Adjunctive rifampicin for Staphylococcus aureus bacteraemia (ARREST): a multicentre, randomised, double-blind, placebo-controlled trial.

BACKGROUND: Staphylococcus aureus bacteraemia is a common cause of severe community-acquired and hospital-acquired infection worldwide. We tested the hypothesis that adjunctive rifampicin would reduce bacteriologically confirmed treatment failure or disease recurrence, or death, by enhancing early S aureus killing, sterilising infected foci and blood faster, and reducing risks of dissemination and metastatic infection. METHODS: In this multicentre, randomised, double-blind, placebo-controlled trial, adults (≥18 years) with S aureus bacteraemia who had received ≤96 h of active antibiotic therapy were recruited from 29 UK hospitals. Patients were randomly assigned (1:1) via a computer-generated sequential randomisation list to receive 2 weeks of adjunctive rifampicin (600 mg or 900 mg per day according to weight, oral or intravenous) versus identical placebo, together with standard antibiotic therapy. Randomisation was stratified by centre. Patients, investigators, and those caring for the patients were masked to group allocation. The primary outcome was time to bacteriologically confirmed treatment failure or disease recurrence, or death (all-cause), from randomisation to 12 weeks, adjudicated by an independent review committee masked to the treatment. Analysis was intention to treat. This trial was registered, number ISRCTN37666216, and is closed to new participants. FINDINGS: Between Dec 10, 2012, and Oct 25, 2016, 758 eligible participants were randomly assigned: 370 to rifampicin and 388 to placebo. 485 (64%) participants had community-acquired S aureus infections, and 132 (17%) had nosocomial S aureus infections. 47 (6%) had meticillin-resistant infections. 301 (40%) participants had an initial deep infection focus. Standard antibiotics were given for 29 (IQR 18-45) days; 619 (82%) participants received flucloxacillin. By week 12, 62 (17%) of participants who received rifampicin versus 71 (18%) who received placebo experienced treatment failure or disease recurrence, or died (absolute risk difference -1·4%, 95% CI -7·0 to 4·3; hazard ratio 0·96, 0·68-1·35, p=0·81). From randomisation to 12 weeks, no evidence of differences in serious (p=0·17) or grade 3-4 (p=0·36) adverse events were observed; however, 63 (17%) participants in the rifampicin group versus 39 (10%) in the placebo group had antibiotic or trial drug-modifying adverse events (p=0·004), and 24 (6%) versus six (2%) had drug interactions (p=0·0005). INTERPRETATION: Adjunctive rifampicin provided no overall benefit over standard antibiotic therapy in adults with S aureus bacteraemia. FUNDING: UK National Institute for Health Research Health Technology Assessment

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Weed Suppression by Deleterious Rhizobacteria is Affected by Formulation and Soil Properties

Deleterious rhizobacteria (DRB) suppress weed growth in field tests and are considered potential weed biological control agents. This study compared the relative inhibitory action of the DRB Pseudomonas fluorescens strain G2-11 in different formulations, corn gluten meal (CGM), and semolina flour, toward wheat (Triticum aestivum L.), green foxtail (Setaria viridis (L.) Beauv.), and velvetleaf (Abutilon theophrasti Medik) seeds and seedlings in soil assays. Strain G2-11 successfully established in semolina flour as an inoculum formulation but was incompatible with CGM presumably because of antibacterial factors present. The effect of DRB and plant products on seed germination and plant growth were influenced by soil, with the strongest effects seen in fine sandy loam. Semolina flour alone reduced root growth of all target plants except for velvetleaf in silt loam. Green foxtail seed germination was greatly reduced by strain G2-11. With the exception of wheat seedling growth, strain G2-11 enhanced growth-suppressive qualities of semolina flour. Results suggest that natural plant products such as CGM and semolina flour alone and formulated with selected DRB may be important components for weed management considerations in sustainable agriculture

Gene transfer of endothelial nitric oxide synthase improves nitric oxide-dependent endothelial function in a hypertensive rat model

Objective: We have shown previously that there is a relative nitric oxide deficiency at the level of vascular endothelium in the stroke-prone spontaneously hypertensive rat (SHRSP), a model of human essential hypertension, as compared to its normotensive reference strain Wistar Kyoto (WKY) rat. The aim of the current study was to investigate whether adenoviral-mediated gene transfer of an endothelial nitric oxide synthase (eNOS) cDNA (AdCMVeNOS) into carotid arteries of the SHRSP may improve endothelial function. Methods: Enzyme activity of the recombinant eNOS protein encoded by AdCMVeNOS was tested using a Griess assay in endothelial cells in culture. Left carotid arteries of SHRSP were surgically isolated and exposed to either the AdCMVeNOS or control β-galactosidase-containing virus, (2×109 pfu/ml) ex vivo and in vivo. The vessels were harvested 24 h after surgery and analysed by Western blotting, immunohistochemistry and by examining endothelial function ex vivo. Results: Cultured endothelial cells showed almost 100% transduction with both viruses and a dose response of eNOS expression showed a five-fold increase in nitrite production for AdCMVeNOS with no change for β-galactosidase-containing virus. Western blotting demonstrated a significant increase of eNOS expression in vessels infused with AdCMVeNOS when compared to controls. Immunohistochemistry showed highly positive staining with monoclonal antibodies against eNOS in the intact endothelial cells of the AdCMVeNOS infused vessels. The areas under the curve of the concentration responses to phenylephrine (10−9 to 3×10−6M) in the absence and presence of NG-nitroarginine methyl ester (100 μM) showed increased basal nitric oxide bioavailability in the carotid arteries infused with AdCMVeNOS compared to the control (n=6 for each; P=0.0069; 95% CI, 0.864 to 3.277). Conclusions: Our results show that AdCMVeNOS is an effective tool for vascular gene transfer and that it can improve endothelial NO availability in the SHRSP, a genetic model of essential hypertension and endothelial dysfunction

Changing trends in mortality among solid organ transplant recipients hospitalized for COVID-19 during the course of the pandemic.

Mortality among patients hospitalized for COVID-19 has declined over the course of the pandemic. Mortality trends specifically in solid organ transplant recipients (SOTR) are unknown. Using data from a multicenter registry of SOTR hospitalized for COVID-19, we compared 28-day mortality between early 2020 (March 1, 2020-June 19, 2020) and late 2020 (June 20, 2020-December 31, 2020). Multivariable logistic regression was used to assess comorbidity-adjusted mortality. Time period of diagnosis was available for 1435/1616 (88.8%) SOTR and 971/1435 (67.7%) were hospitalized: 571/753 (75.8%) in early 2020 and 402/682 (58.9%) in late 2020 (p \u3c .001). Crude 28-day mortality decreased between the early and late periods (112/571 [19.6%] vs. 55/402 [13.7%]) and remained lower in the late period even after adjusting for baseline comorbidities (aOR 0.67, 95% CI 0.46-0.98, p = .016). Between the early and late periods, the use of corticosteroids (≥6 mg dexamethasone/day) and remdesivir increased (62/571 [10.9%] vs. 243/402 [61.5%], p \u3c .001 and 50/571 [8.8%] vs. 213/402 [52.2%], p \u3c .001, respectively), and the use of hydroxychloroquine and IL-6/IL-6 receptor inhibitor decreased (329/571 [60.0%] vs. 4/492 [1.0%], p \u3c .001 and 73/571 [12.8%] vs. 5/402 [1.2%], p \u3c .001, respectively). Mortality among SOTR hospitalized for COVID-19 declined between early and late 2020, consistent with trends reported in the general population. The mechanism(s) underlying improved survival require further study

COVID‐19 in hospitalized lung and non‐lung solid organ transplant recipients: A comparative analysis from a multicenter study

Lung transplant recipients (LTR) with coronavirus disease 2019 (COVID-19) may have higher mortality than non-lung solid organ transplant recipients (SOTR), but direct comparisons are limited. Risk factors for mortality specifically in LTR have not been explored. We performed a multicenter cohort study of adult SOTR with COVID-19 to compare mortality by 28 days between hospitalized LTR and non-lung SOTR. Multivariable logistic regression models were used to assess comorbidity-adjusted mortality among LTR vs. non-lung SOTR and to determine risk factors for death in LTR. Of 1,616 SOTR with COVID-19, 1,081 (66%) were hospitalized including 120/159 (75%) LTR and 961/1457 (66%) non-lung SOTR (p = .02). Mortality was higher among LTR compared to non-lung SOTR (24% vs. 16%, respectively, p = .032), and lung transplant was independently associated with death after adjusting for age and comorbidities (aOR 1.7, 95% CI 1.0-2.6, p = .04). Among LTR, chronic lung allograft dysfunction (aOR 3.3, 95% CI 1.0-11.3, p = .05) was the only independent risk factor for mortality and age >65 years, heart failure and obesity were not independently associated with death. Among SOTR hospitalized for COVID-19, LTR had higher mortality than non-lung SOTR. In LTR, chronic allograft dysfunction was independently associated with mortality

Covid-19 in hospitalized lung and non-lung solid organ transplant recipients: a comparative analysis from a multicenter study.

Lung transplant recipients (LTR) with Covid-19 may have higher mortality than non-lung solid organ transplant recipients (SOTR), but direct comparisons are limited. Risk factors for mortality specifically in LTR have not been explored. We performed a multicenter cohort study of adult SOTR with Covid-19 to compare mortality by 28-days between hospitalized LTR and non-lung SOTR. Multivariable logistic regression models were used to assess comorbidity-adjusted mortality among LTR vs. non-lung SOTR and to determine risk factors for death in LTR. Of 1,616 SOTR with Covid-19, 1,051 (65%) were hospitalized including 117/159 (74%) LTR and 934/1457 (64%) non-lung SOTR (p=0.02). Mortality was higher among LTR compared to non-lung SOTR (24% vs. 16%, respectively, p=0.035) and lung transplant was independently associated with death after adjusting for age and comorbidities (aOR 1.7, 95% CI 1.0-2.6, p=0.05). Among LTR, independent risk factors for mortality included single lung transplant (aOR 2.8, 95% CI 1.0-7.7, p=0.04) and chronic lung allograft dysfunction (aOR 3.6, 95% CI 1.0-12.4, p=0.05), but not age \u3e65 years, heart failure, or obesity. Among SOTR hospitalized for Covid-19, LTR had higher mortality than non-lung SOTR. In LTR, single lung transplant and chronic allograft dysfunction were independently associated with mortality