 to the active site of the protein. Our results illustrate that peptidyl nitroalkenes are potent covalent reversible inhibitors of the Mpro and cathepsin L, and that inhibitors FGA145, FGA146 and FGA147 prevent infection becoming promising drugs against SARS-CoV-2.This research was funded by the Consejo Superior de Investigaciones Científicas, grant number PIE- 202020E224, the Spanish Ministerio de Ciencia e Innovación (ref. PID2021-123332OB-C21 and PID2019- 107098RJ-I00), the Generalitat Valenciana (PROMETEO with ref. CIPROM/2021/079, and SEJI/2020/007), Universitat Jaume I (UJI-B2020-03, UJI-B2021-71 and SomUJIcontracovid crowdfunding campaign).K.Ś.thanks to Ministerio de Ciencia e Innovación and Fondo Social Europeo for a Ramon y Cajal contract (Ref. RYC2020-030596-I). The authors wish to thank the staff of beamlines ID30B (ESRF Synchrotron) and BL13- XALOC (ALBA Synchrotron) for their generous and much appreciated support, and the Serveis Centrals d’Instrumentació Científica of Universitat Jaume I for technical support. Finally, the authors acknowledge the computer resources at Mare Nostrum of the Barcelona Supercomputing Center (QH-2022-2-0004 and QH- 2022-3-0008), as well as the local computational resources founded by Generalitat Valenciana - European Regional Development Fund (REF: IDIFEDER/2021/02).Peer reviewe

One-year breakthrough SARS-CoV-2 infection and correlates of protection in fully vaccinated hematological patients

The long-term clinical efficacy of SARS-CoV-2 vaccines according to antibody response in immunosuppressed patients such as hematological patients has been little explored. A prospective multicenter registry-based cohort study conducted from December 2020 to July 2022 by the Spanish Transplant and Cell Therapy group, was used to analyze the relationship of antibody response over time after full vaccination (at 3-6 weeks, 3, 6 and 12 months) (2 doses) and of booster doses with breakthrough SARS-CoV-2 infection in 1551 patients with hematological disorders. At a median follow-up of 388 days after complete immunization, 266 out of 1551 (17%) developed breakthrough SARS-CoV-2 infection at median of 86 days (range 7-391) after full vaccination. The cumulative incidence was 18% [95% confidence interval (C.I.), 16-20%]. Multivariate analysis identified higher incidence in chronic lymphocytic leukemia patients (29%) and with the use of corticosteroids (24.5%), whereas female sex (15.5%) and more than 1 year after last therapy (14%) were associated with a lower incidence (p < 0.05 for all comparisons). Median antibody titers at different time points were significantly lower in breakthrough cases than in non-cases. A serological titer cut-off of 250 BAU/mL was predictive of breakthrough infection and its severity. SARS-CoV-2 infection-related mortality was encouragingly low (1.9%) in our series. Our study describes the incidence of and risk factors for COVID-19 breakthrough infections during the initial vaccination and booster doses in the 2021 to mid-2022 period. The level of antibody titers at any time after 2-dose vaccination is strongly linked with protection against both breakthrough infection and severe disease, even with the Omicron SARS-CoV-2 variant

Proyecto Puentes: conectando la universidad con la salud mental comunitaria

Se presenta la memoria del Proyecto Puentes, cuya finalidad es explorar e implementar vías de participación entre la comunidad universitaria y las personas con problemas de salud mental. Es decir, tender puentes entre lo académico y la realidad de esas personas, con el propósito de conseguir una fuente de aprendizaje significativo para el estudiantado de la UCM, pero también herramientas útiles en los procesos de recuperación e integración de las personas con problemáticas de salud mental.Depto. de Personalidad, Evaluación y Psicología ClínicaFac. de PsicologíaFALSEsubmitte

COVID-19 Severity and Survival over Time in Patients with Hematologic Malignancies: A Population-Based Registry Study

Mortality rates for COVID-19 have declined over time in the general population, but data in patients with hematologic malignancies are contradictory. We identified independent prognostic factors for COVID-19 severity and survival in unvaccinated patients with hematologic malignancies, compared mortality rates over time and versus non-cancer inpatients, and investigated post COVID-19 condition. Data were analyzed from 1166 consecutive, eligible patients with hematologic malignancies from the population-based HEMATO-MADRID registry, Spain, with COVID-19 prior to vaccination roll-out, stratified into early (February–June 2020; n = 769 (66%)) and later (July 2020–February 2021; n = 397 (34%)) cohorts. Propensity-score matched non-cancer patients were identified from the SEMI-COVID registry. A lower proportion of patients were hospitalized in the later waves (54.2%) compared to the earlier (88.6%), OR 0.15, 95%CI 0.11–0.20. The proportion of hospitalized patients admitted to the ICU was higher in the later cohort (103/215, 47.9%) compared with the early cohort (170/681, 25.0%, 2.77; 2.01–3.82). The reduced 30-day mortality between early and later cohorts of non-cancer inpatients (29.6% vs. 12.6%, OR 0.34; 0.22–0.53) was not paralleled in inpatients with hematologic malignancies (32.3% vs. 34.8%, OR 1.12; 0.81–1.5). Among evaluable patients, 27.3% had post COVID-19 condition. These findings will help inform evidence-based preventive and therapeutic strategies for patients with hematologic malignancies and COVID-19 diagnosis.Depto. de MedicinaFac. de MedicinaTRUEFundación Madrileña de Hematología y HemoterapiaFundación Leucemia y LinfomaAsociación Madrileña de Hematología y Hemoterapiapu

Applicability of probabilistic graphical models for early detection of SARS-CoV-2 reactive antibodies after SARS-CoV-2 vaccination in hematological patients

Prior studies of antibody response after full SARS-CoV-2 vaccination in hematological patients have confirmed lower antibody levels compared to the general population. Serological response in hematological patients varies widely according to the disease type and its status, and the treatment given and its timing with respect to vaccination. Through probabilistic machine learning graphical models, we estimated the conditional probabilities of having detectable anti-SARS-CoV-2 antibodies at 3–6 weeks after SARS-CoV-2 vaccination in a large cohort of patients with several hematological diseases (n= 1166). Most patients received mRNA-based vaccines (97%), mainly Moderna® mRNA-1273 (74%) followed by Pfizer-BioNTech® BNT162b2 (23%). The overall antibody detection rate at 3 to 6 weeks after full vaccination for the entire cohort was 79%. Variables such as type of disease, timing of anti-CD20 monoclonal antibody therapy, age, corticosteroids therapy, vaccine type, disease status, or prior infection with SARS-CoV-2 are among the most relevant conditions influencing SARS-CoV-2-IgG-reactive antibody detection. A lower probability of having detectable antibodies was observed in patients with B-cell non-Hodgkin’s lymphoma treated with anti-CD20 monoclonal antibodies within 6 months before vaccination (29.32%), whereas the highest probability was observed in younger patients with chronic myeloproliferative neoplasms (99.53%). The Moderna® mRNA-1273 compound provided higher probabilities of antibody detection in all scenarios. This study depicts conditional probabilities of having detectable antibodies in the whole cohort and in specific scenarios such as B cell NHL, CLL, MM, and cMPN that may impact humoral responses. These results could be useful to focus on additional preventive and/or monitoring interventions in these highly immunosuppressed hematological patients.REDCap is developed and supported by Vanderbilt Institute for Clinical and Translational Research. We thank the Spanish Society of Hematology (SEHH) for its support on the study. We sincerely want to thanks the invaluable aid of microbiology services for their commitment in SARS-CoV-2-reactive IgG antibody monitoring in these highly immunosuppressed patients from all participating centers. Finally, we also want to thank the patients, nurses, and study coordinators for their foremost contributions in this study.Peer reviewe