nc Clock Ticking on Senate Bill to Overhaul NCLB By feedproxy.google.com Published On :: Mon, 31 Oct 2011 00:00:00 +0000 A measure to renew the Elementary and Secondary Education Act faces steep political hurdles. Full Article Multimedia
nc Cremer group developing sensors to detect coronavirus in enclosed spaces By news.psu.edu Published On :: Tue, 28 Apr 2020 10:06 -0400 Professor of Chemistry Paul Cremer is developing a biosensor platform that could be used to perform real-time, continuous detection of SARS-CoV-2, the virus that causes COVID-19. Full Article
nc Eberly College of Science selects two student marshals for Spring 2020 By news.psu.edu Published On :: Wed, 29 Apr 2020 08:36 -0400 Chemistry major Sojung Kim and microbiology major Cuyler Luck will represent the Eberly College of Science as student marshals during Penn State’s virtual spring commencement ceremonies on Saturday, May 9. Full Article
nc Enter for Your Chance to Win a OnePlus 2 By www.pcmag.com Published On :: Is $349 still too pricey for a OnePlus 2? Enter our contest and you could get one for free. Full Article
nc France 2000 drill By www.uefa.com Published On :: Sun, 04 Mar 2012 07:32:00 GMT A training routine focused on movement, passing and dribbling inspired by the winning France team at UEFA EURO 2000. Full Article
nc Personalize Learning and Build Agency By Using the 4 PLC Questions By feedproxy.google.com Published On :: Wed, 22 Aug 2018 00:00:00 +0000 In this episode of the podcast, Tom chats with Tim Stuart about his new book, Personalized Learning in a PLC at Work: Student Agency Through the Four Critical Questions. Full Article Professionaldevelopment
nc Why We Need Transformative Learning Experiences By feedproxy.google.com Published On :: Tue, 23 Apr 2019 00:00:00 +0000 Two things are true as I sort through my reflections on transformative learning experiences: We need intensive, immersive opportunities for learning (such as a trip to Kenya) and we also need to build in mini-opportunities for transformative learning every day. Full Article Professionaldevelopment
nc A Gap in Teacher Training: Working With Students Who Have Concussions By feedproxy.google.com Published On :: Wed, 12 Jun 2019 00:00:00 +0000 A growing number of students have experienced a brain injury that could affect their ability to learn in school. Yet most teachers aren't prepared to work with these students. Full Article Professionaldevelopment
nc 'It's Not Just Yoga and Nail Paint': Inside the Teacher Self-Care Conference By feedproxy.google.com Published On :: Mon, 24 Jun 2019 00:00:00 +0000 The two-day event, now in its third year, offers workshops on mental health and burnout, time-management and goal-setting, and strategies for navigating toxic workplace environments. Full Article Professionaldevelopment
nc Fin24.com | Saudis begin internal probe into journo's disappearance as US tensions intensify By www.fin24.com Published On :: Mon, 15 Oct 2018 18:23:25 +0200 Saudi Arabia has begun an internal investigation into the disappearance of a prominent journalist at its Istanbul consulate and could hold people accountable if the evidence warrants it, according to a Saudi official. Full Article
nc Fin24.com | WATCH: How would Saudi Arabia retaliate if US imposes sanctions? By www.fin24.com Published On :: Tue, 16 Oct 2018 10:38:46 +0200 An op-ed in Saudi-owned Al Arabiya news has warned of repercussions should the US impose sanctions on Saudi Arabia over the disappearance of journalist Jamal Khashoggi. Full Article
nc Fin24.com | Saudi Crown Prince has `blood on his hands', Erdogan aide says By www.fin24.com Published On :: Wed, 24 Oct 2018 10:03:20 +0200 Saudi Crown Prince Mohammed bin Salman has “blood on his hands” in the killing of journalist Jamal Khashoggi, a top aide to Turkey’s president said, in his country’s first direct accusation against the power behind the Saudi throne. Full Article
nc Energy, environmental strategic planning community forums announced for May By news.psu.edu Published On :: Mon, 27 Apr 2020 15:02 -0400 The Institutes of Energy and the Environment, in collaboration with Stewarding Our Planet's Resources, announced two separate community forums aimed at providing reports on existing energy and environmental activities and strategic opportunities as well as soliciting community input and recommendations for the future. Full Article
nc College of Agricultural Sciences stays connected with alumni during pandemic By news.psu.edu Published On :: Fri, 01 May 2020 15:32 -0400 Penn State’s College of Agricultural Sciences is staying connected to alumni during the COVID-19 pandemic by moving its monthly Alumni Society board meetings and other alumni activities online. Full Article
nc Graduating food-science student parlays undergrad research experience into job By news.psu.edu Published On :: Wed, 06 May 2020 17:50 -0400 Gabriella Pinto provides a great example of what undergraduate research can do for a student. The Penn State food science major, who graduates this month, is headed for a good job armed with a wealth of experience and knowledge from her research, which gives her a leg up on her career. Full Article
nc Burundi Under Seige: Lift the Sanctions; Re-launch the Peace Process By feedproxy.google.com Published On :: Mon, 27 Apr 1998 22:00:00 GMT Full Article
nc Burundi: Internal and Regional Implications of the Suspension of Sanctions By feedproxy.google.com Published On :: Mon, 03 May 1999 22:00:00 GMT Full Article
nc How Kabila Lost His Way: The Performance of Laurent Désiré Kabila's Government By feedproxy.google.com Published On :: Thu, 20 May 1999 22:00:00 GMT Full Article
nc Journey through Congo. A new chance for Africa's ravaged heart By feedproxy.google.com Published On :: Mon, 03 Nov 2003 23:00:00 GMT Full Article
nc The Congo: Solving the FDLR Problem Once and for All By feedproxy.google.com Published On :: Wed, 11 May 2005 22:00:00 GMT Full Article
nc Inclusive Security: Hope for Congo By feedproxy.google.com Published On :: Wed, 28 Dec 2005 23:00:00 GMT Full Article
nc Escaping the Conflict Trap: Promoting Good Governance in the Congo By feedproxy.google.com Published On :: Wed, 19 Jul 2006 22:00:00 GMT Full Article
nc Struggle for a Functioning Congo By feedproxy.google.com Published On :: Thu, 03 Aug 2006 22:00:00 GMT Full Article
nc Central African Republic: "Relancer le dialogue politique By feedproxy.google.com Published On :: Mon, 01 Feb 2010 23:00:00 GMT Full Article
nc Elections au Burundi : Prévenir toute escalade de violence By feedproxy.google.com Published On :: Tue, 02 Mar 2010 23:00:00 GMT Full Article
nc Libya/Chad: Beyond Political Influence By feedproxy.google.com Published On :: Mon, 22 Mar 2010 23:00:00 GMT Full Article
nc Violencia y elecciones en los Grandes Lagos By feedproxy.google.com Published On :: Sun, 04 Apr 2010 22:00:00 GMT Burundi escapó de una guerra civil y años de terror. Hoy se supone que vive en democracia, pero eso está por verse. Ante las próximas elecciones de mayo, y con el panorama de violencia política que asuela el país, parece imposible que éstas se celebren pacíficamente y bajo el paraguas de la democracia. Full Article
nc Le dilemme de l’assistance électorale internationale en Afrique centrale By feedproxy.google.com Published On :: Thu, 10 Jun 2010 22:00:00 GMT La fièvre des élections s’empare de l’Afrique centrale. Pour la seconde fois depuis la fin des guerres qui ont dévasté la région, les scrutins s’enchaînent au Burundi, au Rwanda, en République centrafricaine et au Congo. Full Article
nc The dilemma of electoral assistance in Central Africa By feedproxy.google.com Published On :: Tue, 29 Jun 2010 22:00:00 GMT Election fever has spread across Central Africa. For the second time since the end of the disastrous civil wars in the region, electoral processes have been launched in Burundi, Rwanda, Central African Republic and the Congo. Full Article
nc Congo Crimes Should Be on the Agenda of the UN Security Council By feedproxy.google.com Published On :: Wed, 13 Oct 2010 22:00:00 GMT The UN's release of a long awaited report on crimes committed in the Democratic Republic of Congo between 1993-2003 is not only an opportunity to re-examine the historical record of mass violence in DRC -- the scale and nature of which was often overlooked in the wake of the genocide in neighboring Rwanda -- but is also a chance to correct the terms of the deceptive and fragile peace some leaders wish to proclaim in the resource-rich Great Lakes region of Africa. Full Article
nc Derrière le problème des minerais des conflits, la gouvernance du Congo By feedproxy.google.com Published On :: Tue, 12 Apr 2011 22:00:00 GMT A la veille de l’entrée en vigueur le 15 avril de l’obligation de rendre publique l’origine des minerais pour les grandes compagnies basées aux Etats-Unis, ICG a effectué une mission au Nord Kivu afin d’évaluer les différentes stratégies de lutte contre les minerais des conflits et leur impact sur le terrain. Full Article
nc Behind the Problem of Conflict Minerals in DR Congo: Governance By feedproxy.google.com Published On :: Mon, 18 Apr 2011 22:00:00 GMT As legislation requiring large U.S. companies to disclose the origins of the minerals they use is meant to come into force this year, Crisis Group sent a mission to North Kivu to assess the different strategies used to fight conflict minerals and their impact in the field. Full Article
nc The Lord’s Resistance Army: End Game? By feedproxy.google.com Published On :: Wed, 16 Nov 2011 23:00:00 GMT Insufficient political will has thwarted regional efforts to stop the murderous Lord’s Resistance Army (LRA) but vigorous diplomacy led by the African Union (AU), an immediate military push and complementary civilian initiatives could end the misery of thousands. Full Article
nc Francophonie : aller ou ne pas aller à Kinshasa By feedproxy.google.com Published On :: Sun, 01 Jul 2012 22:00:00 GMT François Hollande semble hésiter à se rendre à Kinshasa en octobre pour le sommet de la francophonie. Il serait bien inspiré de ne pas offrir au président, Joseph Kabila, une telle occasion de s’afficher réconcilié avec les démocraties après les élections présidentielle et législative calamiteuses en République démocratique du Congo (RDC) qui privent le régime d’une véritable légitimité démocratique. En se rendant à Kinshasa, François Hollande enverrait un message plus que trouble aux pays d’Afrique où la démocratisation est encore une lutte quotidienne que l’on paie au prix du sang. Full Article
nc Fields of Bitterness (II): Restitution and Reconciliation in Burundi By feedproxy.google.com Published On :: Mon, 17 Feb 2014 09:35:00 GMT To avoid a revival of past ethnic tensions between Hutu and Tutsi, Burundi needs to find the right balance between land restitution and national reconciliation. Full Article
nc Danger de rechute au Burundi : question foncière et consolidation de la paix By feedproxy.google.com Published On :: Wed, 19 Feb 2014 23:00:00 GMT Le Burundi est l’un des pays les plus pauvres (le taux de pauvreté atteint 67 %) et les plus petits d’Afrique (27 834 kilomètres carrés) avec l’une des plus grandes densités humaines du continent (près de 400 habitants par kilomètre carré). C’est du reste un pays profondément rural où seulement 11 % de la population réside en ville. Alors que l’accès à la terre et à la propriété est un véritable enjeu socio-économique, le Burundi fait face à de sérieux problèmes agricoles. Full Article
nc Les élections seront-elles l’étincelle qui mettra le feu au Burundi ? By feedproxy.google.com Published On :: Wed, 03 Jun 2015 22:00:00 GMT Tous les éléments d’une confrontation violente sont en place en Burundi. En observant les derniers développements, il semble que les éléments qui ont conduit par le passé à des massacres et à une longue guerre civile au début des années 1990 se remettent en place. Full Article
nc Central African Republic: The Roots of Violence By feedproxy.google.com Published On :: Sun, 20 Sep 2015 22:00:00 GMT In Central African Republic, the conflict between armed groups is now compounded by a conflict between armed communities. The roadmap to end the crisis including elections late 2015 presents only a short-term answer and risks exacerbating existing tensions. The transitional authorities and their international partners must address crucial issues by implementing a comprehensive disarmament policy and reaffirming that Muslims belong within the nation. Full Article
nc Testing and Accountability in the NCLB Era By feedproxy.google.com Published On :: Tue, 19 Aug 2008 00:00:00 +0000 David Figlio and Eduwonkette discuss if today's testing and accountability policies accurately depict student performance and the size of the achievement Full Article Assessment+Accountability+Achievement
nc Assessment of drug resistance during phase 2b clinical trials of presatovir in adults naturally infected with respiratory syncytial virus [Antiviral Agents] By aac.asm.org Published On :: 2020-02-18T08:15:40-08:00 Background: This study summarizes drug resistance analyses in 4 recent phase 2b trials of the respiratory syncytial virus (RSV) fusion inhibitor presatovir in naturally infected adults.Methods: Adult hematopoietic cell transplant (HCT) recipients, lung transplant recipients, or hospitalized patients with naturally acquired, laboratory-confirmed RSV infection were enrolled in 4 randomized, double-blind, placebo-controlled studies with study-specific presatovir dosing. Full-length RSV F sequences amplified from nasal swabs obtained at baseline and postbaseline were analyzed by population sequencing. Substitutions at RSV fusion inhibitor resistance-associated positions are reported.Results: Genotypic analyses were performed on 233 presatovir-treated and 149 placebo-treated subjects. RSV F variant V127A was present in 8 subjects at baseline. Population sequencing detected treatment-emergent substitutions in 10/89 (11.2%) HCT recipients with upper and 6/29 (20.7%) with lower respiratory tract infection, 1/35 (2.9%) lung transplant recipients, and 1/80 (1.3%) hospitalized patients treated with presatovir; placebo-treated subjects had no emergent resistance-associated substitutions. Subjects with substitutions at resistance-associated positions had smaller decreases in viral load during treatment relative to those without, but similar clinical outcomes.Conclusions: Subject population type and dosing regimen may have influenced RSV resistance development during presatovir treatment. Subjects with vs without genotypic resistance development had decreased virologic responses but comparable clinical outcomes. Full Article
nc Biochemical Characterization of QPX7728, a New Ultra-Broad-Spectrum Beta-lactamase Inhibitor of Serine and Metallo-Beta-Lactamases [Mechanisms of Resistance] By aac.asm.org Published On :: 2020-03-09T08:34:13-07:00 QPX7728 is a new ultra-broad-spectrum inhibitor of serine and metallo beta-lactamases from a class of cyclic boronates that gave rise to vaborbactam. The spectrum and mechanism of beta-lactamase inhibition by QPX7728 were assessed using purified enzymes from all molecular classes. QPX7728 inhibits class A ESBLs (IC50 range 1-3 nM) and carbapenemases such as KPC (IC50 2.9±0.4 nM) as well as class C P99 (IC50 of 22±8 nM) with a potency that is comparable or higher than recently FDA approved BLIs avibactam, relebactam and vaborbactam. Unlike those other BLIs, QPX7728 is also a potent inhibitor of class D carbapenemases such as OXA-48 from Enterobacteriaceae and OXA enzymes from A. baumannii (OXA-23/24/58, IC50 range 1-2 nM) as well as MBLs such as NDM-1 (IC50 55±25 nM), VIM-1 (IC50 14±4 nM) and IMP-1 (IC50 610±70 nM). Inhibition of serine enzymes by QPX7728 is associated with progressive inactivation with a high efficiency k2/K ranging from of 6.3 x 104 (for P99) to 9.9 x 105 M-1 s-1 (for OXA-23). This inhibition is reversible with variable stability of the QPX7728-beta-lactamase complexes with target residence time ranging from minutes to several hours: 5-20 minutes for OXA carbapenemases from A. baumanii, ~50 minutes for OXA-48 and 2-3 hours for KPC and CTX-M-15. QPX7728 inhibited all tested serine enzymes at 1:1 molar ratio. Metallo-beta-lactamases NDM, VIM, and IMP were inhibited by a competitive mechanism with fast-on-fast-off kinetics, with Kis of 7.5±2.1 nM, 32±14 nM and 240±30 nM for VIM-1, NDM-1 and IMP-1, respectively. QPX7728 ultra-broad-spectrum of BLI inhibition combined with its high potency enables combinations with multiple different beta-lactam antibiotics. Full Article
nc A histone methyltransferase inhibitor can reverse epigenetically acquired drug resistance in the malaria parasite Plasmodium falciparum [Mechanisms of Resistance] By aac.asm.org Published On :: 2020-03-16T08:17:37-07:00 Malaria parasites invade and replicate within red blood cells (RBCs), extensively modifying their structure and gaining access to the extracellular environment by placing the plasmodial surface anion channel (PSAC) into the RBC membrane. Expression of members of the cytoadherence linked antigen gene 3 (clag3) family is required for PSAC activity, a process that is regulated epigenetically. PSAC is a well-established route of uptake for large, hydrophilic antimalarial compounds and parasites can acquire resistance by silencing clag3 gene expression, thereby reducing drug uptake. We found that exposure to sub-IC50 concentrations of the histone methyltransferase inhibitor chaetocin caused substantial changes in both clag3 gene expression and RBC permeability, reversing acquired resistance to the antimalarial compound blasticidin S that is transported through PSAC. Chaetocin treatment also altered progression of parasites through their replicative cycle, presumably by changing their ability to modify chromatin appropriately to enable DNA replication. These results indicate that targeting histone modifiers could represent a novel tool for reversing epigenetically acquired drug resistance in P. falciparum. Full Article
nc Effect of drug pressure on promoting the emergence of antimalarial resistant parasites among pregnant women in Ghana [Mechanisms of Resistance] By aac.asm.org Published On :: 2020-03-16T08:17:37-07:00 Continuous spread of antimalarial drug resistance is a threat to current chemotherapy efficacy. Therefore, characterizing the genetic diversity of drug resistance markers is needed to follow treatment effectiveness and further update control strategies. Here, we genotyped Plasmodium falciparum resistance gene markers associated with sulfadoxine-pyrimethamine (SP) and artemisinin-based combination therapy (ACT) in isolates from pregnant women in Ghana. The prevalence of the septuple IRNI-A/FGKGS/T pfdhfr/pfdhps haplotypes including the pfdhps A581G and A613S/T mutations was high at delivery among post-SP treatment isolates (18.2%) compared to those of first-antenatal care (before initiation of intermittent preventive treatment of malaria in pregnancy with sulfadoxine-pyrimethamine (IPTp-SP); 6.1%; p = 0.03). Regarding the pfk13 marker gene, two non-synonymous mutations (N458D and A481C) were detected at positions previously related to artemisinin resistance in isolates from Southeast-Asia. These mutations were predicted in silico to alter the stability of the pfk13 propeller-encoding domain. Overall, these findings highlight the need for intensified monitoring and surveillance on additional mutations associated with increased SP resistance as well as emergence of resistance against artemesinin derivatives. Full Article
nc Significant efficacy of single low dose primaquine compared to stand alone artemisinin combination therapy in reducing gametocyte carriage in Cambodian patients with uncomplicated multidrug resistant Plasmodium falciparum malaria [Epidemiology and Surveil By aac.asm.org Published On :: 2020-03-16T08:17:37-07:00 Since 2012, single low dose of primaquine (SLDPQ, 0.25mg/kg) has been recommended with artemisinin-based combination therapies, as first-line treatment of acute uncomplicated Plasmodium falciparum malaria, to interrupt its transmission, especially in low transmission settings of multidrug, including artemisinin, resistance. Policy makers in Cambodia have been reluctant to implement this recommendation due to primaquine safety concerns and lack of data on its efficacy.In this randomized controlled trial, 109 Cambodians with acute uncomplicated P. falciparum malaria received dihydroartemisinin-piperaquine (DP) alone or combined with SLDPQ on the first treatment day. Transmission-blocking efficacy of SLDPQ was evaluated on Days 0, 1, 2, 3, 7, 14, 21, 28 and recrudescence by reverse transcriptase polymerase chain reaction (RT-PCR) (gametocyte prevalence) and membrane-feeding assays with Anopheles minimus mosquitoes (gametocyte infectivity). Without the influence of recrudescent infections, DP+SLDPQ reduced gametocyte carriage 3 fold compared to DP. Of 48 patients tested on Day 0, only three patients were infectious to mosquitoes (~6%). Post-treatment, three patients were infectious: on D14 (3.5%, 1/29), and on the first and seventh day of recrudescence (8.3%, 1/12 for each); this overall low infectivity precluded our ability to assess its transmission blocking efficacy.Our study confirms effective gametocyte clearance of SLDPQ when combined with DP in multidrug resistant P. falciparum and the negative impact of recrudescent infections due to poor DP efficacy. Artesunate-mefloquine (ASMQ) has replaced DP and ASMQ-SLDPQ has been deployed to treat all P. falciparum symptomatic patients to further support the elimination of multidrug resistant P. falciparum in Cambodia. Full Article
nc Stp1 loss of function promotes {beta}-lactam resistance in S. aureus that is independent of classical genes [Mechanisms of Resistance] By aac.asm.org Published On :: 2020-03-16T08:17:37-07:00 β-lactam resistance in Staphylococcus aureus limits treatment options. Stp1 and Stk1, a serine-threonine phosphatase and kinase respectively, mediate serine-threonine kinase (STK) signaling. Loss of function point mutations in stp1 were detected among laboratory passaged, β-lactam resistant S. aureus strains lacking mecA and blaZ, the major determinants of β-lactam resistance in the bacteria. Loss of Stp1 function facilitates β-lactam resistance of the bacteria. Full Article
nc ZN148 - a modular synthetic metallo-{beta}-lactamase inhibitor reverses carbapenem-resistance in Gram-negative pathogens in vivo [Experimental Therapeutics] By aac.asm.org Published On :: 2020-03-16T08:17:37-07:00 Carbapenem-resistant Gram-negative pathogens are a critical public health threat and there is an urgent need for new treatments. Carbapenemases (β-lactamases able to inactivate carbapenems) have been identified in both serine β-lactamase (SBL) and metallo β-lactamase (MBL) families. The recent introduction of SBL carbapenemase-inhibitors has provided alternative therapeutic options. Unfortunately, there are no approved inhibitors of MBL-mediated carbapenem-resistance and treatment options for infections caused by MBL-producing Gram-negatives are limited. Here, we present ZN148, a zinc-chelating MBL-inhibitor capable of restoring the bactericidal effect of meropenem and in vitro clinical susceptibility to carbapenems in >98% of a large international collection of MBL-producing clinical Enterobacterales strains (n=234). Moreover, ZN148 was able to potentiate the effect of meropenem against NDM-1-producing Klebsiella pneumoniae in a murine neutropenic peritonitis model. ZN148 showed no inhibition of the human zinc-containing enzyme glyoxylase II at 500 μM and no acute toxicity was observed in an in vivo mouse model with cumulative dosages up to 128 mg/kg. Biochemical analysis showed a time-dependent inhibition of MBLs by ZN148 and removal of zinc ions from the active site. Addition of exogenous zinc after ZN148 exposure only restored MBL activity by ~30%, suggesting an irreversible mechanism of inhibition. Mass-spectrometry and molecular modelling indicated potential oxidation of the active site Cys221 residue. Overall, these results demonstrate the therapeutic potential of a ZN148-carbapenem combination against MBL-producing Gram-negative pathogens and that ZN148 is a highly promising MBL inhibitor, capable of operating in a functional space not presently filled by any clinically approved compound. Full Article
nc The Als3 cell wall adhesin plays a critical role in human Serum amyloid A1 (SAA1)-induced cell death and aggregation in Candida albicans [Mechanisms of Resistance] By aac.asm.org Published On :: 2020-03-23T08:47:35-07:00 Antimicrobial peptides and proteins play critical roles in the host defense against invading pathogens. We recently discovered that recombinantly expressed human and mouse serum amyloid A1 (rhSAA1 and rmSAA1) proteins have potent antifungal activities against the major human fungal pathogen Candida albicans. At high concentrations, rhSAA1 disrupts C. albicans membrane integrity and induces rapid fungal cell death. In the current study, we find that rhSAA1 promotes cell aggregation and targets the C. albicans cell wall adhesin Als3. Inactivation of ALS3 in C. albicans leads to a striking decrease in cell aggregation and cell death upon rhSAA1 treatment, suggesting that Als3 plays a critical role in SAA1 sensing. We further demonstrate that deletion of the transcriptional regulators controlling the expression of ALS3, such as AHR1, BCR1, and EFG1 in C. albicans results in similar effects to that of the als3/als3 mutant upon rhSAA1 treatment. Global gene expression profiling indicates that rhSAA1 has a discernible impact on the expression of cell wall- and metabolism-related genes, suggesting that rhSAA1 treatment could lead to a nutrient starvation effect on C. albicans cells. Full Article
nc Structure and molecular recognition mechanism of IMP-13 metallo-{beta}-lactamase [Mechanisms of Resistance] By aac.asm.org Published On :: 2020-03-23T08:47:35-07:00 Multi-drug resistance among Gram-negative bacteria is a major global public health threat. Metallo-β-lactamases (MBLs) target the most widely-used antibiotic class, the β-lactams, including the most recent-generation carbapenems. Interspecies spread renders these enzymes a serious clinical threat and there are no clinically-available inhibitors. We present crystal structures of IMP-13, a structurally-uncharacterized MBL from Gram-negative Pseudomonas aerugionasa found in clinical outbreaks globally, and characterize the binding using solution NMR-spectroscopy and molecular-dynamics simulations. Crystal structures of apo IMP-13 and bound to four clinically-relevant carbapenem antibiotics (doripenem, ertapenem, imipenem and meropenem) are presented. Active site plasticity and the active-site loop, where a tryptophan residue stabilizes the antibiotic core scaffold, are essential to the substrate-binding mechanism. The conserved carbapenem scaffold plays the most significant role in IMP-13 binding, explaining the broad substrate specificity. The observed plasticity and substrate-locking mechanism provide opportunities for rational drug design of novel metallo-β-lactamase inhibitors, essential in the fight against antibiotic resistance. Full Article
nc Reconciling the potentially irreconcilable? Genotypic and phenotypic amoxicillin-clavulanate resistance in Escherichia coli [Mechanisms of Resistance] By aac.asm.org Published On :: 2020-03-23T08:47:35-07:00 Resistance to amoxicillin-clavulanate, a widely used beta-lactam/beta-lactamase inhibitor combination antibiotic, is rising globally, yet susceptibility testing remains challenging. To test whether whole-genome sequencing (WGS) could provide a more reliable assessment of susceptibility than traditional methods, we predicted resistance from WGS for 976 E. coli bloodstream infection isolates from Oxfordshire, UK, comparing against phenotypes from the BD Phoenix (calibrated against EUCAST guidelines). 339/976 (35%) isolates were amoxicillin-clavulanate resistant. Predictions based solely on beta-lactamase presence/absence performed poorly (sensitivity 23% (78/339)) but improved when genetic features associated with penicillinase hyper-production (e.g. promoter mutations, copy number estimates) were considered (sensitivity 82% (277/339); p<0.0001). Most discrepancies occurred in isolates with peri-breakpoint MICs. We investigated two potential causes; the phenotypic reference and the binary resistant/susceptible classification. We performed reference standard, replicated phenotyping in a random stratified subsample of 261/976 (27%) isolates using agar dilution, following both EUCAST and CLSI guidelines, which use different clavulanate concentrations. As well as disagreeing with each other, neither agar dilution phenotype aligned perfectly with genetic features. A random-effects model investigating associations between genetic features and MICs showed that some genetic features had small, variable and additive effects, resulting in variable resistance classification. Using model fixed-effects to predict MICs for the non-agar dilution isolates, predicted MICs were in essential agreement (±1 doubling dilution) with observed (BD Phoenix) MICs for 691/715 (97%) isolates. This suggests amoxicillin-clavulanate resistance in E. coli is quantitative, rather than qualitative, explaining the poorly reproducible binary (resistant/susceptible) phenotypes and suboptimal concordance between different phenotypic methods and with WGS-based predictions. Full Article
nc Impact of KPC-production and high-level meropenem resistance on all-cause mortality of ventilator-associated pneumonia in association with Klebisella pneumoniae [Clinical Therapeutics] By aac.asm.org Published On :: 2020-03-23T08:47:35-07:00 Objectives: Carbapenemase-producing Enterobacterales and specifically KPC-producing Klebsiella pneumoniae (KPC-Kp) are rapidly spreading worldwide. The prognosis of ventilator-associated pneumonia (VAP) caused by KPC-producing Klebsiella pneumoniae (KPC-Kp) is not well known. Our study tries to assess whether ventilator-associated pneumonia caused by a KPC-Kp strain is associated with higher all-cause mortality than if caused by carbapenem-susceptible isolates.Study design and methods: This is a retrospective cohort study of patients with VAP due to K. pneumoniae from a 35-bed polyvalent Intensive Care Unit in a university hospital (> 40,000 annual admissions) between January 2012 and December 2016. Adjusted multivariate analysis was used to study the association of KPC-Kp with 30-day all-cause mortality (Cox regression).Results. We analyze 69 cases of K. pneumoniae VAP of which 39 were produced by a KPC-Kp strain with high-level resistance to meropenem (MIC > 16 mg/mL). All-cause mortality at 30 days was 41% in the KPC-Kp group (16/39) and 33.3% in the carbapenem-susceptible cases (10/30). KPC-Kp etiology was not associated with higher mortality when controlled for confounders (adjusted hazard ratio [lsqb]HR[rsqb] 1.25; 95% CI: 0.46–3.41). Adequate targeted therapy (HR 0.03; 95% CI: <0.01–0.23) was associated with all-cause mortality.Conclussion. Assuming the limitations due to the available sample size, the prognosis of VAP caused by KPC-Kp is similar to VAPs caused by carbapenem-susceptible K. pneumoniae when appropriate treatment is used. Full Article