The efficacy of convalescent plasma for coronavirus disease 2019 (COVID-19) is unclear. Although most randomized controlled trials have shown negative results, uncontrolled studies have suggested that the antibody content could influence patient outcomes. We conducted an open-label, randomized controlled trial of convalescent plasma for adults with COVID-19 receiving oxygen within 12 d of respiratory symptom onset (NCT04348656). Patients were allocated 2:1 to 500 ml of convalescent plasma or standard of care. The composite primary outcome was intubation or death by 30 d. Exploratory analyses of the effect of convalescent plasma antibodies on the primary outcome was assessed by logistic regression. The trial was terminated at 78% of planned enrollment after meeting stopping criteria for futility. In total, 940 patients were randomized, and 921 patients were included in the intention-to-treat analysis. Intubation or death occurred in 199/614 (32.4%) patients in the convalescent plasma arm and 86/307 (28.0%) patients in the standard of care arm—relative risk (RR) = 1.16 (95% confidence interval (CI) 0.94–1.43, P = 0.18). Patients in the convalescent plasma arm had more serious adverse events (33.4% versus 26.4%; RR = 1.27, 95% CI 1.02–1.57, P = 0.034). The antibody content significantly modulated the therapeutic effect of convalescent plasma. In multivariate analysis, each standardized log increase in neutralization or antibody-dependent cellular cytotoxicity independently reduced the potential harmful effect of plasma (odds ratio (OR) = 0.74, 95% CI 0.57–0.95 and OR = 0.66, 95% CI 0.50–0.87, respectively), whereas IgG against the full transmembrane spike protein increased it (OR = 1.53, 95% CI 1.14–2.05). Convalescent plasma did not reduce the risk of intubation or death at 30 d in hospitalized patients with COVID-19. Transfusion of convalescent plasma with unfavorable antibody profiles could be associated with worse clinical outcomes compared to standard care.

The ACC deaminase gene (acdS) from Enterobacter cloacae UW4 was replaced by homologous recombination with the acdS gene with a tetracycline resistance gene inserted within the coding region. Upon characterization of this AcdS minus mutant, it was determined that both ACC deaminase activity and the ability to promote the elongation of canola roots under gnotobiotic conditions were greatly diminished. This result is consistent with a previously postulated model that suggests that a major mechanism utilized by plant growth-promoting bacteria involves the lowering of plant ethylene levels, and hence ethylene inhibition of root elongation, by bacterial ACC deaminase.

Background: The role of remdesivir inThe primary outcome was in-hospital 24.8% and 28.2%, respectively (95% CI the treatment of patients in hospital mortality. Secondary outcomes 0.72 to 1.07). For patients not mechanwith COVID-19 remains ill defined in a included changes in clinical severity, ically ventilated at baseline, the need for global context. The World Health Organ-oxygen-and ventilator-free days (at mechanical ventilation was 8.0% in those ization Solidarity randomized controlled 28 d), incidence of new oxygen or assigned remdesivir, and 15.0% in those trial (RCT) evaluated remdesivir in mechanical ventilation use, duration of receiving standard of care (RR 0.53, 95% CI patients across many countries, with hospital stay, and adverse event rates. 0.38 to 0.75). Mean oxygen-free and Canada enrolling patients using anWe performed a priori subgroup analy-ventilator-free days at day 28 were 15.9 expanded data collection format in the ses according to duration of symptoms (± standard deviation [SD] 10.5) and 21.4 Canadian Treatments for COVID-19 before enrolment, age, sex and severity (± SD 11.3) in those receiving remdesivir (CATCO) trial. We report on the Canad-of symptoms on presentation. and 14.2 (± SD 11) and 19.5 (± SD 12.3) in ian findings, with additional demo-those receiving standard of care (p = 0.006 graphics, characteristics and clinical Results: Across 52 Canadian hospitals, and 0.007, respectively). There was no difoutcomes, to explore the potential for we randomized 1282 patients between ference in safety events of new dialysis, differential effects across different Aug. 14, 2020, and Apr. 1, 2021, to remde-change in creatinine, or new hepatic dyshealth care systems.sivir (n = 634) or standard of care (n = function between the 2 groups. 648). Of these, 15 withdrew consent or Methods: We performed an open-label, were still in hospital, for a total sample of Interpretation: Remdesivir, when compragmatic RCT in Canadian hospitals, in 1267 patients. Among patients assigned pared with standard of care, has a modest conjunction with the Solidarity trial. We to receive remdesivir, in-hospital mortal-but significant efect on outcomes imporrandomized patients to 10 days of rem-ity was 18.7%, compared with 22.6% in tant to patients and health systems, such desivir (200 mg intravenously [IV] on day the standard-of-care arm (relative risk as the need for mechanical ventilation. 0, followed by 100 mg IV daily), plus[RR] 0.83 (95% confidence interval [CI] Trial registration: ClinicalTrials.gov, no. standard care, or standard care alone. 0.67 to 1.03), and 60-day mortality was NCT04330690.

for the Prevention of Severe Pneumonia and Endotracheal Colonization Trial (PROSPECT) Investigators and the Canadian Critical Care Trials Group IMPORTANCE Growing interest in microbial dysbiosis during critical illness has raised questions about the therapeutic potential of microbiome modification with probiotics. Prior randomized trials in this population suggest that probiotics reduce infection, particularly ventilator-associated pneumonia (VAP), although probiotic-associated infections have also been reported.OBJECTIVE To evaluate the effect of Lactobacillus rhamnosus GG on preventing VAP, additional infections, and other clinically important outcomes in the intensive care unit (ICU). DESIGN, SETTING, AND PARTICIPANTS Randomized placebo-controlled trial in 44 ICUs in Canada, the United States, and Saudi Arabia enrolling adults predicted to require mechanical ventilation for at least 72 hours. A total of 2653 patients were enrolled from October 2013 to March 2019 (final follow-up, October 2020). INTERVENTIONS Enteral L rhamnosus GG (1 × 10 10 colony-forming units) (n = 1321) or placebo (n = 1332) twice daily in the ICU. MAIN OUTCOMES AND MEASURES The primary outcome was VAP determined by duplicate blinded central adjudication. Secondary outcomes were other ICU-acquired infections including Clostridioides difficile infection, diarrhea, antimicrobial use, ICU and hospital length of stay, and mortality. RESULTS Among 2653 randomized patients (mean age, 59.8 years [SD], 16.5 years), 2650 (99.9%) completed the trial (mean age, 59.8 years [SD], 16.5 years; 1063 women [40.1%.]with a mean Acute Physiology and Chronic Health Evaluation II score of 22.0 (SD, 7.8) and received the study product for a median of 9 days (IQR, 5-15 days). VAP developed among 289 of 1318 patients (21.9%) receiving probiotics vs 284 of 1332 controls (21.3%; hazard ratio [HR], 1.03 (95% CI, 0.87-1.22; P = .73, absolute difference, 0.6%, 95% CI, -2.5% to 3.7%). None of the 20 prespecified secondary outcomes, including other ICU-acquired infections, diarrhea, antimicrobial use, mortality, or length of stay showed a significant difference. Fifteen patients (1.1%) receiving probiotics vs 1 (0.1%) in the control group experienced the adverse event of L rhamnosus in a sterile site or the sole or predominant organism in a nonsterile site (odds ratio, 14.02; 95% CI, 1.79-109.58; P < .001).CONCLUSIONS AND RELEVANCE Among critically ill patients requiring mechanical ventilation, administration of the probiotic L rhamnosus GG compared with placebo, resulted in no significant difference in the development of ventilator-associated pneumonia. These findings do not support the use of L rhamnosus GG in critically ill patients.

A chief concern over the first months of the coronavirus disease 2019 (COVID-19) pandemic was the capacity to provide care for acutely ill patients in hospitals and intensive care units (ICUs). The variability in outcomes of patients with COVID-19 internationally has been striking, with some reports describing ICU mortality in ranges between 40 and 90%. 1-3 Systematic reviews including Characteristics and outcomes of patients with COVID-19 admitted to hospital and intensive care in the first phase of the pandemic in Canada: a national cohort study