Citations

Abstract Rationale Legionella species can cause severe community-acquired pneumonia requiring targeted antimicrobial therapy. The impact of time to effective Legionella-directed therapy on mortality is not well defined. Objectives To evaluate the association between time to effective Legionella-directed therapy and mortality in hospitalized patients with community-acquired Legionella pneumonia and to determine whether differences in treatment timing contribute to the excess mortality observed among immunocompromised patients. Methods A retrospective multicenter cohort study of adults hospitalized with laboratory-confirmed community-acquired Legionella pneumonia (2019–2025) was performed. Time from presentation to effective therapy (macrolide, fluoroquinolone, or doxycycline) was recorded. The primary outcome was 90-day mortality. Multivariable logistic regression analysis was performed, adjusting for age, SOFA-2 score (first 6 hours), and immunocompromised status. Secondary analyses included a 24-hour landmark Cox model for 90-day survival and multivariable logistic regression for 30-day mortality. Results Among 310 patients (median age 66.9 years, 44.8% immunocompromised), 90-day mortality was 17.4%. Every 6-hour delay in effective therapy was independently associated with increased 90-day mortality (adjusted OR per 6 hours: 1.11; 95% CI, 1.06–1.17; P < 0.001). Delays >24 hours were associated with worse 90-day survival (adjusted HR, 2.72; 95% CI, 1.65–4.77; P < 0.001). Time to effective therapy was also independently associated with increased odds of 30 day mortality (adjusted OR per 6 hours: 1.06; 95% CI: 1.01-1.11, p = 0.024). Immunocompromised patients experienced longer delays (median, 7.1 versus 3.3 hours; P < 0.001) and higher unadjusted 90-day mortality (22.3% versus 13.5%; P = 0.041), but immunocompromised status was not independently associated with mortality after adjusting for severity and treatment timing. Conclusion Longer time to effective Legionella-directed therapy was independently associated with increased mortality in a graded fashion. Delays were more common among immunocompromised patients, partially accounting for excess mortality in this group, suggesting that timely pathogen-directed therapy may represent a clinically important and potentially modifiable contributor to risk.

OBJECTIVES: Pneumocystis jirovecii pneumonia (PCP) can cause severe hypoxemic respiratory failure in immunocompromised patients. Contemporary outcomes of venovenous extracorporeal membrane oxygenation (VV ECMO) support for PCP are poorly characterized, and existing reports are limited to small case series. DESIGN: Retrospective cohort study. SETTING: International registry study using the Extracorporeal Life Support Organization (ELSO) registry. PATIENTS/SUBJECTS: Adults with PCP-associated hypoxemic respiratory failure supported with VV ECMO between 2011 and 2024. INTERVENTIONS: VV ECMO. MEASUREMENTS AND MAIN RESULTS: A total of 209 patients with PCP-associated respiratory failure supported with VV ECMO were identified. The overall in-hospital mortality was 60.8%. Survivors were younger than nonsurvivors (median age 41.9 vs. 46.8 yr; p = 0.047). Duration of mechanical ventilation before VV ECMO was longer among nonsurvivors (median 4.7 vs. 1.6 d; p = 0.019). The proportion of patients with HIV infection was similar among survivors and nonsurvivors (19.5% vs. 22.1%; p = 0.73). Pre-ECMO vasopressor use, prone positioning, and renal replacement therapy were common and did not differ between groups. Clinical course was characterized by prolonged VV ECMO support (median 18.6 d) and frequent complications, including pneumothorax (21.1%), renal replacement therapy during VV ECMO (31.6%), intracranial hemorrhage or stroke (7.7%), and major pulmonary or gastrointestinal hemorrhage (16.8%). PCP accounted for a small proportion of VV ECMO runs reported to the ELSO registry throughout the study period at 0.36% of reported cases. No significant temporal trend in mortality was observed. CONCLUSIONS: PCP-associated respiratory failure supported with VV ECMO is associated with substantial mortality and prolonged VV ECMO support. These findings provide contemporary benchmarks that may inform VV ECMO candidacy discussions and expectations in this challenging patient population.

Abstract Introduction Combat casualty care requires standardized proficiency criteria to ensure readiness in austere environments, yet gaps persist in defining performance thresholds for critical trauma skills. The Combat Medical Skills Sustainment Consortium (CMSSC), a novel military-civilian collaboration, aimed to validate competency thresholds for 21 Department of Defense-identified trauma skills. Materials and Methods A prospective cohort study (2022-2025) enrolled 1,495 military and civilian personnel across five academic centers, stratified by experience (novice, intermediate, expert). Skills, including cricothyroidotomy, whole blood transfusion, and ultrasound-guided vascular access, were assessed using validated checklists in Role 2-congruent simulations. Statistical analysis compared checklist performance against participant experience with a priori checklist scores estimated at 40% (novices) and 90% (experts). Results Competency thresholds were established, ranging from 77% (mechanical ventilation) to 100% (handoff). Experts achieved 85%-98% proficiency across most skills, with novices at 34%-97%. A ceiling effect was observed for less complex skills consistent with the power law of practice. Conclusion The Combat Medical Skills Sustainment Consortium validated standardized assessment tools, with potential to address readiness gaps through military-civilian synergy. Findings support consortium-guided curriculum development and highlight the need for longitudinal skill decay studies. Impact This study sets a benchmark for trauma care skills assessment, facilitating rapid adoption across military and civilian settings.

Abstract Background Legionella pneumonia is an important cause of severe pneumonia, yet contemporary data describing its clinical phenotype, diagnostic patterns, and outcomes in the modern era are limited. Methods We conducted a retrospective multicenter cohort study of adults with laboratory-confirmed Legionella pneumonia across an integrated health system between January 2019 and September 2025. The primary outcome was 30-day mortality. Severe disease was defined as having a requirement for high-flow nasal cannula, noninvasive ventilation, mechanical ventilation, or extracorporeal membrane oxygenation (ECMO). Univariate and multivariable logistic regression were used to identify predictors of mortality and severe disease. Results There were 344 patients with laboratory-confirmed Legionella pneumonia during the study period. The median age was 66.6 years, and 45.1% were immunocompromised. Most patients required hospital admission (94.2%), with 36.1% admitted to the intensive care unit; 22.7% required mechanical ventilation and 1.5% ECMO. Thirty- and 90-day mortality were 11.9% and 16.6%, respectively. In multivariable analysis, cirrhosis (OR 10.2, 95% CI 2.15–48.3, P = .003), immunocompromised status (odds ratio [OR] 2.24, 95% CI 1.05–4.77, P = .036), age (OR 1.03, 95% CI 1.00–1.06, P = .031), and lymphopenia at presentation (OR 2.09, 95% CI 1.02–4.24, P = .043) were independently associated with increased 30-day mortality. Among patients who were polymerase chain reaction (PCR) or culture positive, urinary antigen testing was positive in only 25.6%. Conclusions Legionella pneumonia was associated with substantial short-term mortality. Cirrhosis, age, immunocompromised status, and lymphopenia at presentation emerged as independent predictors of 30-day mortality, underscoring the importance of host vulnerability in determining outcomes.

ABSTRACT Background Solid organ transplant (SOT) recipients are at risk for Pneumocystis jirovecii pneumonia (PCP), yet how their clinical phenotype and outcomes compare with other immunocompromised patients without HIV remains poorly defined. Methods We conducted a multicenter retrospective cohort study of adults with proven or probable PCP from 2017 to 2025, including 95 SOT recipients and 588 non‐SOT, non‐HIV immunocompromised patients. The primary outcome was 90‐day mortality, secondary outcomes included new renal failure requiring dialysis, and 30‐day mortality. Outcomes were analyzed using inverse probability weighting (IPW) with winsorization to adjust for baseline differences. Results In unadjusted analysis, SOT recipients had lower 90‐day mortality (hazard ratio [HR]: 0.62, 95% CI 0.39–0.97, p = 0.037). After IPW with winsorization of extreme weights, SOT status remained associated with lower 90‐day mortality (HR: 0.32, 95% CI 0.13–0.76, p = 0.009), and 30‐day mortality (HR: 0.35, 95% CI: 0.14–0.92, p = 0.034). SOT recipients had higher odds of renal failure requiring dialysis in unadjusted analysis (OR: 3.49, 95% CI 1.94–6.14, p < 0.001), which persisted after IPW adjustment (OR: 1.62, 95% CI: 1.04–2.51, p = 0.032). Conclusions Despite higher rates of renal failure requiring dialysis, SOT recipients with PCP experienced significantly improved short‐ and intermediate‐term survival compared with other non‐HIV immunocompromised patients, underscoring the need for further investigation into transplant‐associated contributors to PCP outcomes.

Pneumocystis jirovecii pneumonia (PCP) is a life-threatening opportunistic infection increasingly recognized among non-HIV immunocompromised patients. In severe cases progressing to acute respiratory distress syndrome, venovenous extracorporeal membrane oxygenation (VV-ECMO) may serve as a rescue therapy. We conducted a retrospective multicenter review of 10 adult patients with proven or probable PCP who received VV-ECMO between 2017 and 2024. Seven of 10 patients survived to discharge, including all three HIV-positive patients and 4 of 7 non-HIV immunocompromised patients. The mean Respiratory ECMO Survival Prediction Score was –1.5, corresponding to a predicted survival of 33–57%. Multiorgan dysfunction was common, including renal failure requiring dialysis in 6 of 10 patients, need for neuromuscular blockade in 8 of 10, and pulmonary vasodilator use in 8 of 10. Despite high acuity and prolonged ECMO support, outcomes were favorable. These findings suggest that VV-ECMO may be a viable salvage therapy for select patients with severe PCP, including those without HIV.

Abstract Background Pneumocystis jirovecii pneumonia (PCP) is increasingly seen in patients who are non-HIV immunocompromised hosts, yet modern risk factors and outcomes are poorly recognized and defined. Methods A retrospective review was conducted of adult patients who met criteria for proven or probable PCP from 2017 to 2024 across a large academic multicenter health system. The primary outcome was mortality among cohorts, defined by etiology of immunosuppression through univariate and age-adjusted logistic regression. Secondary analyses included trends in annual diagnoses and testing patterns. Results A total of 701 patients met criteria for inclusion, representing one of the largest clinically characterized cohorts of PCP to date. The median age was 65 years (IQR, 54–73) and 62% were male. The most common risk groups were hematologic malignancy (32.2%), solid tumor cancers receiving chemotherapy (22.4%), and autoimmune disease with immunosuppression (17.7%). Annual PCP diagnoses increased at a rate of 15.8% (95% CI, 8.9%–23.2%) in parallel with increased testing. Only 5.4% of patients were receiving prophylaxis at the time of diagnosis. Overall mortality was 20% (95% CI, 17%–23%) and highest in cirrhosis (adjusted odds ratio, 6.24; 95% CI, 2.84–13.69; P &lt; .001). Conclusions PCP in the current era affects a broad range of patients who are immunocompromised, with high associated mortality and low rates of prophylaxis. Patients with solid tumors and those with cirrhosis are at particularly high risk of mortality. These findings highlight the need to reassess and redefine PCP prophylaxis guidelines in specific populations and our understanding of who is at risk.

Abstract Hemophagocytic lymphohistiocytosis (HLH) is a rare but critical hyperinflammatory condition that affects around 1.5% of liver transplant patients, with mortality rates reaching up to 33%. This syndrome is characterized by intense, dysregulated activation of macrophages and T-cells, sparking a cytokine surge that leads to severe systemic inflammation and rapid organ failure. Prompt identification and early management are crucial to improve outcomes. Case Presentation: A 61-year-old man with Hepatitis C-induced end-stage liver disease (MELD score 20) underwent a deceased-donor liver transplant. Postoperative complications included atrial fibrillation, stress cardiomyopathy, and a right-sided pleural effusion treated with thoracentesis and extended course of antibiotics. Two weeks later, he presented with fever, hypotension, and nausea, prompting the initiation of IV Zosyn, Vancomycin and Posaconazole. Despite fluid resuscitation, he became hemodynamically unstable, necessitating ICU transfer for vasopressor support. While in the ICU, his condition worsened, with increased fever, tachycardia, anuria and hypoxic respiratory failure that required intubation and continuous renal replacement therapy. Marked hyperferritinemia (ferritin 62,000 µg/L) and hypofibrinogenemia (91 mg/dL) raised suspicion for HLH, with an H score of 244. Comprehensive infectious workup ruled out CMV, EBV, HSV, and other pathogens. Bone marrow biopsy confirmed hemophagocytosis (Figure 1), and flow cytometry ruled out malignant infiltration. Given the strong suspicion for HLH and no identifiable infectious trigger, he was initiated on Dexamethasone, Etoposide, and Ruxolitinib, which lowered ferritin levels and improved vasopressor requirements. However, mentation declined, and imaging revealed a right frontal subarachnoid hemorrhage, likely from disseminated intravascular coagulation, precluding surgical intervention. Despite transient improvement, he developed ventilator associated pneumonia secondary to Stenotrophomonas infections and vancomycin-sensitive Enterococcus bacteremia, leading to refractory hypoxemia. After family and multi-disciplinary team discussions, care was withdrawn. Discussion: HLH remains an exceedingly rare, rapidly fatal syndrome in liver transplant recipients, with only 11 cases documented. Early recognition of HLH can be challenging, as its features, such as fever, cytopenias, and organ dysfunction, overlap with common post-transplant complications, which can delay diagnosis. HLH can be differentiated into primary (genetic) and secondary (acquired) forms, with the latter more common among adults, often triggered by infection, malignancies and autoimmune disorders. Immunosuppressants may inadvertently modulate HLH risk by tempering macrophage and T-cell activation, yet, paradoxically, also predisposing patients to secondary triggers. Clinicians should maintain vigilance for HLH in post-transplant patients with unexplained systemic inflammation, as early intervention is critical, often with Etoposide based regimens to modulate hypercytokinemia, though prognosis remains guarded due to multiorgan failure.