Impact of ethnicity and socio-economic status on Staphylococcus aureus bacteremia incidence and mortality: a heavy burden in Indigenous Australians

Extent: 9p.Background: Investigations of the impact of ethnicity and socio-economic status on incidence and outcomes of Staphylococcus aureus bacteraemia are limited. Methods: We prospectively identified all S. aureus bacteraemia episodes in the Australian New Zealand Cooperative on Outcomes in Staphylococcal Sepsis cohort study between 2007 and 2010. We calculated population level incidence rates using regional postcodes and stratified the analysis by ethnicity, age and socio-economic status indexes. Results: There were 7539 episodes of S. aureus bacteraemia with an annual incidence of 11·2 episodes per 100,000 population. The age-adjusted incidence in the Indigenous population was 62·5 per 100,000 population with an age standardized incidence rate ratio of 5·9 compared to the non-Indigenous population and an incidence rate ratio of 29.2 for community-associated methicillin-resistant S. aureus (MRSA). Populations in the lowest socio-economic status quintile had an increased S. aureus bacteraemia incidence compared to higher quintiles. However, there was a disparity between Indigenous and non-Indigenous populations across all socio-economic status quintiles. The lower 30-day mortality for Indigenous patients (7%) compared to non-Indigenous patients (17%) was explained by differences in age. Conclusions: Indigenous Australians suffer from a higher rate of S. aureus bacteraemia than non-Indigenous Australians, particularly for community-associated MRSA. Ethnicity and socio-economic status had little impact on subsequent mortality, with other host factors contributing more significantly.Steven Y C Tong, Sebastian J van Hal, Lloyd Einsiedel, Bart J Currie, John D Turnidg

Rapidly Escalating Hepcidin and Associated Serum Iron Starvation Are Features of the Acute Response to Typhoid Infection in Humans

BACKGROUND: Iron is a key pathogenic determinant of many infectious diseases. Hepcidin, the hormone responsible for governing systemic iron homeostasis, is widely hypothesized to represent a key component of nutritional immunity through regulating the accessibility of iron to invading microorganisms during infection. However, the deployment of hepcidin in human bacterial infections remains poorly characterized. Typhoid fever is a globally significant, human-restricted bacterial infection, but understanding of its pathogenesis, especially during the critical early phases, likewise is poorly understood. Here, we investigate alterations in hepcidin and iron/inflammatory indices following experimental human typhoid challenge. METHODOLOGY/PRINCIPAL FINDINGS: Fifty study participants were challenged with Salmonella enterica serovar Typhi and monitored for evidence of typhoid fever. Serum hepcidin, ferritin, serum iron parameters, C-reactive protein (CRP), and plasma IL-6 and TNF-alpha concentrations were measured during the 14 days following challenge. We found that hepcidin concentrations were markedly higher during acute typhoid infection than at baseline. Hepcidin elevations mirrored the kinetics of fever, and were accompanied by profound hypoferremia, increased CRP and ferritin, despite only modest elevations in IL-6 and TNF-alpha in some individuals. During inflammation, the extent of hepcidin upregulation associated with the degree of hypoferremia. CONCLUSIONS/SIGNIFICANCE: We demonstrate that strong hepcidin upregulation and hypoferremia, coincident with fever and systemic inflammation, are hallmarks of the early innate response to acute typhoid infection. We hypothesize that hepcidin-mediated iron redistribution into macrophages may contribute to S. Typhi pathogenesis by increasing iron availability for macrophage-tropic bacteria, and that targeting macrophage iron retention may represent a strategy for limiting infections with macrophage-tropic pathogens such as S. Typhi

Comparing methotrexate monotherapy with methotrexate plus leflunomide combination therapy in psoriatic arthritis (COMPLETE-PsA): a double-blind, placebo-controlled, randomised, trial

Background Conventional synthetic disease-modifying anti-rheumatic drugs (DMARDs) are the preferred first-line treatment in patients with psoriatic arthritis, although there is a paucity of evidence for the efficacy of conventional synthetic DMARDs and especially their combination. We aimed to investigate whether a combination of methotrexate plus leflunomide is superior to methotrexate monotherapy at improving disease activity in patients with psoriatic arthritis. Methods This single centre, investigator-initiated, double-blind, randomised, placebo-controlled trial was conducted at Sint Maartenskliniek in the Netherlands (locations included Boxmeer, Geldrop, Woerden, and Nijmegen). Patients aged 16 years or older with a clinical diagnosis of psoriatic arthritis and active disease (defined as two or more swollen joints; dactylitis counting as one swollen joint) were included. Patients were randomly allocated (1:1) and stratified by high disease activity (psoriatic arthritis disease activity score [PASDAS] ≥5·4) to either methotrexate plus leflunomide (combination therapy) or methotrexate plus placebo (monotherapy), using computer-generated stratified variable block randomisation. In both groups, patients received oral methotrexate 15 mg per week for the first 4 weeks and 25 mg per week thereafter combined with two leflunomide 10 mg tablets once per day or two placebo tablets. During the study period, the patients, nurses, researchers, and treating physicians were all masked to treatment allocation. The primary outcome was the difference in mean PASDAS at week 16, adjusted for baseline PASDAS, between the combination and monotherapy groups, assessed in the intention-to-treat population. This trial was registered with the Netherlands Trial Register (NL7404) on Dec 3, 2018. Findings Between Feb 19, 2019, and March 11, 2021, 82 patients were screened for eligibility. Four patients were ineligible and 78 were enrolled and randomly assigned to either methotrexate plus leflunomide (n=39) or methotrexate plus placebo (n=39). 50 (64%) of 78 patients were male, 28 (36%) were female, and the median age of patients was 55·0 years (IQR 42·0–64·0). Methotrexate plus leflunomide combination therapy was superior to methotrexate monotherapy at week 16 (PASDAS 3·1 [SD 1·4] vs 3·7 [SD 1·3]; treatment difference –0·6, 90% CI –1·0 to –0·1; p=0·025). There were no study deaths. The most frequently occurring adverse events were nausea or vomiting (17 [44%] of 39 patients in the methotrexate plus leflunomide group vs 11 [28%] of 39 in the methotrexate plus placebo group), tiredness (9 [23%] vs 13 [33%]) and elevated alanine aminotransferase (12 [31%] vs 7 [18%]. Generally, the incidence of mostly mild adverse events was higher in the methotrexate plus leflunomide group than in the methotrexate plus placebo group. Interpretation Methotrexate plus leflunomide combination therapy results in greater improvement in disease activity according to PASDAS in patients with psoriatic arthritis. However, methotrexate plus leflunomide combination therapy is less well tolerated than methotrexate monotherapy. Funding Regional Junior Researcher Grant from the Sint Maartenskliniek

Upscaling, integration and electrical characterization of molecular junctions

The ultimate target of molecular electronics is to combine different types of functional molecules into integrated circuits, preferably through an autonomous self-assembly process. Charge transport through self-assembled monolayers has been investigated previously, but problems remain with reliability, stability and yield, preventing further progress in the integration of discrete molecular junctions. Here we present a technology to simultaneously fabricate over 20,000 molecular junctions—each consisting of a gold bottom electrode, a self-assembled alkanethiol monolayer, a conducting polymer layer and a gold top electrode—on a single 150-mm wafer. Their integration is demonstrated in strings where up to 200 junctions are connected in series with a yield of unity. The statistical analysis on these molecular junctions, for which the processing parameters were varied and the influence on the junction resistance was measured, allows for the tentative interpretation that the perpendicular electrical transport through these monolayer junctions is factorized.

Expression of the oxygen-sensitive transcription factor subunit HIF-1 alpha in patients suffering from secondary Raynaud syndrome

Anti-ischemic therapy remains a challenge due to the complexity of hypoxia response pathways. Hypoxia-inducible factor (HIF)-1 is a heterodimer transcription factor consisting of 2 subunits, HIF-1 alpha and HIF-1 beta. Hypoxia-dependent activation of HIF-1 alpha regulates cellular O-2 homeostasis. Raynaud syndrome (RS), as a comorbidity of the autoimmune disease systemic sclerosis (SS), is characterized by vasospasms that limit blood flow to the limbs, resulting in hypoxia. A single-center randomized study was conducted to compare prostaglandin E1 (PgE1) therapy with a treatment combining PgE1 and an endothelin-1 blocker, bosentan. A total of 30 patients suffering from SS with RS were enrolled. We examined the regulation of HIF-1 alpha, its target heme oxygenase-1 (HMOX-1), and the serum levels of the HIF-1 alpha protein in a subset of patients as well as in ten healthy individuals. The expression of HIF-1 alpha and HMOX-1 in monocytes was measured using absolute plasmid-based quantitative real-time PCR, whereas serum HIF-1 alpha levels were measured with ELISA. Samples were taken at the time of randomization and after 24 weeks. We found that HIF-1 alpha and HMOX-1 mRNA expression in monocytes and serum HIF-1 alpha protein levels were significantly higher in the SS/RS patients compared to the healthy control group. Single-drug therapy significantly increased HIF-1 alpha and HMOX-1 mRNA expression in monocytes and serum HIF-1 alpha protein levels in the SS/RS patients compared to those at the time of randomization, whereas combining PgE1 with an endothelin-1 blocker prevented the further increases in HIF-1 alpha and HMOX-1 expression. We propose HIF-1 alpha and HMOX-1 as novel markers for anti-ischemic therapy in RS