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Extracorporeal membrane oxygenation (ECMO) provides life support for severe respiratory and cardiac failure, including failure from severe infection such as sepsis and acute respiratory distress syndrome. Additionally, ECMO-acquired infections are frequent and associated with prolonged hospitalization, increased healthcare utilization, and higher mortality. This review summarizes current evidence regarding the epidemiology, pathophysiology, diagnosis, prevention, and management of infectious adverse events during ECMO. Future work should aim to refine ECMO-related infectious adverse event definitions, improve harmonized multicenter data collection, and to invest in high-quality, well-designed studies.

Abstract Alternaria spp. are dematiaceous ascomycetes that can cause opportunistic infections in immunocompromised hosts. They are challenging to identify and treat. However, optimal antifungal therapy remains undefined. We retrospectively reviewed antifungal susceptibilities (AST) of all Alternaria spp. isolates from adults at a tertiary care center between 2011 and 2025. We evaluated culture sources, minimum inhibitory concentration (MIC) and minimal effective concentration (MEC) distributions, and MIC₅₀/MIC₉₀ and MEC50/MEC90 values. Clinical characteristics, treatment measures, and outcomes of patients with clinically significant Alternaria spp. infections were described. Forty-one patients had Alternaria spp. isolated, most commonly from skin (n = 13), bone/joint (n = 5), nail (n = 3), or cornea (n = 3). Posaconazole and itraconazole demonstrated low MICs (MIC₅₀/MIC₉₀: 0.06/0.5 and 0.25/0.5 µg/mL, respectively). Voriconazole and isavuconazole showed higher MIC₅₀/MIC₉₀ (1/2 and 2/4 µg/mL). Caspofungin (0.125/0.5 µg/mL) and amphotericin B (0.25/1 µg/mL) had low MICs and MECs.s. Alternaria spp. represented clinically significant infection in 27 cases (66%); 26% were solid organ transplant recipients and 15% had hematologic malignancies. Other risk factors included preceding trauma (22%) and autoimmune disease (15%). Posaconazole was the most frequently used empiric agent (6, 32%). Following AST results, 14 patients (52%) received oral antifungal therapy; posaconazole was used in all 14. In addition, 7 patients (26%) received combination therapy with IV amphotericin B. Adjunctive surgery occurred in 14 cases (52%). Five patients (19%) died before completing therapy; Alternaria infections occurred predominantly in immunocompromised hosts and were frequently managed with posaconazole and surgery. Interpretive criteria for Alternaria spp. are needed to guide empiric and definitive therapy.

In this retrospective cohort study at a quaternary referral hospital, 829 adult patients supported by extracorporeal membrane oxygenation (ECMO) between January 1, 2014, and October 31, 2024, were screened for ventilator-associated pneumonia (VAP). The incidence of VAP in ECMO-supported patients was 17.7 per 1,000 ECMO days (venoarterial [VA] ECMO, 22.1 per 1,000 ECMO days; venovenous [VV] ECMO, 13.8 per 1,000 ECMO days). Median time from ECMO cannulation to diagnosis of VAP was 4 (interquartile range [IQR], 3–8; range 1–84) days. Gram-negative bacteria comprised most respiratory pathogens. A significant increase in minimum ECMO sweep was noted from 2 days before to 1 day after VAP diagnosis (0.79 L/min increase, p = 0.004). Only 38 of 153 patients (24.8%) met National Healthcare Safety Network (NHSN) VAP definitions. After creating a modified VAP definition, which included an ECMO sweep increase of 0.5 L/min as evidence of worsening respiratory status, 78 (51.0%) met the modified definition. Those who met the modified VAP definition had worse in-hospital (60.3% vs. 28.0%, p < 0.001), 30 day (33.3% vs. 17.3%, p = 0.023), and 90 day (53.8% vs. 25.3%, p < 0.001) mortality compared with those who did not meet the modified VAP definition. The incorporation of ECMO parameters into diagnostic criteria may improve detection sensitivity, but further validation is necessary before implementation.

Background Chlorhexidine is commonly used in prevention bundles for ventilator-associated pneumonia. Results for use of chlorhexidine in critically ill patients requiring mechanical ventilation via an endotracheal tube are mixed, and data for patients using a tracheostomy are lacking. Objectives To assess the risk for ventilator-associated pneumonia according to chlorhexidine exposure in patients requiring a new tracheostomy for mechanical ventilation. Methods This single-center, retrospective cohort study compared the development of ventilator-associated pneumonia according to chlorhexidine exposure in adult intensive care unit patients requiring new tracheostomy at a large academic medical center. Adults who received a new tracheostomy and required ventilator support for at least 48 hours were included. Patients treated for pneumonia at the time of tracheostomy or who met additional exclusion criteria were excluded. Results Of 235 patients who met the inclusion criteria, 203 received chlorhexidine and 32 did not. The cohort was predominantly White, male, and admitted to a surgical intensive care unit. Incidence of ventilator-associated pneumonia did not differ significantly between patients exposed or not to chlorhexidine (by 30 days, 32.5% vs 35.7%, P = .87). Time to development of ventilator-associated pneumonia also did not differ significantly between patients exposed or not (9 vs 12 days, respectively, P = .34). Conclusions Chlorhexidine exposure was not associated with a difference in the incidence of or time to ventilator-associated pneumonia after new tracheostomy. Further study is needed on the role of chlorhexidine in preventing ventilator-associated pneumonia after a new tracheostomy.

Background: Candidemia is a serious complication after gastrointestinal (GI) perforation and/or ischemia, yet most evidence pools candidemia with intra-abdominal candidiasis (IAC). We sought candidemia-specific risk factors after GI perforation and/or ischemia and evaluated associated outcomes. Methods: We conducted a single-center, retrospective matched case–control study of adults undergoing emergency surgical procedure for GI perforation and/or ischemia and admitted to a surgical intensive care unit. Cases with candidemia during index admission were matched 4:1 to controls by age, Charlson Comorbidity Index, and surgical procedure year. Conditional logistic regression assessed pre-specified risk factors, and exploratory outcomes included mortality, length of stay, and days on invasive ventilation. Results: Twenty-four cases were matched to 99 controls. Factors identified to be independently associated with candidemia include the presence of IAC (adjusted OR [aOR]: 5.51, 95% CI: 1.61, 18.89; p = 0.007), upper GI injury (aOR: 4.28, 95% CI: 1.52–12.08; p = 0.006), and diffuse intra-abdominal contamination, compared with contained/none (aOR: 3.21, 95% CI: 1.06–9.74; p = 0.040). Among candidemia cases, species distribution was Candida albicans 41.7%, C. glabrata 33.3%, C. parapsilosis 12.5%, with single cases of C. tropicalis, C. krusei , and C. dubliniensis . Candidemia was associated with a longer hospital length of stay (+13.97 d; 95% CI: 0.90–27.04; p = 0.036), without significant differences in ICU stay, duration of invasive ventilation, or mortality. Conclusions: After GI perforation and/or ischemia, the risk of candidemia is highest in patients with upper GI injury and diffuse contamination, independent of IAC. These readily identifiable operative features may guide targeted surveillance and selective early antifungal strategies. Prospective validation is warranted.

Abstract Healthcare personnel (HCP) are at risk for occupational exposure to tuberculosis. Current guidelines for managing exposed HCP are broad and resource intensive. Based on review of our internal data, we propose a risk-based stratification approach to streamline exposure follow-up testing and optimize resource utilization.

Abstract Background Candidemia can occur as a consequence of gastrointestinal (GI) injury. The mortality of candidemia is high, ranging 30-60%, even with treatment with antifungal agents. In this retrospective matched case-control study, we aimed to elucidate the medical and surgical risk factors of developing candidemia in patients who received emergency surgery for GI ischemia and/or perforation, and compare clinical outcomes in these patients with or without candidemia. Methods All patients ≥ 18 years of age who had emergency GI surgery at Mayo Clinic Rochester, MN, for the indication of GI ischemia and/or perforation between 01/01/2018 to 07/31/2024 were included. Cases were defined as patients who developed candidemia during index admission and had no alternative sources of candidemia. Controls and cases were matched 4:1 on age (± 5 years), Charlson Comorbidity Index (± 3), and year of surgery (± 2 years). The relationships between risk factors of interest and case/control were assessed using conditional logistic regression. Results Among medical risk factors, any shock requiring vasopressor (OR = 3.44, 95% CI 1.00, 11.97) or respiratory failure (OR = 8.20, 95% CI 1.04, 64.53) during hospitalization were associated with increased risk of candidemia. Among surgical risk factors, perforation in the upper GI tract was strongly associated with development of candidemia (OR = 16.99, 95% CI 2.11, 136.95) and perforation in the lower GI tract were less likely to lead to candidemia (OR = 0.06, 95% CI 0.01, 0.44). The patients who had diffuse intraabdominal contamination were more likely to develop candidemia compared to those who had no contamination or contained contamination (OR = 3.87, 95% CI 1.33, 11.25). The patients with candidemia showed signal towards higher in-hospital and 30-day mortality, and had significantly longer stay in the hospital. Conclusion Candidemia was more frequently identified in patients with shock, respiratory failure, upper GI perforation, and intra-abdominal contamination, and contributed to significant morbidity and mortality. Further analysis will include building a multivariate logistic regression model to implement prospective trial for early initiation of antifungal therapy for high-risk population. Disclosures All Authors: No reported disclosures

Abstract Background In 2019, the US performed 290,000 breast reconstructions with an estimated infection rate of 3-35%. Tissue expander infections detract from desired aesthetic effects, delay adjuvant treatments, increase morbidity and mortality, and have high recurrence rates (20-40%). Little is known about risk factors for recurrent tissue expander infections, particularly the impacts of different treatment modalities. Methods We conducted a single-center retrospective cohort study of adult women post-mastectomy who developed microbiologically-proven tissue expander infection between the period of 2017 – 2024. Outcomes including 12-month infection recurrence and risk factors for recurrence were compared between surgical versus nonoperative groups, as well as between three surgical strategies (i.e., one-stage, two-stage, explantation). Unadjusted and adjusted logistic regression models were used to assess the associations between the treatment modalities and the outcomes. Univariate models assessed the relationship between the covariates of interest and infection recurrence. Results 107 patients were included, with the majority treated with combination of antibiotics and surgical therapy (Table 1). There was no significant difference in outcomes when the operative versus antibiotics alone cohorts were compared (Table 2). The odds of infection recurrence and rehospitalization in patients who underwent two-staged exchange or explantation were significantly lower when compared with the one-staged group (Table 3). Univariate modeling found severity and radiation therapy to be numerically more common in the group experiencing recurrence, with a trend towards statistical significance (Table 4). Conclusion Our study demonstrates reduced risk of recurrent tissue expander infection with two-staged exchange or explantation, compared to one-staged exchange. Though limited by small sample size, the strengths of our study include our presentation of the real-world variability of these syndromes and their management, adjustment for infection severity and other potential confounders; and the focus on microbiologically-defined infections. Disclosures All Authors: No reported disclosures

Abstract Background Hematopoietic cell transplantation (HCT) is associated with a net state of immunosuppression to enable graft acceptance and mitigate graft-versus-host disease risk1. Most of these patients require multiple prophylactic antimicrobials to prevent opportunistic infections during the post-transplant course2, including central nervous system (CNS) infections3. Brain abscesses are a form of CNS infection with a high incidence of morbidity and mortality4 Methods We conducted a retrospective cohort study of adults diagnosed with brain abscess following HCT between January 2009 and December 2024, including patients from all Mayo Clinic sites (Arizona, Florida, and Minnesota). The study was approved by our institutional review board with a protocol number 24-011428. The data was extracted from the electronic medical records into a secure database in REDCap. Statistical analyses were conducted using R version 4.4.1 (R Foundation for Statistical Computing). Results We identified 22 patients with brain abscess diagnosis following HCT. 50% of patients had leukemia. 81.8% of them received prior chemotherapy. 16 patients had prior allogeneic HCT, and 54.5% received a myeloablative conditioning regimen (table 1). 21 patients had neuroimaging available. More than one cerebral lobe was involved in 42.9% of the cases. 14 patients had extra-axial infection, the lung being the most frequently affected organ. Nocardia accounted for 40.9% of the brain abscesses (table 2). 45.5% underwent surgical intervention, and most of our patients were treated with a combination of intravenous and oral antimicrobials, many of them followed by long-term suppression. 54.5% of the brain abscesses resolved, with a median time to resolution of 156 days. All-cause mortality was 59.1%, with a median time to death of 540 days after brain abscess diagnosis (table 3). Conclusion Although rare, brain abscess is a devastating complication of HCT, with high morbidity and mortality. The most common pathogen encountered was Nocardia species. The required treatment is usually extensive, and these patients often need long-term suppression. Further investigation is required to determine risk factors for specific pathogen infection, non-resolution, and mortality. Disclosures All Authors: No reported disclosures