Should we, and how to, optimize cefiderocol administration during severe nosocomial pneumonia due to carbapenem-resistant Acinetobacter baumanii? A viewpoint.

INTRODUCTION: Acinetobacter baumannii is classified by the Center for Disease Control and Prevention (CDC) as an "urgent threat" due to its ability to acquire and develop resistance to multiple classes of antibiotics. As a result, it is one of the most concerning pathogens in healthcare settings, with increasing incidence of infections due to carbapenem-resistant Acinetobacter baumannii (CRAB) associated with high morbidity and mortality rates. Therefore, there are ongoing efforts to find novel treatment options, one of which is cefiderocol. We aim to review available evidence on cefiderocol use for severe nosocomial pneumonia due to carbapenem-resistant Acinetobacter baumannii METHODS: A comprehensive review was conducted from 2017 to 2023, covering articles from databases such as Pubmed, Scopus, and Embase, along with conference proceedings from ECCMID 2023. The primary focus was on severe nosocomial pneumonia due A. baumannii and cefiderocol. DISCUSSION: Cefiderocol, targeting periplasmic space Penicillin-Binding Proteins (PBPs) via siderophore transport pathways, exhibits promise against multi-drug resistant Gram-negative bacilli. Its effectiveness in treating CRAB pneumonia remains debated. The CREDIBLE trial reported higher mortality with cefiderocol compared to the best available treatment, while other cohort studies showed contrasting outcomes. Patient variations and pharmacokinetic factors may underlie these discrepancies. The recommended cefiderocol dosage regimen may fall short of desired pharmacokinetic targets, especially in critically ill patients and lung infections. Pulmonary factors hindering cefiderocol's entry into bacteria through iron transporters are overlooked in clinical breakpoints. Optimized dosing or combination regimens may enhance infection site exposure and outcomes. CONCLUSION: Further research is needed to determine the optimal cefiderocol dosage and administration (mono vs. dual therapy, continuous vs. intermittent infusion), in severe Acinetobacter baumannii nosocomial pneumonia.

Skin biopsy in adult patients with meningococcal purpura fulminans: a multicenter retrospective cohort study.

BACKGROUND: Neisseria meningitidis is the leading responsible bacterium of Purpura Fulminans (PF) accounting for two thirds of PF. Skin biopsy is a simple and minimally invasive exam allowing to perform skin culture and polymerase chain reaction (PCR) to detect Neisseria meningitidis. We aimed to assess the sensitivity of skin biopsy in adult patients with meningococcal PF. METHODS: A 17-year multicenter retrospective cohort study including adult patients admitted to the ICU for a meningococcal PF in whom a skin biopsy with conventional and/or meningococcal PCR was performed. RESULTS: Among 306 patients admitted for PF, 195 had a meningococcal PF (64%) with a skin biopsy being performed in 68 (35%) of them. Skin biopsy was performed in median 1 day after the initiation of antibiotic therapy. Standard culture of skin biopsy was performed in 61/68 (90%) patients and grew Neisseria meningitidis in 28 (46%) of them. Neisseria meningitidis PCR on skin biopsy was performed in 51/68 (75%) patients and was positive in 50 (98%) of them. Among these 50 positive meningococcal PCR, five were performed 3 days or more after initiation of antibiotic therapy. Finally, skin biopsy was considered as contributive in 60/68 (88%) patients. Identification of the meningococcal serogroup was obtained with skin biopsy in 48/68 (71%) patients. CONCLUSIONS: Skin biopsy with conventional culture and meningococcal PCR has a global sensitivity of 88% and should be systematically considered in case of suspected meningococcal PF even after the initiation of antimicrobial treatment.

Levosimendan in patients undergoing extracorporeal membrane oxygenation after cardiac surgery: an emulated target trial using observational data.

BACKGROUND: Retrospective cohorts have suggested that levosimendan may facilitate the weaning of veno-arterial extracorporeal membrane oxygenation (VA-ECMO). We therefore studied this clinical question by emulating a randomized trial with observational data. METHODS: All patients with refractory postcardiotomy cardiogenic shock and assisted with VA-ECMO, admitted to a surgical intensive care unit at La Pitié-Salpêtrière Hospital between 2016 and 2019, were eligible. To avoid immortal-time bias, we emulated a target trial sequentially comparing levosimendan administration versus no levosimendan administration in patients treated with VA-ECMO. The primary outcome was time to successful ECMO weaning. The secondary outcomes were 30-day and 1-year mortality. We performed a multivariable analysis to adjust for confounding at baseline. RESULTS: Two hundred and thirty-nine patients were included in the study allowing building a nested trials cohort of 1434 copies of patients. No association of levosimendan treatment and VA-ECMO weaning was found (HR = 0.91, [0.57; 1.45], p = 0.659 in multivariable analysis), or 30-day mortality (OR = 1.03, [0.52; 2.03], p = 0.940) and 1-year mortality (OR = 1.00, [0.53; 1.89], p = 0.999). CONCLUSIONS: Using the emulated target trial framework, this study did not find any association of levosimendan treatment and ECMO weaning success after postcardiotomy cardiogenic shock. However, the population of interest remains heterogeneous and subgroups might benefit from levosimendan.

Postoperative Bleeding After Laparoscopic Pancreaticoduodenectomy: the Achilles' Heel?

BACKGROUND: Laparoscopic pancreaticoduodenectomy (LPD) is technically demanding, and its impact on postoperative outcomes remains controversial. OBJECTIVE: To compare short-term outcomes between laparoscopic versus open pancreaticoduodenectomy (OPD) in order to assess the safety of LPD. METHODS: From 2002 to 2014, all consecutive patients undergoing LPD or OPD at two tertiary centers were retrospectively analyzed. Patients were matched for demographics, comorbidities, pathological diagnosis, and pancreatic texture. Results for the two groups were compared for postoperative outcomes. RESULTS: Sixty-five LPD were performed and compared to 290 OPD. In the whole population, postoperative pancreatic fistula (PF) was higher in the LPD group, but the proportion of ampullary adénocarcinoma (25 vs. 10%, p = 0.004) and soft pancreatic parenchyma (52 vs. 38%, p = 0.001) were higher in the LDP group. After matching (n = 65), LPD was associated with longer operative time (429 vs. 328 min, p < 0.001) and lower blood loss (370 vs. 515 mL, p = 0.047). The PF rate and its severity were similar (33 vs. 27%, p = 0.439, p = 0.083) in the two groups. However, both complications (78 vs. 71%, p = 0.030) and major complications (40 vs. 23%, p = 0.033) were more frequent in the LPD group. LPD patients experience more postoperative bleeding (21 vs. 14%, p = 0.025) compared to their open counterparts. In multivariate analysis, perioperative transfusion (OR = 5 IC 95% (1.5-16), p = 0.008), soft pancreas (OR = 2.5 IC 95% (1.4-4.6), p = 0.001), and ampullary adenocarcinoma (OR = 2.6 IC 95% (1.2-5.6), p = 0.015) were independent risks factors of major complications. CONCLUSION: Despite lower blood loss and lower intraoperative transfusion, LPD leads to higher rate of postoperative complications with postoperative bleeding in particular.

The metapopulation fitness criterion: proof and perspectives.

Metapopulation theory has recently been stirred by the development of a metapopulation persistence criterion (R(m)) quantifying the "lifetime dispersal success" of a newly colonized deme in a sparsely occupied metapopulation. No rigorous proof of this criterion in continuous time has been available so far. Here, we show that this criterion can be mathematically justified from standard Jacobian arguments. A summary of the key elements of this proof emphasizes the assumptions under which this criterion is valid. Examples illustrate how to generally compute metapopulation fitness in continuous time models. The underlying assumptions behind the criterion are discussed, as well as theoretical puzzles surrounding the concept of metapopulation fitness.