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When School's a Battleground for Transgender Kids, Teachers Learn to Protect, Affirm Them

Equipping teachers to help transgender students feel safe and included requires special training, advocates say.




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Special Education Funding Gets Moment in Spotlight at Democratic Debate

Advocates for increased federal funding for special education cheered Thursday when the issue was raised on the Democratic presidential debate stage in Los Angeles.




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As dating apps try to pivot to virtual events, some users are trying to get people to violate social distancing rules

Source: www.businessinsider.com - Saturday, May 09, 2020
Dating apps like Tinder, Bumble, and Hinge have reported increased use amid the coronavirus pandemic, while touting virtual dating alternatives for users instead of meeting up in person. Swaths of users are still encouraging matches to break quarantine to have sex and go on dates, despite social distancing guidelines and fines to comply with them. An illustrator on Instagram has been collecting screenshots of these situations, and told Business Insider that users will brand themselves as "badasses," dispute the effectiveness of isolating, and lash out in anger and hurl abusive language when they're rejected. Spokespeople for Grindr, Tinder and Bumble told Business Insider they've informed users to adhere to social-distancing guidelines, but did not respond to inquiries about actions they're taking against users in places where violating lockdown orders can be against the law. Visit Business Insider's homepage for more stories . As millions remain confined to their homes to prevent the spread of coronavirus, the desire for human contact and connection has risen dramatically and led some to search for ways to break those social distancing rules. Popular dating apps — including Tinder , Bumble , and Hinge — have reported significant increases during the outbreak of swiping activity, matches between users, and messages exchanged. It's also led to the introduction of a breed of users who are interested in shirking lockdown orders, an




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Promote Books with Free Online Multimedia Slideshow Tools

Just like grocery stores offer free food samples, technology companies, such as VoiceThread, offer free accounts for educators who want to try their products.




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Guide to shooting on the run

One of Azerbaijan's young female stars offer a masterclass to help you find the way to goal.




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Circle football drill II

A drill focused on improving movement, teamwork and making the most of scoring chances.




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Cirilo's pivot guide

The Russia and MFK Dinamo Moskva forward offers you a futsal masterclass.




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Voronin's shooting guide

FC Dinamo Moskva's Ukrainian forward star Andriy Voronin offers you his shooting tips.




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What Other Countries Can Teach the U.S. About Teacher Professional Development

Countries that score highest on an international measure of student achievement tend to have these three things in common when it comes to professional development for teachers.




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Haves and Have-Nots: We Must Prioritize Outside Professional Development for ALL Teachers

Many outside PD opportunities still separate the "haves" from the "have-nots" and uphold systemic oppression.




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'It's Not Just Yoga and Nail Paint': Inside the Teacher Self-Care Conference

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.




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Sony Cyber-shot DSC-RX100 VII

The Sony Cyber-shot DSC-RX100 VII point-and-shoot is a modest update to the RX100 VI, offering better autofocus and video stabilization for a bit more money.




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The Best Point-and-Shoot Cameras for 2020

Unwilling to haul a heavy SLR or mirrorless camera? If you want a capable compact camera you can slip into your pocket, these are the top models we've tested.




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HUB-Robeson Galleries presents exhibit of graduate student's photography

The HUB-Robeson Galleries are proud to present "moments," an online thesis exhibition of photography by Zsuzsanna Nagy, a second-year master of fine arts student in photography.




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First hatches reported: Spotted lanternfly expert provides tips for management

Even before the recent news of the season’s first confirmed spotted lanternfly hatches in the Philadelphia region, homeowners in many parts of Pennsylvania were gearing up for their annual battle with the destructive pest.




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Online newsletter provides updates, recommendations on spotted lanternfly

A new online newsletter offered by Penn State Extension will give readers “the scoop” on the spotted lanternfly.




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Burundi: Breaking the Deadlock, The Urgent Need for a New Negotiating Framework




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The Inter-Congolese Dialogue: Political Negotiation or Game of Bluff?




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The Burundi Rebellion and the Ceasefire Negotiations




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The Kivus: The Forgotten Crucible of the Congo Conflict




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The UN must act. Africa is on the verge of another genocide




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The Rwandan Genocide: Memory Is Not Enough




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Africa's forgotten war




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"In Congo, 1,000 Die per Day", Why Isn't it a Media Story?




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Africa Needs Aid for Security not Just Poverty




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Elections in the Congo Not an End in Themselves




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Katanga: The Congo’s Forgotten Crisis




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DR Congo: Another Modern Tragedy




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Escaping the Conflict Trap: Promoting Good Governance in the Congo




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Central African Republic: "Relancer le dialogue politique




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Time to pull out UN troops in Congo? Not so fast

With a fledgling democratic government and a formal peace process finally in place in the Democratic Republic of Congo (DRC), the country will celebrate its 50th year of independence next month.




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Burundi: From Electoral Boycott to Political Impasse

Burundi risks reversing the decade of progress it has enjoyed since its civil war ended unless the government resumes political dialogue with the opposition.




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The DRC is a Hornet’s Nest South Africa Should not Kick

South Africa’s efforts to foster peace and security have placed it centre stage in some of the continent’s most intractable conflicts. This is an inevitable result of the quest to promote “African solutions for African problems”.




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Cameroon: Africa's Pivot

Since President Paul Biya came to power in 1982, Cameroon has been a sleepy regime with a soft and aging dictator, a nation all but forgotten in a remote corner of the African continent. This has dramatically changed with the spillover of Boko Haram from Nigeria into Cameroon in 2014 and its transformation into a regional threat. Now there is not a single day without reports of Boko Haram attacks in northern Cameroon. Even before it realized what it meant, the Cameroonian regime had become part of the fight against terrorism. After initially downplaying the problem, Cameroon’s leaders are now discovering the challenges and dangers of this new war. This rising, external threat sheds a new light on a forgotten country with a strategic position in Africa. The geography of Cameroon is both its blessing and its curse—a pivot between West and Central Africa, divided by language, culture, and history, its very existence depending on a regional stability so often beyond its grasp.




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Hotel Burundi

Am 20. August 2015 legte Burundis Präsident Pierre Nkurunziza schnell und leise zum dritten Mal den Amtseid ab. Die Vereidigung war erst am selben Morgen angekündigt worden, und die in der Hauptstadt akkreditierten Botschafter aus Europa und den USA blieben ebenso demonstrativ fern wie die Vertreter der Afrikanischen Union. Mit Blick auf die Sicherheitslage und die hohe Zahl politischer Morde im August hatte man sich entschlossen, die Vereidigung rasch und ohne großes Aufheben durchzuziehen.




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Central African Republic: The Roots of Violence

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.




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WITHDRAWN: Very strong synergy between modified RANTES and gp41 binding peptides leads to potent anti-HIV-1 activity [Article]

This article, published ahead of print on 28 July 2008, has been withdrawn by the authors. Although moderate synergy between P2-RANTES and C peptides can be observed with high statistical significance in cell fusion assays, this synergy was not able to be verified in HIV viral assays. The authors regret the overstatement of synergy and will revise the paper for publication at a later date.




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In Vitro and In Vivo Characterization of Potent Antileishmanial Methionine Aminopeptidase-1 Inhibitors [Experimental Therapeutics]

Leishmania major is the causative agent of cutaneous leishmaniasis (CL). No human vaccine is available for CL and current drug regimens present several drawbacks such as emerging resistance, severe toxicity, medium effectiveness, and/or high cost. Thus, the need for better treatment options against CL is a priority. In the present study, we validate the enzyme methionine aminopeptidase-1 (MetAP1), a metalloprotease that catalyzes the removal of N-terminal methionine from peptides and proteins, as a chemotherapeutic target against CL infection. The in vitro antileishmanial activity of eight novel MetAP1 inhibitors (OJT001-OJT008) were investigated. Three compounds OJT006, OJT007, and OJT008 demonstrated potent anti-proliferative effect in macrophages infected with L. major amastigotes and promastigotes at submicromolar concentrations, with no cytotoxicity against host cells. Importantly, the leishmanicidal effect was diminished by almost 10-fold in transgenic L. major promastigotes overexpressing MetAP1LM in comparison to wild-type promastigotes. Furthermore, the in vivo activity of OJT006, OJT007, and OJT008 were investigated in L. major-infected BALB/c mice. In comparison to the control group, OJT008 significantly decreased footpad parasite load by 86%, and exhibited no toxicity against in treated mice. We propose MetAP1 inhibitor OJT008 as a potential chemotherapeutic candidate against CL infection caused by L. major infection.




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Effect of drug pressure on promoting the emergence of antimalarial resistant parasites among pregnant women in Ghana [Mechanisms of Resistance]

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.




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An engineered double lipid II binding motifs-containing lantibiotic displays potent and selective antimicrobial activity against E. faecium [Chemistry; Biosynthesis]

Lipid II is an essential precursor of the bacterial cell wall biosynthesis and thereby an important target for various antibiotics. Several lanthionine-containing peptide antibiotics target lipid II with lanthionine-stabilized lipid II-binding motifs. Here, we used the biosynthesis system of the lantibiotic nisin to synthesize a two lipid II binding motifs-containing lantibiotic, termed TL19, which contains the N-terminal lipid II binding motif of nisin and the distinct C-terminal lipid II binding motif of one peptide of the two-component haloduracin (i.e. HalA1). Further characterization demonstrated that (i) TL19 exerts 64-fold stronger antimicrobial activity against E. faecium than nisin (1-22), which has only one lipid II binding site, and (ii) both the N- and C-terminal domains are essential for the potent antimicrobial activity of TL19, as evidenced by mutagenesis of each single and double domains. These results show the feasibility of a new approach to synthesize potent lantibiotics with two different lipid II binding motifs to treat specific antibiotic-resistant pathogens.




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MK-571, a cysteinyl leukotriene receptor-1 antagonist, inhibits hepatitis C virus (HCV) replication [Antiviral Agents]

The quinoline MK-571 is the most commonly used inhibitor of multidrug resistance protein-1 (MRP-1) but was originally developed as a cysteinyl leukotriene receptor 1 (CysLTR1) antagonist. While studying the modulatory effect of MRP-1 on anti-hepatitis C virus (HCV) direct acting-antivirals (DAA) efficiency, we observed an unexpected anti-HCV effect of compound MK-571 alone. This anti-HCV activity was characterized in Huh7.5 cells stably harboring a subgenomic genotype 1b replicon. A dose-dependent decrease of HCV RNA levels was observed upon MK-571 administration, with an EC50 of 9±0.3 μM and a maximum HCV RNA level reduction of approximatively 1 Log10. MK-571 also reduced the replication of the HCV full-length J6/JFH1 model in a dose-dependent manner. However, probenecid and apigenin homodimer (APN), two specific inhibitors of MRP-1, had no effect on HCV replication. In contrast, the CysLTR1 antagonists SR2640 increased HCV-SGR RNA levels in a dose-dependent manner, with a maximum increase of 10-fold. In addition, a combination of natural CysLTR1 agonist (LTD4) or antagonists (zafirlukast, cinalukast, and SR2640) with MK-571 completely reversed its antiviral effect, suggesting its anti-HCV activity is related to CysLTR1 rather to MRP-1 inhibition. In conclusion, we showed that MK-571 inhibits HCV replication in hepatoma cell cultures by acting as a CysLTR1 receptor antagonist, thus unraveling a new host-virus interaction in the HCV life cycle.




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Evaluation of the efficacy of antibiotic combinations against multidrug-resistant Pseudomonas aeruginosa in automated time-lapse microscopy and static time-kill experiments [Clinical Therapeutics]

Objectives: Antibiotic combination therapy is used for severe infections caused by multidrug-resistant (MDR) Gram-negative bacteria. Yet, data of which combinations are most effective is lacking. This study aimed to evaluate the in vitro efficacy of polymyxin B in combination with 13 other antibiotics against four clinical strains of MDR Pseudomonas aeruginosa.

Methods: We evaluated the interactions of polymyxin B in combination with amikacin, aztreonam, cefepime, chloramphenicol, ciprofloxacin, fosfomycin, meropenem, minocycline, rifampicin, temocillin, thiamphenicol or trimethoprim by automated time-lapse microscopy using predefined cut-off values indicating inhibition of growth (≤106 CFU/mL) at 24 h. Promising combinations were subsequently evaluated in static time-kill experiments.

Results: All strains were intermediate or resistant to polymyxin B, anti-pseudomonal β-lactams, ciprofloxacin and amikacin. Genes encoding β-lactamases (e.g., blaPAO and blaOXA-50) and mutations associated with permeability and efflux were detected in all strains. In the time-lapse microscopy experiments, positive interactions were found with 39 of 52 antibiotic combination/bacterial strain setups. Enhanced activity was found against all four strains with polymyxin B used in combination with aztreonam, cefepime, fosfomycin, minocycline, thiamphenicol and trimethoprim. Time kill experiments showed additive or synergistic activity with 27 of the 39 tested polymyxin B combinations, most frequently with aztreonam, cefepime, and meropenem.

Conclusion: Positive interactions were frequently found with the tested combinations, also against strains that harboured several resistance mechanisms to the single drugs and with antibiotics that are normally not active against P. aeruginosa. Further study is needed to explore the clinical utility of these combinations.




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Stp1 loss of function promotes {beta}-lactam resistance in S. aureus that is independent of classical genes [Mechanisms of Resistance]

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.




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Reconciling the potentially irreconcilable? Genotypic and phenotypic amoxicillin-clavulanate resistance in Escherichia coli [Mechanisms of Resistance]

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.




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Mutations in ArgS arginine-tRNA synthetase confer additional antibiotic-tolerance protection to ESBL-producing Burkholderia thailandensis [Mechanisms of Resistance]

Highly conserved PenI-type class A β-lactamase in pathogenic members of Burkholderia can evolve to extended-spectrum β-lactamase (ESBL), which exhibits hydrolytic activity towards third-generation cephalosporins, while losing its activity towards the original penicillin substrates. We describe three single-amino-acid-substitution mutations in the ArgS arginine-tRNA synthetase that confer extra antibiotic tolerance protection to ESBL-producing Burkholderia thailandensis. This pathway can be exploited to evade antibiotic tolerance induction in developing therapeutic measures against Burkholderia species, targeting their essential aminoacyl-tRNA synthetases.




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Spectrum of Beta-Lactamase Inhibition by the Cyclic Boronate QPX7728, an Ultra-Broad-Spectrum Beta-lactamase Inhibitor of Serine and Metallo Beta-Lactamases: Enhancement of Activity of Multiple Antibiotics Against Isogenic Strains Expressing Single {beta}

QPX7728 is an ultra-broad-spectrum boronic acid beta-lactamase inhibitor with potent inhibition of key serine and metallo beta-lactamases observed in biochemical assays. Microbiological studies using characterized strains were used to provide a comprehensive characterization of the spectrum of beta-lactamase inhibition by QPX7728. The MIC of multiple IV only (ceftazidime, piperacillin, cefepime, ceftolozane and meropenem) and orally bioavailable (ceftibuten, cefpodoxime, tebipenem) antibiotics alone and in combination with QPX7728 (4 μg/ml), as well as comparator agents, were determined against the panels of laboratory strains of P. aeruginosa and K. pneumoniae expressing over 55 diverse serine and metallo beta-lactamases. QPX7728 significantly enhanced the potency of antibiotics against the strains expressing Class A extended spectrum beta-lactamases (CTX-M, SHV, TEM, VEB, PER) and carbapenemases (KPC, SME, NMC-A, BKC-1), consistent with beta-lactamase inhibition demonstrated in biochemical assays. It also inhibits both plasmidic (CMY, FOX, MIR, DHA) and chromosomally encoded (P99, PDC, ADC) Class C beta-lactamases and Class D enzymes including carbapenemases such as OXA-48 from Enterobacteriaceae and OXA enzymes from Acinetobacter baumannii (OXA-23/24/72/58). QPX7728 is also a potent inhibitor of many class B metallo beta-lactamases (NDM, VIM, CcrA1, IMP, GIM but not SPM or L1). Addition of QPX7728 (4 μg/ml) reduced the MICs in a majority of strains to the level observed for the vector alone control, indicative of complete beta-lactamase inhibition. The ultra-broad-spectrum beta-lactamase inhibition profile makes QPX7728 a viable candidate for further development.




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Complex response of the CpxAR two-component system to {beta}-lactams on antibiotic resistance and envelop homeostasis in Enterobacteriaceae [Mechanisms of Resistance]

The Cpx stress response is widespread among Enterobacteriaceae. We have previously reported a mutation in cpxA in a multidrug resistant strain of Klebsiella aerogenes isolated from a patient treated with imipenem. This mutation yields to a single amino acid substitution (Y144N) located in the periplasmic sensor domain of CpxA. In this work, we sought to characterize this mutation in Escherichia coli by using genetic and biochemical approaches. Here, we show that cpxAY144N is an activated allele that confers resistance to β-lactams and aminoglycosides in a CpxR-dependent manner, by regulating the expression of the OmpF porin and the AcrD efflux pump, respectively. We also demonstrate the intimate interconnection between Cpx system and peptidoglycan integrity on the expression of an exogenous AmpC β-lactamase by using imipenem as a cell wall active antibiotic or inactivation of penicillin-binding proteins. Moreover, our data indicate that the Y144N substitution abrogates the interaction between CpxA and CpxP and increase phosphotransfer activity on CpxR. Because the addition of a strong AmpC inducer such as imipenem is known to causes abnormal accumulation of muropeptides (disaccharide-pentapeptide, N-acetylglucosamyl-1,6-anhydro-N-acetylmuramyl-l-alanyl-d-glutamy-meso-diaminopimelic-acid-d-alanyl-d-alanine) in the periplasmic space, we propose these molecules activate the Cpx system by displacing CpxP from the sensor domain of CpxA. Altogether, these data could explain why large perturbations to peptidoglycan caused by imipenem lead to mutational activation of the Cpx system and bacterial adaptation through multidrug resistance. These results also validate the Cpx system, in particular the interaction between CpxA and CpxP, as a promising therapeutic target.




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Nonclinical Pharmacokinetics, Protein Binding, and Elimination of KBP-7072, An Aminomethylcycline Antibiotic in Animal Models [Pharmacology]

KBP-7072 is a semi-synthetic aminomethylcycline with broad-spectrum activity against Gram-positive and Gram-negative pathogens including multidrug resistant bacterial strains. The pharmacokinetics (PK) of KBP-7072 after oral and intravenous (IV) administration of single and multiple doses were investigated in animal models including during fed and fasted states and also evaluated the protein binding and excretion characteristics. In Sprague-Dawley (SD) rats, Beagle dogs, and CD-1 mice, KBP-7072 demonstrated a linear PK profile after administration of single oral and IV and multiple oral doses. Oral bioavailability ranged from 12% to 32%. Mean Tmax ranged from 0.5 to 4 hours, and mean half-life ranged from approximately 6 to 11 hours. Administration of oral doses in the fed state resulted in a marked reduction in Cmax and AUC compared with dosing in fasted animals. The mean bound fractions of KBP-7072 were 77.5%, 69.8%, 64.5%, 69.3%, and 69.2% in mouse, rat, dog, monkey, and human plasma, respectively. Following a single 22.5 mg/kg oral dose of KBP-7072 in SD rats, cumulative excretion in feces was 64% and in urine was 2.5% of the administered dose. The PK results in animal models are consistent with single and multiple ascending dose studies in healthy volunteers and confirm the suitability of KBP-7072 for once daily oral and IV administration in clinical studies.




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The Impact of Intrinsic Resistance Mechanisms on Potency of QPX7728, a New Ultra-Broad-Spectrum Beta-lactamase Inhibitor of Serine and Metallo Beta-Lactamases in Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii. [Mechanisms of Resis

QPX7728 is an ultra-broad-spectrum boronic acid beta-lactamase inhibitor that demonstrates inhibition of key serine and metallo beta-lactamases at a nano molar range in biochemical assays with purified enzymes. The broad-spectrum inhibitory activity of QPX7728 observed in biochemical experiments translates into enhancement of the potency of many beta-lactams against strains of target pathogens producing beta-lactamases. The impact of bacterial efflux and permeability on inhibitory potency were determined using isogenic panels of KPC-3 producing isogenic strains of K. pneumoniae and P. aeruginosa and OXA-23-producing strains of A. baumannii with various combinations of efflux and porin mutations. QPX7728 was minimally affected by multi-drug resistance efflux pumps in either Enterobacteriaceae, or in non-fermenters such as P. aeruginosa or A. baumannii. In P. aeruginosa, the potency of QPX7728 was further enhanced when the outer membrane is permeabilized. The potency of QPX7728 in P. aeruginosa is not affected by inactivation of the carbapenem porin OprD. While changes in OmpK36 (but not OmpK35) reduced the potency of QPX7728 (8-16-fold), QPX7728 (4 μg/ml) nevertheless completely reversed KPC-mediated meropenem resistance in strains with porin mutations, consistent with a lesser effect of these mutations on the potency of QPX7728 compared to other agents. The ultra-broad-spectrum beta-lactamase inhibition profile combined with enhancement of the activity of multiple beta-lactam antibiotics with varying sensitivity to the intrinsic resistance mechanisms of efflux and permeability indicate QPX7728 is a useful inhibitor for use with multiple beta-lactam antibiotics.




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OPC-167832, a novel carbostyril derivative with potent anti-tuberculosis activity as a DprE1 inhibitor [Pharmacology]

There is an urgent need for new, potent anti-tuberculosis (TB) drugs with novel mechanisms of action that can be included in new regimens to shorten the treatment period for TB. After screening a library of carbostyrils, we optimized 3, 4-dihydrocarbostyril derivatives and identified OPC-167832 as having potent anti-tuberculosis activity. The minimum inhibitory concentrations of the compound for Mycobacterium tuberculosis ranged from 0.00024 to 0.002 μg/mL. It had bactericidal activity against both growing and intracellular bacilli, and the frequency of spontaneous resistance for Mycobacterium tuberculosis H37Rv was less than 1.91 x 10-7. It did not show antagonistic effects with other anti-TB agents in an in vitro checkerboard assay. Whole genome and targeted sequencing of resistant isolates to OPC-167832 identified the decaprenylphosphoryl-β-D-ribose 2'-oxidase (DprE1), an essential enzyme for cell wall biosynthesis, as the target of this compound, and further studies demonstrated inhibition of the DprE1 enzymatic activity by OPC-167832. In a mouse model of chronic TB, OPC-167832 showed potent bactericidal activities starting at a dose of 0.625 mg/kg. Further, it exhibited significant combination effects in 2-drug combinations with delamanid, bedaquiline, or levofloxacin. Finally, 3-4 drug regimens comprised of delamanid and OPC-167832 as the core along with bedaquiline, moxifloxacin, or linezolid showed superior efficacy in reducing bacterial burden and preventing relapse compared to the standard treatment regimen. In summary, these results suggest that OPC-167832 is a novel and potent anti-TB agent and regimens containing OPC-167832 and new or repurposed anti-TB drugs may have the potential to shorten the duration of treatment for TB.