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Congo's Elections: Making or Breaking the Peace




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Le coup de poker des élections au Congo




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Chad: Back towards War?




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Über Weihnachten im Kongo




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Securing Congo’s Elections: Lessons from the Kinshasa Showdown




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Burundi: Democracy and Peace at Risk




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Congo: Bringing Peace to North Kivu




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North Kivu: How to End a War




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Chad: A New Conflict Resolution Framework




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Chad: Powder Keg in the East




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Chad: A Powder Keg Ready to Explode




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UN Must Stop Backing Congo's Disastrous Operation Against Marauding Rebel Militias




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Central African Republic: Keeping the Dialogue Alive




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Kongo muss jetzt Verbrechen aufarbeiten

Es ist eine einmalige Chance, die sich dieser Tage bietet: Die Veröffentlichung eines lang erwarteten Berichts der Vereinten Nationen über Verbrechen in der Demokratischen Republik Kongo (DRK) ist die Gelegenheit für eine Wiederaufarbeitung der Geschichte der massiven Gewalt im Kongo zwischen 1993 und 2003.




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Congo: No Stability in Kivu despite Rapprochement with Rwanda

The attempt by Congo and Rwanda to end the deadly conflict in eastern Congo by a secret presidential deal and military force is failing and must be changed fundamentally by the Kinshasa government and the international community.




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DR Congo: Why is there still a Kivu problem?

Despite three agreements between the rebels and the government, peace is still elusive in eastern Democratic Republic of Congo. The Kivus need regional dialogue and a clear, fair repatriation plan, argues Thierry Vircoulon at the International Crisis Group.




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Chad’s North West: <br> The Next High-risk Area?

Chad’s North West may become the next stage for insurgency, drug-running and religious extremism in the Sahel if the government continues to actively neglect the poorest of the violence-plagued country’s poor regions.




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Central African Republic: The Dark Side of Diamonds

The international watchdog which seeks to prevent diamonds from fuelling conflict, the Kimberley Process, should take a very close look at the situation in the Central African Republic




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Rohstoffdiplomatie kann dem Kongo helfen

Der Abbau seltener Mineralien ist ein Grund für die Gewalt im Kongo. Die EU könnte hier eine wirkungsvolle Regelung durchsetzen.




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Francophonie : aller ou ne pas aller à Kinshasa

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.




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Black Gold in the Congo: Threat to Stability or Development Opportunity?

Renewed oil interest in the Democratic Republic of the Congo (DRC) could nurture communal resentments, exacerbate deep-rooted conflict dynamics and weaken national cohesion.




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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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Central African Republic: Thinking Out of the Box to Save the CAR

All this foreign involvement has failed to prevent the recent coup or stabilize its aftermath. BINUCA has not been able to implement a disarmament, demobilisation and reintegration program, and it failed to convince Bozizé’s regime to reform the security sector or consolidate the peace. ECCAS has been unable to restore order in one of the smallest capitals of Africa, and troop-contributing countries have proved unable to deliver the 600 extra soldiers they committed to provide in April. Paradoxically, France, while securing Bangui’s airport, is also hosting ousted president Bozizé, who declared from exile in Paris his wish to retake power by force with the “support” of private actors.




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Central African Republic - Making the Mission Work

By failing to engage when Crisis Group and others warned that the Central African Republic had become a phantom state, the international community has now had to become much more heavily involved, at much greater expense, after horrifying loss of life and massive displacement, with much greater odds of failure.




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The CAR Crisis: Thinking Beyond Traditional Peacekeeping

The crisis that has been occurring in CAR is certainly the most dramatic in its history: more than 600 000 Central Africans are internally displaced or sought refuge in neighbouring countries; according to the United Nations, 1.7 million live in a constant situation of food insecurity and 878 000 need immediate medical assistance; Muslim communities are fleeing Bangui and the western region, subsistence economy no longer exists and the de facto partition of the country, caused by the sectarian violence, is gradually becoming a reality.




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Burundi: Godefroid Niyombaré avait mis en garde Nkurunziza

Alors qu’une tentative de coup d’Etat contre Pierre Nkurunziza, émanant de l’ex-chef d’état-major, Godefroid Niyombaré, est en cours au Burundi, Thierry Vircoulon chercheur à l'International Crisis Group, explique qui est le général putschiste et analyse, plus généralement, l'appareil sécuritaire du Burundi.




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Cameroun : au-delà de Boko Haram, la menace insidieuse du radicalisme religieux

L’image de havre de paix dans une région en proie aux conflits dont bénéficiait le Cameroun a volé en éclats depuis l’irruption de Boko Haram en 2013 au nord du pays. Ce mouvement, devenu l’Etat islamique en Afrique de l’Ouest en mars 2015, revendique son affiliation à Daech. Néanmoins, l’apparition brutale et sanglante de ce djihadisme africain est moins liée à l’essor de Daech en Irak et en Syrie qu’aux bouleversements du paysage religieux de l’Afrique en général et du Cameroun en particulier.




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AU was set up for an explosive crisis like Burundi; it must act

The deteriorating situation in Burundi is a perfect storm of much that undermines stability in Africa today — presidents seeking impunity and power through dubious new terms, authoritarian regimes muzzling opposition and independent media, regional rivalries stalemating efforts to bring peace and outside powers unwilling or unable to act.




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Burundi : anatomie du troisième mandat de Nkurunziza

Le 1er juin dernier à Mugamba (province de Bururi), Pierre Nkurunziza a lancé un ultimatum. « Du haut d’une camionnette, micro à la main, sous très haute protection de l’armée et de la police », rapporte l’AFP, le président burundais a ordonné aux insurgés de cette commune du Sud du pays de déposer les armes dans les quinze jours : « Téléphonez à vos frères qui ont pris les armes, dites-leur que nous leur donnons quinze jours pour qu’ils y renoncent […] Quinze jours, pas plus. Dites-leur cela ». Hasard ou préméditation, la fin de cet ultimatum devrait coïncider avec la reprise prévue des discussions à Arusha, en Tanzanie, entre le gouvernement et l’opposition.




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Burundi turns to WhatsApp as political turmoil brings media blackout

Burundi’s year-long crisis has not gone away. It started with President Pierre Nkurunziza’s determination to claim a third term, trampling over the constitutional arrangements that ended a decade-long civil war. Press freedom is a major casualty of the new strife; but the turmoil has also transformed the way in which Burundians get information. For better or worse, social media has filled the vacuum left by the shutting down of the most popular radio stations and forcing out of many of the country’s professional journalists.




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U.S. Department of Education OKs Modified Texas Assessment

Texas has become the first state to have its "alternate assessment aligned to modified academic-achievement standards" pass the U.S. Department of Education's peer-review process.




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Rethinking the Way We Hold Schools Accountable

Test-based accountability has not generated the significant gains in student achievement that proponents intended, Helen F. Ladd contends.




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Some Waiver States Can Seek Pause on School Ratings

States looking to renew NCLB waivers while they transition to new assessments ask to freeze school ratings in place for one year, the Education Department says.




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Panel Finds Few Learning Benefits in High-Stakes Exams

A 10-year study by a blue-ribbon panel of scientists concludes that high-stakes testing and other accountability measures have largely failed to translate to real improvements in student achievement.




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Data: Student Achievement in the Era of Accountability - Education Week

The Education Week Research Center looks at student scores on the National Assessment of Educational Progress from 2003 to 2015, a period overlapping with the No Child Left Behind Act.





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Throwback Thursday: Achievement, Assessment, and Accountability

If we continue to focus on student growth and improvement as learners, keep track of that progress, and watch its impact on standard test results, will we be able to know if what we are doing is helping students develop as learners and thinkers.





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Efficacy of early oral switch with beta-lactams for low-risk Staphylococcus aureus bacteremia. [Clinical Therapeutics]

Objectives. The aim of this study was to assess the safety of early oral switch (EOS) prior to 14 days for low-risk Staphylococcus aureus bacteremia (LR-SAB), which is the primary treatment strategy employed at our institution. Usually recommended therapy is 14 days of intravenous (IV) antibiotics.

Methods. All patients with SAB at our hospital were identified between 1 January 2014 and 31 December 2018. Those meeting low-risk criteria (healthcare-associated, no evidence of deep infection or demonstrated involvement of prosthetic material, and no further positive blood cultures after 72-hours) were included in the study. The primary outcome was occurrence of a SAB-related complication within 90 days.

Results. There were 469 SAB episodes during the study period, 100 (21%) of whom met inclusion criteria. EOS was performed in 84 patients. In this group, line infection was the source in 79%, methicillin-susceptible S. aureus caused 95% of SABs and 74% of patients received IV flucloxacillin. The median duration of IV and oral antibiotics in the EOS group was 5 (IQR 4-6) and 10 days (IQR 9-14), respectively. Seventy-one percent of patients received flucloxacillin as their EOS agent. Overall, 86% of oral step-down therapy was with beta-lactams. One patient (1%) undergoing EOS had SAB relapse within 90 days. No deaths attributable to SAB occurred within 90 days.

Conclusions. In this low MRSA prevalence LR-SAB cohort, EOS was associated with a low incidence of SAB-related complications. This was achieved with oral beta-lactam therapy in most patients. Larger prospective studies are needed to confirm these findings.




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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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Ceftobiprole Activity against Bacteria from Skin and Skin Structure Infections in the United States from 2016 through 2018 [Susceptibility]

Ceftobiprole medocaril is an advanced-generation cephalosporin prodrug that has qualified infectious disease product status granted by the US-FDA and is currently being evaluated in phase 3 clinical trials in patients with acute bacterial skin and skin structure infections (ABSSSIs) and in patients with Staphylococcus aureus bacteremia. In this study, the activity of ceftobiprole and comparators was evaluated against more than 7,300 clinical isolates collected in the United States from 2016 through 2018 from patients with skin and skin structure infections. The major species/pathogen groups were S. aureus (53%), Enterobacterales (23%), Pseudomonas aeruginosa (7%), β-hemolytic streptococci (6%), Enterococcus spp. (4%), and coagulase-negative staphylococci (2%). Ceftobiprole was highly active against S. aureus (MIC50/90, 0.5/1 mg/L; 99.7% susceptible by EUCAST criteria; 42% methicillin-resistant S. aureus [lsqb]MRSA[rsqb]). Ceftobiprole also exhibited potent activity against other Gram-positive cocci. The overall susceptibility of Enterobacterales to ceftobiprole was 84.8% (>99.0% susceptible for isolate subsets that exhibited a non-extended-spectrum β-lactamase [lsqb]ESBL[rsqb]-phenotype). A total of 74.4% of P. aeruginosa, 100% of β-hemolytic streptococci and coagulase-negative staphylococci, and 99.6% of Enterococcus faecalis isolates were inhibited by ceftobiprole at ≤4 mg/L. As expected, ceftobiprole was largely inactive against Enterobacterales that contained ESBL genes and Enterococcus faecium. Overall, ceftobiprole was highly active against most clinical isolates from the major Gram-positive and Gram-negative skin and skin structure pathogen groups collected at U.S. medical centers participating in the SENTRY Antimicrobial Surveillance Program during 2016–2018. The broad-spectrum activity of ceftobiprole, including potent activity against MRSA, supports its further evaluation for the potential ABSSSI indication.




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Impact of KPC-production and high-level meropenem resistance on all-cause mortality of ventilator-associated pneumonia in association with Klebisella pneumoniae [Clinical Therapeutics]

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.




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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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Towards harmonization of voriconazole CLSI and EUCAST breakpoints for Candida albicans using a validated in vitro pharmacokinetic/pharmacodynamic model [Susceptibility]

Background. CLSI and EUCAST susceptibility breakpoints for voriconazole and C. albicans differ by one dilution (≤0.125 and ≤0.06 mg/l, respectively) whereas the epidemiological cutoff values (ECOFF/ECV) with both methodologies are the same (0.03 mg/L). We therefore determined the pharmacokinetic-pharmacodynamic (PK/PD) breakpoints of voriconazole against C. albicans for both methodologies with an in vitro PK/PD model, which was validated using existing animal PK/PD data.

Methods. Four clinical wild-type and non-wild-type C. albicans isolates (voriconazole MICs 0.008-0.125 mg/l) were tested in an in vitro PK/PD model. For validation purposes, mouse PK were simulated and in vitro PD were compared with in vivo outcome. Human PK were simulated and the exposure-effect relationship fAUC0-24/MIC was described for EUCAST and CLSI24/48h methods. PK/PD breakpoints were determined using the fAUC0-24/MIC associated with half-maximal activity (EI50) and Monte Carlo simulation analysis.

Results. The in vitro 24h-PD EI50 of voriconazole against C. albicans were 2.5-5 (1.5-17) fAUC/MIC. However, the 72h-PD were higher, 133 (51-347) fAUC/MIC for EUCAST and 94 (35-252) fAUC/MIC for CLSI. The mean (95% confidence interval) probability of target attainment (PTA) was 100(95-100)%, 97(72-100)%, 83(35-99)%, and 49(8-91)% and 100(97-100)%, 99(85-100)%, 91(52-100)% and 68(17-96)% for EUCAST and CLSI MICs 0.03, 0.06, 0.125, and 0.25 mg/L, respectively. Significantly, >95% PTAs were found for EUCAST/CLSI MICs ≤0.03 mg/ll. For MICs 0.06-0.125 mg/l trough levels 1-4 mg/ll would be required.

Conclusion. A PK/PD breakpoint of C. albicans voriconazole at the ECOFF/ECV of 0.03 mg/L was determined for both EUCAST/CLSI methods, indicating the need for breakpoint harmonization for the reference methodologies.




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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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Proteomic changes of Klebsiella pneumoniae in response to colistin treatment and crrB mutation-mediated colistin resistance [Mechanisms of Resistance]

Polymyxins are increasingly used as the critical last-resort therapeutic options for multidrug-resistant gram-negative bacteria. Unfortunately, polymyxin resistance has increased gradually for the last few years. Although studies on mechanisms of polymyxin are expanding, system-wide analyses of the underlying mechanism for polymyxin resistance and stress response are still lacking. To understand how Klebsiella pneumoniae adapt to colistin (polymyxin E) pressure, we carried out proteomic analysis of Klebsiella pneumoniae strain cultured with different concentrations of colistin. Our results showed that the proteomic responses to colistin treatment in Klebsiella pneumoniae involving several pathways, including (i) gluconeogenesis and TCA cycle; (ii) arginine biosynthesis; (iii) porphyrin and chlorophyll metabolism; and (iv) enterobactin biosynthesis. Interestingly, decreased abundance of class A β-lactamases including TEM, SHV-11, SHV-4 were observed in cells treated with colistin. Moreover, we also present comprehensive proteome atlases of paired polymyxin-susceptible and -resistant Klebsiella pneumoniae strains. The polymyxin-resistant strain Ci, a mutant of Klebsiella pneumoniae ATCC BAA 2146, showed missense mutation in crrB. The crrB mutant Ci, which displayed lipid A modification with 4-amino-4-deoxy-L-arabinose (L-Ara4N) and palmitoylation, showed striking increases of CrrAB, PmrAB, PhoPQ, ArnBCADT and PagP. We hypothesize that crrB mutations induce elevated expression of the arnBCADTEF operon and pagP via PmrAB and PhoPQ. Moreover, multidrug efflux pump KexD, which was induced by crrB mutation, also contributed to colistin resistance. Overall, our results demonstrated proteomic responses to colistin treatment and the mechanism of CrrB-mediate colistin resistance, which may further offer valuable information to manage polymyxin resistance.




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Pharmacokinetics-pharmacodynamics of enmetazobactam combined with cefepime in a neutropenic murine thigh infection model [Pharmacology]

Third-generation cephalosporin (3GC)-resistant Enterobacteriaceae are classified as critical priority pathogens, with extended-spectrum β-lactamases (ESBLs) as principal resistance determinants. Enmetazobactam (formerly AAI101) is a novel ESBL inhibitor developed in combination with cefepime for empiric treatment of serious Gram-negative infections in settings where ESBLs are prevalent. Cefepime-enmetazobactam has been investigated in a phase 3 trial in patients with complicated urinary tract infections or acute pyelonephritis. This study examined pharmacokinetic-pharmacodynamic (PK-PD) relationships of enmetazobactam, in combination with cefepime, for ESBL-producing isolates of Klebsiella pneumoniae in 26-hour murine neutropenic thigh infection models. Enmetazobactam dose fractionation identified time above a free threshold concentration (fT > CT) as the PK-PD index predictive of efficacy. Nine ESBL-producing isolates of K. pneumoniae, resistant to cefepime and piperacillin-tazobactam, were included in enmetazobactam dose-ranging studies. The isolates encoded CTX-M-type, SHV-12, DHA-1 and OXA-48 β-lactamases and covered a cefepime-enmetazobactam MIC range from 0.06 to 2 μg/ml. Enmetazobactam restored the efficacy of cefepime against all isolates tested. Sigmoid curve fitting across the combined set of isolates identified enmetazobactam PK-PD targets for stasis and for a 1-log10 bioburden reduction of 8% and 44% fT > 2 μg/ml, respectively, with a concomitant cefepime PK-PD target of 40 – 60% fT > cefepime-enmetazobactam MIC. These findings support clinical dose selection and breakpoint setting for cefepime-enmetazobactam.




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Population Pharmacokinetics and Dosage Optimization of Linezolid in Patients with Liver Dysfunction [Pharmacology]

Linezolid is the first synthetic oxazolidone agent to treat infections caused by Gram-positive pathogens. Infected patients with liver dysfunction (LD) are more likely to suffer from adverse reactions such as thrombocytopenia when standard-dose linezolid is used than patients with LD who didn't use linezolid. Currently, pharmacokinetics data of linezolid in patients with LD are limited. The study aimed to characterize pharmacokinetics parameters of linezolid in patients with LD, identify the factors influencing the pharmacokinetics, and propose an optimal dosage regimen. We conducted a prospective study and established population pharmacokinetics model with the Phoenix NLME. The final model was evaluated by goodness-of-fit plots, bootstrap analysis, and prediction corrected-visual predictive check. A total of 163 concentration samples from 45 patients with LD were adequately described by a one-compartment model with first-order elimination along with prothrombin activity (PTA) and creatinine clearance as significant covariates. Linezolid clearance (CL) was 2.68 L/h (95% confidence interval [CI]: 2.34-3.03 L/h); the volume of distribution (Vd) was 58.34 L (95% CI: 48.00-68.68 L). Model-based simulation indicated that the conventional dose was at risk for overexposure in patients with LD or severe renal dysfunction; reduced dosage (300 mg/12 h) would be appropriate to achieve safe (Cmin, ss at 2-8 ug/mL) and effective targets (the ratio of AUC0-24 at steady state to MIC, 80-100). In addition, for patients with severe LD (PTA <= 20%), the dosage (400 mg/24 h) was sufficient at an MIC <= 2 ug/mL. This study recommended therapeutic drug monitoring for patients with LD.




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Novel peptide from commensal Staphylococcus simulans blocks MRSA quorum sensing and protects host skin from damage [Mechanisms of Action]

Recent studies highlight the abundance of commensal coagulase-negative staphylococci (CoNS) on healthy skin. Evidence suggests that CoNS actively shape the skin immunological and microbial milieu to resist colonization or infection by opportunistic pathogens, including methicillin resistant Staphylococcus aureus (MRSA), in a variety of mechanisms collectively termed colonization resistance. One potential colonization resistance mechanism is the application of quorum sensing, also called the Accessory Gene Regulator (agr) system, which is ubiquitous among staphylococci. Common and rare CoNS make autoinducing peptides (AIPs) that function as MRSA agr inhibitors, protecting the host from invasive infection. In a screen of CoNS spent media we found that Staphylococcus simulans, a rare human skin colonizer and frequent livestock colonizer, released potent inhibitors of all classes of MRSA agr signaling. We identified three S. simulans agr classes, and have shown intraspecies cross-talk between non-cognate S. simulans agr types for the first time. The S. simulans AIP-I structure was confirmed, and the novel AIP-II and AIP-III structures were solved via mass spectrometry. Synthetic S. simulans AIPs inhibited MRSA agr signaling with nanomolar potency. S. simulans in competition with MRSA reduced dermonecrotic and epicutaneous skin injury in murine models. Addition of synthetic AIP-I also effectively reduced MRSA dermonecrosis and epicutaneous skin injury in murine models. These results demonstrate potent anti-MRSA quorum sensing inhibition by a rare human skin commensal, and suggest that cross-talk between CoNS and MRSA may be important in maintaining healthy skin homeostasis and preventing MRSA skin damage during colonization or acute infection.