Comparing the cost-effectiveness of linezolid to trimethoprim/sulfamethoxazole plus rifampicin for the treatment of MRSA infection: a health-care system perspective

To date few industry-independent studies were conducted to compare the relative costs and benefits of drugs to treat MRSA infection. We performed a stochastic cost-effectiveness analysis comparing two treatment strategies -- linezolid versus trimethoprim-sulfamethoxazole plus rifampicin -- for the treatment of MRSA infection

Randomized non-inferiority trial to compare trimethoprim/sulfamethoxazole plus rifampicin versus linezolid for the treatment of MRSA infection

Objectives The therapeutic arsenal for MRSA infections is limited. The aim of this study was to assess the non-inferiority of a combination of trimethoprim/sulfamethoxazole plus rifampicin versus linezolid alone for the treatment of MRSA infection. Methods We conducted a randomized, open-label, single-centre, non-inferiority trial comparing trimethoprim/sulfamethoxazole (160 mg/800 mg three times daily) plus rifampicin (600 mg once a day) versus linezolid (600 mg twice a day) alone in adult patients with various types of MRSA infection. Patients were allocated 1: 1 to either regimen. The primary outcome was clinical cure at 6 weeks after the end of treatment (non-inferiority margin 20%) assessed by both ITT and PP analyses. Secondary outcomes included the microbiologically documented persistence of MRSA in clinical cultures, mortality and adverse events. The study protocol has been registered with ClinicalTrials.gov (NCT00711854). Results Overall, 150 patients were randomized to one of the two treatment arms between January 2009 and December 2013 and were included in the ITT analysis. Of these 56/75 (74.7%) in the linezolid group and 59/75 (78.7%) in the trimethoprim/sulfamethoxazole and rifampicin group experienced clinical success (risk difference 4%, 95% CI −9.7% to 17.6%). The results were confirmed by the PP analysis, with 54/66 (81.8%) cured patients in the linezolid group versus 52/59 (88.1%) in the trimethoprim/sulfamethoxazole and rifampicin group (risk difference 6.3%, 95% CI −6.8% to 19.2%). There were no statistically significant differences between the two groups in any of the secondary outcomes, including microbiologically documented failure. Four adverse drug reactions attributed to the study medication occurred in the linezolid group versus nine in the trimethoprim/sulfamethoxazole and rifampicin group. Conclusions Compared with linezolid, trimethoprim/sulfamethoxazole and rifampicin seems to be non-inferior in the treatment of MRSA infectio

Steering Away from Current Amoxicillin Dose Reductions in Hospitalized Patients with Impaired Kidney Function to Avoid Subtherapeutic Drug Exposure.

Current dose reductions recommended for amoxicillin in patients with impaired kidney function could lead to suboptimal treatments. In a prospective, observational study in hospitalized adults with varying kidney function treated with an IV or oral dose of amoxicillin, amoxicillin concentrations were measured in 1-2 samples on the second day of treatment. Pharmacometric modelling and simulations were performed to evaluate the probability of target attainment (PTA) for 40% of the time above MIC following standard (1000 mg q6h), reduced or increased IV dosing strategies. A total of 210 amoxicillin samples was collected from 155 patients with kidney function based on a CKD-EPI of between 12 and 165 mL/min/1.73 m2. Amoxicillin clearance could be well predicted with body weight and CKD-EPI. Recommended dose adjustments resulted in a clinically relevant reduction in the PTA for the nonspecies-related PK/PD breakpoint MIC of 8 mg/L (92%, 62% and 38% with a CKD-EPI of 10, 20 and 30 mL/min/1.73 m2, respectively, versus 100% for the standard dose). For MICs ≤ 2 mg/L, PTA > 90% was reached in these patients following both reduced and standard dose regimens. Our study showed that for amoxicillin, recommended dose reductions with impaired kidney function could lead to subtherapeutic amoxicillin concentrations in hospitalized patients, especially when targeting less susceptible pathogens

Impact of exposure of methicillin-resistant Staphylococcus aureus to polyhexanide in vitro and in vivo.

Staphylococcus aureus (MRSA) resistant to decolonization agents such as mupirocin and chlorhexidine increase the need to develop alternative decolonization molecules. The absence of reported adverse reactions and bacterial resistance to polyhexanide makes it an excellent choice as topical antiseptic. In the present study we evaluated the in vitro and in vivo capacity to generate strains with reduced polyhexanide susceptibility and cross-resistance with chlorhexidine and/or antibiotics currently used in clinic. Here we report the in vitro emergence of reduced-susceptibility to polyhexanide by prolonged-stepwise exposure to low concentrations in broth culture. Reduced susceptibility to polyhexanide was associated with genomic changes in the mprF and purR genes, and with concomitant decreased susceptibility to daptomycin and other cell-wall active antibiotics. However, the in vitro emergence of reduced-susceptibility to polyhexanide did not result in cross-resistance to chlorhexidine antiseptic. During in vivo polyhexanide clinical decolonization treatment, neither polyhexanide reduced-susceptibility nor chlorhexidine cross-resistance were observed. Together, these observations suggest that polyhexanide could be used safely for decolonisation of carriers of chlorhexidine-resistant S. aureus strains but highlight the need for careful use of polyhexanide at low antiseptic concentrations

Population Pharmacokinetics of Imipenem in Critically Ill Patients: A Parametric and Nonparametric Model Converge on CKD-EPI Estimated Glomerular Filtration Rate as an Impactful Covariate

Background: Population pharmacokinetic (popPK) models for antibiotics are used to improve dosing strategies and individualize dosing by therapeutic drug monitoring. Little is known about the differences in results of parametric versus nonparametric popPK models and their potential consequences in clinical practice. We developed both parametric and nonparametric models of imipenem using data from critically ill patients and compared their results. Methods: Twenty-six critically ill patients treated with intravenous imipenem/cilastatin were included in this study. Median estimated glomerular filtration rate (eGFR) measured by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation was 116 mL/min/1.73 m2 (interquartile range 104–124) at inclusion. The usual dosing regimen was 500 mg/500 mg four times daily. On average, five imipenem levels per patient (138 levels in total) were drawn as peak, intermediate, and trough levels. Imipenem concentration-time profiles were analyzed using parametric (NONMEM 7.2) and nonparametric (Pmetrics 1.5.2) popPK software. Results: For both methods, data were best described by a model with two distribution compartments and the CKD-EPI eGFR equation unadjusted for body surface area as a covariate on the elimination rate constant (Ke). The parametric population parameter estimates were Ke 0.637 h−1 (between-subject variability [BSV]: 19.0% coefficient of variation [CV]) and central distribution volume (Vc) 29.6 L (without BSV). The nonparametric values were Ke 0.681 h−1 (34.0% CV) and Vc 31.1 L (42.6% CV). Conclusions: Both models described imipenem popPK well; the parameter estimates were comparable and the included covariate was identical. However, estimated BSV was higher in the nonparametric model. This may have consequences for estimated exposure during dosing simulations and should be further investigated in simulation studies

Deficiency of the clock gene Bmal1 affects neural progenitor cell migration

We demonstrate the impact of a disrupted molecular clock in Bmal1-deficient (Bmal1−/−) mice on migration of neural progenitor cells (NPCs). Proliferation of NPCs in rostral migratory stream (RMS) was reduced in Bmal1−/− mice, consistent with our earlier studies on adult neurogenesis in hippocampus. However, a significantly higher number of NPCs from Bmal1−/− mice reached the olfactory bulb as compared to wild-type littermates (Bmal1+/+ mice), indicating a higher migration velocity in Bmal1−/− mice. In isolated NPCs from Bmal1−/− mice, not only migration velocity and expression pattern of genes involved in detoxification of reactive oxygen species were affected, but also RNA oxidation of catalase was increased and catalase protein levels were decreased. Bmal1+/+ migration phenotype could be restored by treatment with catalase, while treatment of NPCs from Bmal1+/+ mice with hydrogen peroxide mimicked Bmal1−/− migration phenotype. Thus, we conclude that Bmal1 deficiency affects NPC migration as a consequence of dysregulated detoxification of reactive oxygen species

Exploring synergies and trade-offs among the sustainable development goals: collective action and adaptive capacity in marginal mountainous areas of India

Global environmental change (GEC) threatens to undermine the sustainable development goals (SDGs). Smallholders in marginal mountainous areas (MMA) are particularly vulnerable due to precarious livelihoods in challenging environments. Acting collectively can enable and constrain the ability of smallholders to adapt to GEC. The objectives of this paper are: (i) identify collective actions in four MMA of the central Indian Himalaya Region, each with differing institutional contexts; (ii) assess the adaptive capacity of each village by measuring livelihood capital assets, diversity, and sustainable land management practices. Engaging with adaptive capacity and collective action literatures, we identify three broad approaches to adaptive capacity relating to the SDGs: natural hazard mitigation (SDG 13), social vulnerability (SDG 1, 2 and 5), and social–ecological resilience (SDG 15). We then develop a conceptual framework to understand the institutional context and identify SDG synergies and trade-offs. Adopting a mixed method approach, we analyse the relationships between collective action and the adaptive capacity of each village, the sites where apparent trade-offs and synergies among SDGs occur. Results illustrate each village has unique socio-environmental characteristics, implying distinct development challenges, vulnerabilities and adaptive capacities exist. Subsequently, specific SDG synergies and trade-offs occur even within MMA, and it is therefore crucial that institutions facilitate locally appropriate collective actions in order to achieve the SDGs. We suggest that co-production in the identification, prioritisation and potential solutions to the distinct challenges facing MMA can increase understandings of the specific dynamics and feedbacks necessary to achieve the SDGs in the context of GEC