Yetmar, Zachary A.

ABSTRACT Background Cytomegalovirus (CMV) infection remains one of the most prevalent and consequential post solid organ transplant (SOT) infections. Treatment is often challenging, especially when dealing with refractory and resistant CMV infections. Methods We performed a retrospective multicenter cohort study of SOT recipients with clinically significant CMV infection (csCMVi) during 2010–2016. The primary outcome was early refractory CMV infection and secondary outcomes were drug resistance, CMV recurrence, and mortality. Analysis was done with Kaplan‐Meier, univariable logistic regression analysis, and multivariable Cox regression. Results We included 145 SOT recipients with csCMVi, majority were liver transplant (49%). Most common induction was an anti‐IL‐2 antibody (43.9%). The majority ( n = 82; 56.5%) were CMV D+/R‐ mismatch and presented asymptomatic infection (50.3%). After the initial 3 weeks of antiviral therapy, 13 (8.9%) patients had probable refractory csCMVi; most of them (10 [76.9%]) were CMV D+/R‐ mismatch. Longer time after transplant had lower risk (OR 0.68; CI 0.48–0.95, p = 0.029) while lower absolute lymphocyte count (ALC) had a higher risk of early refractory csCMVi (OR 1.54; CI 1.01–2.44, p = 0.048). Drug‐resistant csCMVi occurred in 7 patients (4.8%); a high initial CMV DNA level was associated with resistant csCMVi (OR 2.00; CI 1.08–3.93, p = 0.031). 25 patients (17.2%) experienced recurrent csCMVi within 6 months. 30 patients (20.7%) died; refractory, resistant or recurrent CMV infections were not associated with mortality. Conclusion Refractory csCMVi is associated with a low ALC and an earlier onset after transplant. Resistant csCMVi is associated with high initial CMV DNA levels. Recurrence of csCMVi is common and potentially associated with low ALC at the end of antiviral treatment.

Abstract Patent foramen ovale (PFO) has a prevalence of approximately 25%. Its association with pyogenic brain abscess (PBA) is unclear. We reviewed adults with PBA and known PFO status from 1 January 2009 through 31 December 2021 at Mayo Clinic. High PFO prevalence (40.5%) was seen. PBA patients with PFO had distinct abscess characteristics but unchanged 1-year, all-cause mortality.

Abstract Background Cytomegalovirus (CMV) infection remains one of the most prevalent and important infections following solid organ transplant (SOT). Treatment is often challenging, especially when dealing with refractory and resistant CMV infections.Table 1:Univariable logistic regression analyses of associations with early refractory CMV infectionTable 2:Univariable logistic regression analyses of associations with resistant CMV infection Methods We performed a retrospective cohort study of SOT recipients with clinically significant CMV infection (csCMVi) at a tertiary transplant center in the US during 2010-2016. The primary outcome was early refractory CMV infection and secondary outcomes were drug resistance, CMV recurrence, and mortality. Kaplan-Meier estimation, univariable logistic regression analysis, and multivariable Cox regression were used for outcome analysis.Table 3:Multivariable Cox regression analysis of associations with recurrent CMV infection after primary treatment endedNote: Refractory CMV was not included in the model for recurrent CMV as no patients with refractory infection had recurrence. Results A total of 145 SOT recipients with csCMVi were included. Most patients were recipients of liver (49%), followed by kidney (22.1%), heart (6.9%), lung (5.5%), and pancreas (4.1%). Multiple organ transplants accounted for 12.4% of the cohort. Most common induction was an anti-IL-2 antibody (43.9%) followed by ATG (29.5%). 82 (56.5%) had CMV D+/R- mismatch. In total, 34 (23.4%) had CMV syndrome, 38 (26.2%) had tissue-invasive CMV disease, while the rest (50.3%) were asymptomatic. After the initial 3 weeks of antiviral therapy, 13 (8.9%) patients had probable refractory csCMVi; most of them (10 [76.9%]) were CMV D+/R- mismatch. Longer time after transplant had lower risk (OR 0.68; CI 0.48-0.95, p=0.029) while lower absolute lymphocyte count (ALC) was higher risk of early refractory csCMVi (OR 1.54; CI 1.01-2.44, p=0.048) (Table 1). Drug-resistant CMV occurred in 7 patients (4.8%); a high initial CMV DNA level was associated with resistant csCMVi (OR 2; CI 1.08-3.93, p=0.031) (Table 2). Of 144 patients with post-treatment follow-up, 25 (17.2%) experienced recurrent csCMVi within 6 months. Table 3 shows the associations with recurrence of csCMVi after initial treatment. 30 patients (20.7%) died during a median follow-up of 4 years, but refractory, resistant or recurrent CMV were not associated with mortality. Conclusion Refractory csCMVi is associated with low ALC and an earlier onset post-transplant. Resistant csCMVi is associated with high levels of initial CMV DNA. Recurrence of csCMVi is common and possibly associated with low ALC at the end of antiviral treatment. Disclosures All Authors: No reported disclosures

Abstract Background Despite effective therapy for methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia with anti-staphylococcal penicillins (ASP; e.g., oxacillin, nafcillin) or cefazolin, persistent bacteremia is associated with poorer clinical outcomes and increased complications. Emerging strategies, such as combination therapy with an ASP or cefazolin and ertapenem, have demonstrated the potential to accelerate microbiologic clearance in persistent MSSA bacteremia. However, despite its increasing utilization in clinical practice, data on the effectiveness of this combination regimen remains limited. We sought to describe the clinical characteristics and outcomes of patients with MSSA bacteremia receiving combination therapy. Methods We performed a single-center, retrospective study of adult patients with MSSA bacteremia who received ASP or cefazolin and ertapenem combination therapy from 2019-2023. Time to blood culture clearance, in-hospital mortality, and 90-day relapse were examined. Results A total of 57 patients were included: median age of 65 years [IQR 53-73] with 75.4% male. MSSA bacteremia complicated by infective endocarditis and cardiac implantable electronic device infection occurred in 35.1% and 12.3%, respectively. The median length-of-stay was 16 days [IQR 12-28], and 57.9% required ICU admission. Forty (70.2%) patients underwent source control interventions such as valve replacement, device extraction or surgical debridement. The median duration of bacteremia prior to combination therapy initiation was 4 days [IQR 3-6]. Blood culture clearance occurred in a median of 1 day. The median duration of combination therapy was 4 days [IQR 3-6]. In-hospital mortality was 15.8%. None of the patients surviving the hospitalization experienced relapsed bacteremia within 90 days. Conclusion This study supports growing evidence that combination therapy may offer benefits in managing persistent MSSA bacteremia, specifically with regards to time to blood culture clearance. Further investigation is warranted to determine optimal timing of combination therapy and if known benefits of combination therapy translate into superior clinical outcomes as compared to monotherapy. Disclosures All Authors: No reported disclosures

ABSTRACT Purpose The purpose of this study was to evaluate the incidence and risk factors for developing recurrent clinically significant cytomegalovirus infections (csCMVi) in heart transplant recipients. Methods We conducted a retrospective cohort study involving adult heart transplant recipients at three large transplant centers in the United States between January 2011 and March 2019. All patients with a history of csCMVi, defined as CMV disease or CMV infection requiring preemptive therapy, were followed from the date of treatment completion for the primary csCMVi episode. Outcomes of interest were recurrent csCMVi and all‐cause mortality. Results Among 98 heart transplant recipients with csCMVi, 22 (22.4%) episodes of recurrent csCMVi occurred. Median time‐to‐recurrent csCMVi was 31.5 (IQR 21.3–59.8) days following treatment completion. A preceding episode of CMV disease (versus infection) was associated with a lower risk of recurrent csCMVi (HR 0.29, 95% CI 0.08–0.98; p = 0.047). Patients with lymphopenia had higher rates of recurrent csCMVi without statistical significance (HR 2.13, 95% CI 0.88–5.13; p = 0.093). Seroconversion by the end‐of‐therapy among CMV D+/R− mismatched patients was associated with a reduced risk of csCMVi recurrence (HR 0.07, 95% CI 0.02–0.30; p < 0.001). Overall, 17 (17.3%) patients died during follow‐up, which was not significantly higher among those with recurrent csCMVi (HR 2.13, 95% CI 0.78–5.79; p = 0.141). Conclusions About one in five heart recipients with csCMVi developed post‐treatment recurrence. A preceding episode of CMV disease and seroconversion was protective against recurrence. Lymphopenia may be a practical biomarker to stratify recurrence risk. Overall, recurrent csCMVi was not significantly associated with mortality.

Abstract Background There is a lack of comprehensive, large cohort studies investigating the predictors for severity and hospitalization in human granulocytic anaplasmosis (HGA). Methods We conducted a retrospective cohort study including all cases of HGA identified by positive blood Anaplasma polymerase chain reaction (PCR) at the Mayo Clinic Laboratory, Rochester between 2011 and 2021. Multivariable logistic regression was performed to evaluate risk factors associated with hospitalization. Results A total of 465 cases were identified. Of those, 67% (n = 312) were managed in the outpatient setting. Hospitalized patients (n = 153, 33%) were more likely to be older (median age of 71 vs 61; P ≤ .001) and immunocompromised (17% vs 7%; P ≤ .001). The triad of leukopenia, thrombocytopenia, and transaminitis was observed in 24% of the cases, but was associated with risk of hospitalization (odds ratio [OR] 1.78, 95% confidence interval [CI]: 1.05–3.03; P ≤ .033). The presence of a coinfection did not impact mortality or hospitalization. Conclusions The risk factors for hospitalization in patients with HGA include altered mental status, higher absolute neutrophil count (ANC), advanced age, comorbidities, and immunosuppression. The classic hematological and biochemical profile may be absent in the majority of cases. Co-testing may be of higher benefit in select cases.

Abstract Background Infective endocarditis (IE) is a life-threatening infection often challenging to diagnose, particularly in culture-negative cases. Plasma microbial cell-free DNA (mcfDNA) sequencing has shown potential for detecting pathogens in IE. However, its clinical utility, diagnostic impact, and limitations remain debated. This study evaluates its use in diagnosing and managing IE in a tertiary care setting. Methods This single-center retrospective cohort study included adult patients (≥18 years) who underwent mcfDNA sequencing via the Karius test for suspected IE at Mayo Clinic Rochester between December 2019 and February 2024. Diagnostic classification followed the 2023 Duke–International Society of Cardiovascular Infectious Diseases criteria. Data on demographics, clinical features, routine microbiologic workup, and mcfDNA sequencing results were collected. Statistical analysis was conducted to evaluate diagnostic utility and treatment impact. Results Among 141 patients, 66 had a diagnosis of IE, with mcfDNA sequencing identifying pathogens in 60.6% of them, compared with 39.4% with routine workup. mcfDNA sequencing was the sole microbiologic test with positive results in 33.3% of patients, leading to antimicrobial adjustments in 50.0% of that group. Clinically insignificant mcfDNA sequence detection occurred in 28.6% of patients without a diagnosis of IE. Conclusions mcfDNA sequencing is a valuable adjunctive tool for diagnosing culture-negative IE and guiding antimicrobial therapy when clinical suspicion is high. However, its utility depends on appropriate clinical context, highlighting the need for careful test interpretation and further prospective studies to assess patient-centered outcomes and cost-effectiveness.