Relative inhibitory activities of the broad-spectrum ß-lactamase inhibitor xeruborbactam in comparison with taniborbactam against metallo-ß-lactamases produced in Escherichia coli and Pseudomonas aeruginosa.

Xeruborbactam is a newly developed ß-lactamase inhibitor designed for metallo-ß-lactamases (MBLs). This study assessed the relative inhibitory properties of this novel inhibitor in comparison with another MBL inhibitor, namely taniborbactam (TAN), against a wide range of acquired MBL produced either in Escherichia coli or Pseudomonas aeruginosa. As observed with taniborbactam, the combination of xeruborbactam (XER) with ß-lactams, namely, ceftazidime, cefepime and meropenem, led to significantly decreased MIC values for a wide range of B1-type MBL-producing E. coli, including most recombinant strains producing NDM, VIM, IMP, GIM-1, and DIM-1 enzymes. Noteworthily, while TAN-based combinations significantly reduced MIC values of ß-lactams for MBL-producing P. aeruginosa recombinant strains, those with XER were much less effective. We showed that this latter feature was related to the MexAB-OprM efflux pump significantly impacting MIC values when testing XER-based combinations in P. aeruginosa. The relative inhibitory concentrations (IC50 values) were similar for XER and TAN against NDM and VIM enzymes. Noteworthily, XER was effective against NDM-9, NDM-30, VIM-83, and most of IMP enzymes, although those latter enzymes were considered resistant to TAN. However, no significant inhibition was observed with XER against IMP-10, SPM-1, and SIM-1 as well as the representative subclass B2 and B3 enzymes, PFM-1 and AIM-1. The determination of the constant inhibition (Ki) of XER revealed a much higher value against IMP-10 than against NDM-1, VIM-2, and IMP-1. Hence, IMP-10 that differs from IMP-1 by a single amino-acid substitution (Val67Phe) can, therefore, be considered resistant to XER.

Effect of modification of penicillin-binding protein 3 on susceptibility to ceftazidime-avibactam, imipenem-relebactam, meropenem-vaborbactam, aztreonam-avibactam, cefepime-taniborbactam, and cefiderocol of Escherichia coli strains producing broad-spectrum ß-lactamases.

The impact of penicillin-binding protein 3 (PBP3) modifications that may be identified in Escherichia coli was evaluated with respect to susceptibility to ß-lactam/ß-lactamase inhibitor combinations including ceftazidime-avibactam, imipenem-relebactam, meropenem-vaborbactam, aztreonam-avibactam, cefepime-taniborbactam, and to cefiderocol. A large series of E. coli recombinant strains producing broad-spectrum ß-lactamases was evaluated. While imipenem-relebactam showed a similar activity regardless of the PBP3 background, susceptibility to other molecules tested was affected at various levels. This was particularly the case for ceftazidime-avibactam, aztreonam-avibactam, and cefepime-taniborbactam.

Reduced susceptibility to aztreonam-avibactam conferred by acquired AmpC-type ß-lactamases in PBP3-modified Escherichia coli.

PURPOSE: Carbapenemase-producing Enterobacterales are a growing threat, and very few therapeutic options remain active against those multidrug resistant bacteria. Aztreonam is the molecule of choice against metallo-beta-lactamases (MBL) producers since it is not hydrolyzed by those enzymes, but the co-production of acquired plasmidic cephalosporinases or extended-spectrum ß-lactamases leading to aztreonam resistance may reduce the efficacy of this molecule. Hence, the development of the aztreonam-avibactam (AZA) combination provides an interesting therapeutic alternative since avibactam inhibits the activity of both cephalosporinases and extended-spectrum ß-lactamases. However, structural modifications of penicillin binding protein PBP3, the target of aztreonam, may lead to reduced susceptibility to aztreonam-avibactam. METHODS: Here the impact of various plasmid-encoded AmpC-type ß-lactamases (ACC-1, ACT-7, ACT-17, CMY-2, CMY-42, DHA-1, FOX-1, and FOX-5) on susceptibility to aztreonam-avibactam was evaluated using isogenic E. coli MG1655 strains harboring insertions in PBP3 (YRIN and YRIK). The inhibitory activity of various ß-lactamase inhibitors (clavulanic acid, tazobactam, avibactam, relebactam, and vaborbactam) were also compared against these enzymes. RESULTS: Hence, we showed that reduced susceptibility to AZA was due to the combined effect of both AmpC production and amino acid insertions in PBP3. The highest resistance level was achieved in strains possessing the insertions in PBP3 in association with the production of ACT-7, ACC-1, or CMY-42. CONCLUSION: Although none of the recombinant strains tested displayed clinical resistance to aztreonam-avibactam, our data emphasize that the occurrence of such profile might be of clinical relevance for MBL-producing strains.

Pulmonary embolism impacts clinical outcomes of intubated patients with acute respiratory distress syndrome related to COVID-19.

BACKGROUND: Pulmonary embolism (PE) in critically ill patients with acute respiratory distress syndrome (ARDS) caused by COVID-19 is a major complication which might impact survival. We aimed to determine the prevalence of PE and assess its impact of PE on clinical outcomes in intubated patients with ARDS due to COVID-19. METHODS: All intubated patients with ARDS due to COVID-19 admitted to the intensive care unit (ICU) of Geneva University Hospitals between March 9, 2020, and May 31, 2022, were included. A retrospective analysis was conducted on the occurrence of PE and its association with clinical outcomes. The primary outcome was ventilator-free days during the first 28 days after ICU admission. Linear regressions were performed to investigate the association between PE and outcomes. RESULTS: Among the 370 intubated patients with ARDS related to COVID-19, 58 (15.7%) presented with PE. Patients with PE had significantly fewer ventilator-free days than patients without PE (median (IQR) of 3 (0-11) days versus 12 (0-19) days; p < 0.001). Mortality did not differ significantly between groups (12/58 [20.7%] of patients with PE versus 71/312 [22.8%] of patients without PE; p = 0.72). Duration of IMV, and ICU and hospital LOS were significantly longer among patients with PE. The need for ECMO support was similar among both groups. CONCLUSIONS: The occurrence of PE in patients with ARDS due to COVID-19 had a significant impact on clinical outcomes. They had fewer ventilator-free days, longer duration of IMV, and longer ICU and hospital lengths of stay. However, pulmonary embolism was not associated with higher mortality. ETHICS APPROVAL: Ethical committee of Geneva (BASEC #: 2020-00917).

Multidrug-resistant Gram-negative clinical isolates with reduced susceptibility/resistance to cefiderocol: which are the best present and future therapeutic alternatives?

PURPOSE: To evaluate the different present and future therapeutic ß-lactam/ß-lactamase inhibitor (BL/BLI) alternatives, namely aztreonam-avibactam, imipenem-relebactam, meropenem-vaborbactam, cefepime-zidebactam, cefepime-taniborbactam, meropenem-nacubactam, and sulbactam-durlobactam against clinical isolates showing reduced susceptibility or resistance to cefiderocol in Enterobacterales, Acinetobacter baumannii, and Pseudomonas aeruginosa. METHODS: MIC values of aztreonam, aztreonam-avibactam, cefepime, cefepime-taniborbactam, cefepime-zidebactam, imipenem, imipenem-relebactam, meropenem, meropenem-vaborbactam, meropenem-nacubactam, sulbactam-durlobactam, and cefiderocol combined with a BLI were determined for 67, 9, and 11 clinical Enterobacterales, P. aeruginosa or A. baumannii isolates, respectively, showing MIC values of cefiderocol being ≥1 mg/L. If unavailable, the respective ß-lactam breakpoints according to EUCAST were used for BL/BLI combinations. RESULTS: For Enterobacterales, the susceptibility rates for aztreonam, cefepime, imipenem, and meropenem were 7.5%, 0%, 10.4%, and 10.4%, respectively, while they were much higher for cefepime-zidebactam (91%), cefiderocol-zidebactam (91%), meropenem-nacubactam (71.6%), cefiderocol-nacubactam (74.6%), and cefiderocol-taniborbactam (76.1%), as expected. For P. aeruginosa isolates, the higher susceptibility rates were observed for imipenem-relebactam, cefiderocol-zidebactam, and meropenem-vaborbactam (56% for all combinations). For A. baumannii isolates, lower susceptibility rates were observed with commercially or under development BL/BLI combos; however, a high susceptibility rate (70%) was found for sulbactam-durlobactam and when cefiderocol was associated to some BLIs. CONCLUSIONS: Zidebactam- and nacubactam-containing combinations showed a significant in vitro activity against multidrug-resistant Enterobacterales clinical isolates with reduced susceptibility to cefiderocol. On the other hand, imipenem-relebactam and meropenem-vaborbactam showed the highest susceptibility rates against P. aeruginosa isolates. Finally, sulbactam-durlobactam and cefiderocol combined with a BLI were the only effective options against A. baumannii tested isolates.

Structural basis of metallo-ß-lactamase resistance to taniborbactam.

The design of inhibitors against metallo-ß-lactamases (MBLs), the largest family of carbapenemases, has been a strategic goal in designing novel antimicrobial therapies. In this regard, the development of bicyclic boronates, such as taniborbactam (TAN) and xeruborbactam, is a major achievement that may help in overcoming the threat of MBL-producing and carbapenem-resistant Gram-negative pathogens. Of concern, a recent report has shown that New Delhi MBL-9 (NDM-9) escapes the inhibitory action of TAN by a single amino acid substitution with respect to New Delhi MBL-1 (NDM-1), the most widely disseminated MBL. Here, we report a docking and computational analysis that identifies that "escape variants" against TAN can arise by disruption of the electrostatic interaction of negative charges in the active site loops of MBLs with the N-(2-aminoethyl)cyclohexylamine side chain of TAN. These changes result in non-productive binding modes of TAN that preclude reaction with the MBLs, a phenomenon that is not restricted to NDM-9. This analysis demonstrates that single amino acid substitutions in non-essential residues in MBL loops can unexpectedly elicit resistance to TAN.

Relative inhibitory activities of the broad-spectrum ß-lactamase inhibitor taniborbactam against metallo-ß-lactamases.

Taniborbactam (TAN) is a novel broad-spectrum ß-lactamase inhibitor with significant activity against subclass B1 metallo-ß-lactamases (MBLs). Here, we showed that TAN exhibited an overall excellent activity against B1 MBLs including most NDM- and VIM-like as well as SPM-1, GIM-1, and DIM-1 enzymes, but not against SIM-1. Noteworthy, VIM-1-like enzymes (particularly VIM-83) were less inhibited by TAN than VIM-2-like. Like NDM-9, NDM-30 (also differing from NDM-1 by a single amino acid substitution) was resistant to TAN.

Impact of acquired broad-spectrum ß-lactamases on susceptibility to oral penems/carbapenems (tebipenem, sulopenem, and faropenem) alone or in combination with avibactam and taniborbactam ß-lactamase inhibitors in Escherichia coli.

The impact of ß-lactamases on susceptibility to oral penems/carbapenems (tebipenem, sulopenem, and faropenem) and other carbapenem molecules was evaluated in Escherichia coli, alone and in combination with avibactam or taniborbactam ß-lactamase inhibitors. Tebipenem and sulopenem exhibited a similar spectrum of activity compared to the intravenous carbapenems and displayed lower MIC values than ceftibuten-avibactam against E. coli producing extended-spectrum ß-lactamases or AmpC enzymes. Combined with taniborbactam, tebipenem and sulopenem exhibited low MIC values against almost all tested recombinant E. coli, including metallo-ß-lactamase producers.

Association of Trace Element Levels with Outcomes in Critically Ill COVID-19 Patients.

The primary objective of this study was to compare the plasma levels of copper, selenium, and zinc between critically ill COVID-19 patients and less severe COVID-19 patients. The secondary objective was to investigate the association of these trace element levels with adverse outcomes, including the duration of mechanical ventilation, occurrence of septic shock, and mortality in critically ill COVID-19 patients. All COVID-19 patients admitted to the ICU of the Geneva University Hospitals between 9 March 2020 and 19 May 2020 were included in the study. Plasma levels of copper, selenium and zinc were measured on admission to the ICU and compared with levels measured in COVID-19 patients hospitalized on the ward and in non-hospitalized COVID-19 patients. To analyze the association of trace elements with clinical outcomes, multivariate linear and logistic regressions were performed. Patients in the ICU had significantly lower levels of selenium and zinc and higher levels of copper compared to COVID-19 patients hospitalized on the ward and in non-hospitalized COVID-19 patients. In ICU patients, lower zinc levels tended to be associated with more septic shock and increased mortality compared to those with higher zinc levels (p = 0.07 for both). Having lower copper or selenium levels was associated with a longer time under mechanical ventilation (p = 0.01 and 0.04, respectively). These associations remained significant in multivariate analyses (p = 0.03 for copper and p = 0.04 for selenium). These data support the need for interventional studies to assess the potential benefit of zinc, copper and selenium supplementation in severe COVID-19 patients.

No waiting lying in a corridor: a quality improvement initiative in an emergency department.

BACKGROUND: Overcrowding in the emergency department (ED) is a global problem and a source of morbidity and mortality and exhaustion for the teams. Despite multiple strategies proposed to overcome overcrowding, the accumulation of patients lying in bed awaiting treatment or hospitalisation is often inevitable and a major obstacle to quality of care. We initiated a quality improvement project with the objective of zero patients lying in bed awaiting care/referral outside a care area. METHODS: Several plan-do-study-act (PDSA) cycles were tested and implemented to achieve and especially maintain the goal of having zero patients waiting for care outside the ED care area. The project team introduced and adapted five rules during these cycles: (1) no patients lying down outside of a care unit; (2) forward movement; (3) examination room always available; (4) team huddle and (5) an organisation overcrowding plan. RESULTS: Adaptation of ED organisation in the form of PDSA cycles allowed to obtain a collective team dimension to patient flow management. Since December 2021, despite an increase in activity, no patient is placed in a lying-in waiting area outside a care zone, irrespective of their care level. Vital distress and fragile patients who need to be kept in a supine position are treated immediately. In 2022, waiting time before medical contact was <2 hours for 90% of all patients combined. CONCLUSIONS: The PDSA strategy based on these five measures allowed to remove in-house obstacles to the internal flow of patients and to fight against their installation outside the care area. These measures are easily replicable by other management teams. Quality indicators of EDs are often heterogeneous, but we propose that the absence of patients lying on a stretcher outside a care area could be part of these indicators, and thus contribute to the improvement and safety of care provided to all patients.

The Effect of Positive Therapeutic Communication on Pain (POPAIN) and Anxiety During Arterial Blood Gas Standardized Procedures in the Emergency Department Compared to Traditional Communication: Protocol for a Monocentric Randomized Controlled Trial.

BACKGROUND: In the emergency department (ED), medical procedures, such as arterial blood gas (ABG) testing, can cause pain and high stress levels. However, ABG testing is a routine procedure assessing the severity of the patient's condition. To reduce the pain of ABG, several methods have been investigated without significant difference in pain perception. Communication, a key element of care, has shown a significant effect on pain perception. A positive communication strategy, including positive, kind, or reassuring words, can reduce pain perception, while negative words can raise this perception, causing discomfort, known as the "nocebo effect." Although some studies have compared the impact of verbal attitudes, particularly in anesthesia and mainly with staff already trained in hypnosis, to the best of our knowledge, none have investigated the effect of communication in the emergency setting, where patients may be more suggestible to the words used. OBJECTIVE: In this study, we will investigate the effect of positive therapeutic communication on pain, anxiety, discomfort, and global satisfaction in patients requiring ABG compared to nocebo and neutral communication. METHODS: A single-center, double-blind randomized controlled trial (RCT) with 3 parallel arms will be conducted with 249 patients requiring ABG during their ED visit. Patients will be randomly assigned to 1 of 3 groups before receiving ABG: positive communication group, negative communication (nocebo) group, or neutral communication (neutral) group. The communication and the words used by the physicians during hygiene preparation, artery location, and puncture will be imposed in each group. The study will be proposed to each patient corresponding to the inclusion criteria. The physicians will not be trained in hypnosis or in positive therapeutic communication. The procedure will be recorded with audio recorders to test its quality. Intention-to-treat analysis will be performed. The primary endpoint is the onset of pain. The secondary outcomes are patient comfort, patient anxiety, and global satisfaction of the patient with the communication strategy used. RESULTS: On average, 2000 ABG procedures are performed each year in the EDs of hospitals. In this study, 249 patients are expected to be included. With a projected positive response rate of 80%, we intend to include 25 (10%) patients per month. The inclusion period began in April 2023 and will run until July 2024. We hope to publish the results of the study during the fall of 2024. CONCLUSIONS: To the best of our knowledge, this study is the first RCT assessing the use of positive communication on pain and anxiety in patients undergoing the ABG procedure in the ED. A reduction in pain, discomfort, and anxiety is expected when using positive communication. If the results are positive, this could be useful to the medical community and encourage clinicians to monitor their communication during care. TRIAL REGISTRATION: ClinicalTrials.gov NCT05434169; https://clinicaltrials.gov/ct2/show/NCT05434169. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/42043.

Impact of Acquired Broad Spectrum ß-Lactamases on Susceptibility to Novel Combinations Made of ß-Lactams (Aztreonam, Cefepime, Meropenem, and Imipenem) and Novel ß-Lactamase Inhibitors in Escherichia coli and Pseudomonas aeruginosa.

The impact of broad-spectrum ß-lactamases on the susceptibility to novel ß-lactamase/ß-lactamase inhibitor combinations was evaluated both in Pseudomonas aeruginosa and Escherichia coli using isogenic backgrounds. Cefepime-zidebactam displayed low MICs, mainly due to the significant intrinsic antibacterial activity of zidebactam. Cefepime-taniborbactam showed excellent activity against recombinant E. coli strains, including metallo-ß-lactamase producers, whereas aztreonam-avibactam remained the best therapeutic option against class B ß-lactamase-producing P. aeruginosa.

In vitro activity of cefepime/zidebactam and cefepime/taniborbactam against aztreonam/avibactam-resistant NDM-like-producing Escherichia coli clinical isolates.

BACKGROUND: Aztreonam/avibactam is one of the last therapeutic options for treating infections caused by NDM-like-producing Enterobacterales. However, PBP3-modified and NDM-producing Escherichia coli strains that co-produce CMY-42 have been shown to be resistant to this drug combination. The aim of our study was to assess the in vitro activity of cefepime/taniborbactam and cefepime/zidebactam against such aztreonam/avibactam-resistant E. coli strains. METHODS: MIC values of aztreonam, aztreonam/avibactam, cefepime, cefepime/taniborbactam, cefepime/zidebactam and zidebactam alone were determined for 28 clinical aztreonam/avibactam-resistant E. coli isolates. Those isolates produced either NDM-5 (n = 24), NDM-4 (n = 2) or NDM-1 (n = 2), and they all co-produced CMY-42 (n = 28). They all harboured a four amino acid insertion in PBP-3 (Tyr-Arg-Ile-Asn or Tyr-Arg-Ile-Lys). RESULTS: All strains were resistant to aztreonam/avibactam and cefepime, as expected. The resistance rate to cefepime/taniborbactam was 100%, with MIC50 and MIC90 being at 16 mg/L and 64 mg/L, respectively. Conversely, all strains were susceptible to cefepime/zidebactam, with both MIC50 and MIC90 at 0.25 mg/L. Notably, all strains showed low MICs for zidebactam alone, with MIC50 and MIC90 at 0.5 mg/L and 1 mg/L. CONCLUSIONS: Our data highlighted the excellent in vitro performance of the newly developed ß-lactam/ß-lactamase inhibitor combination cefepime/zidebactam against aztreonam/avibactam-resistant E. coli strains, suggesting that this combination could be considered as an efficient therapeutic option in this context. Our study also highlights the cross-resistance between acquired resistance to aztreonam/avibactam and the cefepime/taniborbactam combination.

Limitation of life-sustaining therapies in critically ill patients with COVID-19: a descriptive epidemiological investigation from the COVID-ICU study.

BACKGROUND: Limitations of life-sustaining therapies (LST) practices are frequent and vary among intensive care units (ICUs). However, scarce data were available during the COVID-19 pandemic when ICUs were under intense pressure. We aimed to investigate the prevalence, cumulative incidence, timing, modalities, and factors associated with LST decisions in critically ill COVID-19 patients. METHODS: We did an ancillary analysis of the European multicentre COVID-ICU study, which collected data from 163 ICUs in France, Belgium and Switzerland. ICU load, a parameter reflecting stress on ICU capacities, was calculated at the patient level using daily ICU bed occupancy data from official country epidemiological reports. Mixed effects logistic regression was used to assess the association of variables with LST limitation decisions. RESULTS: Among 4671 severe COVID-19 patients admitted from February 25 to May 4, 2020, the prevalence of in-ICU LST limitations was 14.5%, with a nearly six-fold variability between centres. Overall 28-day cumulative incidence of LST limitations was 12.4%, which occurred at a median of 8 days (3-21). Median ICU load at the patient level was 126%. Age, clinical frailty scale score, and respiratory severity were associated with LST limitations, while ICU load was not. In-ICU death occurred in 74% and 95% of patients, respectively, after LST withholding and withdrawal, while median survival time was 3 days (1-11) after LST limitations. CONCLUSIONS: In this study, LST limitations frequently preceded death, with a major impact on time of death. In contrast to ICU load, older age, frailty, and the severity of respiratory failure during the first 24 h were the main factors associated with decisions of LST limitations.

Bleeding on oral anticoagulants: overview of reversal strategies.

Oral anticoagulants (antivitamin K, direct oral anticoagulants) are routinely prescribed for the prevention or treatment of thromboembolic events, and many patients are now on long-term anticoagulant therapy. However, this complicates the management of urgent surgical conditions or major bleeding. Various strategies have been developed to reverse the anticoagulant effect and this narrative review provides an overview of the wide range of therapies currently available.

Is the prognosis of non-hypertensive, COVID-19 patients treated with renin-angiotensin-aldosterone system inhibitors more uncertain?

Previous studies suggested that ongoing treatment with renin-angiotensin-aldosterone system (RAAS) inhibitor drugs may alter the course of SARS-CoV-2 infection and promote the development of more severe forms of the disease. The authors conducted a comparative, observational study to retrospectively analyze data collected from 394 patients admitted to ICU due to SARS-CoV-2 pneumonia. The primary aim of the study was to establish an association between the use of RAAS inhibitor drugs and mortality in the ICU. The secondary aims of the study were to establish an association between the use of RAAS inhibitor drugs and clinical severity at ICU admission, the need for tracheal intubation, total days of mechanical ventilation, and the ICU length of stay. The authors found no statistically significant difference in ICU mortality between patients on RAAS inhibitor drugs at admission and those who were not (31.3% versus 26.2% mortality, p-value 0.3). However, the group of patients taking RAAS inhibitor drugs appeared to be more critical at ICU admission, and this difference became statistically significant in the subgroup of non-hypertensive patients. ICU mortality in the subgroup of non-hypertensive patients treated with RAAS inhibitor drugs also tended to be higher. Overexpression of the angiotensin-converting enzyme 2 (ACE2) in human cells, induced by RAAS inhibitor drugs, promotes viral entry-replication of SARS-CoV-2 and alters the basal balance of the RAAS, which may explain the findings observed in the present study. These phenomena may be amplified in non-hypertensive patients treated with RAAS inhibitor therapy.