Lower airway microbiota compositions differ between influenza, COVID-19 and bacteria-related acute respiratory distress syndromes

BACKGROUND

Acute respiratory distress syndrome (ARDS) is responsible for 400,000 deaths annually worldwide. Few improvements have been made despite five decades of research, partially because ARDS is a highly heterogeneous syndrome including various types of aetiologies. Lower airway microbiota is involved in chronic inflammatory diseases and recent data suggest that it could also play a role in ARDS. Nevertheless, whether the lower airway microbiota composition varies between the aetiologies of ARDS remain unknown. The aim of this study is to compare lower airway microbiota composition between ARDS aetiologies, i.e. pulmonary ARDS due to influenza, SARS-CoV-2 or bacterial infection.

METHODS

Consecutive ARDS patients according to Berlin's classification requiring invasive ventilation with PCR-confirmed influenza or SARS-CoV-2 infections and bacterial infections (> 105 CFU/mL on endotracheal aspirate) were included. Endotracheal aspirate was collected at admission, V3-V4 and ITS2 regions amplified by PCR, deep-sequencing performed on MiSeq sequencer (Illumina®) and data analysed using DADA2 pipeline.

RESULTS

Fifty-three patients were included, 24 COVID-19, 18 influenza, and 11 bacterial CAP-related ARDS. The lower airway bacteriobiota and mycobiota compositions (β-diversity) were dissimilar between the three groups (p = 0.05 and p = 0.01, respectively). The bacterial α-diversity was significantly lower in the bacterial CAP-related ARDS group compared to the COVID-19 ARDS group (p = 0.04). In contrast, influenza-related ARDS patients had higher lung mycobiota α-diversity than the COVID-19-related ARDS (p = 0 < 01).

CONCLUSION

Composition of lower airway microbiota (both microbiota and mycobiota) differs between influenza, COVID-19 and bacterial CAP-related ARDS. Future studies investigating the role of lung microbiota in ARDS pathophysiology should take aetiology into account.

Impact of dexamethasone in severe COVID-19-induced acute kidney injury: a multicenter cohort study

BACKGROUND

Acute kidney injury (AKI) in intensive care unit (ICU) patients with severe COVID-19 is common (> 50%). A specific inflammatory process has been suggested in the pathogenesis of AKI, which could be improved by dexamethasone (DXM). In a small monocenter study (n = 100 patients), we reported a potential protective effect of DXM on the risk of AKI. This study aimed to investigate the preventive impact of DXM on AKI in a multicenter study of patients with severe COVID-19.

METHODS

We conducted a multicenter study in three French ICUs from March 2020 to August 2021. All patients admitted to ICU for severe COVID-19 were included. Individuals with preexistent AKI or DXM administration before admission to ICU were excluded. While never used during the first wave, DXM was used subsequently at ICU entry, providing two treatment groups. Multivariate Cause-specific Cox models taking into account changes in ICU practices over time, were utilized to determine the association between DXM and occurrence of AKI.

RESULTS

Seven hundred and ninety-eight patients were included. Mean age was 62.6 ± 12.1 years, 402/798 (50%) patients had hypertension, and 46/798 (6%) had previous chronic kidney disease. Median SOFA was 4 [3-6] and 420/798 (53%) required invasive mechanical ventilation. ICU mortality was 208/798 (26%). AKI was present in 598/798 (75%) patients: 266/598 (38%), 163/598 (27%), and 210/598 (35%) had, respectively, AKI KDIGO 1, 2, 3, and 61/598 (10%) patients required renal replacement therapy. Patients receiving DXM had a significantly decreased hazard of AKI occurrence compared to patients without DXM (HR 0.67; 95CI 0.55-0.81). These results were consistent in analyses that (1) excluded patients with DXM administration to AKI onset delay of less than 12 h, (2) incorporating the different 'waves' of the COVID-19 pandemic.

CONCLUSIONS

DXM was associated with a decrease in the risk of AKI in severe COVID-19 patients admitted to ICU. This supports the hypothesis that the inflammatory injury of AKI may be preventable.

Critically ill patients with infective endocarditis, neurological complications and indication for cardiac surgery: a multicenter propensity-adjusted study

BACKGROUND

The benefit-risk balance and optimal timing of surgery for severe infective endocarditis (IE) with ischemic or hemorrhagic strokes is unknown. The study aim was to compare the neurological outcome between patients receiving surgery or not.

METHODS

In a prospective register-based multicenter ICU study, patients were included if they met the following criteria: (i) left-sided IE with an indication for heart surgery; (ii) with cerebral complications documented by cerebral imaging before cardiac surgery; (iii) with Sequential Organ Failure Assessment score ≥ 3. Exclusion criteria were isolated right-sided IE, in-hospital acquired IE and patients with cerebral complications only after cardiac surgery. In the primary analysis, the prognostic value of surgery in term of disability at 6 month was assessed by using a propensity score-adjusted logistic regression.

RESULTS

192 patients were included including ischemic stroke (74.5%) and hemorrhagic lesion (15.6%): 67 (35%) had medical treatment and 125 (65%) cardiac surgery. In the propensity score-adjusted logistic regression, a favorable 6-month neurological outcome was associated with surgery (odds ratio 13.8 (95% CI 6.2-33.7). The 1-year mortality was strongly reduced with surgery in the fixed-effect propensity-adjusted Cox model (hazard ratio 0.18; 95% CI 0.11-0.27; p < 0.001). These effects remained whether the patients received delayed surgery (n = 62/125) or not and whether they were deeply comatose (Glasgow Coma Scale ≤ 10) or not.

CONCLUSIONS

In critically ill IE patients with an indication for surgery and previous cerebral events, a better propensity-adjusted neurological outcome was associated with surgery compared with medical treatment.

Invasive group A streptococcal infections requiring admission to ICU: a nationwide, multicenter, retrospective study (ISTRE study)

BACKGROUND

Group A Streptococcus is responsible for severe and potentially lethal invasive conditions requiring intensive care unit (ICU) admission, such as streptococcal toxic shock-like syndrome (STSS). A rebound of invasive group A streptococcal (iGAS) infection after COVID-19-associated barrier measures has been observed in children. Several intensivists of French adult ICUs have reported similar bedside impressions without objective data. We aimed to compare the incidence of iGAS infection before and after the COVID-19 pandemic, describe iGAS patients' characteristics, and determine ICU mortality associated factors.

METHODS

We performed a retrospective multicenter cohort study in 37 French ICUs, including all patients admitted for iGAS infections for two periods: two years before period (October 2018 to March 2019 and October 2019 to March 2020) and a one-year after period (October 2022 to March 2023) COVID-19 pandemic. iGAS infection was defined by Group A Streptococcus isolation from a normally sterile site. iGAS infections were identified using the International Classification of Diseases and confirmed with each center's microbiology laboratory databases. The incidence of iGAS infections was expressed in case rate.

RESULTS

Two hundred and twenty-two patients were admitted to ICU for iGAS infections: 73 before and 149 after COVID-19 pandemic. Their case rate during the period before and after COVID-19 pandemic was 205 and 949/100,000 ICU admissions, respectively (p < 0.001), with more frequent STSS after the COVID-19 pandemic (61% vs. 45%, p = 0.015). iGAS patients (n = 222) had a median SOFA score of 8 (5-13), invasive mechanical ventilation and norepinephrine in 61% and 74% of patients. ICU mortality in iGAS patients was 19% (14% before and 22% after COVID-19 pandemic; p = 0.135). In multivariate analysis, invasive mechanical ventilation (OR = 6.08 (1.71-21.60), p = 0.005), STSS (OR = 5.75 (1.71-19.22), p = 0.005), acute kidney injury (OR = 4.85 (1.05-22.42), p = 0.043), immunosuppression (OR = 4.02 (1.03-15.59), p = 0.044), and diabetes (OR = 3.92 (1.42-10.79), p = 0.008) were significantly associated with ICU mortality.

CONCLUSION

The incidence of iGAS infections requiring ICU admission increased by 4 to 5 after the COVID-19 pandemic. After the COVID-19 pandemic, the rate of STSS was higher, with no significant increase in ICU mortality rate.

Food-borne botulism outbreak during the Rugby World Cup linked to marinated sardines in Bordeaux, France, September 2023

In September 2023, a botulism outbreak affecting 15 individuals occurred in Bordeaux, France, during the Rugby World Cup. We report on eight individuals from four different countries on two continents admitted to the intensive care unit at our hospital, where six required invasive mechanical ventilation. Cases reported consuming locally produced canned sardines at a restaurant. This report highlights the importance of rapid, worldwide alerts from health authorities to prevent severe consequences of such outbreaks, particularly during events attracting international visitors.

The gut microbiota composition is linked to subsequent occurrence of ventilator-associated pneumonia in critically ill patients

Ventilator-associated pneumonia (VAP) is the most frequent nosocomial infection in critically ill-ventilated patients. Oropharyngeal and lung microbiota have been demonstrated to be associated with VAP occurrence, but the involvement of gut microbiota has not been investigated so far. Therefore, the aim of this study is to compare the composition of the gut microbiota between patients who subsequently develop VAP and those who do not. A rectal swab was performed at admission of every consecutive patient into the intensive care unit (ICU) from October 2019 to March 2020. After DNA extraction, V3-V4 and internal transcribed spacer 2 regions deep-sequencing was performed on MiSeq sequencer (Illumina) and data were analyzed using Divisive Amplicon Denoising Algorithm 2 (DADA2) pipeline. Among 255 patients screened, 42 (16%) patients with invasive mechanical ventilation for more than 48 h were included, 18 (43%) with definite VAP and 24 without (57%). Patients who later developed VAP had similar gut bacteriobiota and mycobiota α-diversities compared to those who did not develop VAP. However, gut mycobiota was dissimilar (β-diversity) between these two groups. The presence of Megasphaera massiliensis was associated with the absence of VAP occurrence, whereas the presence of the fungal genus Alternaria sp. was associated with the occurrence of VAP. The composition of the gut microbiota, but not α-diversity, differs between critically ill patients who subsequently develop VAP and those who do not. This study encourages large multicenter cohort studies investigating the role of gut-lung axis and oropharyngeal colonization in the development of VAP in ICU patients. Trial registration number: NCT04131569, date of registration: 18 October 2019. IMPORTANCE The composition of the gut microbiota, but not α-diversity, differs between critically ill patients who subsequently develop ventilator-associated pneumonia (VAP) and those who do not. Investigating gut microbiota composition could help to tailor probiotics to provide protection against VAP.

Pulmonary hypertension without heart failure causes cardiorenal syndrome in a porcine model

Cardiorenal syndromes type 1 and 2 are complex disorders in which cardiac dysfunction leads to kidney dysfunction. However, the mechanisms remain incompletely explained, during pulmonary hypertension in particular. The objective of this study is to develop an original preclinical model of cardiorenal syndrome secondary to a pulmonary hypertension in piglets. Twelve 2-month-old Large White piglets were randomized in two groups: (1) induction of pulmonary hypertension by ligation of the left pulmonary artery and iterative embolizations of the right lower pulmonary artery, or (2) Sham interventions. We evaluated the cardiac function using right heart catheterization, echocardiography and measurement of biochemistry markers). Kidney was characterized using laboratory blood and urine tests, histological evaluation, immunostainings for renal damage and repair, and a longitudinal weekly assessment of the glomerular filtration rate using creatinine-based estimation and intravenous injection of an exogenous tracer on one piglet. At the end of the protocol (6 weeks), the mean pulmonary artery pressure (32 ± 10 vs. 13 ± 2 mmHg; p = 0.001), pulmonary vascular resistance (9.3 ± 4.7 vs. 2.5 ± 0.4 WU; p = 0.004) and central venous pressure were significantly higher in the pulmonary hypertension group while the cardiac index was not different. Piglets with pulmonary hypertension had higher troponin I. We found significant tubular damage and an increase in albuminuria in the pulmonary hypertension group and negative correlation between pulmonary hypertension and renal function. We report here the first porcine model of cardiorenal syndrome secondary to pulmonary hypertension.

Bridging gut microbiota composition with extended-spectrum beta-lactamase Enterobacteriales faecal carriage in critically ill patients (microbe cohort study)

BACKGROUND

The worldwide dissemination of extended spectrum beta-lactamase producing Enterobacteriales (ESBL-E) is of major concern. Microbiota may play a role in the host resistance to colonization with ESBL-E, but the underlying mechanisms remain unknown. We aimed to compare the gut microbiota composition between ESBL-producing E. coli or K. pneumoniae carriers and ESBL-E non-carriers according to the bacterial species.

RESULTS

Among 255 patients included, 11 (4,3%) were colonized with ESBL-producing E. coli and 6 (2,4%) with ESBL-producing K. pneumoniae, which were compared with age- and sex-matched ESBL-E non carriers. While no significant differences were found between ESBL-producing E. coli carriers and non-carriers, gut bacteriobiota α-diversity was decreased in ESBL-K. pneumoniae faecal carriers compared both with non-carriers (p = 0.05), and with ESBL-producing E. coli carriers. The presence of Sellimonas intestinalis was associated with the absence of ESBL-producing E. coli fecal carriage. Campylobacter ureolyticus, Campylobacter hominis, bacteria belonging to Clostridium cluster XI and Saccharomyces sp. were associated with the absence of ESBL-producing K. pneumoniae faecal carriage.

CONCLUSIONS

The composition of the gut microbiota differs between ESBL-producing E. coli and K. pneumoniae faecal carriers suggesting that microbial species should be taken into account when investigating the role of gut microbiota in resistance to gut colonization with ESBL-E.

TRIAL REGISTRATION NUMBER

NCT04131569, date of registration: October 18, 2019.

Lung Mycobiota α-Diversity Is Linked to Severity in Critically Ill Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) affects more than 200 million people worldwide. The chronic course of COPD is frequently worsened by acute exacerbations (AECOPD). Mortality in patients hospitalized for severe AECOPD remains dramatically high, and the underlying mechanisms are poorly understood. Lung microbiota is associated with COPD outcomes in nonsevere AECOPD, but no study specifically investigated severe AECOPD patients. The aim of this study is thus to compare lung microbiota composition between severe AECOPD survivors and nonsurvivors. Induced sputum or endotracheal aspirate was collected at admission from every consecutive severe AECOPD patient. After DNA extraction, the V3-V4 and ITS2 regions were amplified by PCR. Deep-sequencing was performed on a MiSeq sequencer (Illumina); the data were analyzed using DADA2 pipeline. Among 47 patients admitted for severe AECOPD, 25 (53%) with samples of sufficient quality were included: 21 of 25 (84%) survivors and 4 of 25 (16%) nonsurvivors. AECOPD nonsurvivors had lower α-diversities indices than survivors for lung mycobiota but not for lung bacteriobiota. Similar results were demonstrated comparing patients receiving invasive mechanical ventilation (n = 13 [52%]) with those receiving only noninvasive ventilation (n = 12 [48%]). Previous systemic antimicrobial therapy and long-term inhaled corticosteroid therapy could alter the lung microbiota composition in severe AECOPD patients. In acidemic AECOPD, lower lung mycobiota α-diversity is linked to the severity of the exacerbation, assessed by mortality and the requirement for invasive mechanical ventilation, whereas lung bacteriobiota α-diversity is not. This study encourages a multicenter cohort study investigating the role of lung microbiota, especially fungal kingdom, in severe AECOPD. IMPORTANCE In AECOPD with acidemia, more severe patients-i.e., nonsurvivors and patients requiring invasive mechanical ventilation-have lower lung mycobiota α-diversity than survivors and patients receiving only noninvasive ventilation, respectively. This study encourages a large multicenter cohort study investigating the role of lung microbiota in severe AECOPD and urges investigation of the role of the fungal kingdom in severe AECOPD.

Efficacy of carbapenem vs non carbapenem β-lactam therapy as empiric antimicrobial therapy in patients with extended-spectrum β-lactamase-producing Enterobacterales urinary septic shock: a propensity-weighted multicenter cohort study

BACKGROUND

The rise in antimicrobial resistance is a global threat responsible for about 33,000 deaths in 2015 with a particular concern for extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) and has led to a major increase in the use of carbapenems, last-resort antibiotics.

METHODS

In this retrospective propensity-weighted multicenter observational study conducted in 11 ICUs, the purpose was to assess the efficacy of non carbapenem regimen (piperacillin-tazobactam (PTZ) + aminoglycosides or 3rd-generation cephalosporin (3GC) + aminoglycosides) as empiric therapy in comparison with carbapenem in extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E) urinary septic shock. The primary outcome was Day-30 mortality.

RESULTS

Among 156 patients included in this study, 69 received a carbapenem and 87 received non carbapenem antibiotics as empiric treatment. Baseline clinical characteristics were similar between the two groups. Patients who received carbapenem had similar Day-30 mortality (10/69 (15%) vs 6/87 (7%), OR = 1.99 [0.55; 5.34] p = 0.16), illness severity, resolution of septic shock, and ESBL-E infection recurrence rates than patients who received an empiric non carbapenem therapy. The rates of secondary infection with C. difficile were comparable.

CONCLUSIONS

In ESBL-E urinary septic shock, empiric treatment with a non carbapenem regimen, including systematically aminoglycosides, was not associated with higher mortality, compared to a carbapenem regimen.

Clinical trajectories and impact of acute kidney disease after acute kidney injury in the intensive care unit: a 5-year single-centre cohort study

BACKGROUND

Patients suffering from acute kidney injury(AKI) in the intensive care unit (ICU) can have various renal trajectories and outcomes. Aims were to assess the various clinical trajectories after AKI in the ICU and to determine risk factors for developing chronic kidney disease (CKD).

METHODS

We conducted a prospective 5-year follow-up study in a medical ICU at Bordeaux University Hospital (France). The patients who received invasive mechanical ventilation, catecholamine infusion or both and developed an AKI from September 2013 to May 2015 were included. In the Cox analysis, the violation of the proportional hazard assumption for AKD was handled using appropriate interaction terms with time, resulting in a time-dependent hazard ratio (HR).

RESULTS

A total of 232 patients were enrolled, with an age of 62 ± 16 years and a median follow-up of 52 days (interquartile range 6-1553). On day 7, 109/232 (47%) patients progressed to acute kidney disease (AKD) and 66/232 (28%) recovered. A linear trajectory (AKI, AKD to CKD) was followed by 44/63 (70%) of the CKD patients. The cumulative incidence of CKD was 30% [95% confidence interval (CI) 24-36] at the 5-year follow-up. In a multivariable Cox model, in the 6 months following AKI, the HR for CKD was higher in AKD patients [HR 29.2 (95% CI 8.5-100.7); P < 0.0001). After 6 months, the HR for CKD was 2.2 (95% CI 0.6-7.9; P = 0.21; n = 172 patients).

CONCLUSION

There were several clinical trajectories of kidney disease after ICU-acquired AKI. CKD risk was higher in AKD patients only in the first 6 months. Lack of renal recovery rather than AKD per se was associated with the risk of CKD.

Acute respiratory distress syndrome after SARS-CoV-2 infection on young adult population: International observational federated study based on electronic health records through the 4CE consortium

PURPOSE

In young adults (18 to 49 years old), investigation of the acute respiratory distress syndrome (ARDS) after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been limited. We evaluated the risk factors and outcomes of ARDS following infection with SARS-CoV-2 in a young adult population.

METHODS

A retrospective cohort study was conducted between January 1st, 2020 and February 28th, 2021 using patient-level electronic health records (EHR), across 241 United States hospitals and 43 European hospitals participating in the Consortium for Clinical Characterization of COVID-19 by EHR (4CE). To identify the risk factors associated with ARDS, we compared young patients with and without ARDS through a federated analysis. We further compared the outcomes between young and old patients with ARDS.

RESULTS

Among the 75,377 hospitalized patients with positive SARS-CoV-2 PCR, 1001 young adults presented with ARDS (7.8% of young hospitalized adults). Their mortality rate at 90 days was 16.2% and they presented with a similar complication rate for infection than older adults with ARDS. Peptic ulcer disease, paralysis, obesity, congestive heart failure, valvular disease, diabetes, chronic pulmonary disease and liver disease were associated with a higher risk of ARDS. We described a high prevalence of obesity (53%), hypertension (38%- although not significantly associated with ARDS), and diabetes (32%).

CONCLUSION

Trough an innovative method, a large international cohort study of young adults developing ARDS after SARS-CoV-2 infection has been gather. It demonstrated the poor outcomes of this population and associated risk factor.

Actes de la 2ème Journée des Jeunes Chercheurs de la Société de Réanimation de Langue Française (Paris, 21 Janvier 2022)

La deuxième édition de la Journée des Jeunes Chercheurs organisée par la Commission de la Recherche Translationnelle de la SRLF a eu lieu en distanciel Paris le 21 janvier 2021. Cette journée a offert aux jeunes acteurs de la Médecine Intensive Réanimation l’opportunité de présenter leurs travaux  de  recherche  en  Master  2  ou  Thèse  d’université  à  un  collège  de  chercheurs  experts.  Pour  cette  deuxième Journée, Les professeurs Pierre Asfar (Angers), Bruno Levy (Nancy), Steve Lancel (Lille) et Fabio Taccone (Bruxelle) ont accepté de venir apporter aux jeunes candidats leur soutien critique et bienveillant. Les présentations couvrant les domaines des neurosciences à l’immunologie en passant par le métabolisme, l’hémodynamique ou la pharmacologie ont illustré la richesse et la diversité de la recherche translationnelle en réanimation.

Predictive factors of glomerular filtration rate loss associated with living kidney donation: a single-center retrospective study

PURPOSE

Living kidney donors (LKD) partially compensate the initial loss of glomerular filtration rate (GFR), a phenomenon known as renal functional reserve (RFR). RFR is reduced in the elderly, a population with increased prevalence of chronic kidney disease. We hypothesized that the selected, healthy population of LKD, would specifically inform about the physiological determinants of the RFR and studied it using measured GFR (mGFR).

METHODS

We retrospectively analyzed pre-donation and post-donation mGFR in 76 LKD from Tenon Hospital (Paris, France) between 2002 and 2018. In addition to GFR measurements, we collected pre-donation morphologic parameters, demographic data, and kidney volumes.

RESULTS

Mean pre-donation mGFR was 90.11 ± 12.64 mL/min/1.73 m² and decreased to 61.26 ± 9.57 mL/min/1.73 m² 1 year after donation. Pre-donation mGFR correlated with age (p = 0.0003), total kidney volume (p = 0.0004) and pre-donation serum creatinine (p = 0.0453). Pre-donation mGFR strongly predicted 1-year post-donation mGFR. Mean RFR (increase in GFR of the remnant kidney between pre-donation and post-donation) was 36.67 ± 16.67% 1 year after donation. In the multivariate linear model, RFR was negatively correlated to total kidney volume (p = 0.02) but not with age or pre-donation serum creatinine.

CONCLUSIONS

We found that pre-donation mGFR decreases with age and identified low total kidney volume as a predictor of RFR in healthy individuals. This suggests an adaptative and reversible decrease in kidney function rather than age-related damage. Older subjects may have reduced metabolic requirements with subsequent reduction in glomerular filtration and kidney volume and preserved RFR. Therefore, low GFR in older subjects should not preclude kidney donation.

Plasma Markers of Neutrophil Extracellular Trap Are Linked to Survival but Not to Pulmonary Embolism in COVID-19-Related ARDS Patients

Introduction

Coronavirus disease 2019 (COVID-19) can cause life-threatening acute respiratory distress syndrome (ARDS). Recent data suggest a role for neutrophil extracellular traps (NETs) in COVID-19-related lung damage partly due to microthrombus formation. Besides, pulmonary embolism (PE) is frequent in severe COVID-19 patients, suggesting that immunothrombosis could also be responsible for increased PE occurrence in these patients. Here, we evaluate whether plasma levels of NET markers measured shorty after admission of hospitalized COVID-19 patients are associated with clinical outcomes in terms of clinical worsening, survival, and PE occurrence.

Patients and Methods

Ninety-six hospitalized COVID-19 patients were included, 50 with ARDS (severe disease) and 46 with moderate disease. We collected plasma early after admission and measured 3 NET markers: total DNA, myeloperoxidase (MPO)–DNA complexes, and citrullinated histone H3. Comparisons between survivors and non-survivors and patients developing PE and those not developing PE were assessed by Mann–Whitney test.

Results

Analysis in the whole population of hospitalized COVID-19 patients revealed increased circulating biomarkers of NETs in patients who will die from COVID-19 and in patients who will subsequently develop PE. Restriction of our analysis in the most severe patients, i.e., the ones who enter the hospital for COVID-19-related ARDS, confirmed the link between NET biomarker levels and survival but not PE occurrence.

Conclusion

Our results strongly reinforce the hypothesis that NETosis is an attractive therapeutic target to prevent COVID-19 progression but that it does not seem to be linked to PE occurrence in patients hospitalized with COVID-19.

Plasma creatinine below limit of quantification in a patient with acute kidney injury

BACKGROUND

Acute kidney injury (AKI) is an infrequent complication of inflammatory bowel disease and can be exceptionally linked to interstitial nephritis secondary to anti-inflammatory drugs, such as Pentasa® (5-ASA).

CASE PRESENTATION

We present an case of an 80-year-old man who presented chronic diarrheas treated by Pentasa®. He developed AKI, evidenced by high plasma creatinine dosed in his local laboratory. At the hospital admission, plasma creatinine was exceptionally undetectable by the enzymatic method while Jaffe's method successfully determined it. Creatinine measurement by the enzymatic method was gradually restored during hospital stay, concomitant with the discontinuation of 5-ASA administration, suggesting that this drug could interfere with creatinine enzymatic assay. Creatinine enzymatic assays combine serial reactions. The last one called Trinder reaction, catalyzed by a peroxidase, uses H₂O₂ to convert uncolored dye in a colored compound, proportionally to creatinine concentration. We showed that AKI related-plasma accumulation of 5-ASA, could participate in the negative interference observed on creatinine measurement, by scavenging H₂O₂. Interestingly, all Trinder reaction-based measurements (uric acid, lipase, lactate, triglycerides and cholesterol) were affected. Negative interference of 5-ASA was confirmed by interferogram experiments on all Trinder reaction-dependent assays.

CONCLUSION

All Trinder-dependent parameters should be interpreted with the patient's treatment knowledge, in particular salicylate derivatives.

MO348CLINICAL TRAJECTORIES AND IMPACT OF ACUTE KIDNEY DISEASE AFTER ACUTE KIDNEY INJURY IN INTENSIVE CARE UNIT: A 5-YEAR SINGLE-CENTER COHORT STUDY

Background and Aims

Acute kidney injury (AKI) is observed in more than 50% of patients admitted in intensive care units (ICU) and more than 10% of them require renal replacement therapy (RRT) Acute kidney disease (AKD) has been recently proposed to describe a highly vulnerable period with pathophysiological process following AKI during which the patient could experience a decline in glomerular filtration and finally developed CKD. Patients suffering from AKI in ICU could have various renal trajectories and outcomes (early, late, or absence of recovery; early or late relapse; acute kidney disease (AKD); or chronic kidney disease (CKD)) after discharge. No cohort study described them accurately. Aims were to assess the various clinical trajectories after AKI in ICU and to determine risk factors for developing CKD taking into account the new concept of AKD and to assess the long-term incidence of CKD.

Method

We conducted a prospective five-year follow-up study in a medical ICU in Bordeaux University Hospital (France). The patients who received invasive mechanical ventilation, catecholamine infusion or both and developed an AKI (defined by KDIGO criteria) from September 2013 to May 2015 were included. We excluded the patients with a previous estimated glomerular filtration rate (eGFR) of &lt;90mL/min/1.73m2. AKD was defined as a condition wherein the criteria for AKI stage 1 or greater persists ≥7 days after exposure. CKD was defined by an eGFR of &lt;60ml/min/1.73m2 at least 90 days after the AKI. Renal recovery was defined by serum creatinine ≤125% of serum basal creatinine. Using the Aalen-Johansen estimator to account for competing risks, we estimated the cumulative incidence of CKD. To estimate adjusted hazard ratios (HRs) we used standard Cox proportional hazard models adjusted for age, sex, hypertension, diabetes, cardiovascular history, SOFA and AKI stage. Proportional hazard assumptions were checked using Schoenfeld residuals. Violation of proportional hazard assumption for AKD was handled by using appropriate interaction terms with time, resulting in time-dependent HR.

Results

232 patients were enrolled. The age was 62 ± 16 years, 142/232 (61%) were male.

AKI stage 1 was present in 62/232 (27%) patients, AKI stage 2 in 50/232 (21%), and AKI stage 3 in 120/232 (52%). Among patients with AKI, 65/232 (28%) recovered before day 7. At day 7, 106/232 (46%) had been progressing to AKD. AKD also developed secondary in 3/65 because of a second episode of AKI without recovery. Among the AKD patients, 21/109 (19%) recovered before day 90, 41/109 (38%) dead and 47/109 (43%) progressed to CKD (figure). The cumulative incidence of CKD was 17 [12-21]% at 1-year follow-up and 30 [24-36] % at 5-years follow-up. This incidence was higher in AKD-patients (44 [35-54]%, and 48 [39-58]%) than in non-AKD patients (9 [1-16]% and 22 [10-34]%) after 1 and 5 years of follow-up, respectively (p=6.10-5). The risk of developing CKD in AKD-patients was increased up to six months compared to those without AKD (HR 27.1 [7.9-93.5]; p&lt;0.0001). Six months after AKI, the risk of progression to CKD was not statistically different between AKD patients and non-AKD patients (HR 2.45 [0.68 – 8.85]; p = 0.17). In this model only gender (male sex: HR 0.5 [0.3-0.9]; p= 0.02) was also significantly associated with CKD.

Conclusion

There were many clinical trajectories after AKI in ICU. Risk for developing CKD remained during the 5 years of follow-up. AKD was the main risk factors for developing CKD only in the first 6 months. After, the risk was similar in AKD or non-AKD patients. Female gender was associated with CKD during all the follow-up. These patients need a specific follow-up after ICU discharge.

Characterization of acute kidney injury in critically ill patients with severe coronavirus disease 2019

BACKGROUND

Coronavirus disease 2019 (COVID-19)-associated acute kidney injury (AKI) frequency, severity and characterization in critically ill patients has not been reported.

METHODS

Single-centre cohort performed from 3 March 2020 to 14 April 2020 in four intensive care units in Bordeaux University Hospital, France. All patients with COVID-19 and pulmonary severity criteria were included. AKI was defined using Kidney Disease: Improving Global Outcomes (KDIGO) criteria. A systematic urinary analysis was performed. The incidence, severity, clinical presentation, biological characterization (transient versus persistent AKI; proteinuria, haematuria and glycosuria) and short-term outcomes were evaluated.

RESULTS

Seventy-one patients were included, with basal serum creatinine (SCr) of 69 ± 21 µmol/L. At admission, AKI was present in 8/71 (11%) patients. Median [interquartile range (IQR)] follow-up was 17 (12-23) days. AKI developed in a total of 57/71 (80%) patients, with 35% Stage 1, 35% Stage 2 and 30% Stage 3 AKI; 10/57 (18%) required renal replacement therapy (RRT). Transient AKI was present in only 4/55 (7%) patients and persistent AKI was observed in 51/55 (93%). Patients with persistent AKI developed a median (IQR) urine protein/creatinine of 82 (54-140) (mg/mmol) with an albuminuria/proteinuria ratio of 0.23 ± 20, indicating predominant tubulointerstitial injury. Only two (4%) patients had glycosuria. At Day 7 after onset of AKI, six (11%) patients remained dependent on RRT, nine (16%) had SCr >200 µmol/L and four (7%) had died. Day 7 and Day 14 renal recovery occurred in 28% and 52%, respectively.

CONCLUSION

Severe COVID-19-associated AKI is frequent, persistent, severe and characterized by an almost exclusive tubulointerstitial injury without glycosuria.

Active engineering of four-wave mixing spectral correlations in multiband hollow-core fibers

We demonstrate theoretically and experimentally a high level of control of the four-wave mixing process in an inert gas-filled inhibited-coupling guiding hollow-core photonic crystal fiber. The specific multiple-branch dispersion profile in such fibers allows both correlated and separable bi-photon states to be produced. By controlling the choice of gas and its pressure and the fiber length, we experimentally generate various joint spectral intensity profiles in a stimulated regime that is transferable to the spontaneous regime. The generated profiles may cover both spectrally separable and correlated bi-photon states and feature frequency tuning over tens of THz, demonstrating a large dynamic control that will be very useful when implemented in the spontaneous regime as a photon pair source.

Raman-tailored photonic crystal fiber for telecom band photon-pair generation

We report on the experimental characterization of a novel nonlinear liquid-filled hollow-core photonic crystal fiber for the generation of photon pairs at a telecommunication wavelength through spontaneous four-wave mixing (SFWM). We show that the optimization procedure in view of this application links the choice of the nonlinear liquid to the design parameters of the fiber, and we give an example of such an optimization at telecom wavelengths. Combining the modeling of the fiber and classical characterization techniques at these wavelengths, we identify for the chosen fiber and liquid combination SFWM phase-matching frequency ranges with no Raman scattering noise contamination. This is a first step toward obtaining a telecom band fibered photon-pair source with a high signal-to-noise ratio.

Direct Bell states generation on a III-V semiconductor chip at room temperature

We demonstrate the direct generation of polarization-entangled photon pairs at room temperature and telecom wavelength in an AlGaAs semiconductor waveguide. The source is based on spontaneous parametric down-conversion with a counterpropagating phase-matching scheme. The quality of the two-photon state is assessed by the reconstruction of the density matrix giving a raw fidelity to a Bell state of 0.83; a theoretical model, taking into account the experimental parameters, provides ways to understand and control the amount of entanglement. Its compatibility with electrical injection, together with the high versatility of the generated two-photon state, make this source an attractive candidate for completely integrated quantum photonics devices.

Two-photon interference with a semiconductor integrated source at room temperature

We experimentally demonstrate an integrated semiconductor ridge microcavity source of counterpropagating twin photons at room temperature in the telecom range. Based on type II parametric down conversion with a counterpropagating phase-matching, pump photons generate photon pairs with an efficiency of about 10(-11) and a spectral linewidth of 0.3 nm for a 1 mm long sample. The indistiguishability of the photons of the pair is measured via a Hong-Ou-Mandel two-photon interference experiment showing a visibility of 85 %. This work opens a route towards new guided-wave semiconductor quantum devices.

Manipulation of cadmium selenide nanorods with an atomic force microscope

We have used an atomic force microscope (AFM) to manipulate and study ligand-capped cadmium selenide nanorods deposited on highly oriented pyrolitic graphite (HOPG). The AFM tip was used to manipulate (i.e., translate and rotate) the nanorods by applying a force perpendicular to the nanorod axis. The manipulation result was shown to depend on the point of impact of the AFM tip with the nanorod and whether the nanorod had been manipulated previously. Forces applied parallel to the nanorod axis, however, did not give rise to manipulation. These results are interpreted by considering the atomic-scale interactions of the HOPG substrate with the organic ligands surrounding the nanorods. The vertical deflection of the cantilever was recorded during manipulation and was combined with a model in order to estimate the value of the horizontal force between the tip and nanorod during manipulation. This horizontal force is estimated to be on the order of a few tens of nN.