Antibiotic definitive treatment in ventilator associated pneumonia caused by AmpC-producing Enterobacterales in critically ill patients: a prospective multicenter observational study.

BACKGROUND: Ventilator associated pneumonia (VAP) due to wild-type AmpC-producing Enterobacterales (wtAE) is frequent in intensive care unit (ICU) patients. Despite a low level of evidence, definitive antimicrobial therapy (AMT) with third generation cephalosporins (3GCs) or piperacillin is discouraged. METHODS: Observational prospective study including consecutive wtAE VAP patients in 20 French ICUs. The primary objective was to assess the association of the choice of definitive AMT, i.e. piperacillin ± tazobactam (PTZ), 3GCs or other molecule (4GCs, carbapenems, quinolones, cotrimoxazole; control group), with treatment success at day-7. Recurrence of infection was collected as a secondary outcome, and analyzed accounting for the competing risk of death. RESULTS: From February 2021 to June 2022, 274 patients were included. Enterobacter cloacae was the most prevalent specie (31%). Seventy-eight patients (28%) had PTZ as definitive AMT while 44 (16%) had 3GCs and 152 (56%) were classified in the control group. Day-7 success rate was similar between the 3 groups (74% vs. 73% vs. 68% respectively, p = 0.814). Recurrence probability at day-28 was 31% (95% CI 21-42), 40% (95% CI 26-55) and 21% (95% CI 15-28) for PTZ, 3GCs and control groups (p = 0.020). In multivariable analysis, choice of definitive AMT was not associated with clinical success, but definitive AMT with 3GCs was associated with recurrence at day-28 [csHR(95%CI) 10.9 (1.92-61.91)]. CONCLUSION: Choice of definitive antimicrobial therapy was not associated with treatment success at day 7. However, recurrence of pneumonia at day-28 was higher in patients treated with third generation cephalosporins with no differences in mortality or mechanical ventilation duration.

Diagnostic yield, safety and therapeutic consequences of myocardial biopsy in clinically suspected fulminant myocarditis unweanable from mechanical circulatory support.

BACKGROUND: Fulminant myocarditis is a rare and severe disease whose definite and etiological diagnoses rely on pathological examination. Albeit, myocardial biopsy can be associated with significant morbidity and mortality, its therapeutic consequences are unclear. We conducted a study to determine the diagnostic yield, the safety and the therapeutic consequences of myocardial biopsy in patients with fulminant clinically suspected myocarditis unweanable from mechanical circulatory support (MCS). METHODS: Monocenter, retrospective, observational cohort study in a 26-bed French tertiary ICU between January 2002 and February 2019. Inclusion of all fulminant clinically suspected myocarditis patients undergoing in-ICU myocardial biopsy while being on MCS. The primary endpoint was the proportion of patients classified as definite myocarditis using Bonaca criteria before and after including myocardial biopsy results. RESULTS: Forty-seven patients (median age 41 [30-47], female 53%) were included: 55% died before hospital discharge, 34% could be bridged-to-recovery and 15% bridged-to-transplant. Myocardial biopsy was endomyocardial or surgical in 36% and 64% cases respectively. Tamponade requiring emergency pericardiocentesis occurred in 29% patients after endomyocardial biopsy. After adding the biopsy results in the Bonaca classification algorithm the percentage of definite myocarditis raised from 13 to 55% (p < 0.0001). The rate of biopsy-related treatments modifications was 13%, leading to patients' recovery in only 4% patients. CONCLUSIONS: In clinically suspected myocarditis unweanable from MCS, myocardial biopsy increased the rate of definite myocarditis but was associated with a low rate of treatment modification and a significant proportion of adverse events. We believe the benefit/risk ratio of myocardial biopsy should be more carefully weighted in these frail and selected patients than suggested by actual guidelines. Further prospective studies are now needed to determine its value in patients under MCS.

Pharmacokinetics/pharmacodynamics of ceftobiprole in patients on extracorporeal membrane oxygenation.

INTRODUCTION: Due to its bacteriological spectrum and efficacy in skin and soft tissue infections, ceftobiprole may be of interest for extracorporeal membrane oxygenation (ECMO) cannula-related infection. It is unknown whether ceftobiprole pharmacokinetics (PK) are changed by ECMO. METHODS: A retrospective monocentric cohort study was performed of 35 patients with suspected ECMO-related cannula infections (28 on ECMO, seven after ECMO removal), who received ceftobiprole as empiric treatment and had ceftobiprole blood levels measured at trough, peak and CT50 (50% of the dosing interval). Ceftobiprole blood levels of the 28 patients on ECMO were compared with those of the seven patients without ECMO. Factors associated with low ceftobiprole trough levels were also explored. RESULTS: Among the 35 patients included, 29 had a confirmed cannula-related infection and 48 pathogens were isolated. Ceftobiprole MIC was determined in 29 of these 48, and 23 (79%) were susceptible to ceftobiprole. Ceftobiprole blood levels (at trough, peak and CT50) were similar in ECMO and non-ECMO patients. Moreover, in patients whose pathogens responsible for infection were susceptible to ceftobiprole, 94% had a ceftobiprole trough level above the MIC. Ceftobiprole blood levels were decreased in patients with acute renal failure requiring renal replacement therapy (RRT) and in those with increased renal clearance (defined as creatinine clearance > 130 mL/min), independent of ECMO. No other factor was associated with modification of ceftobiprole PK/pharmacodynamics (PK/PD). CONCLUSIONS: The ceftobiprole PK/PD was no different in patients during ECMO or after its withdrawal. Factors associated with decreased ceftobiprole blood levels were patients requiring RRT and those with increased renal clearance.

Updates in the management of respiratory virus infections in ICU patients: revisiting the non-SARS-CoV-2 pathogens.

INTRODUCTION: Although viruses are an underestimated cause of community-acquired pneumonias (CAP) and hospital-acquired pneumonias (HAP)/ventilator-associated pneumonias (VAP) in intensive care unit (ICU) patients, they have an impact on morbidity and mortality. AREAS COVERED: In this perspective article, we discuss the available data regarding the management of severe influenza CAP and herpesviridae HAP/VAP. We review diagnostic and therapeutic strategies in order to give clear messages and address unsolved questions. EXPERT OPINION: Influenza CAP affects yearly thousands of people; however, robust data regarding antiviral treatment in the most critical forms are scarce. While efficacy of oseltamivir has been investigated in randomized controlled trials (RCT) in uncomplicated influenza, only observational data are available in ICU patients. Herpesviridae are an underestimated cause of HAP/VAP in ICU patients. Whilst incidence of herpesviridae identification in samples from lower respiratory tract of ICU patients is relatively high (from 20% to 50%), efforts should be made to differentiate local reactivation from true lung infection. Only few randomized controlled trials evaluated the efficacy of antiviral treatment in herpesviridae reactivation/infection in ICU patients and all were exploratory or negative. Further studies are needed to evaluate the impact of such treatment in specific populations.

Delivery decision in pregnant women rescued by ECMO for severe ARDS: a retrospective multicenter cohort study.

BACKGROUND: Although rarely addressed in the literature, a key question in the care of critically pregnant women with severe acute respiratory distress syndrome (ARDS), especially at the time of extracorporeal membrane oxygenation (ECMO) decision, is whether delivery might substantially improve the mother's and child's conditions. This multicenter, retrospective cohort aims to report maternal and fetal short- and long-term outcomes of pregnant women with ECMO-rescued severe ARDS according to the timing of the delivery decision taken before or after ECMO cannulation. METHODS: We included critically ill women with ongoing pregnancy or within 15 days after a maternal/child-rescue-aimed delivery supported by ECMO for a severe ARDS between October 2009 and August 2021 in four ECMO centers. Clinical characteristics, critical care management, complications, and hospital discharge status for both mothers and children were collected. Long-term outcomes and premature birth complications were assessed. RESULTS: Among 563 women on venovenous ECMO during the study period, 11 were cannulated during an ongoing pregnancy at a median (range) of 25 (21-29) gestational weeks, and 13 after an emergency delivery performed at 32 (17-39) weeks of gestation. Pre-ECMO PaO2/FiO2 ratio was 57 (26-98) and did not differ between the two groups. Patients on ECMO after delivery reported more major bleeding (46 vs. 18%, p = 0.05) than those with ongoing pregnancy. Overall, the maternal hospital survival was 88%, which was not different between the two groups. Four (36%) of pregnant women had a spontaneous expulsion on ECMO, and fetal survival was higher when ECMO was set after delivery (92% vs. 55%, p = 0.03). Among newborns alive, no severe preterm morbidity or long-term sequelae were reported. CONCLUSION: Continuation of the pregnancy on ECMO support carries a significant risk of fetal death while improving prematurity-related morbidity in alive newborns with no difference in maternal outcomes. Decisions regarding timing, place, and mode of delivery should be taken and regularly (re)assess by a multidisciplinary team in experienced ECMO centers.

Augmented renal clearance in the ICU: estimation, incidence, risk factors and consequences-a retrospective observational study.

BACKGROUND: Augmented renal clearance (ARC) remains poorly evaluated in ICU. The objective of this study is to provide a full description of ARC in ICU including prevalence, evolution profile, risk factors and outcomes. METHODS: This was a retrospective, single-center, observational study. All the patients older than 18 years admitted for the first time in Medical ICU, Bichat, University Hospital, APHP, France, between January 1, 2017, and November 31, 2020 and included into the Outcomerea database with an ICU length of stay longer than 72 h were included. Patients with chronic kidney disease were excluded. Glomerular filtration rate was estimated each day during ICU stay using the measured creatinine renal clearance (CrCl). Augmented renal clearance (ARC) was defined as a 24 h CrCl greater than 130 ml/min/m2. RESULTS: 312 patients were included, with a median age of 62.7 years [51.4; 71.8], 106(31.9%) had chronic cardiovascular disease. The main reason for admission was acute respiratory failure (184(59%)) and 196(62.8%) patients had SARS-COV2. The median value for SAPS II score was 32[24; 42.5]; 146(44%) and 154(46.4%) patients were under vasopressors and invasive mechanical ventilation, respectively. The overall prevalence of ARC was 24.6% with a peak prevalence on Day 5 of ICU stay. The risk factors for the occurrence of ARC were young age and absence of cardiovascular comorbidities. The persistence of ARC during more than 10% of the time spent in ICU was significantly associated with a lower risk of death at Day 30. CONCLUSION: ARC is a frequent phenomenon in the ICU with an increased incidence during the first week of ICU stay. Further studies are needed to assess its impact on patient prognosis.

Phenotypic Heterogeneity of Fulminant COVID-19--Related Myocarditis in Adults.

BACKGROUND: Adults who have been infected with SARS-CoV-2 can develop a multisystem inflammatory syndrome (MIS-A), including fulminant myocarditis. Yet, several patients fail to meet MIS-A criteria, suggesting the existence of distinct phenotypes in fulminant COVID-19-related myocarditis. OBJECTIVES: This study sought to compare the characteristics and clinical outcome between patients with fulminant COVID-19-related myocarditis fulfilling MIS-A criteria (MIS-A+) or not (MIS-A-). METHODS: A monocentric retrospective analysis of consecutive fulminant COVID-19-related myocarditis in a 26-bed intensive care unit (ICU). RESULTS: Between March 2020 and June 2021, 38 patients required ICU admission (male 66%; mean age 32 ± 15 years) for suspected fulminant COVID-19-related myocarditis. In-ICU treatment for organ failure included dobutamine 79%, norepinephrine 60%, mechanical ventilation 50%, venoarterial extracorporeal membrane oxygenation 42%, and renal replacement therapy 29%. In-hospital mortality was 13%. Twenty-five patients (66%) met the MIS-A criteria. MIS-A- patients compared with MIS-A+ patients were characterized by a shorter delay between COVID-19 symptoms onset and myocarditis, a lower left ventricular ejection fraction, and a higher rate of in-ICU organ failure, and were more likely to require mechanical circulatory support with venoarterial extracorporeal membrane oxygenation (92% vs 16%; P < 0.0001). In-hospital mortality was higher in MIS-A- patients (31% vs 4%). MIS-A+ had higher circulating levels of interleukin (IL)-22, IL-17, and tumor necrosis factor-α (TNF-α), whereas MIS-A- had higher interferon-α2 (IFN-α2) and IL-8 levels. RNA polymerase III autoantibodies were present in 7 of 13 MIS-A- patients (54%) but in none of the MIS-A+ patients. CONCLUSION: MIS-A+ and MIS-A- fulminant COVID-19-related myocarditis patients have 2 distinct phenotypes with different clinical presentations, prognosis, and immunological profiles. Differentiating these 2 phenotypes is relevant for patients' management and further understanding of their pathophysiology.

Venoarterial extracorporeal membrane oxygenation flow or dobutamine to improve microcirculation during ECMO for refractory cardiogenic shock.

PURPOSE: Venoarterial extracorporeal membrane oxygenation (VA ECMO) effectively supports refractory cardiogenic shock (rCS), and sustains macro- and microcirculations. We investigated the respective impact of increasing VA ECMO flow or dobutamine dose on microcirculation in stabilized VA ECMO-treated patients with rCS. METHODS: In this prospective interventional study, we included consecutive intubated patients, with ECMO-supported rCS and hemodynamic stability, able to tolerate stepwise incremental dobutamine doses (from 5 to 20 gamma/kg/min) or ECMO flows (progressive increase by 25% above baseline ECMO flow. Baseline was defined as the lowest VA ECMO flow and dobutamine 5 µg/kg/min (DOBU5) to maintain mean arterial pressure (MAP) ≥ 65 mmHg. Macro- and microcirculations were evaluated after 30 min at each level. RESULTS: Fourteen patients were included. Macro- and microcirculations were assessed 2 [2-5] days post-ECMO onset. Dobutamine-dose increments did not modify any microcirculation parameters. Only the De Backer score tended to be reduced (p = 0.08) by ECMO-flow increments whereas other microcirculation parameters were not affected. These findings did not differ between patients successfully weaned-off ECMO (n = 6) or not. CONCLUSIONS: When macrocirculation has already been restored in patients with ECMO-supported rCS, increasing dobutamine (above 5 µg/kg/min) or ECMO flow did not further improve microcirculation.

Evolving outcomes of extracorporeal membrane oxygenation support for severe COVID-19 ARDS in Sorbonne hospitals, Paris.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) was frequently used to treat patients with severe coronavirus disease-2019 (COVID-19)-associated acute respiratory distress (ARDS) during the initial outbreak. Care of COVID-19 patients evolved markedly during the second part of 2020. Our objective was to compare the characteristics and outcomes of patients who received ECMO for severe COVID-19 ARDS before or after July 1, 2020. METHODS: We included consecutive adults diagnosed with COVID-19 in Paris-Sorbonne University Hospital Network ICUs, who received ECMO for severe ARDS until January 28, 2021. Characteristics and survival probabilities over time were estimated during the first and second waves. Pre-ECMO risk factors predicting 90-day mortality were assessed using multivariate Cox regression. RESULTS: Characteristics of the 88 and 71 patients admitted, respectively, before and after July 1, 2020, were comparable except for older age, more frequent use of dexamethasone (18% vs. 82%), high-flow nasal oxygenation (19% vs. 82%) and/or non-invasive ventilation (7% vs. 37%) after July 1. Respective estimated probabilities (95% confidence intervals) of 90-day mortality were 36% (27-47%) and 48% (37-60%) during the first and the second periods. After adjusting for confounders, probability of 90-day mortality was significantly higher for patients treated after July 1 (HR 2.27, 95% CI 1.02-5.07). ECMO-related complications did not differ between study periods. CONCLUSIONS: 90-day mortality of ECMO-supported COVID-19-ARDS patients increased significantly after July 1, 2020, and was no longer comparable to that of non-COVID ECMO-treated patients. Failure of prolonged non-invasive oxygenation strategies before intubation and increased lung damage may partly explain this outcome.

Innate T-αß lymphocytes as new immunological components of anti-tumoral "off-target" effects of the tyrosine kinase inhibitor dasatinib.

Kinase inhibitors hold great potential as targeted therapy against malignant cells. Among them, the tyrosine kinase inhibitor dasatinib is known for a number of clinically relevant off-target actions, attributed in part to effects on components of the immune system, especially conventional T-cells and natural killer (NK)-cells. Here, we have hypothesized that dasatinib also influences non-conventional T-αß cell subsets known for their potential anti-tumoral properties, namely iNKT cells and the distinct new innate CD8 T-cell subset. In mice, where the two subsets were originally characterized, an activated state of iNKT cells associated with a shift toward an iNKT cell Th1-phenotype was observed after dasatinib treatment in vivo. Despite decreased frequency of the total memory CD8 T-cell compartment, the proportion of innate-memory CD8 T-cells and their IFNγ expression in response to an innate-like stimulation increased in response to dasatinib. Lastly, in patients administered with dasatinib for the treatment of BCR-ABL-positive leukemias, we provided the proof of concept that the kinase inhibitor also influences the two innate T-cell subsets in humans, as attested by their increased frequency in the peripheral blood. These data highlight the potential immunostimulatory capacity of dasatinib on innate T-αß cells, thereby opening new opportunities for chemoimmunotherapy.

Sustained treatment-free remission in chronic myeloid leukaemia is associated with an increased frequency of innate CD8(+) T-cells.

Immunological mechanisms of treatment-free remission (TFR) in chronic myeloid leukaemia (CML) are poorly defined and, to date, no correlation between successful TFR and CD8(+) T-cell subsets has been found. We analysed a new identified human subset of CD8(+) T-cells, namely innate CD8(+) T-cells, in CML patients with TFR ≥ 2 years. We demonstrated a dramatic increase of functionally active innate CD8(+) T-cells in these patients as compared to control subjects and patients in remission under tyrosine kinase inhibitors. Moreover, we found a positive correlation between frequencies of innate CD8(+) T-cells and natural killer cells, possibly representing a new innate biomarker profile of successful TFR.

Phenotype of NK-Like CD8(+) T Cells with Innate Features in Humans and Their Relevance in Cancer Diseases.

Unconventional T cells are defined by their capacity to respond to signals other than the well-known complex of peptides and major histocompatibility complex proteins. Among the burgeoning family of unconventional T cells, innate-like CD8(+) T cells in the mouse were discovered in the early 2000s. This subset of CD8(+) T cells bears a memory phenotype without having encountered a foreign antigen and can respond to innate-like IL-12 + IL-18 stimulation. Although the concept of innate memory CD8(+) T cells is now well established in mice, whether an equivalent memory NK-like T-cell population exists in humans remains under debate. We recently reported that CD8(+) T cells responding to innate-like IL-12 + IL-18 stimulation and co-expressing the transcription factor Eomesodermin (Eomes) and KIR/NKG2A membrane receptors with a memory/EMRA phenotype may represent a new, functionally distinct innate T cell subset in humans. In this review, after a summary on the known innate CD8(+) T-cell features in the mouse, we propose Eomes together with KIR/NKG2A and CD49d as a signature to standardize the identification of this innate CD8(+) T-cell subset in humans. Next, we discuss IL-4 and IL-15 involvement in the generation of innate CD8(+) T cells and particularly its possible dependency on the promyelocytic leukemia zinc-finger factor expressing iNKT cells, an innate T cell subset well documented for its susceptibility to tumor immune subversion. After that, focusing on cancer diseases, we provide new insights into the potential role of these innate CD8(+) T cells in a physiopathological context in humans. Based on empirical data obtained in cases of chronic myeloid leukemia, a myeloproliferative syndrome controlled by the immune system, and in solid tumors, we observe both the possible contribution of innate CD8(+) T cells to cancer disease control and their susceptibility to tumor immune subversion. Finally, we note that during tumor progression, innate CD8(+) T lymphocytes could be controlled by immune checkpoints. This study significantly contributes to understanding of the role of NK-like CD8(+) T cells and raises the question of the possible involvement of an iNKT/innate CD8(+) T cell axis in cancer.

The Hypothesis of the Human iNKT/Innate CD8(+) T-Cell Axis Applied to Cancer: Evidence for a Deficiency in Chronic Myeloid Leukemia.

We recently identified a new human subset of NK-like [KIR/NKG2A(+)] CD8(+) T cells with a marked/memory phenotype, high Eomesodermin expression, potent antigen-independent cytotoxic activity, and the capacity to generate IFN-γ rapidly after exposure to pro-inflammatory cytokines. These features support the hypothesis that this new member of the innate T cell family in humans, hereafter referred to as innate CD8(+) T cells, has a role in cancer immune surveillance analogous to invariant natural killer T (iNKT) cells. Here, we report the first quantitative and functional analysis of innate CD8(+) T cells in a physiopathological context in humans, namely chronic myeloid leukemia (CML), a well-characterized myeloproliferative disorder. We have chosen CML based on our previous report that IL-4 production by iNKT cells was deficient in CML patients at diagnosis and considering the recent evidence in mice that IL-4 promotes the generation/differentiation of innate CD8(+) T cells. We found that the pool of innate CD8(+) T cells was severely reduced in the blood of CML patients at diagnosis. Moreover, like iNKT and NK cells, innate CD8(+) T cells were functionally impaired, as attested by their loss of antigen-independent cytotoxic activity and IFN-γ production in response to innate-like stimulation with IL-12 + IL-18. Remarkably, as previously reported for IL-4 production by iNKT cells, both quantitative and functional deficiencies of innate CD8(+) T cells were at least partially corrected in patients having achieved complete cytogenetic remission following tyrosine kinase inhibitor therapy. Finally, direct correlation between the functional potential of innate CD8(+) T and iNKT cells was found when considering all healthy donors and CML patients in diagnosis and remission, in accordance with the iNKT cell-dependent generation of innate CD8(+) T cells reported in mice. All in all, our data demonstrate that CML is associated with deficiencies of innate CD8(+) T cells that are restored upon remission, thereby suggesting their possible contribution to disease control. More generally, our study strongly supports the existence of an innate iNKT/innate CD8(+) T-cell axis in humans and reveals its potential contribution to the restoration of tumor immune surveillance.