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Background: Itraconazole is the preferred antifungal agent for mild to moderate histoplasmosis and step-down therapy following amphotericin B treatment. Although hydroxy-itraconazole, a major metabolite of itraconazole, displays antifungal activity comparable with that of the parent compound, its role in therapeutic drug monitoring targets for histoplasmosis remains uncertain. Methods: The objective was to compare clinical outcomes and adverse events using itraconazole parent-compound concentrations alone versus combined itraconazole and hydroxy-itraconazole concentrations in patients treated for histoplasmosis. This retrospective cohort study included adults with probable or proven histoplasmosis who received itraconazole and had at least 1 documented serum concentration. The primary outcome was clinical response across 3 groups: (1) parent (itraconazole parent-compound concentration >1.0 mcg/mL), (2) combined (parent-compound concentration <1.0 mcg/mL with combined itraconazole plus hydroxy-itraconazole >1.0 mcg/mL), and (3) subtherapeutic (failure to reach either threshold). Treatment response and adverse events were analyzed using the Fisher exact test. Results: Among 108 patients (parent, n = 40; combined, n = 40; subtherapeutic, n = 28), response rates differed across groups (parent (95%); combined (90%); subtherapeutic (67.9%); P = 0.006). There was no difference between the parent and combined groups. Adverse events did not differ, although drug discontinuation occurred more frequently in the subtherapeutic group (parent (5%); combined (20%); subtherapeutic (25%); P = 0.04). Conclusions: Patients who failed to achieve either an itraconazole concentration >1 mcg/mL or a combined itraconazole plus hydroxy-itraconazole concentration >1 mcg/mL had lower response rates. Similar outcomes among patients achieving the itraconazole target alone and those achieving the combined target suggest that hydroxy-itraconazole concentrations may contribute to therapeutic drug monitoring targets in histoplasmosis.

Itraconazole is the recommended first-line antifungal agent in blastomycosis treatment. However, pharmacokinetic limitations and adverse drug events may necessitate the use of alternative antifungal agents. The primary objective of the study was to retrospectively describe a cohort of patients with blastomycosis who received voriconazole (as partial or complete therapy), for complete or partial treatment, compared to those who received itraconazole alone. Secondary objectives included rationale for voriconazole selection, treatment response, mortality, and adverse drug events. This retrospective multicenter cohort study included adult patients with proven/probable blastomycosis who received itraconazole or voriconazole. Treatment response was evaluated at one year or end of therapy, whichever came first. Mortality outcomes were assessed within 7 days of the last documented azole dose. Propensity score weighting and subgroup analysis were utilized to control confounding variables between cohorts. A total of 119 patients receiving itraconazole and 25 receiving voriconazole as complete or partial treatment were included. Voriconazole was often selected for CNS involvement or after intolerance to alternative azoles. After propensity score weighting, no significant difference in complete or partial treatment response was observed. Rates of all-cause mortality and blastomycosis-related mortality were numerically higher in the voriconazole cohort. Adverse drug event rates were similar between cohorts; however, discontinuation due to adverse events was more common in the voriconazole cohort. Voriconazole was most utilized for the treatment of blastomycosis in cases with CNS involvement or intolerance to other azoles. A statistically significant difference in response rate was not identified between voriconazole-containing or itraconazole-treated patients; however, given limited sample sizes, further data is needed to assess the equivalency of these agents in the treatment of blastomycosis.

Abstract Background Outpatient antibiotic stewardship programs (ASP) are recommended by the CDC and Joint Commission. We analyzed the impact of annual, focused syndrome-specific ASP interventions on trends in long-duration antibiotic prescribing (LDAP). Methods This was a retrospective, observational, multicenter cohort study from November 2020 through June 2025. All ambulatory encounters generating systemic antibiotic prescriptions within the healthcare enterprise were screened. Hospitalizations, emergency department visits, and infectious diseases encounters were excluded. Encounters generating ≥1 systemic antibiotic with &gt;7 days duration were categorized as long-duration. Targeted departments (primary and urgent care) received direct intervention (eg, education, peer-comparison reporting, data tracking). LDAP was modeled over time by month and compared by diagnosis group (ASP-priority diagnoses vs nonpriority) and provider specialty department (ASP-targeted vs nontargeted) using linear regression models. Results Of 642 579 encounters included, 42.2% were long duration. LDAP in ASP-targeted departments dropped from 46.8% to 34.8% (difference −12 percentage points [pp]), whereas nontargeted departments dropped from 45.5% to 39.1% (difference −6.4 pp). The estimated annual LDAP decrease was 3.4 pp in targeted versus 2.4 pp in nontargeted departments (difference 1.0 pp, P = .009). Within targeted departments, significant LDAP decreases were seen both in priority and nonpriority diagnoses, whereas nontargeted departments showed no change in LDAP in priority diagnoses. In a sensitivity analysis of nonpriority diagnoses, ASP-targeted departments had a larger estimated annual decrease in LDAP versus nontargeted (difference 1.4 pp, P &lt; .001). Conclusions Annual syndrome-specific ASP interventions correlated with improvements in LDAP, including outside of priority syndromes in targeted departments. LDAP is a viable metric for evaluating ambulatory ASPs.

Abstract Background Chimeric antigen receptor T-cell therapy (CAR-T) has transformed care for relapsed or refractory B-cell malignancies. Cytokine-release syndrome (CRS) complicates most infusions, yet the ensuing infection risk is ill-defined.Table 1Profile of 230 patients undergoing with CRS following CAR-T therapyTable 2Cytokine Release Syndrome Severity, Management, and Early Outcomes by 90-Day Infection Status Methods CAR-T recipients who developed CRS at our institution from 1 Jan 2018 to 3 June 2024 were retrospectively reviewed. Variables were abstracted into REDCap. CRS was graded with American Society for Transplantation and Cellular Therapy (ASTCT) criteria. All infections occuring after CRS onset to day 90 were adjudicated. Continuous data are reported as medians with interquartile ranges (IQR); categorical data as counts and percentages. Table 2 comparisons used Mann-Whitney U for continuous and χ² or Fisher exact tests for categorical variables (two sided, P &lt; 0.05). Multivariable logistic regression was used to identify independent predictors of infection.Table 3Infectious Syndromes, Pathogens, and Timing of First Infection Following CRS Onset Results Among 230 CRS cases, median age was 64 yr (IQR 57–70) and 59% were male. Non-Hodgkin lymphoma accounted for 62% and multiple myeloma for 38%. Median prior therapy lines were 3. CRS was grade 1–2 in 97%. CAR-HEMATOTOX was low in 156 (68%) (Table 1). Within 90 days, 51 patients (22%) developed infection; median onset was 15 days (IQR 5–26). Infected patients more often received anakinra (22% vs 8%, p = 0.02) and required ICU care (18% vs 7%, p = 0.05); grade ≥3 CRS trended higher (10% vs 3%, p = 0.06). In multivariable analysis adjusting for age, CAR-HEMATOTOX, ICU admission, and anakinra, both ICU admission (aOR 2.06; 95% CI 0.70–5.81; p = 0.18) and anakinra use (aOR 2.18; 95% CI 0.83–5.53; p = 0.10) were associated with higher infection odds, though not statistically significant. 90-day survival was 88% with infection versus 96% without (p = 0.09) (Table 2). 51 infectious episodes were documented: bacteremia 22; gastrointestinal 9; central line–associated bloodstream infection 7; other sites 22. Bacteria caused 59%, viruses 37% (15 CMV, 4 SARS-CoV-2), and fungi 4%. No infection-related deaths occurred (Table 3). Conclusion Infection was common after CRS, but did not alter early survival. Anakinra exposure and ICU admission were associated with a higher likelihood of infection, though not statistically significant. Targeted surveillance should focus on patients requiring intensified CRS management. Disclosures Yi Lin, M.D., BMS: Board Member|Caribou: Advisor/Consultant|Genentech: Board Member|Jassen: Board Member|Jassen: Steering Committee|Kite/Gilead: Steering Committee|Legend: Board Member|NexImmune: Advisor/Consultant|NexT Therapeutics: Board Member|Pfizer: Board Member|Regeneron: Board Member|Sanofi: Board Member|Tessera: Board Member Paschalis Vergidis, MD, MSc, Current Fungal Infection Reports: Honoraria|F2G: Grant/Research Support|Merck Manuals: Honoraria|Mundipharma: Grant/Research Support|Scynexis: Advisor/Consultant|Scynexis: Grant/Research Support

Abstract Background Persistent candidemia (PC) occurs in a minority of Candida bloodstream infections (BSIs) but is associated with increased morbidity. Comparative data on patient profile, species distribution and outcomes are limited.Table 1Clinical profile and outcomes of patients with persistent candidemia in the primary study cohort. ANC = absolute neutrophil count. SD = standard deviation.Table 2Comparative analysis of persistent candidemia and non-persistent candidemia cases. Methods All candidemia episodes at three academic medical centers (2018-2025) were reviewed. Persistence was defined as ≥72 hours of positive blood cultures after appropriate antifungal initiation. Each PC case was matched 1:2 to non-PC controls who survived ≥72 hours. Demographics, Charlson Comorbidity Index (CCI), Candida species distribution, and outcomes were used for comparative analysis. Continuous variables were summarized as median (interquartile range [IQR]) and compared with Wilcoxon rank-sum, while categorical data (n%) were analyzed by Fisher’s exact test (species by χ²), yielding odds ratios (ORs) with 95% confidence intervals (CIs). Two-tailed p &lt; 0.05 denoted significance. Results Each PC case (n = 46) was matched 1:2 to non-PC controls (n = 92). Clinical profiles and outcomes of PC cases are presented in Table 1. Most PC patients (54.3%) had an immunocompromising condition, and non-urinary intra-abdominal sources were the most frequently suspected infection source (21/46; 45.7%). All but one of 46 PC cases had antibiotic exposure within the preceding 90 days. Comparative demographics and outcomes for PC cases and non-PC controls are displayed in Table 2. PC patients were younger (median 62 yr, IQR 45–69 vs 68 yr, 57–76; p = 0.01), more often female (59% vs 30%; OR 3.3, 95% CI 1.5–7.1; p = 0.002), and had higher comorbidity (CCI 5, IQR 3–8 vs 3, 1–4; p &lt; 0.001). Species distribution differed (χ² p = 0.04), driven by C. guilliermondii over-representation in PC cases (9% vs 0%) (Figures 1 and 2). Hospital stay was longer in PC cases (median 36 d, 24–54 vs 16 d, 8–28; p &lt; 0.001) and time from admission to first culture greater (12 d, 3–26 vs 3 d, 1–10; p = 0.003). 90-day mortality was 54.3% (25/46) in PC cases versus 31.5% (29/92) in controls (OR 2.57, 95% CI 1.17–5.71; p = 0.016). Conclusion In this 7-year multicenter study, there were significant differences in demographics, microbiology, and clinical outcomes between PC and non-PC cases, including higher short-term mortality rates with PC in univariate analysis. Disclosures Paschalis Vergidis, MD, MSc, Current Fungal Infection Reports: Honoraria|F2G: Grant/Research Support|Merck Manuals: Honoraria|Mundipharma: Grant/Research Support|Scynexis: Advisor/Consultant|Scynexis: Grant/Research Support

We report a case of a triazole and echinocandin-resistant C. glabrata right shoulder prosthetic joint infection in a 60-year-old woman. The patient underwent surgery and received the novel triterpenoid antifungal agent ibrexafungerp. She initially improved, but relapsed four months post-treatment. This case highlights the potential role of ibrexafungerp in multidrug-resistant Candida infections.

Abstract Infection is increasingly recognized as a significant cause of morbidity and mortality in patients with relapsed/refractory (R/R) large B-cell lymphoma (LBCL) receiving CD19 chimeric antigen receptor (CAR) T-cell therapy. The current study analyzed the natural history, risk factors, and outcomes of infection in 3350 patients with R/R LBCL receiving commercial CD19 CAR T-cell therapy (n = 2804 axicabtagene ciloleucel [axi-cel], n = 546 tisagenlecleucel) from December 2017 to June 2022. Infection developed in 834 patients (24.9%) within 100 days after infusion, resulting in an infection density of 0.43 per 100 patient days and a 100-day cumulative incidence of 22%. Bacterial, viral, and fungal infections were recorded in 527 (15.7%), 374 (11.2%), and 108 patients (3.2%), respectively, with corresponding infection densities of 0.23, 0.15, and 0.04 per 100 patient days. After a 24-month median follow-up, 1482 patients (44%) had died, with infection as the primary cause in 173 cases (12%). The 100-day infection-related mortality (IRM) was 1.6% (95% confidence interval, 1.2-2.0). Patients with a Karnofsky performance score of ≤80, infection history before CAR T-cell therapy, axi-cel therapy, severe cytokine release syndrome (grade ≥3), and severe immune effector cell–associated neurotoxicity syndrome (grade ≥3) had increased infection risk. Infections within 100 days were an independent risk factor for inferior overall survival beyond day 100 after CD19 CAR T-cell therapy. In conclusion, study results show a significant incidence of infection and IRM in patients with R/R LBCL treated with CD19 CAR T-cell therapy. Furthermore, results identify patients at a heightened risk of infection, offering insights to guide potential interventions aimed at mitigating infection and improving patient outcomes after CAR T-cell therapy.

e19008 Background: Cytokine release syndrome (CRS) is typically reversible in CAR-T therapy, while hyperinflammatory syndromes like macrophage activation-like syndrome (MAS-L) and high-grade immune effector cell-associated hemophagocytic syndrome (IEC-HS) are associated with significant morbidity and mortality. Early interventions are critical for improving outcomes. We aim to analyze clinical cytokine assays and cellular phenotypes early in hyperinflammatory syndromes to identify profiles for severe cases to inform management decisions. Methods: This study included 113 CAR-T patients (pt) (September 2019-March 2024) with cytokine profiles (CP) performed at the second tocilizumab dose or with suspected hyperinflammatory states (CP1), followed by assessments at 24 hours (CP24) and 48 hours (CP48). 52 pts consented to blood (PB) and bone marrow (BM) cell immune phenotyping at pre-treatment (pre-LD) and day 1 for PB. Results: Among the 113 pts, CRS pts (N=74), when compared to MAS-L(N=19) & IEC-HS (N=20) at CP1, had lower levels of TNF (median in pg/mL; 31, 62.9, 47.7) , IL-18 (794, 1353, 2011), and MCP-1 (689, 2722, 2485.5). While MAS-L and IEC-HS had similar CP1 profiles, CP24 and CP48 differed between them: TNF & MCP-1 levels decreased in MAS-L but remained elevated or increased in IEC-HS. IL-18 was stable in MAS-L but increased steadily daily in IEC-HS. Infections were more frequent in IEC-HS (CRS: 43%; MAS-L: 58%; IEC-HS: 85%; p=0.002). Notably, patients who died with persistent E. faecium bacteremia had higher IL-18 in CP48. In the 52 pts with cell phenotypes available by flow, 33 had CRS, 18 MAS-L and 8 IEC-HS. The correlation between cell phenotypes and cytokine levels showed that elevated TNF at CP1 correlated with increased non-classical monocytes in pre-LD BM and higher NK and NK-T cells in pre-LD PB. Similarly, elevated IL-18 CP48 levels correlated with increased CD8 T-cells, NK-T cells, and intermediate monocytes in pre-LD PB, as well as increased NK cells at both pre-LD and day 1 (Table). Conclusions: We report distinct cytokine profiles in IEC-HS early in the inflammatory course post-CAR-T therapy. These elevated cytokines correlate with specific immune cell subsets, including BM-resident monocytes, intermediate monocytes with heightened cytokine trafficking and inflammatory capacity. This study demonstrates the feasibility for identifying potential biomarkers for early risk stratification and targeted interventions. Cytokine Sample source Immune cells R P value TNF CP1 BM pre-LD Non-classical monocytes (CD14loCD16+) 0.38 0.025 PB pre-LD Monocytes (All) 0.47 0.022 NK cells (CD56+CD16+) 0.34 0.024 NK-T cells (CD3+CD56+CD16-) 0.29 0.04 IL-18 CP48 PB pre-LD CD8+ T-cells 0.59 0.0093 NK-T cells (CD3+CD56+CD16-) 0.53 0.023 Intermediate monocytes (CD14+CD16+) 0.58 0.012 PB pre-LD NK cells (CD56+CD16+) 0.56 0.49 0.015 0.024

ABSTRACT Pneumonia may be caused by a diverse group of microorganisms; however, a microbiologic diagnosis is not universally made. Molecular tests such as the BIOFIRE FILMARRAY Pneumonia Panel (BF-PP) offer the possibility of rapid identification of potential pneumonia pathogens. This retrospective analysis was conducted as a sub-study of a recently published randomized controlled trial. Specimens from patients with suspected pneumonia were tested by the BF-PP, with results compared to cultures. The overall BF-PP positivity rate was 44.8% (252/563), and was higher [64.6% (164/254)] in specimens from patients ultimately diagnosed with pneumonia. Discrepancies between the BF-PP and cultures were most common for Streptococcus pneumoniae , Haemophilus influenzae , Moraxella catarrhalis, and Streptococcus agalactiae . Positive percent agreement (PPA) and negative percent agreement (NPA) between the BF-PP and culture were 91.4% (CI 86.3%–94.9%) and 83.6% (CI 79.5%–87.2%), respectively. For most bacteria, a correlation between high genomic abundance (genomic copies/mL) reported from the BF-PP and culture growth abundance was found. In specimens from patients ultimately diagnosed with pneumonia, clinical consistency—assessed based on whether BF-PP results aligned with associated culture results—was 79.9% and was highest for bronchoalveolar lavage fluid specimens. The BF-PP has reliable analytical performance and offers the potential advantage over conventional cultures of providing higher detection rates and more rapid results. Interestingly, despite the use of this advanced molecular diagnostic tool, one-third of pneumonia cases remained without a microbiologic etiology. IMPORTANCE This study evaluates the BIOFIRE FILMARRAY Pneumonia Panel by comparing its performance to conventional cultures in a real-world patient population (including patients ultimately diagnosed as not having pneumonia) using different types of specimens. Findings show a higher detection rate of microorganisms with the panel compared to cultures, suggesting that this test could aid in tailoring treatments for pneumonia. However, challenges remain and require further study, including distinguishing true pathogens from colonizing microorganisms and determinig why one-third of patients diagnosed with pneumonia still lacked a microbiologic etiology.

Abstract Antifungal susceptibility testing among 1740 Candida parapsilosis blood isolates submitted to a United States reference laboratory (2015–2024) revealed a significant increase in fluconazole resistance from 8.2% to 20.3% (odds ratio [OR] per year, 1.13 [95% confidence interval {CI}, 1.06–1.20]; P &lt; .001), with notable acceleration since 2021. Voriconazole resistance remained stable over this period. Micafungin resistance was rare, but intermediate susceptibility significantly increased, especially after 2021 (OR per year, 1.42 [95% CI, 1.25–1.63]; P &lt; .001). These findings highlight important recent shifts in antifungal susceptibility among C parapsilosis isolates, emphasizing the need for ongoing surveillance and stewardship.