The benefit of tocilizumab on mortality and time to recovery in people with severe COVID pneumonia may depend on appropriate timing. The objective was to estimate the impact of tocilizumab administration on switching respiratory support states, mortality and time to recovery. In an observational study, a continuous-time Markov multi-state model was used to describe the sequence of respiratory support states including: no respiratory support (NRS), oxygen therapy (OT), non-invasive ventilation (NIV) or invasive mechanical ventilation (IMV), OT in recovery, NRS in recovery. Two hundred seventy-one consecutive adult patients were included in the analyses contributing to 695 transitions across states. The prevalence of patients in each respiratory support state was estimated with stack probability plots, comparing people treated with and without tocilizumab since the beginning of the OT state. A positive effect of tocilizumab on the probability of moving from the invasive and non-invasive mechanical NIV/IMV state to the OT in recovery state (HR = 2.6, 95% CI = 1.2–5.2) was observed. Furthermore, a reduced risk of death was observed in patients in NIV/IMV (HR = 0.3, 95% CI = 0.1–0.7) or in OT (HR = 0.1, 95% CI = 0.0–0.8) treated with tocilizumab. To conclude, we were able to show the positive impact of tocilizumab used in different disease stages depicted by respiratory support states. The use of the multi-state Markov model allowed to harmonize the heterogeneous mortality and recovery endpoints and summarize results with stack probability plots. This approach could inform randomized clinical trials regarding tocilizumab, support disease management and hospital decision making.

Background/Objectives: Multidrug-resistant (MDR) Pseudomonas aeruginosa pneumonia and bloodstream infections (BSI) remain challenging because of their severity, limited therapeutic options, and high mortality, despite the availability of novel β-lactam-based agents. We aimed to describe real-world treatment patterns, characteristics associated with treatment and infusion-strategy selection, and the association of these strategies with clinical outcomes in the retrospective, multicentre Italian SUSANA cohort, an observational study evaluating the use, safety, and outcomes of novel antibiotics in hospitalized patients. Methods: Adults with MDR P. aeruginosa pneumonia and/or BSI treated with novel antipseudomonal agents for ≥72 h were included. Treatment was classified as monotherapy or combination therapy, and infusion strategy as prolonged/continuous or standard. The primary outcome was 28-day all-cause mortality. A multivariable Cox regression analysis was performed. Results: Among 173 patients, pneumonia was the most frequent clinical presentation (74.0%). Monotherapy was used in 111 patients (64.2%), combination therapy in 62 (35.8%), and prolonged/continuous infusion in 120 (69.4%). Ceftolozane–tazobactam (CT) (64.7%) and ceftazidime–avibactam (CZA) (20.2%) were the most prescribed agents. Patients receiving prolonged/continuous infusion, regardless of monotherapy or combination therapy, had greater baseline clinical severity than those receiving standard infusion. Overall, 28-day mortality was 23.7%. In the multivariable analysis, neither combination therapy nor prolonged/continuous infusion was independently associated with reduced mortality, whereas septic shock (aHR 4.10, 95% CI 1.01–16.66) and ICU admission (aHR 2.53, 95% CI 1.06–6.08) increased mortality risk. Conclusions: In this multicentre real-world cohort, treatment strategies for MDR P. aeruginosa pneumonia and BSI appeared to be influenced by baseline severity and patient-related factors. Mortality was more strongly associated with markers of severe illness, including ICU admission and septic shock. No independent association with improved survival was observed for combination therapy compared with monotherapy or for prolonged/continuous compared with standard infusion. These findings highlight the prognostic role of baseline clinical severity and support the need for prospective, randomized, pharmacokinetic/pharmacodynamic (PK/PD)-guided studies to identify patients who may benefit from these strategies.

Sweet’s syndrome (SS) is a rare neutrophilic dermatosis often associated with hematologic malignancies. Due to its infectious mimicry, diagnosis is frequently delayed. We report a case of primary myelofibrosis initially treated for suspected cellulitis, which progressed to necrotic lesions and refractory fever despite broad‐spectrum antibiotics. A skin biopsy confirmed neutrophilic vasculitis consistent with SS. Prompt treatment with corticosteroids followed by ruxolitinib achieved rapid resolution by suppressing the underlying cytokine storm.

Background: Blood culture-negative endocarditis remains a major clinical challenge with potentially fatal consequences due to diagnostic difficulty and inadequacy of empirical antibiotic treatment. Case Summary: In late 2024, a 75-year-old man underwent aortic and mitral valve replacement with bioprostheses due to methicillin-resistant Staphylococcus epidermidis endocarditis. Six months after cardiac surgery, the patient was admitted to the hospital for suspected ischemic stroke, confirmed on brain computed tomography (CT), with fever and a slight increase in inflammatory biomarkers. Transesophageal echocardiography revealed degeneration of the prosthetic aortic valve, with leaflet thickening and a hyperechoic nodular lesion. CT imaging showed bilateral renal emboli and pleural effusion. Repeated blood cultures, serologic testing for Brucella, Bartonella , Legionella , Mycoplasma pneumoniae , and Coxiella burnetii , as well as screening for autoimmune disease, were negative. Two weeks later, the patient developed acute right iliac artery occlusion requiring urgent revascularization. Finally, repeated extended-incubation blood cultures and culture of the thrombus yielded Sarocladium kiliense , a rare opportunistic filamentous mold, supported by persistently positive serum β-D-glucan. Empirical therapy with liposomal amphotericin B was initiated. Following multidisciplinary discussion, the patient was deemed ineligible for surgery due to clinical deterioration and high operative risk. He was transitioned to palliative care and died shortly thereafter. Conclusion: To date, this represents the third case of endocarditis due to S. kiliense reported in the literature. When typical causes of endocarditis and differential diagnoses are excluded, fungal endocarditis should be ruled out with proper microbiological testing, even in immunocompetent patients.