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ABSTRACT Host cell damage is a key parameter for research in infection biology, drug testing, and substance safety screening. In this study, we introduce a luciferase reporter system as a new and reliable assay to measure cell damage and validate it with the pathogenic yeast, Candida albicans, as a test case. We transduced human epithelial cell lines with a lentiviral vector to stably express an optimized luciferase enzyme, Nanoluc. Upon cell damage, the release of cytoplasmic luciferase into the extracellular space can be easily detected by a luminometer. We used the luciferase reporter system to investigate the damage caused by C. albicans to different newly generated epithelial reporter cell lines. We found that fungus-induced cell damage, as determined by established methods, correlated tightly with the release of the luciferase. The new luciferase reporter system is a simple, sensitive, robust, and inexpensive method for measuring host cell damage and has a sensitivity comparable to the standard assay, release of lactate dehydrogenase. It is suitable for high-throughput studies of pathogenesis mechanisms of any microbe, for antimicrobial drug screening, and many other applications.IMPORTANCEWe present a quick, easy, inexpensive, and reliable assay to measure damage to mammalian cells. To this end, we created reporter cell lines which artificially express luciferase, an enzyme that can be easily detected in the supernatant when these cells are damaged. We used infections with the well-investigated fungal pathogen of humans, Candida albicans, as a test case of our system. Using our reporter, we were able to recapitulate the known effects of strain variability, gene deletions, and antifungal treatments on host cell damage. This easily adaptable reporter system can be used to screen for damage in infection models with different microbial species, assay cell-damaging potential of substances, discover new non-toxic antibiotics, and many other damage-based applications.

Autotrophic bacteria are able to fix CO 2 in a great diversity of habitats, even though this dissolved gas is relatively scarce at neutral pH and above. As many of these bacteria rely on CO 2 fixation by ribulose 1,5-bisphospate carboxylase/oxygenase (RubisCO) for biomass generation, they must compensate for the catalytical constraints of this enzyme with CO 2 -concentrating mechanisms (CCMs). CCMs consist of CO 2 and HCO 3 - transporters and carboxysomes. Carboxysomes encapsulate RubisCO and carbonic anhydrase (CA) within a protein shell and are essential for the operation of a CCM in autotrophic Bacteria that use the Calvin-Benson-Basham cycle. Members of the genus Thiomicrospira lack genes homologous to those encoding previously described CA, and prior to this work, the mechanism of function for their carboxysomes was unclear. In this paper, we provide evidence that a member of the recently discovered iota family of carbonic anhydrase enzymes (ιCA) plays a role in CO 2 fixation by carboxysomes from members of Thiomicrospira and potentially other Bacteria . Carboxysome enrichments from Thiomicrospira pelophila and Thiomicrospira aerophila were found to have CA activity and contain ιCA, which is encoded in their carboxysome loci. When the gene encoding ιCA was interrupted in T. pelophila , cells could no longer grow under low-CO 2 conditions, and CA activity was no longer detectable in their carboxysomes. When T. pelophila ιCA was expressed in a strain of Escherichia coli lacking native CA activity, this strain recovered an ability to grow under low CO 2 conditions, and CA activity was present in crude cell extracts prepared from this strain., Importance: Here, we provide evidence that iota carbonic anhydrase (ιCA) plays a role in CO 2 fixation by some organisms with CO 2 -concentrating mechanisms; this is the first time that ιCA has been detected in carboxysomes. While ιCA genes have been previously described in other members of bacteria, this is the first description of a physiological role for this type of carbonic anhydrase in this domain. Given its distribution in alkaliphilic autotrophic bacteria, ιCA may provide an advantage to organisms growing at high pH values and could be helpful for engineering autotrophic organisms to synthesize compounds of industrial interest under alkaline conditions., Competing Interests: The authors declare no conflict of interest.

Purpose: The ordering of routine blood test panels in advance is common in intensive care units (ICUs), with limited consideration of the pretest probability of finding abnormalities. This practice contributes to anemia, false positive results, and health care costs. We sought to understand practices and attitudes of Canadian adult intensivists regarding ordering of blood tests in critically ill patients., Methods: We conducted a nationwide Canadian cross-sectional survey consisting of 15 questions assessing three domains (global perceptions, test ordering, daily practice), plus 11 demographic questions. The target sample was one intensivist per adult ICU in Canada. We summarized responses using descriptive statistics and present data as mean with standard deviation (SD) or count with percentage as appropriate., Results: Over seven months, 80/131 (61%) physicians responded from 77 ICUs, 50% of which were from Ontario. Respondents had a mean (SD) clinical experience of 12 (9) years, and 61% worked in academic centres. When asked about their perceptions of how frequently unnecessary blood tests are ordered, 61% responded "sometimes" and 23% responded "almost always." Fifty-seven percent favoured ordering complete blood counts one day in advance. Only 24% of respondents believed that advanced blood test ordering frequently led to changes in management. The most common factors perceived to influence blood test ordering in the ICU were physician preferences, institutional patterns, and order sets., Conclusion: Most respondents to this survey perceived that unnecessary blood testing occurs in the ICU. The survey identified possible strategies to decrease the number of blood tests., (© 2024. Canadian Anesthesiologists' Society.)

Purpose: To categorize, quantify and interpret findings documented in feedback letters of monitoring or auditing visits for an investigator-initiated, peer-review funded multicenter randomized trial testing probiotics for critically ill patients., Materials & Methods: In 37 Canadian centers, monitoring and auditing visits were performed by 3 trained individuals; findings were reported in feedback letters. At trial termination, we performed duplicate content analysis on letters, categorizing observations first into unique findings, followed by 10 pre-determined trial quality management domains. We further classified each observation into a) missing operational records, b) errors in process, and potential threats to c) data integrity, d) patient privacy or e) safety., Results: Across 37 monitoring or auditing visits, 75 unique findings were categorized into 10 domains. Most frequently, observations were in domains of training documentation (180/566 [32%]) and the informed consent process (133/566 [23%]). Most observations were missing operational records (438/566 [77%]) rather than errors in process (128/566 [23%]). Of 75 findings, 13 (62/566 observations [11%]) posed a potential threat to data integrity, 1 (1/566 observation [0.18%]) to patient privacy, and 9 (49/566 observations [8.7%]) to patient safety., Conclusions: Monitoring and auditing findings predominantly concerned missing documentation with minimal threats to data integrity, patient privacy or safety., Trial Registration: PROSPECT (Probiotics: Prevention of Severe Pneumonia and Endotracheal Colonization Trial): NCT02462590., Competing Interests: Declaration of Competing Interest Dr. F D'Aragon is a recipient of a Research Career Award from the Fonds de la recherche du Québec-Santé. Dr. S English holds a National New Investigator award from the Heart and Stroke Foundation. Dr. D Cook holds a Canada Research Chair in Knowledge Translation in Critical Care., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Studies that have evaluated the use of intravenous vitamin C in adults with sepsis who were receiving vasopressor therapy in the intensive care unit (ICU) have shown mixed results with respect to the risk of death and organ dysfunction., Methods: In this randomized, placebo-controlled trial, we assigned adults who had been in the ICU for no longer than 24 hours, who had proven or suspected infection as the main diagnosis, and who were receiving a vasopressor to receive an infusion of either vitamin C (at a dose of 50 mg per kilogram of body weight) or matched placebo administered every 6 hours for up to 96 hours. The primary outcome was a composite of death or persistent organ dysfunction (defined by the use of vasopressors, invasive mechanical ventilation, or new renal-replacement therapy) on day 28., Results: A total of 872 patients underwent randomization (435 to the vitamin C group and 437 to the control group). The primary outcome occurred in 191 of 429 patients (44.5%) in the vitamin C group and in 167 of 434 patients (38.5%) in the control group (risk ratio, 1.21; 95% confidence interval [CI], 1.04 to 1.40; P = 0.01). At 28 days, death had occurred in 152 of 429 patients (35.4%) in the vitamin C group and in 137 of 434 patients (31.6%) in the placebo group (risk ratio, 1.17; 95% CI, 0.98 to 1.40) and persistent organ dysfunction in 39 of 429 patients (9.1%) and 30 of 434 patients (6.9%), respectively (risk ratio, 1.30; 95% CI, 0.83 to 2.05). Findings were similar in the two groups regarding organ-dysfunction scores, biomarkers, 6-month survival, health-related quality of life, stage 3 acute kidney injury, and hypoglycemic episodes. In the vitamin C group, one patient had a severe hypoglycemic episode and another had a serious anaphylaxis event., Conclusions: In adults with sepsis receiving vasopressor therapy in the ICU, those who received intravenous vitamin C had a higher risk of death or persistent organ dysfunction at 28 days than those who received placebo. (Funded by the Lotte and John Hecht Memorial Foundation; LOVIT ClinicalTrials.gov number, NCT03680274.)., (Copyright © 2022 Massachusetts Medical Society.)

Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited., Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19., Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020., Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108)., Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%)., Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively., Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions., Trial Registration: ClinicalTrials.gov Identifier: NCT02735707.

Background: Sepsis is a health problem of global importance; treatments focus on controlling infection and supporting failing organs. Recent clinical research suggests that intravenous vitamin C may decrease mortality in sepsis. We have designed a randomized controlled trial (RCT) to ascertain the effect of vitamin C on the composite endpoint of death or persistent organ dysfunction at 28 days in patients with sepsis., Methods: LOVIT (Lessening Organ dysfunction with VITamin C) is a multicenter, parallel-group, blinded (participants, clinicians, study personnel, Steering Committee members, data analysts), superiority RCT (minimum n = 800). Eligible patients have sepsis as the diagnosis for admission to the intensive care unit (ICU) and are receiving vasopressors. Those admitted to the ICU for more than 24 h are excluded. Eligible patients are randomized to high-dose intravenous vitamin C (50 mg/kg every 6 h for 96 h) or placebo. The primary outcome is a composite of death or persistent organ dysfunction (need for vasopressors, invasive mechanical ventilation, or new and persisting renal replacement therapy) at day 28. Secondary outcomes include persistent organ dysfunction-free days to day 28, mortality and health-related quality of life at 6 months, biomarkers of dysoxia, inflammation, infection, endothelial function, and adverse effects (hemolysis, acute kidney injury, and hypoglycemia). Six subgroup analyses are planned., Discussion: This RCT will provide evidence of the effect of high-dose intravenous vitamin C on patient-important outcomes in patients with sepsis., Trial Registration: clinicaltrials.gov, NCT03680274, first posted 21 September 2018.

Purpose: We prospectively assessed inter-rater reliability of three physical function measures in Canadian intensive care unit (ICU) survivors in the inpatient setting., Methods: We enrolled patients who had an ICU length of stay of ≥ three days, were mechanically ventilated for ≥ 24 hr, and were ambulating independently before hospital admission. Weekly from ICU discharge to hospital discharge, two trained frontline clinicians, blinded to each other's findings, independently performed the Physical Function ICU Test-scored (PFIT-s; score out of 10), 30-sec sit-to-stand (30STS; # of stands), and two-minute walk test (2MWT; distance in m), all within 24 hr. We calculated the intraclass correlation coefficient (ICC), standard error of measurement (SEM), and minimal detectable change (MDC 90 )., Results: We enrolled 42 patients. PFIT-s: in 36 patients with 66 paired scores, the ICC was 0.78 (95% confidence interval [CI], 0.66 to 0.86), the SEM was 1.04, and the MDC 90 was 2.42. 30STS: in 35 patients with 67 paired scores, the ICC was 0.85 (95% CI, 0.76 to 0.90), the SEM was 1.91, and the MDC 90 was 4.45. 2MWT: in 35 patients with 58 paired scores, the ICC was 0.78 (95% CI, 0.66 to 0.87), the SEM was 20.87, and the MDC 90 was 48.69., Conclusion: These three measures show good inter-rater reliability when used by trained frontline clinicians to assess physical function in ICU survivors in the inpatient setting.

Purpose: To describe pre-ICU frailty in critically ill patients using the Clinical Frailty Scale (CFS)., Methods: We included patients ≥18years admitted to 2 ICUs in Hamilton, Canada. The ICU Research Coordinator (RC) generated 3 CFS scores using: 1) chart review, 2) family interview, 3) patient interview. Subsequently, an overall impression was captured in a final score. Mean differences were calculated to assess the RC intra-rater reliability and inter-rater reliability of chart reviews by the RC, Occupational Therapist (OT), and Geriatrics Resident (GR). Scores were also compared between younger and older patients. We also analyzed the relationship between CFS scores and mortality., Results: We prospectively enrolled 150 patients (mean age 63.8 [SD 15.3] years, APACHE II score 21 [SD 7.3]). CFS were similar between RC, OT, and GR chart reviews (p>0.05 for all comparisons). There was no difference between RC chart review and RC final score, or between RC patient interview and RC final score. Scores following the RC family interview and the RC final score were significantly different (-0.24, 95% CI -0.38, -0.09, p<0.01). Each 1-point increase in the final CFS scored by the RC was weakly associated with ICU mortality (odds ratio 1.18, 95% CI 0.84-1.66, p=0.33), and hospital mortality (OR 1.19, 95% CI 0.89, -1.59, p=0.24)., Conclusions: CFS scores can be generated using medical chart review and can be reliably completed by ICU clinicians and research staff., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objective: Use of hyperchloremic IV fluids for resuscitation in sepsis may be associated with increased mortality and use of renal replacement therapy. After crystalloids, 5% human albumin represents the second most common resuscitation fluid in the ICU. Its chloride concentration is rarely considered in the clinical setting. This study quantifies previously undocumented chloride concentrations of three 5% albumin solutions using biochemical analysis., Design: We performed blinded analysis of the electrolyte concentration of albumin samples obtained directly from the national blood supplier (Canadian Blood Services). Two-tailed independent t tests were performed for all possible comparative analyses. Analysis of variance testing was performed for relevant three-way comparisons. Significance threshold was set at p less than 0.05., Setting: All samples were analyzed in the core laboratory at an academic hospital associated with McMaster University in Hamilton, Ontario, Canada., Subjects: We analyzed 65 albumin samples from three available brands obtained through Canadian Blood Services. They include Plasbumin (n = 21), Alburex (n = 24), Octalbin (n = 20)., Intervention: Laboratory technologists blinded to product identification measured the concentration of electrolytes, extended electrolytes, lactate, and albumin of each sample using the Abbott ARCHITECT c8000 chemistry analyzer., Measurements and Main Results: The mean chloride concentration of Plasbumin, Alburex, and Octalbin, respectively, were 109.4 mmol/L (SD, 1.3), 123.6 mmol/L (SD, 1.3), and 136.8 mmol/L (SD, 0.4). The mean sodium concentration of Plasbumin, Alburex, and Octalbin, respectively, were 139.6 mmol/L (SD, 1.6), 137.3 mmol/L (SD, 2.2), and 149.4 mmol/L (SD, 0.5). The chloride and sodium concentration differed significantly for all two-way comparisons (p < 0.0001) and multiple comparison testing (p < 0.0001)., Conclusion: This study is the first to identify and document a statistically significant variability in the chloride concentration of available 5% albumin products. This study has also informed a pilot randomized controlled trial examining the effect of administering high chloride versus low chloride fluids in critically ill patients with sepsis.

Introduction: Observational evidence suggests physiological benefits and lower mortality with lower chloride solutions; however, 0.9% saline remains the most widely used fluid worldwide. Given uncertainty regarding the association of lower chloride on mortality, it is unlikely that practice will change without direct randomised clinical trial (RCT) evidence. This pilot RCT will investigate the feasibility of a large-scale trial directly comparing low chloride with high chloride fluids in patients with septic shock., Methods and Analysis: This is a randomised, concealed, blinded parallel-group multicentre pilot trial. We will include adult critically ill patients with septic shock, defined as ongoing hypotension despite 1 L of fluid, or a serum lactate >4 mmol/L, who are within 6 hours of hospital presentation or rapid response team activation. We will exclude patients if they have an aetiology of shock other than sepsis, if they have acute burn injury, elevated intracranial pressure, intent to withdraw life support or previous enrolment in this or a competing trial. Following informed consent, patients will be randomised to a low chloride fluid strategy or a high chloride fluid strategy for the duration of their ICU stay or until 30 days postrandomisation. Clinicians, patients, families and research staff will be blinded. The primary outcome for this trial will be feasibility, assessed by consent rate, recruitment success and protocol adherence. Patient-important clinical outcomes include mortality, receipt of renal replacement therapy, intensive care unit and hospital lengths of stay and surrogate outcomes of incidence of acidosis, hyperkalaemia and acute kidney injury., Ethics and Dissemination: This pilot trial will test the feasibility of conducting the main trial, which will examine the effect of high versus low chloride fluids in patients with septic shock on patient-important outcomes., Trial Registration Number: NCT02748382, registered 8 April 2016., Protocol Date: 1 July 2016., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

The contribution of mixed infection in recurrent Clostridium difficile infection (CDI) episodes is not known. Among paired isolates from 52 patients, mixed infection due to >1 toxigenic strain of C. difficile was identified in 8% of first episodes. Among recurrences, relapse from 1 or both co-infecting strains was uncommon; it was detected in a single case each. Infect Control Hosp Epidemiol 2016;1481-1484.