Mahmood, Maryam

ABSTRACT Background Valganciclovir is the preferred antiviral agent for cytomegalovirus (CMV) prophylaxis in solid organ transplant (SOT) recipients; however, limited data exist to guide optimal dosing in patients requiring intermittent hemodialysis (iHD). This study evaluated the safety and efficacy of our institution's current dosing strategy of valganciclovir 450 mg three times weekly. Methods In this single‐center, retrospective study, adult liver, heart, lung, and kidney transplant recipients from January 2014 to November 2024 were included. Patients requiring ≥ 3 iHD sessions posttransplant and receiving valganciclovir 450 mg three times weekly were compared with recipients with normal renal function receiving 900 mg once daily. The primary outcomes were the risk of neutropenia, leukopenia, and thrombocytopenia within 3.5 months posttransplant. Results A total of 116 patients were included in the iHD cohort and were matched 1:2 to 232 patients in the normal renal function cohort. Rates of leukopenia and neutropenia were comparable between cohorts. However, thrombocytopenia occurred significantly more frequently in the iHD cohort (45.2% vs. 26.7%; p = 0.002). No significant differences were observed in rates of CMV infection between groups. Conclusion Valganciclovir 450 mg three times weekly appears safe and effective for CMV prophylaxis in SOT recipients requiring iHD, though it may be associated with an increased risk of thrombocytopenia. image

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.

Abstract Background Plasma microbial cell-free DNA (mcfDNA) sequencing, commercially available from Karius® (Redwood City, CA), has been increasingly utilized in diagnosing endovascular infections. The 2023 updated Duke criteria incorporated detection of pathogen via metagenomic sequencing in its microbiologic criteria. We analyzed the clinical impact of mcfDNA sequencing in the diagnosis and treatment of suspected infective endocarditis (IE) cases. Methods We performed retrospective review of patients with suspected IE who underwent Karius® test at Mayo Clinic, MN, between 2017 to 2023. Results We preformed preliminary analysis of 25 patients. Analysis of baseline characteristics (table 1) revealed that these patients had significant predisposing factors for IE. Before accounting for mcfDNA sequencing, 3 (12%) met criteria for definite IE, 10 (40%) met criteria for possible IE, and 12 (48%) were rejected per 2023 Duke criteria. After incorporating mcfDNA sequencing result, 1 patient who was classified as possible IE was escalated to definite IE. This patient had previous infection of implantable cardioverter-defibrillator (ICD) with Streptococcus dysgalactiae. ICD was removed. She had development of endophthalmitis and stroke, 1 week and 2 weeks after the completion of IV antibiotics, respectively, with echocardiogram showing new tricuspid valve vegetation. Routine work-up was negative despite that she was not on any systemic antibiotics at the time of blood culture collection. mcfDNA sequencing detected Streptococcus dysgalactiae, making definite diagnosis of IE, leading to the physician’s decision to extend the IV antibiotic treatment (treatment escalation). Overall, after mcfDNA sequencing result, treatment decision was not impacted in 14 (56%), ongoing treatment was escalated in 4 (16%), de-escalated in 5 (20%), and antimicrobials was newly initiated in 2 (8%) (figure 1). Positive mcfDNA sequencing result often led to treatment escalation or initiation; negative result often led to treatment de-escalation (figure 2). Conclusion In challenging cases of suspected IE, mcfDNA sequencing led to alteration of antimicrobial treatment in 44% of cases. Further data collection and final analysis will include larger number of patients. Disclosures All Authors: No reported disclosures

Background. Identification and treatment of latent tuberculosis infection (LTBI) mitigate the risk of tuberculosis (TB) reactivation after transplantation. TB reactivation is higher in those with indeterminate QuantiFERON (QFT) than those with negative results. Management of indeterminate QFT results in the pretransplant period remains unclear. Methods. We conducted a retrospective study of solid organ transplant (SOT) recipients, 18 y and older, who were screened with QFT assay pretransplantation at Mayo Clinic between January 2010 and June 2023. We examined the frequency of indeterminate QFT results, results of repeat LTBI screening, treatment decisions, and rate of posttransplant TB infection. Results. Of 13 008 patients screened for LTBI before SOT, 736 (6%) patients had indeterminate QFT results. Among these, 247 (34%) underwent a second LTBI screening test, and 39 (5%) received LTBI treatment. Among 247 patients with a repeat LTBI screening test, 185 (75%), 48 (19%), and 14 (6%) were tested by QFT, T-SPOT.TB, or TST, respectively. The repeat QFT remained indeterminate in 160 (86%) patients, whereas all T-SPOT.TB results were negative. Posttransplant TB infection occurred in 2 (0.3%) patients; neither had a second TB screening test pretransplant nor received LTBI treatment. Conclusions. In SOT recipients with indeterminate QFT results at pretransplant evaluation, opting for T-SPOT.TB as a second test may be preferable over repeat QFT. TB infection after transplantation in patients with a pretransplant indeterminate QFT result was rare. Patient management and LTBI treatment in those with indeterminate QFT pretransplant should account for epidemiological risk factors, and shared decision-making is recommended.

Background. Solid organ transplant (SOT) candidates should be screened and treated for latent tuberculosis infection (LTBI) to prevent tuberculosis (TB) reactivation after transplantation. We aimed to assess the steps from positive QuantiFERON (QFT) through LTBI treatment (cascade of care) in the SOT population. Methods. We conducted a retrospective study of SOT recipients older than 18 y with a positive QFT during pretransplant evaluation at the Mayo Clinic from January 2010 to June 2023. We analyzed each cascade step to determine associated drop-out factors for LTBI management. Results. Of 629 patients who had positive QFT results, 587 (93%) were evaluated by an infectious disease (ID) specialist, 478 (76%) were recommended to start LTBI treatment, 473 (75%) initiated LTBI treatment, and 457 (73%) completed LTBI treatment. LTBI treatment was not recommended in 109 patients evaluated by infectious disease, most of whom had previously received either LTBI (n = 72) or TB (n = 14) treatment. LTBI treatment was initiated before or after transplantation for 45% and 55% of patients, respectively. Isoniazid monotherapy was the most common regimen (92%), and adverse events were rare (7%). Seven patients developed active TB infection posttransplantation under various circumstances (3 without LTBI treatment, 1 during LTBI treatment, and 3 after completing LTBI treatment). Conclusions. Our findings demonstrate the variability of LTBI management in SOT recipients with positive QFT. When recommended, most patients completed LTBI treatment successfully. Nonetheless, active TB was noted regardless of whether patients received LTBI treatment. This study highlights the importance of optimizing LTBI management in this population.

Abstract Background We compared long-term mortality and readmission rates after COVID-19 hospitalization based on rural-urban status and assessed the impact of COVID-19 vaccination introduction on clinical outcomes by rurality. Methods The study comprised adults hospitalized for COVID-19 at 17 hospitals in 4 US states between March 2020 and July 2022, followed until May 2023. The main analysis included all patients, whereas a sensitivity analysis focused on residents from 4 states containing 17 hospitals. Additional analyses compared the pre- and postvaccination periods. Results The main analysis involved 9325 COVID-19 hospitalized patients: 31% were from 187 rural counties in 31 states; 69% from 234 urban counties in 44 states; the mean age was 65 years (rural, 66 years; urban, 64 years); 3894 women (rural, 41%; urban, 42%); 8007 Whites (rural, 87%; urban, 83%); 1738 deaths (rural, 21%; urban, 17%); and 2729 readmissions (rural, 30%; urban, 29%). During a median follow-up of 602 days, rural residence was associated with a 22% higher all-cause mortality (log-rank, P < .001; hazard ratio, 1.22; 95% confidence interval, 1.10-1.34, P < .001), and a trend toward a higher readmission rate (log-rank, P = .038; hazard ratio, 1.06; 95% confidence interval, .98-1.15; P = .130). The results remained consistent in the sensitivity analysis and in both pre- and postvaccination time periods. Conclusions and Relevance Patients from rural counties experienced higher mortality and tended to be readmitted more frequently following COVID-19 hospitalization over the long term compared with those from urban counties, a difference that remained even after the introduction of COVID-19 vaccines.

Background. Surgical-site infections (SSIs) are common in liver transplant recipients. The optimal SSI antimicrobial prophylaxis agent and duration are not established. We aimed to explore risk factors for SSIs after transplant, with a particular interest in the impact of perioperative antibiotic regimen on the development of SSIs. Methods. Retrospective study of adults undergoing liver transplant across 3 transplant programs between January 1, 2020, and June 01, 2021. Results. Of 557 patients included in the study, 32 (5.7%) were infected or colonized with a multidrug-resistant organism (MDRO) within 1 y before liver transplant. Narrow-spectrum SSI prophylaxis with ceftriaxone or cefazolin alone was administered in 488 of 577 patients (87.6%); the remaining 69 patients (12.4%) received broad-spectrum prophylaxis with vancomycin and aztreonam (n = 40), piperacillin–tazobactam (n = 11), carbapenems (n = 8), ceftriaxone and another antibiotic (n = 7), and others. Patients with pretransplant MDRO were more likely to receive broad-spectrum coverage than those without pretransplant MDROs (28.1% versus 11.4%, P = 0.005). SSIs were identified in 40 patients (7.2%); 25 (62.5%) were organ–space infections, 3 (7.5%) were deep incisional infections, and 12 (30.0%) were superficial incisional infections. The median time from liver transplant to SSIs was 14 d (interquartile range, 10–20.2). MDROs were identified in 12 SSIs (30%). Multivariable analysis revealed no significant association between antimicrobial spectrum and risk of SSIs (P = 0.5), whereas surgical leak (P<0.001) and reoperation (P = 0.017) were independently associated with increased risk of SSIs. SSIs were not significantly associated with composite risk of death or liver allograft failure. Conclusions. The spectrum of antimicrobial prophylaxis did not impact the development of SSIs in liver transplant recipients.

Abstract Background Vancomycin resistant enterococcus (VRE) infective endocarditis (IE) is associated with poor outcomes. There are limited data to guide the antimicrobial choice and duration of therapy. Several in vitro and limited clinical studies demonstrate the synergistic effect of β-lactams with other agents, particularly daptomycin, in this setting. We sought to compare clinical outcomes in patients with VRE IE treated with adjunctive β-lactam therapy. Methods This was an IRB-approved, retrospective, single-center cohort study. The study included patients ≥18 years of age diagnosed with VRE IE via modified Duke criteria from 2011-2021. Data were collected by electronic medical record review. Descriptive statistics were obtained. The primary outcome was 90-day treatment failure compared between those receiving and not receiving adjunctive β-lactams. Treatment failure was defined as recurrence of bloodstream infection (BSI) or death within 90 days of diagnosis. Failure-free survival was analyzed by Kaplan-Meier curve with log-rank test. Results A total of 32 cases were identified. 12 received adjunctive β-lactams. Mean age was 67 years, and 71% were male. 13 (41%) had a prosthetic valve and 6 (19%) had a CIED (Table 1). A majority (78%) had E. faecium IE. Mean duration of bacteremia was 9 days (Table 2). About one-third had treatment failure with 7 deaths and 4 BSI recurrences. Adjunctive β-lactams included ampicillin (3), cefepime (1), ceftaroline (6) and ceftriaxone (2). There was no statistical difference in failure-free survival in patients treated with adjunctive β-lactam therapy (Figure 1). The results were similar when restricted only to those who received daptomycin with or without adjunctive β-lactam therapy.Table 1.Patient CharacteristicsTable 2.Disease characteristics Figure 1. Kaplan-Meier curve comparing failure-free survival between patients who were primary treated with adjunctive β-lactams versus non-adjunctive therapy. The p-value is calculated via the log-rank test. Conclusion VRE IE is associated with poor prognosis, including high rates of mortality and relapses. In our experience, adjunctive B-lactam use did not result in improved outcome. Limitations include small sample size, and heterogenous antibiotic use. More prospective randomized data are needed. Disclosures All Authors: No reported disclosures