Search

Objective: Abnormal liver tests have been associated with worse clinical outcomes in patients infected with COVID-19. This retrospective observational study from Singapore aims to elucidate simple clinical predictors of abnormal alanine aminotransferase (ALT) in COVID-19 infections. Design: 717 patients hospitalised with COVID-19 at the National Centre for Infectious Diseases (NCID), Singapore, from 23 January–15 April 2020 were screened, of which 163 patients with baseline normal alanine transferase (ALT) and at least two subsequent ALTs performed were included in the final analysis. Information on baseline demographics, clinical characteristics and biochemical laboratory tests were collected. Results: 30.7% of patients developed abnormal ALT. They were more likely to be older (60 vs. 55, p = 0.022) and have comorbidities of hyperlipidaemia and hypertension. The multivariate logistic regression showed that R-factor ≥1 on admission (adjusted odds ratio (aOR) 3.13, 95% Confidence Interval (CI) 1.41–6.95) and hypoxia (aOR 3.54, 95% CI 1.29–9.69) were independent risk factors for developing abnormal ALT. The patients who developed abnormal ALT also ran a more severe course of illness with a greater proportion needing supplementary oxygen (58% vs. 18.6%, p < 0.0005), admission to the Intensive Care Unit (ICU)/High Dependency Unit (HDU) (32% vs. 11.5%, p = 0.003) and intubation (20% vs. 2.7%, p < 0.0005). There was no difference in death rate between the two groups. Conclusions: Liver injury is associated with poor clinical outcomes in patients with COVID-19. R-factor ≥1 on admission and hypoxia are independent simple clinical predictors for developing abnormal ALT in COVID-19.

The emergence of new SARS-CoV-2 variants, such as the more transmissible Delta and Omicron variants, has raised concerns on efficacy of the COVID-19 vaccines. Here, we examined the waning of antibody responses against different variants following primary and booster vaccination. We found that antibody responses against variants were low following primary vaccination. The antibody response against Omicron was almost non-existent. Efficient boosting of antibody response against all variants, including Omicron, was observed following a third dose. The antibody response against the variants tested was significantly higher at one month following booster vaccination, compared with two months following primary vaccination, for all individuals, including the low antibody responders identified at two months following primary vaccination. The antibody response, for all variants tested, was significantly higher at four months post booster than at five months post primary vaccination, and the proportion of low responders remained low (6-11%). However, there was significant waning of antibody response in more than 95% of individuals at four months, compared to one month following booster. We also observed a robust memory B cell response following booster, which remained higher at four months post booster than prior to booster. However, the memory B cell responses were on the decline for 50% of individuals at four months following booster. Similarly, while the T cell response is sustained, at cohort level, at four months post booster, a substantial proportion of individuals (18.8 – 53.8%) exhibited T cell response at four months post booster that has waned to levels below their corresponding levels before booster. The findings show an efficient induction of immune response against SARS-CoV-2 variants following booster vaccination. However, the induced immunity by the third BNT162b2 vaccine dose was transient. The findings suggest that elderly individuals may require a fourth dose to provide protection against SARS-CoV-2.

BACKGROUND: Ensovibep (MP0420) is a designed ankyrin repeat protein, a novel class of engineered proteins, under investigation as a treatment of SARS-CoV-2 infection. OBJECTIVE: To investigate if ensovibep, in addition to remdesivir and other standard care, improves clinical outcomes among patients hospitalized with COVID-19 compared with standard care alone. DESIGN: Double-blind, randomized, placebo-controlled, clinical trial. (ClinicalTrials.gov: NCT04501978). SETTING: Multinational, multicenter trial. PARTICIPANTS: Adults hospitalized with COVID-19. INTERVENTION: Intravenous ensovibep, 600 mg, or placebo. MEASUREMENTS: Ensovibep was assessed for early futility on the basis of pulmonary ordinal scores at day 5. The primary outcome was time to sustained recovery through day 90, defined as 14 consecutive days at home or place of usual residence after hospital discharge. A composite safety outcome that included death, serious adverse events, end-organ disease, and serious infections was assessed through day 90. RESULTS: An independent data and safety monitoring board recommended that enrollment be halted for early futility after 485 patients were randomly assigned and received an infusion of ensovibep (n = 247) or placebo (n = 238). The odds ratio (OR) for a more favorable pulmonary outcome in the ensovibep (vs. placebo) group at day 5 was 0.93 (95% CI, 0.67 to 1.30; P = 0.68; OR > 1 would favor ensovibep). The 90-day cumulative incidence of sustained recovery was 82% for ensovibep and 80% for placebo (subhazard ratio [sHR], 1.06 [CI, 0.88 to 1.28]; sHR > 1 would favor ensovibep). The primary composite safety outcome at day 90 occurred in 78 ensovibep participants (32%) and 70 placebo participants (29%) (HR, 1.07 [CI, 0.77 to 1.47]; HR

The coronavirus disease 2019 (COVID‐19) pandemic is ongoing and many drugs have been studied in clinical trials. From a pathophysiological perspective, anti‐viral drugs may be more effective in the early stage while immunomodulators may be more effective in severe patients in later stages of infection. While drugs such as lopinavir‐ritonavir, hydroxychloroquine and azithromycin have proved to be ineffective in randomized controlled trials, corticosteroids, neutralizing monoclonal antibodies, remdesivir, tocilizumab and baricitinib have been reported to benefit certain groups of patients with COVID‐19. In this review, we will present the key clinical evidence and progress in promising COVID‐19 therapeutics, as well as summarize the experience and lessons learned from the development of the current therapeutics.

Objectives Antimicrobial stewardship is a strategy to combat antimicrobial resistance in hospitals. Given the burden and impact of antimicrobial resistance in the Asia Pacific, it is important to document capacity and gaps in antimicrobial stewardship programmes (ASP). We aimed to understand existing capacities and practices, and define the resources needed to establish antimicrobial stewardship where it is lacking. Methods An anonymous online survey, consisting of questions on antimicrobial control at country, hospital and programme levels, was circulated to healthcare providers in the field of infectious diseases and microbiology through Asian Network for Surveillance of Resistant Pathogens, ReAct Group and the Australasian Society for infectious Diseases. Results 139 participants from 16 countries or regions completed the survey. The majority of participants were adult infectious diseases physicians (61/139, 43.9%) and microbiologists (31/139, 22.3%). Participants from 7 countries reported that antimicrobials can be obtained without prescriptions. Despite the high percentage (75.5%) of respondents working in large hospitals, only 22/139 participants (15.8%) from Australia, China, Singapore, Taiwan, Thailand and Vietnam reported having more than 10 infectious diseases physicians. Hospital empiric antimicrobial guidelines for common infections were available according to 110/139 (79.1%) participants. Pre-authorisation of antimicrobials was reported by 88/113 (77.9%) respondents while prospective audit and feedback was reported by 93/114 (81.6%). Automatic stop orders and culture-guided de-escalation were reported by only 52/113 (46.0%) and 27/112 (24.1%) respectively. Conclusion The survey reveals a wide range of ASP development in Asia Pacific. Establishing national workgroups and guidelines will help advance antimicrobial stewardship in this diverse region.

Background Appropriate antibiotic prescribing is key to combating antimicrobial resistance. Upper respiratory tract infections (URTIs) are common reasons for emergency department (ED) visits and antibiotic use. Differentiating between bacterial and viral infections is not straightforward. We aim to provide an evidence-based clinical decision support tool for antibiotic prescribing using prediction models developed from local data. Methods Seven hundred-fifteen patients with uncomplicated URTI were recruited and analysed from Singapore’s busiest ED, Tan Tock Seng Hospital, from June 2016 to November 2018. Confirmatory tests were performed using the multiplex polymerase chain reaction (PCR) test for respiratory viruses and point-of-care test for C-reactive protein. Demographic, clinical and laboratory data were extracted from the hospital electronic medical records. Seventy percent of the data was used for training and the remaining 30% was used for validation. Decision trees, LASSO and logistic regression models were built to predict when antibiotics were not needed. Results The median age of the cohort was 36 years old, with 61.2% being male. Temperature and pulse rate were significant factors in all 3 models. The area under the receiver operating curve (AUC) on the validation set for the models were similar. (LASSO: 0.70 [95% CI: 0.62–0.77], logistic regression: 0.72 [95% CI: 0.65–0.79], decision tree: 0.67 [95% CI: 0.59–0.74]). Combining the results from all models, 58.3% of study participants would not need antibiotics. Conclusion The models can be easily deployed as a decision support tool to guide antibiotic prescribing in busy EDs.

Data on use of monoclonal antibodies (mAbs) in hospitalized patients are limited. In this cross-sectional study, we evaluated the use of mAbs for early treatment of unvaccinated hospitalized patients with mild-to-moderate COVID-19. All inpatients at our center were screened on 27 October 2021. Primary outcome was in-hospital deterioration as defined by a composite of oxygen requirement, intensive care unit (ICU) admission, or mortality within 28 days of admission. Ninety-four out of 410 COVID-19 inpatients were included in the final analysis, of whom 19 (20.2%) received early treatment with sotrovimab. The median age was 73 years (IQR 61–83), and 35 (37.2%) were female. Although the treatment group was significantly older and had more comorbidities, there was a lower proportion of progression to oxygen requirement (31.6% vs. 54.7%), ICU admission (10.5% vs. 24.0%), or mortality (5.3% vs. 13.3%). Kaplan–Meier curves showed a significant difference in time to in-hospital deterioration (log-rank test, p = 0.043). Cox proportional hazards model for in-hospital deterioration showed that sotrovimab treatment was protective (hazard ratio, 0.41; 95% CI, 0.17–0.99; p = 0.047) after adjustment for baseline ISARIC deterioration score. Our findings support the use of sotrovimab for early treatment in hospitalized patients with mild-to-moderate COVID-19 at a high risk of disease progression.

Importance: There is a lack of studies comparing the intended and unintended consequences of prospective review and feedback (PRF) with computerized decision support systems (CDSS), especially in the longer term in antimicrobial stewardship. Objective: To examine the outcomes associated with the sequential implementation of PRF and CDSS and changes to these interventions with long-term use of antibiotics for and incidence of multidrug resistant organisms (MDROs) and other unintended outcomes. Design, Setting, and Participants: This cohort study used an interrupted time series with segmented regression analysis of data from January 2007 to December 2018. Data were extracted from the electronic medical records of patients admitted at a large university teaching hospital with high rates of antibiotic resistance in Singapore. Data were analyzed from June 2019 to June 2020. Exposures: PRF of piperacillin-tazobactam and carbapenems (intervention 1, April 2009), with the addition of hospital-wide CDSS (intervention 2, April 2011), and lifting of CDSS for half of the hospital wards for 6 months (intervention 3, March 2017). Main Outcomes and Measures: Monthly antimicrobial use was measured in defined daily doses (DDDs) per 1000 patient-days. The monthly incidence of MDROs was calculated as number of clinical isolates detected per 1000 inpatient-days over a 6-month period. Unintended outcomes examined included in-hospital mortality and age-adjusted length of stay (LOS). Results: The number of inpatients increased from 56263 in 2007 to 63572 in 2018. During the same period, the mean monthly patient days increased from 33929 in 2007 to 45603 in 2018, and the proportion of patients older than 65 years increased from 45.5% in 2007 to 56.6% in 2018. After intervention 1, there were 0.33 (95% CI, 0.18 to 0.48) more DDDs per 1000 patient-days per month of piperacillin-tazobactam and carbapenems and-11.05 (95% CI,-15.55 to-6.55) fewer DDDs per 1000 patient-days per month for other broad-spectrum antibiotics. After intervention 2, there were-0.22 (95% CI,-0.33 to-0.10) fewer DDDs per 1000 patient-days per month of piperacillin-tazobactam and carbapenems and-2.10 (95% CI,-3.13 to-1.07) fewer DDDs per 1000 patient-days per month for other broad-spectrum antibiotics. After intervention 3, use of piperacillin-tazobactam and carbapenem increased by 0.28 (95% CI, 0.02 to 0.55) DDDs per 1000 patient-days per month. After intervention 2, incidence of Clostridioides difficile decreased (estimate,-0.02 [95% CI,-0.03 to-0.01] cases per 1000 patient-days per month). Conclusions and Relevance: In this cohort study, concurrent PRF and CDSS were associated with limiting the use of piperacillin-tazobactam and carbapenems while reducing use of other antibiotics. Published version

Background: COVID-19 imposes challenges in antibiotic decision-making due to similarities between bacterial pneumonia and moderate to severe COVID-19. We evaluated the effects of antibiotic therapy on the clinical outcomes of COVID-19 pneumonia patients and diagnostic accuracy of key inflammatory markers to inform antibiotic decision-making. Methods: An observational cohort study was conducted in patients hospitalised with COVID-19 at the National Centre for Infectious Diseases and Tan Tock Seng Hospital, Singapore, from January to April 2020. Patients were defined as receiving empiric antibiotic treatment for COVID-19 if started within 3 days of diagnosis. Results: Of 717 patients included, 86 (12.0%) were treated with antibiotics and 26 (3.6%) had documented bacterial infections. Among 278 patients with COVID-19 pneumonia, those treated with antibiotics had more diarrhoea (26, 34.7% vs. 24, 11.8%, p < 0.01), while subsequent admissions to the intensive care unit were not lower (6, 8.0% vs. 10, 4.9% p = 0.384). Antibiotic treatment was not independently associated with lower 30-day (adjusted odds ratio, aOR 19.528, 95% confidence interval, CI 1.039–367.021) or in-hospital mortality (aOR 3.870, 95% CI 0.433–34.625) rates after adjusting for age, co-morbidities and severity of COVID-19 illness. Compared to white cell count and procalcitonin level, the C-reactive protein level had the best diagnostic accuracy for documented bacterial infections (area under the curve, AUC of 0.822). However, the sensitivity and specificity were less than 90%. Conclusion: Empiric antibiotic use in those presenting with COVID-19 pneumonia did not prevent deterioration or mortality. More studies are needed to evaluate strategies to diagnose bacterial co-infections in these patients.

Antimicrobial stewardship programmes (ASPs) in hospitals are predominantly led by specific ASP physicians and pharmacists. Limited studies have been conducted to appreciate non-ASP-trained hospital pharmacists' perspectives on their roles in antimicrobial stewardship. Focus group discussions (FGDs) were conducted with 74 pharmacists, purposively sampled from the 3 largest acute-care public hospitals in Singapore, to explore facilitators and barriers faced by them in antimicrobial stewardship. Applied thematic analysis was conducted and codes were categorised using the social-ecological model (SEM). At the intrapersonal level, pharmacists identified themselves as reviewers for drug safety before dispensing, confining to a restricted advisory role due to lack of clinical knowledge, experience, and empowerment to contribute actively to physicians' prescribing decisions. At the interpersonal level, pharmacists expressed difficulties conveying their opinions and recommendations on antibiotic therapy to physicians despite frequent communications, but they assumed critical roles as educators for patients and their caregivers on proper antibiotic use. At the organisational level, in-house antibiotic guidelines supported pharmacists' antibiotic interventions and recommendations. At the community level, pharmacists were motivated to improve low public awareness and knowledge on antibiotic use and antimicrobial resistance. These findings provide important insights into the gaps to be addressed in order to harness the untapped potential of hospital pharmacists and fully engage them in antimicrobial stewardship. National Medical Research Council (NMRC) Published version This work was supported by the National Medical Research Council Singapore, Health Services Research Grant, Grant number: NMRC/HSRG/0083/2017).

The ST131 multilocus sequence type (MLST) of Escherichia coli is a globally successful pathogen whose dissemination is increasing rates of antibiotic resistance. Numerous global surveys have demonstrated the pervasiveness of this clone; in some regions ST131 accounts for up to 30% of all E. coli isolates. However, many regions are underrepresented in these published surveys, including Africa, South America, and Asia. We collected consecutive bloodstream E. coli isolates from three countries in Southeast Asia; ST131 was the most common MLST type. As in other studies, the C2/H30Rx clade accounted for the majority of ST131 strains. Clinical risk factors were similar to other reported studies. However, we found that nearly all of the C2 strains in this study were closely related, forming what we denote the SEA-C2 clone. The SEA-C2 clone is enriched for strains from Asia, particularly Southeast Asia and Singapore. The SEA-C2 clone accounts for all of the excess resistance and virulence of ST131 relative to non-ST131 E. coli. The SEA-C2 strains appear to be locally circulating and dominant in Southeast Asia, despite the intuition that high international connectivity and travel would enable frequent opportunities for other strains to establish themselves.

The immune responses and mechanisms limiting symptom progression in asymptomatic cases of SARS‐CoV‐2 infection remain unclear. We comprehensively characterized transcriptomic profiles, cytokine responses, neutralization capacity of antibodies, and cellular immune phenotypes of asymptomatic patients with acute SARS‐CoV‐2 infection to identify potential protective mechanisms. Compared to symptomatic patients, asymptomatic patients had higher counts of mature neutrophils and lower proportion of CD169+ expressing monocytes in the peripheral blood. Systemic levels of pro‐inflammatory cytokines were also lower in asymptomatic patients, accompanied by milder pro‐inflammatory gene signatures. Mechanistically, a more robust systemic Th2 cell signature with a higher level of virus‐specific Th17 cells and a weaker yet sufficient neutralizing antibody profile against SARS‐CoV‐2 was observed in asymptomatic patients. In addition, asymptomatic COVID‐19 patients had higher systemic levels of growth factors that are associated with cellular repair. Together, the data suggest that asymptomatic patients mount less pro‐inflammatory and more protective immune responses against SARS‐CoV‐2 indicative of disease tolerance. Insights from this study highlight key immune pathways that could serve as therapeutic targets to prevent disease progression in COVID‐19., We show that asymptomatic patients elicit a different repertoire of immune responses from symptomatic patients. Our data suggest that asymptomatic patients could limit symptom development with a well‐balanced inflammatory response and more protective immune responses against SARS‐CoV‐2.

Plasma leakage is a major pathogenic mechanism of severe dengue, but the etiology remains unclear. The association between endothelial glycocalyx integrity and vascular permeability in older adults with dengue has not been evaluated. A prospective cohort study of adults with undifferentiated fever screened for dengue by RT-PCR or NS1 antigen testing was performed. Patients were assessed daily while symptomatic and at convalescence. Serum hyaluronic acid (HA), heparan sulfate (HS) and selected cytokines (TNF-α, IL-6, IL-10) were measured on enrollment and convalescence. Patients were diagnosed as dengue fever (DF, n = 30), dengue hemorrhagic fever (DHF, n = 20) and non-dengue (ND) febrile illness (n = 11). Acute HA and HS levels were significantly higher in all dengue patients compared to ND (p = 0.0033 and p = 0.0441 respectively), but not different between DF and DHF (p = 0.3426 and p = 0.9180 respectively). Enrolment HA inversely correlated with serum albumin, protein and platelets in all dengue and DHF (p 0.05). HA and HS in all dengue patients decreased significantly at convalescence. Serum IL-10 was significantly associated with HA in all dengue patients (p = 0.002). Serum HA and HS levels were increased in adult dengue and HA was associated with markers of disease severity. Endothelial glycocalyx damage may have a role in vascular leakage in dengue.

Background: The complications and sequelae of coronavirus disease 2019 (COVID-19) and their effect on long-term health are unclear, and the trajectory of associated immune dysregulation is poorly understood. Methods: We conducted a prospective longitudinal multicenter cohort study at 4 public hospitals in Singapore. Patients with COVID-19 were monitored for a median of 6 months after recovery from acute infection. Clinical symptoms and radiologic data were collected, along with plasma samples for quantification of immune mediators. The relationship between clinical symptoms and immune cytokine profiles was investigated. Results: Two hundred eighty-eight participants were recruited, and follow-up data were available for 183, 175, and 120 participants at days 30, 90, and 180 postsymptom onset, respectively. Symptoms related to COVID-19 were present in 31 (16.9%), 13 (7.4%), and 14 (11.7%) at days 30, 90, and 180. In a multivariable model, age >65 years, non-Chinese ethnicity, and the severity of acute infection were associated with increased likelihood of persistent symptoms. Recovered COVID-19 patients had elevated levels of proinflammatory interleukin (IL)-17A, stem cell factor, IL-12p70, and IL-1β and pro-angiogenic macrophage inflammatory protein 1β, brain-derived neurotrophic factor, and vascular endothelial growth factor at day 180 compared with healthy controls. Higher levels of monocyte chemoattractant protein-1 and platelet-derived growth factor-BB were detected in patients with persistent symptoms, versus symptom-free patients. Conclusions: Approximately 10% of recovered patients had persistent symptoms 6 months after initial infection. Immune cytokine signatures of the recovered patients reflected ongoing chronic inflammation and angiogenesis. Patients with COVID-19 should be monitored closely for emerging long-term health consequences. Agency for Science, Technology and Research (A*STAR) National Medical Research Council (NMRC) National Research Foundation (NRF) Published version Recruitment of study participants and sample collection was funded by the Singapore National Medical Research Council COVID-19 Research Fund (COVID19RF-001, COVID19RF-060) and A*STAR COVID-19 Research funding (H/20/04/g1/006). The SIgN Immunomonitoring Platform is supported by a BMRC IAF 311006 grant and BMRC transition funds (H16/99/b0/011). The SIgN MAP platform was supported by a grant from the National Research Foundation, Immunomonitoring Service Platform (NRF2017_SISFP09) from the National Research Foundation Singapore.

Highlights • In hospitalized older adults with COVID-19, geriatric syndromes are not uncommon. • Frailty and initial acuity are important predictors of COVID-19 disease severity. • CFS and FI are complementary in predicting disease progression in COVID-19., Introduction Older adults with COVID-19 have disproportionately higher rates of severe disease and mortality. It is unclear whether this is attributable to age or attendant age-associated risk factors. This retrospective cohort study aims to characterize hospitalized older adults and examine if comorbidities, frailty and acuity of clinical presentation exert an age-independent effect on COVID-19 severity. Methods We studied 275 patients admitted to the National Centre of Infectious Disease, Singapore. We measured: 1)Charlson Comorbidity Index(CCI) as burden of comorbidities; 2)Clinical Frailty Scale(CFS) and Frailty Index(FI); and 3)initial acuity. We studied characteristics and outcomes of critical illness, stratified by age groups (50–59,60–69 and ≥70). We conducted hierarchical logistic regression in primary model(N = 262, excluding direct admissions to intensive care unit) and sensitivity analysis(N = 275): age and gender in base model, entering CCI, frailty (CFS or FI) and initial acuity sequentially. Results The ≥70 age group had highest CCI(p

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) that have become dominant as the pandemic progresses bear the ORF8 mutation together with multiple spike mutations. A 382-nucleotide deletion (Δ382) in the ORF7b and ORF8 regions has been associated with milder disease phenotype and less systemic inflammation in COVID-19 patients. However, its impact on host immunity against SARS-CoV-2 remains undefined. Here, RNA-sequencing was performed to elucidate whole blood transcriptomic profiles and identify contrasting immune signatures between patients infected with either wildtype or Δ382 SARS-CoV-2 variant. Interestingly, the immune landscape of Δ382 SARS-CoV-2 infected patients featured an increased adaptive immune response, evidenced by enrichment of genes related to T cell functionality, a more robust SARS-CoV-2-specific T cell immunity, as well as a more rapid antibody response. At the molecular level, eukaryotic initiation factor 2 signaling was found to be upregulated in patients bearing Δ382, and its associated genes were correlated with systemic levels of T cell-associated and pro-inflammatory cytokines. This study provides more in-depth insight into the host-pathogen interactions of ORF8 with great promise as a therapeutic target to combat SARS-CoV-2 infection.

Background: Host determinants of severe coronavirus disease 2019 include advanced age, comorbidities and male sex. Virologic factors may also be important in determining clinical outcome and transmission rates, but limited patient-level data is available. Methods: We conducted an observational cohort study at seven public hospitals in Singapore. Clinical and laboratory data were collected and compared between individuals infected with different SARS-CoV-2 clades. Firth's logistic regression was used to examine the association between SARS-CoV-2 clade and development of hypoxia, and quasi-Poisson regression to compare transmission rates. Plasma samples were tested for immune mediator levels and the kinetics of viral replication in cell culture were compared. Findings: 319 patients with PCR-confirmed SARS-CoV-2 infection had clinical and virologic data available for analysis. 29 (9%) were infected with clade S, 90 (28%) with clade L/V, 96 (30%) with clade G (containing D614G variant), and 104 (33%) with other clades ‘O’ were assigned to lineage B.6. After adjusting for age and other covariates, infections with clade S (adjusted odds ratio (aOR) 0·030 (95% confidence intervals (CI): 0·0002–0·29)) or clade O (B·6) (aOR 0·26 (95% CI 0·064–0·93)) were associated with lower odds of developing hypoxia requiring supplemental oxygen compared with clade L/V. Patients infected with clade L/V had more pronounced systemic inflammation with higher concentrations of pro-inflammatory cytokines, chemokines and growth factors. No significant difference in the severity of clade G infections was observed (aOR 0·95 (95% CI: 0·35–2·52). Though viral loads were significantly higher, there was no evidence of increased transmissibility of clade G, and replicative fitness in cell culture was similar for all clades. Interpretation: Infection with clades L/V was associated with increased severity and more systemic release of pro-inflammatory cytokines. Infection with clade G was not associated with changes in severity, and despite higher viral loads there was no evidence of increased transmissibility. Published version

The ST131 multilocus sequence type (MLST) of Escherichia coli is a globally successful pathogen whose dissemination is increasing rates of antibiotic resistance. Numerous global surveys have demonstrated the pervasiveness of this clone; in some regions ST131 accounts for up to 30% of all E. coli isolates. However, many regions are underrepresented in these published surveys, including Africa, South America, and Asia. We collected consecutive bloodstream E. coli isolates from three countries in Southeast Asia; ST131 was the most common MLST type. As in other studies, the C2/H30Rx clade accounted for the majority of ST131 strains. Clinical risk factors were similar to other reported studies. However, we found that nearly all of the C2 strains in this study were closely related, forming what we denote the SEA-C2 clone. The SEA-C2 clone is enriched for strains from Asia, particularly Southeast Asia and Singapore. The SEA-C2 clone accounts for all of the excess resistance and virulence of ST131 relative to non-ST131 E. coli. The SEA-C2 strains appear to be locally circulating and dominant in Southeast Asia, despite the intuition that high international connectivity and travel would enable frequent opportunities for other strains to establish themselves.

We aim to describe a case series of critically and non-critically ill COVID-19 patients in Singapore. This was a multicentered prospective study with clinical and laboratory details. Details for fifty uncomplicated COVID-19 patients and ten who required mechanical ventilation were collected. We compared clinical features between the groups, assessed predictors of intubation, and described ventilatory management in ICU patients. Ventilated patients were significantly older, reported more dyspnea, had elevated C-reactive protein and lactate dehydrogenase. A multivariable logistic regression model identified respiratory rate (aOR 2.83, 95% CI 1.24–6.47) and neutrophil count (aOR 2.39, 95% CI 1.34–4.26) on admission as independent predictors of intubation with area under receiver operating characteristic curve of 0.928 (95% CI 0.828–0.979). Median APACHE II score was 19 (IQR 17–22) and PaO2/FiO2 ratio before intubation was 104 (IQR 89–129). Median peak FiO2 was 0.75 (IQR 0.6–1.0), positive end-expiratory pressure 12 (IQR 10–14) and plateau pressure 22 (IQR 18–26) in the first 24 h of ventilation. Median duration of ventilation was 6.5 days (IQR 5.5–13). There were no fatalities. Most COVID-19 patients in Singapore who required mechanical ventilation because of ARDS were extubated with no mortality.

Numerous reports of vascular events after an initial recovery from COVID-19 form our impetus to investigate the impact of COVID-19 on vascular health of recovered patients. We found elevated levels of circulating endothelial cells (CECs), a biomarker of vascular injury, in COVID-19 convalescents compared to healthy controls. In particular, those with pre-existing conditions (e.g., hypertension, diabetes) had more pronounced endothelial activation hallmarks than non-COVID-19 patients with matched cardiovascular risk. Several proinflammatory and activated T lymphocyte-associated cytokines sustained from acute infection to recovery phase, which correlated positively with CEC measures, implicating cytokine-driven endothelial dysfunction. Notably, we found higher frequency of effector T cells in our COVID-19 convalescents compared to healthy controls. The activation markers detected on CECs mapped to counter receptors found primarily on cytotoxic CD8+ T cells, raising the possibility of cytotoxic effector cells targeting activated endothelial cells. Clinical trials in preventive therapy for post-COVID-19 vascular complications may be needed. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) Ministry of Health (MOH) Nanyang Technological University National Medical Research Council (NMRC) National Research Foundation (NRF) Published version This research is funded by National Medical Research Council (COVID19RF-001, COVID19RF-060, NMRC/TA/0031/2015, MOH-000153, NMRC/OFIRG/0018/2016, NMRC/BnB/0017/2015, MOH-000358), Biomedical Research Council, A*STAR (H20/04/g1/006), National Research Foundation Singapore (NRF2017_SISFP09), Nanyang Technological University (Nanyang Assistant Professorship Start-Up Grant), Ministry of Education - Singapore (MOE2018-T2-1-042) and Agency for Science, Technology and Research (H18/01/a0/017).

Early detection of infections is crucial to limit the spread of coronavirus 2019 disease (COVID-19). Here, we develop a flow cytometry-based assay to detect SARS-CoV-2 Spike protein (S protein) antibodies in COVID-19 patients. The assay detects specific IgM, IgA and IgG in COVID-19 patients and also the acquisition of all IgG subclasses, with IgG1 being the most dominant. The antibody response is significantly higher at a later stage of the infection. Furthermore, asymptomatic COVID-19 patients also develop specific IgM, IgA and IgG, with IgG1 as the most dominant subclass. Although the antibody levels are lower in asymptomatic infections, the assay is highly sensitive and detect 97% of asymptomatic infections. These findings demonstrate that the assay can be used for serological analysis of symptomatic infections, and also asymptomatic infections, which may, otherwise, go undetected., Graphical Abstract, Highlights Flow cytometry assay detects specific antibodies in symptomatic COVID-19 patients. Asymptomatic COVID-19 patients also develop specific antibodies. IgG1 is the dominant IgG subclass in both symptomatic and asymptomatic patients. The assay is highly sensitive and detects 97% of asymptomatic infections., Using a flow cytometry-based assay, Goh et al. finds specific antibodies in symptomatic COVID-19 patients’ plasma samples. IgG1 is the most dominant IgG subclass. Despite lower antibody levels, the assay detects 97% of asymptomatic infections, suggesting the feasibility of the assay to detect asymptomatic infections, which may otherwise go undetected.

Virus-specific humoral and cellular immunity act synergistically to protect the host from viral infection. We interrogate the dynamic changes of virological and immunological parameters in 12 patients with symptomatic acute SARS-CoV-2 infection from disease onset to convalescence or death. We quantify SARS-CoV-2 viral RNA in the respiratory tract in parallel with antibodies and circulating T cells specific for various structural (nucleoprotein [NP], membrane [M], ORF3a, and spike) and non-structural (ORF7/8, NSP7, and NSP13) proteins. Although rapid induction and quantity of humoral responses associate with an increase in disease severity, early induction of interferon (IFN)-γ-secreting SARS-CoV-2-specific T cells is present in patients with mild disease and accelerated viral clearance. These findings provide support for the prognostic value of early functional SARS-CoV-2-specific T cells with important implications in vaccine design and immune monitoring., Graphical Abstract, Tan et al. longitudinally analyzed the virological and immunological parameters in COVID-19 patients from disease onset until resolution or death. Early induction of functional SARS-CoV-2-specific T cells was observed in patients with mild disease and rapid viral clearance. This supports the prognostic value of detecting SARS-CoV-2-specific T cells.

Objectives The emergence of a SARS‐CoV‐2 variant with a point mutation in the spike (S) protein, D614G, has taken precedence over the original Wuhan isolate by May 2020. With an increased infection and transmission rate, it is imperative to determine whether antibodies induced against the D614 isolate may cross‐neutralise against the G614 variant. Methods Antibody profiling against the SARS‐CoV‐2 S protein of the D614 variant by flow cytometry and assessment of neutralising antibody titres using pseudotyped lentiviruses expressing the SARS‐CoV‐2 S protein of either the D614 or G614 variant tagged with a luciferase reporter were performed on plasma samples from COVID‐19 patients with known D614G status (n = 44 infected with D614, n = 6 infected with G614, n = 7 containing all other clades: O, S, L, V, G, GH or GR). Results Profiling of the anti‐SARS‐CoV‐2 humoral immunity reveals similar neutralisation profiles against both S protein variants, albeit waning neutralising antibody capacity at the later phase of infection. Of clinical importance, patients infected with either the D614 or G614 clade elicited a similar degree of neutralisation against both pseudoviruses, suggesting that the D614G mutation does not impact the neutralisation capacity of the elicited antibodies. Conclusions Cross‐reactivity occurs at the functional level of the humoral response on both the S protein variants, which suggests that existing serological assays will be able to detect both D614 and G614 clades of SARS‐CoV‐2. More importantly, there should be negligible impact towards the efficacy of antibody‐based therapies and vaccines that are currently being developed., A single point mutation from aspartic acid (D) to glycine (G) at position 614 of the SARS‐CoV‐2 spike (S) protein, termed D614G, has garnered global attention due to the observed increase in transmissibility and infection rate. Given that a majority of the developing antibody‐mediated therapies and serological assays are based on the S antigen of the original Wuhan reference sequence, it is crucial to determine whether humoral immunity acquired from the original SARS‐CoV‐2 isolate is able to induce cross‐detection and cross‐protection against the novel prevailing D614G variant. In this study, we demonstrated an overall equivalent neutralising capacity against both the D614 and G614 pseudoviruses, suggesting negligible impact towards the efficacy of antibody‐based therapies and vaccines that are currently being developed.

Introduction This study aims to assess the association of piperacillin/tazobactam and meropenem minimum inhibitory concentration (MIC) and beta-lactam resistance genes with mortality in the MERINO trial. Methods Blood culture isolates from enrolled patients were tested by broth microdilution and whole genome sequencing at a central laboratory. Multivariate logistic regression was performed to account for confounders. Absolute risk increase for 30-day mortality between treatment groups was calculated for the primary analysis (PA) and the microbiologic assessable (MA) populations. Results In total, 320 isolates from 379 enrolled patients were available with susceptibility to piperacillin/tazobactam 94% and meropenem 100%. The piperacillin/tazobactam nonsusceptible breakpoint (MIC >16 mg/L) best predicted 30-day mortality after accounting for confounders (odds ratio 14.9, 95% confidence interval [CI] 2.8–87.2). The absolute risk increase for 30-day mortality for patients treated with piperacillin/tazobactam compared with meropenem was 9% (95% CI 3%–15%) and 8% (95% CI 2%–15%) for the original PA population and the post hoc MA populations, which reduced to 5% (95% CI −1% to 10%) after excluding strains with piperacillin/tazobactam MIC values >16 mg/L. Isolates coharboring extended spectrum β-lactamase (ESBL) and OXA-1 genes were associated with elevated piperacillin/tazobactam MICs and the highest risk increase in 30-day mortality of 14% (95% CI 2%–28%). Conclusions After excluding nonsusceptible strains, the 30-day mortality difference from the MERINO trial was less pronounced for piperacillin/tazobactam. Poor reliability in susceptibility testing performance for piperacillin/tazobactam and the high prevalence of OXA coharboring ESBLs suggests that meropenem remains the preferred choice for definitive treatment of ceftriaxone nonsusceptible Escherichia coli and Klebsiella.

Background: Remdesivir is approved by the US Food and Drug Administration for the treatment of patients hospitalized with coronavirus disease 2019 (COVID-19) and has been shown to shorten time to recovery and improve clinical outcomes in randomized trials. Methods: This was the final day 28 comparative analysis of data from a phase 3, randomized, open-label study comparing 2 remdesivir regimens (5 vs 10 days, combined for this analysis [remdesivir cohort]) and a real-world retrospective longitudinal cohort study of patients receiving standard-of-care treatment (nonremdesivir cohort). Eligible patients, aged ≥18 years, had confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), oxygen saturation ≤94% on room air or required supplemental oxygen, with pulmonary infiltrates. Propensity score matching (up to 1:10 ratio) was used to ensure comparable populations. We assessed day 14 clinical recovery (determined using a 7-point ordinal scale) and day 28 all-cause mortality (coprimary endpoints). Results: A total of 368 (remdesivir) and 1399 (nonremdesivir) patients were included in the matched analysis. The day 14 clinical recovery rate was significantly higher among the remdesivir versus the nonremdesivir cohort (65.2% vs 57.1%; odds ratio [OR], 1.49; 95% confidence interval [CI], 1.16-1.90; P=0.002). The day 28 mortality rate was significantly lower in the remdesivir cohort versus the nonremdesivir cohort (12.0% vs 16.2%; OR, 0.67; 95% CI, 0.47-.95; P=.03). Conclusions: Remdesivir was associated with significantly higher rates of day 14 clinical recovery, and lower day 28 mortality, compared with standard-of-care treatment in hospitalized patients with COVID-19. These data, taken together, support the use of remdesivir to improve clinical recovery and decrease mortality from SARS-CoV-2 infection., SCOPUS: ar.j, info:eu-repo/semantics/published

Objective: We assessed the performance of influenza-like illness (ILI) case definitions by the Centers for Disease Control and Prevention (CDC), European Centers for Disease Control and Prevention and World Health Organization (WHO) in the tropics where seasonal patterns of respiratory viruses in acute upper respiratory tract infections (AURTIs) are ill-defined. Methods: Clinical data and samples for respiratory multiplex polymerase chain reaction test were collected from 717 consecutive patients attending an emergency department in Singapore for uncomplicated AURTI in 2016-2018. Results: Influenza (20.6%), rhinoviruses (14.4%), and coronaviruses (3.6%) were the most common viral pathogens identified. Biannual peaks with year-round activity were identified for influenza. Although higher rhinovirus activity was observed in inter-influenza seasonal periods, rhinoviruses and coronaviruses circulated year-round without distinct seasonal patterns. During high influenza activity months, the CDC and WHO ILI case definitions had moderate-to-high positive likelihood ratio (LR+) of 3.8-6.8 and 4.5-10.7, respectively, for ruling in influenza. They had moderately-high LR + of 3.3-3.8 and 3.9-4.6 for diagnosing influenza during other months. The ILI case definitions had high specificity (77.2%- 85.4%) for rhinoviruses and coronaviruses. Conclusion: The CDC and WHO ILI case definitions can be applied to clinically diagnose influenza in the tropics, regardless of the time of the year. Published version This work was supported by the National Healthcare Group Singapore’s Clinician Scientist Career Scheme [NHG-CSCS/15005].

The rapid spreading of SARS-CoV-2 variants B.1.1.7 originated from the United Kingdom and B.1.351 from South Africa has contributed to the second wave of COVID-19 cases in the respective countries and also around the world. In this study, we employed advanced biochemical and virological methodologies to evaluate the impact of Spike mutations of these strains on the degree of protection afforded by humoral immune responses following natural infection of the ancestral SARS-CoV-2 strain during the early stages of the outbreak. We found that antibody-mediated neutralization activity was partially reduced for B.1.1.7 variant and significantly attenuated for the B.1.351 strain. We also found that mutations outside the receptor-binding domain (RBD) can strongly influence antibody binding and neutralization, cautioning the use of solely RBD mutations in evaluating vaccine efficacy. These findings highlight an urgent need to develop new SARS-CoV-2 vaccines that are not based exclusively on the ancestral SARS-CoV-2 Spike gene sequence. Agency for Science, Technology and Research (A*STAR) National Medical Research Council (NMRC) Published version This work was supported by the Biomedical Research Council (BMRC), the A*ccelerate GAP-funded project (ACCL/19-GAP064-R20H-H) (C.-I.W and L.R.) from the Agency of Science, Technology and Research (A*STAR), and National Medical Research Council (NMRC) COVID-19 Research fund (COVID-19RF-001 [L.F.P.N. and L.R.], COVID-19RF-007 [L.R., L.F.P.N., and C.-I.W.], COVID-19RF-060 [L.F.P.N. and L.R.], and COVID-19RF-004 [S.M.-S.]). This work was also partially funded by the US Food and Drug Administration Medical Countermeasures Initiative contract (75F40120C00085). The article reflects the views of the authors and does not represent the views or policies of the FDA (J.A.H.). This work was also supported by the MRC (MR/W005611/1) G2P-UK: A national virology consortium to address phenotypic consequences of SARS-CoV-2 genomic variation (J.A.H.). J.A.H. and L.F.P.N. are supported by the NIHR Health Protection Research Unit (HPRU) in Emerging and Zoonotic Infections at the University of Liverpool in partnership with Public Health England (PHE), in collaboration with Liverpool School of Tropical Medicine and the University of Oxford (award 200907).

Polymyxin B is the last line of defense in treating multidrug-resistant gram-negative bacterial infections. Dosing of polymyxin B is currently based on total body weight, and a substantial intersubject variability has been reported. We evaluated the performance of different population pharmacokinetic models to predict polymyxin B exposures observed in individual patients. In a prospective observational study, standard dosing (mean 2.5 mg/kg daily) was administered in 13 adult patients. Serial blood samples were obtained at steady state, and plasma polymyxin B concentrations were determined by a validated liquid chromatography tandem mass spectrometry (LC-MS/MS) method. The best-fit estimates of clearance and daily doses were used to derive the observed area under the curve (AUC) in concentration–time profiles. For comparison, 5 different population pharmacokinetic models of polymyxin B were conditioned using patient-specific dosing and demographic (if applicable) variables to predict polymyxin B AUC of the same patient. The predictive performance of the models was assessed by the coefficient of correlation, bias, and precision. The correlations between observed and predicted AUC in all 5 models examined were poor (r2 < 0.2). Nonetheless, the models were reasonable in capturing AUC variability in the patient population. Therapeutic drug monitoring currently remains the only viable approach to individualized dosing.