Nicotinic receptors mediate stress-nicotine detrimental interplay via dopamine cells' activity.

Epidemiological studies report strong association between mood disorders and tobacco addiction. This high comorbidity requires adequate treatment but the underlying mechanisms are unknown. We demonstrate that nicotine exposure, independent of drug withdrawal effects, increases stress sensitivity, a major risk factor in mood disorders. Nicotine and stress concur to induce long-lasting cellular adaptations within the dopamine (DA) system. This interplay is underpinned by marked remodeling of nicotinic systems, causing increased ventral tegmental area (VTA) DA neurons' activity and stress-related behaviors, such as social aversion. Blocking ß2 or α7 nicotinic acetylcholine receptors (nAChRs) prevents, respectively, the development and the expression of social stress-induced neuroadaptations; conversely, facilitating α7 nAChRs activation specifically in the VTA promotes stress-induced cellular and behavioral maladaptations. Our work unravels a complex nicotine-stress bidirectional interplay and identifies α7 nAChRs as a promising therapeutic target for stress-related psychiatric disorders.

Nicotine consumption is regulated by a human polymorphism in dopamine neurons.

Smoking is the most important preventable cause of morbidity and mortality worldwide. Recent genome-wide association studies highlighted a human haplotype on chromosome 15 underlying the risk for tobacco dependence and lung cancer. Several polymorphisms in the CHRNA3-CHRNA5-CHRNB4 cluster coding for the nicotinic acetylcholine receptor (nAChR) α3, α5 and ß4 subunits were implicated. In mouse models, we define a key role in the control of sensitivity to nicotine for the α5 subunit in dopaminergic (DAergic) neurons of the ventral tegmental area (VTA). We first investigated the reinforcing effects of nicotine in drug-naive α5(-/-) mice using an acute intravenous nicotine self-administration task and ex vivo and in vivo electrophysiological recordings of nicotine-elicited DA cell activation. We designed lentiviral re-expression vectors to achieve targeted re-expression of wild-type or mutant α5 in the VTA, in general, or in DA neurons exclusively. Our results establish a crucial role for α5*-nAChRs in DAergic neurons. These receptors are key regulators that determine the minimum nicotine dose necessary for DA cell activation and thus nicotine reinforcement. Finally, we demonstrate that a single-nucleotide polymorphism, the non-synonymous α5 variant rs16969968, frequent in many human populations, exhibits a partial loss of function of the protein in vivo. This leads to increased nicotine consumption in the self-administration paradigm. We thus define a critical link between a human predisposition marker, its expression in DA neurons and nicotine intake.

Comparison of predictive validity of two autism spectrum disorder rat models: Behavioural investigations.

The valproic acid model has been shown to reproduce ASD-like behaviours observed in patients and is now widely validated for construct, face, and predictivity as ASD model in rat. The literature agrees on using a single exposition to 500 mg/kg of VPA at gestational day 12 to induce ASD phenotype with the intraperitoneal route being the most commonly used. However, some studies validated this model with repeated exposure by using oral route. The way of administration may be of great importance in the induction of the ASD phenotype and a comparison is greatly required. We compared two ASD models, one induced by a unique IP injection of 500 mg/kg of body weight at GD12 and the other one by repeated PO administration of 500 mg/kg of body weight/day between GD11 and GD13. The behavioural phenotypes of the offspring were assessed for the core signs of ASD (impaired social behaviour, stereotypical/repetitive behaviours, sensory/communication deficits) as well as anxiety as comorbidity, at developmental and juvenile stages in both sexes. The VPA IP model induced a more literature-compliant ASD phenotype than the PO one. These results confirmed that the mode of administration as well as the window of VPA exposure are key factors in the ASD-induction phenotype. Interestingly, the effects of VPA administration were similar at the developmental stage between both sexes and then tended to differ later in life.

Pharmacokinetic characterisation of a valproate Autism Spectrum Disorder rat model in a context of co-exposure to α-Hexabromocyclododecane.

Assessing the role of α-hexabromocyclododecane α-HBCDD as a factor of susceptibility for Autism Spectrum disorders by using valproic acid-exposed rat model (VPA) required characterizing VPA pharmacokinetic in the context of α-HBCDD-co-exposure in non-pregnant and pregnant rats. The animals were exposed to α-HBCDD by gavage (100 ng/kg/day) for 12 days. This was followed by a single intraperitoneal dose of VPA (500 mg/kg) or a daily oral dose of VPA (500 mg/kg) for 3 days. Exposure to α-HBCDD did not affect the pharmacokinetics of VPA in pregnant or non-pregnant rats. Surprisingly, VPA administration altered the pharmacokinetics of α-HBCDD. VPA also triggered higher foetal toxicity and lethality with the PO than IP route. α-HBCDD did not aggravate the embryotoxicity observed with VPA, regardless of the route of exposure. Based on this evidence, a single administration of 500 mg/kg IP is the most suitable VPA model to investigate α-HBCDD co-exposure.

Identification of genomic deletions spanning the PCDH19 gene in two unrelated girls with intellectual disability and seizures.

Recently, missense and truncating mutations in the gene PCDH19 have been reported to cause female-restricted epilepsy with mental retardation (EFMR). EFMR (MIM#300088) is an X-linked disorder characterized by early onset seizures and intellectual disability (ID). Interestingly, unlike typical X-linked mode of inheritance, the phenotype is restricted to females, and males are unaffected carriers. PCDH19 is highly expressed in brain, and the encoded protein belongs to the cadherin superfamily. Here we report two unrelated female patients with deletions spanning PCDH19 identified by copy number variation (CNV) analysis and validated by qPCR. In one, we have identified a 3 Mb interstitial deletion at Xq21.33-q22.1 which spans PCDH19, LOC442459 & TNMD. This patient had her first seizure at 8 months old, and also has ID and aggressive behavior. In another female patient we identified a de novo 603 kb heterozygous deletion in a female patient with fits (since 1 year of age), ID, hyperactivity and aggressive behavior. The deletion spans the entire PCDH19 gene (also TNMD, SRPX2, TSPAN6 and SYTL4). In conclusion, our results suggest that deletions at PCDH19 also cause EFMR.

Delivery of gelfoam-enabled cells and vectors into the pericardial space using a percutaneous approach in a porcine model.

Intrapericardial drug delivery is a promising procedure, with the ability to localize therapeutics with the heart. Gelfoam particles are nontoxic, inexpensive, nonimmunogenic and biodegradable compounds that can be used to deliver therapeutic agents. We developed a new percutaneous approach method for intrapericardial injection, puncturing the pericardial sac safely under fluoroscopy and intravascular ultrasound (IVUS) guidance. In a porcine model of myocardial infarction (MI), we deployed gelfoam particles carrying either (a) autologous mesenchymal stem cells (MSCs) or (b) an adenovirus encoding enhanced green fluorescent protein (eGFP) 48 h post-MI. The presence of MSCs and viral infection at the infarct zone was confirmed by immunoflourescence and PCR. Puncture was performed successfully in 16 animals. Using IVUS, we successfully determined the size of the pericardial space before the puncture, and safely accessed that space in setting of pericardial effusion and also adhesions induced by the MI. Intrapericardial injection of gelfoam was safe and reliable. Presence of the MSCs and eGFP expression from adenovirus in the myocardium were confirmed after delivery. Our novel percutaneous approach to deliver (stem-) cells or adenovirus was safe and efficient in this pre-clinical model. IVUS-guided delivery is a minimally invasive procedure that seems to be a promising new strategy to deliver therapeutic agents locally to the heart.

Lipopolysaccharide modulates the expression of alpha 1 proteinase inhibitor and other serine proteinase inhibitors in human monocytes and macrophages.

alpha 1 Proteinase inhibitor (PI) is the principle inhibitor of neutrophil elastase, an enzyme that degrades many components of the extracellular matrix. Expression and regulation of alpha 1 PI, therefore, affects the delicate balance of elastase and antielastase, which is critical to turnover of connective tissue during homeostasis, tissue injury, and repair. In this study we show that expression of alpha 1 PI in human monocytes and macrophages is regulated during activation by LPS. LPS mediates a concentration- and time-dependent increase in the rate of synthesis of alpha 1 PI in mononuclear phagocytes. There is a 4.5-8.7-fold increase in functionally active inhibitor delivered to the cell culture fluid of monocytes. The effect of LPS is specific in that it is neutralized by an mAb to the lipid A moiety. The increase in expression of alpha 1 PI mediated by LPS occurs in the context of other specific changes in the expression of serine proteinase inhibitor genes in mononuclear phagocytes. There is an increase in the rate of synthesis of C1 inhibitor and a decrease in synthesis of alpha 2 macroglobulin. Regulation of alpha 1 PI by LPS is distinctive in that it is largely determined by a change in the efficiency of translation of alpha 1 PI mRNA. LPS has no effect on the rate of posttranslational processing and/or secretion of alpha 1 PI and, therein, causes greater intracellular accumulation of alpha 1 PI in mononuclear phagocytes from individuals with homozygous PiZZ alpha 1 PI deficiency.

New injectable self-assembled hydrogels that promote angiogenesis through a bioactive degradation product.

Hydrogels used in regenerative medicine are often designed to allow cellular infiltration, degradation, and neovascularization. Low molecular weight hydrogels (LMWHs), formed by self-assembly via non-covalent interactions, are gaining significant interest because they are soft, easy to use and injectable. We propose LMWHs as suitable body implant materials that can stimulate tissue regeneration. We produced four new LMWHs with molecular entities containing nucleic acid and lipid building blocks and analyzed the foreign body response upon subcutaneous implantation into mice. Despite being infiltrated with macrophages, none of the hydrogels triggered detrimental inflammatory responses. Most macrophages present in the hydrogel-surrounding tissue acquired an immuno-modulatory rather than inflammatory phenotype. Concomitantly, no fibrotic capsule was formed after three weeks. Our glyconucleolipid LMWHs exhibited different degradation kinetics in vivo and in vitro. LMWHs with high angiogenic properties in vivo, were found to release glyconucleoside (glucose covalently linked to thymidine via a triazole moiety) as a common by-product of in vitro LMWH degradation. Chemically synthesized glyconucleoside exhibited angiogenic properties in vitro in scratch assays with monolayers of human endothelial cells and in vivo using the chick chorioallantoic membrane assay. Collectively, LMWHs hold promise as efficient scaffolds for various regenerative applications by displaying good biointegration without causing fibrosis, and by promoting angiogenesis through the release of a pro-angiogenic degradation product. STATEMENT OF SIGNIFICANCE: The main limitations of biomaterials developed in the field of tissue engineering remains their biocompatibility and vascularisation properties. In this context, we developed injectable Low Molecular Weight Hydrogels (LMWH) exhibiting thixotropic (reversible gelation) and thermal reversible properties. LMWH having injectability is of great advantage since it allows for their delivery without wounding the surrounding tissues. The resulting gels aim at forming scaffolds that the host cells colonize without major inflammation, and that won't be insulated by a strong fibrosis reaction. Importantly, their molecular degradation releases a product (a glycosyl-nucleoside conjugate) promoting angiogenesis. In this sense, these LMWH represent an important advance in the development of biomaterials promoting tissue regeneration.

Monoallelic expression of the interleukin-2 locus.

The lymphokine interleukin-2 (IL-2) is responsible for autocrine cell cycle progression and regulation of immune responses. Uncontrolled secretion of IL-2 results in adverse reactions ranging from anergy, to aberrant T cell activation, to autoimmunity. With the use of fluorescent in situ hybridization and single-cell polymerase chain reaction in cells with different IL-2 alleles, IL-2 expression in mature thymocytes and T cells was found to be tightly controlled by monoallelic expression. Because IL-2 is encoded at a nonimprinted autosomal locus, this result represents an unusual regulatory mode for controlling the precise expression of a single gene.

Imaging performance of the hybrid pixel detectors XPAD3-S.

Hybrid pixel detectors, originally developed for tracking particles in high-energy physics experiments, have recently been used in material sciences and macromolecular crystallography. Their capability to count single photons and to apply a threshold on the photon energy suggests that they could be optimal digital x-ray detectors in low energy beams such as for small animal computed tomography (CT). To investigate this issue, we have studied the imaging performance of photon counting hybrid pixel detectors based on the XPAD3-S chip. Two detectors are considered, connected either to a Si or to a CdTe sensor, the latter being of interest for its higher efficiency. Both a standard 'International Electrotechnical Commission' (IEC) mammography beam and a beam used for mouse CT results published in the literature are employed. The detector stability, linearity and noise are investigated as a function of the dose for several imaging exposures ( approximately 0.1-400 microGy). The perfect linearity of both detectors is confirmed, but an increase in internal noise for counting statistics higher than approximately 5000 photons has been found, corresponding to exposures above approximately 110 microGy and approximately 50 microGy for the Si and CdTe sensors, respectively. The noise power spectrum (NPS), the modulation transfer function (MTF) and the detective quantum efficiency (DQE) are then measured for two energy threshold configurations (5 keV and 18 keV) and three doses ( approximately 3, 30 and 300 microGy), in order to obtain a complete estimation of the detector performances. In general, the CdTe sensor shows a clear superiority with a maximal DQE(0) of approximately 1, thanks to its high efficiency ( approximately 100%). The DQE of the Si sensor is more dependent on the radiation quality, due to the energy dependence of its efficiency its maximum is approximately 0.4 with respect to the softer radiation. Finally, we compare the XPAD3-S DQE with published curves of other digital devices in a similar radiation condition. The XPAD3-S/CdTe detector appears to be the best with the highest DQE at low frequency, although some improvements are expected to reduce the increase of noise with the counts statistics and to guarantee a better stability of the detector response.

Learning from our mistakes: using key opportunities to remove the perverse incentives that help drive antibiotic resistance.

Introduction: Governments need to do far more to help curb the emergence and transmission of antibiotic resistance and help protect the efficacy of any new antibiotics that come to the market. Industry is an important stakeholder that must be brought on-board such efforts given its influence on the direction and scale of antibiotic sales. Financial incentives supporting industry R&D of novel antibiotics should structurally remove the drivers of superfluous sales and encourage access to newer antibiotics where infections are otherwise resistant to treatment. Indeed, the use of public money provides an important opportunity to prioritize these public health goals within market structures such that we both adequately reward industry for their efforts and prolong antibiotic efficacy for as long as possible.Areas covered: This work discusses possible financial 'pull' incentives that fully delink the reward paid to the developer from unit sales, examining their primary advantages and limitations.Expert opinion: Pharmaceutical companies need to be rewarded generously for their efforts to develop new, badly needed antibiotics. But the current marketplace does not provide a sustained financial lure and its reliance on unit-sales for profitability jeopardizes the efficacy of antibiotics both new and old. Fully delinked models can make antibiotic R&D more financially appealing and create a market environment that is far less threatening to public health.

Multidisciplinary team meeting and EUSOMA quality indicators in breast cancer care: A French regional multicenter study.

INTRODUCTION: We evaluate breast cancer (BC) pathway at a regional level including public, private and university institutions. We assessed the quality of multidisciplinary team meetings (MTM) and compliance with a panel of European high-quality indicators (EUSOMA QIs). METHODS: We conducted a retrospective multicenter (n = 20) study in the largest health care region in France. Between January and April 2015, we included all patients discussed at an MTM after a diagnosis of BC (n = 619). We analyzed quality of MTM by assessing the quorum, the reliability of data transcription and the exhaustivity of pre-therapeutic MTM. We then analyzed the compliance with a selected panel of 16 EUSOMA QIs. RESULTS: During MTM discussion, data were more than 95% consistent with medical records for 9/11 items. Pre-operative tumor histology (90.6%) and post-operative resection margins (84.3%) were the least concordant between medical records and MTM. Minimum standards as defined by EUSOMA were reached for 11/16 QIs, but not reached for pathology reports in non-invasive BC (78.2%), proportion of exclusive sentinel lymph node biopsies in patients with clinically negative axilla (85.2%), performing adjuvant chemotherapy (76.6%), and proportion of patients discussed in pre-therapeutic and post-operative MTM (63.5%). CONCLUSIONS: In this multicentric study evaluating the quality of BC care with a representative sample of institutions, compliance with EUSOMA indicators was satisfactory for all type of institutions. However, too few patients were discussed in pre-therapeutic MTM (especially in non-university hospitals 43.7% [39.4-48.1]) versus 88.7% for others [82.2-95.1]) and data transcription was likely responsible for up to 15% of discordance.

p.H62L, a rare mutation of the CYP21 gene identified in two forms of 21-hydroxylase deficiency.

CONTEXT: Steroid 21-hydroxylase deficiency is the most common enzymatic defect causing congenital adrenal hyperplasia with good genotype/phenotype relationships for common mutations. To determine the severity of rare mutations is essential for genetic counseling and better understanding of the structure-function of the cytochrome P450c21. OBJECTIVE: The p.H62L mutation was the most frequent of 60 new mutations detected in 2900 steroid 21-hydroxylase deficiency patients, either isolated or associated on the same allele with a mild mutation (p.P453S, p.P30L, or partial promoter). Because phenotypes seemed to differ between patients with isolated or associated p.H62L, a detailed phenotype description and functional studies were performed. RESULTS: Regarding phenotype, patients with isolated p.H62L had a nonclassical form, whereas patients with the association p.H62L + mild mutation had a simple virilizing form. Functional studies showed that p.H62L reduced the conversion of the two substrates, progesterone and 17-hydroxyprogesterone, in the same way as the mild p.P453S; the association p.H62L + p.P453S decreased enzymatic activity more strongly while conserving residual activity at a level intermediate between p.P453S and p.I172N. This suggested that p.H62L was a mild mutation, whereas a synergistic effect occurred when it was associated. Analysis of p.H62L in a three-dimensional model structure of the CYP21 protein explained the observed in vitro effects, the H62 being located in a domain implied in membrane anchoring. CONCLUSION: According to phenotype and functional studies, p.H62L is a mild mutation, responsible for a more severe phenotype when associated with another mild mutation. These data are important for patient management and genetic counseling.

Non-contrast magnetic resonance imaging for monitoring patients with acoustic neuroma.

OBJECTIVE: To assess the feasibility of non-contrast T2-weighted magnetic resonance imaging as compared to T1-weighted post-contrast magnetic resonance imaging for detecting acoustic neuroma growth. METHODS: Adult patients with acoustic neuroma who underwent at least three magnetic resonance imaging scans of the internal auditory canals with and without contrast in the past nine years were identified. T1- and T2-weighted images were reviewed by three neuroradiologists, and tumour size was measured. Accuracy of the measurements on T2-weighted images was defined as a difference of less than or equal to 2 mm from the measurement on T1-weighted images. RESULTS: A total of 107 magnetic resonance imaging scans of 26 patients were reviewed. Measurements on T2-weighted magnetic resonance imaging scans were 88 per cent accurate. Measurements on T2-weighted images differed from measurements on T1-weighted images by an average of 1.27 mm, or 10.4 per cent of the total size. The specificity of T2-weighted images was 88.2 per cent and the sensitivity was 77.8 per cent. CONCLUSION: The T2-weighted sequences are fairly accurate in measuring acoustic neuroma size and identifying growth if one keeps in mind the caveats associated with the tumour characteristics or location.

Unsuccessful treatment attempt: cord blood stem cell transplantation in a patient with Niemann-Pick disease type A.

Niemann-Pick disease type A (NP-A; OMIM 257200) is an autosomal recessive lysosomal storage disorder caused by deficiency of acid sphingomyelinase and resulting in accumulation of sphingomyelin, unesterified cholesterol, and other complex lipids in many tissues. It is characterized by failure to thrive, hepatosplenomegaly, and a rapidly progressive neurodegenerative course culminating in death by 3 years of age. There is no known effective treatment. We report the case of a prenatally diagnosed girl who underwent cord blood stem cell transplantation (CBSCT) at 3 months of age. She was neurologically intact at the time of CBSCT. Hepatosplenomegaly, was detected at 6 weeks of age; the splenomegaly resolved following CBSCT. Recovery was complicated by graft-versus-host disease. She subsequently developed and continues to show marked global developmental delay, generalized hypotonia, and signs of neurological regression, despite continued engraftment. Bilateral cherry red spots were detected at 10 months of age, 7 months post-CBSCT. Although she is doing better than her affected brother, she shows little overall benefit from CBSCT.

Homologous DNA sequences and cellular factors are implicated in the control of glucagon and insulin gene expression.

The glucagon gene is specifically expressed in the alpha cells of pancreatic islets. The promoter of the glucagon gene is responsible for this specificity. Within the promoter, the upstream promoter element G1 is critical to restrict expression to the alpha cells. We define here a composite DNA control element, G4, localized upstream of G1 between nucleotides -100 and -140 which functions as an islet-specific activator in both glucagon- and insulin-producing cells but not in nonislet cells. G4 contains at least three protein binding sites. The most proximal site, E2, is highly homologous to the E1, SMS-UE, and B elements of the rat insulin I, somastatin, and elastase I genes, respectively, and interacts with a pancreas-specific complex; the distal site, E3, represents an E box which is identical to the E boxes of the rat insulin I and II genes and binds to a complex similar or identical to IEF1 which has been implicated in the tissue-specific control of insulin gene expression. These two sites necessitate a third element, the intervening sequence, to activate transcription. We conclude that the first 140 bp of the glucagon gene promoter contains at least two DNA control elements responsible for pancreatic alpha-cell-specific expression: G4, an islet cell-specific element sharing common binding sites with the insulin gene, and G1, which restricts glucagon gene expression to the alpha cells. This double control of specificity might have relevance during islet cell differentiation.

Glucagon gene expression is negatively regulated by hepatocyte nuclear factor 3 beta.

Pancreatic expression of the glucagon gene depends on multiple transcription factors interacting with at least three DNA control elements: G1, the upstream promoter element, and G2 and G3, two enhancer-like sequences. We report here that the major enhancer of the rat glucagon gene, G2, interacts with three protein complexes, A1, A2, and A3. A2 is detected only in islet cells, and impairment of its binding to mutant G2 causes a marked decrease in transcriptional activity. We identify A1 as hepatocyte nuclear factor 3 beta (HNF-3 beta), a member of the HNF-3 DNA-binding protein family found in abundance in the liver which has been proposed to play a role in the formation of gut-related organs. HNF-3 beta binds G2 on a site which overlaps A2 and acts as a repressor of glucagon gene expression, as demonstrated by mutational analyses of G2 and by cotransfection of HNF-3 beta cDNA along with reporter genes containing G2 into glucagon-producing cells. Our data implicate HNF-3 beta in the control of glucagon gene expression and strengthen the idea of endodermal origin of the islet cells.

Preserving the 'commons': addressing the sustainable use of antibiotics through an economic lens.

BACKGROUND: As the growth of antibiotic resistance has resulted in large part from widespread use of antibiotics, every effort must be made to ensure their sustainable use. AIMS: This narrative review aims to assess the potential contribution of health economic analyses to sustainable use efforts. SOURCES: The work draws on existing literature and experience with health economic tools. CONTENT: The study examines some of the weaknesses in the health, regulatory, and industry arenas that could contribute to inappropriate or suboptimal prescribing of antibiotics and describes how economic analysis could be used to improve current practice by comparing both costs and health outcomes to maximize societal wellbeing over the longer-term. It finds that economic considerations underpinning current antibiotic prescribing strategies are incomplete and short-termist, with the result that they may foster suboptimal use. It also stresses that perverse incentives that drive antibiotic sales and inappropriate prescribing practices must be dis-entangled for sustainable use policies to gain traction. Finally, payment structures can be used to re-align incentives and promote optimal prescribing and sustainable use more generally. In particular, eliminating or altering reimbursement differentials could help steer clinical practice more deliberately towards the minimization of selection pressure and the resulting levels of antibiotic resistance. IMPLICATIONS: This work highlights the need for appropriately designed cost-effectiveness analyses, incentives analysis, and novel remuneration systems to underpin sustainable use policies both within and beyond the health sector.

Comparing the cost-effectiveness of linezolid to trimethoprim/sulfamethoxazole plus rifampicin for the treatment of methicillin-resistant Staphylococcus aureus infection: a healthcare system perspective.

OBJECTIVE: Few industry-independent studies have been conducted to compare the relative costs and benefits of drugs to treat methicillin-resistant Staphylococcus aureus (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. METHODS: We used cost and effectiveness data from a previously conducted clinical trial, complementing with other data from published literature, to compare the two regimens from a healthcare system perspective. Effectiveness was expressed in terms of quality-adjusted life-years (QALYs). Several sensitivity analyses were performed using Monte Carlo simulation, to measure the effect of potential parameter changes on the base-case model results, including potential differences related to type of infection and drug toxicity. RESULTS: Treatment of MRSA infection with trimethoprim-sulfamethoxazole plus rifampicin and linezolid were found to cost on average €146 and €2536, and lead to a gain of 0.916 and 0.881 QALYs, respectively. Treatment with trimethoprim-sulfamethoxazole plus rifampicin was found to be more cost-effective than linezolid in the base case and remained dominant over linezolid in most alternative scenarios, including different types of MRSA infection and potential disadvantages in terms of toxicity. With a willingness-to-pay threshold of €0, €50 000 and €200 000 per QALY gained, trimethoprim-sulfamethoxazole plus rifampicin was dominant in 100%, 96% and 85% of model iterations. A 95% discount on the current purchasing price of linezolid would be needed when it goes off-patent for it to represent better value for money compared with trimethoprim-sulfamethoxazole plus rifampicin. CONCLUSIONS: Combined treatment of trimethoprim-sulfamethoxazole plus rifampicin is more cost-effective than linezolid in the treatment of MRSA infection.