DeSimone, Daniel C

Abstract Background Cardiac valve tissue obtained during the surgical management of infective endocarditis (IE) and sent for culture may influence postoperative antibiotic therapy. We sought to identify clinical and microbiologic risk factors associated with positive valve cultures (PVC) and IE relapses in a cohort of patients undergoing surgical management. Methods This is a retrospective, multi-center study of patients with surgical management during the acute (<42 days) course of IE-directed antibiotic therapy. The rate of PVC, IE relapse, and mortality were collected. Univariate and multivariable logistic regressions were performed to identify risk factors associated with PVC. Results Of 113 patients included, 36 (31.9%) had PVC. Univariate and multivariable analyses showed preoperative antibiotic duration and pathogens were associated with PVC. Median (IQR) days of preoperative antibiotics were 6.5 (4.0-11.0) for patients with PVC compared to 13.0 (8.0-21.0) for those with negative valve cultures (NVC). In a multivariable model, preoperative antibiotic administration decreased the risk of PVC (OR 0.85 per day, CI 0.77-0.91). Enterococcal IE increased the risk of PVC compared to streptococcal IE (OR 4.16, CI 1.07-17.48). Of note, 33 (63.2%) patients with NVC received a median (IQR) of 8 (5, 18.5) days of intravenous antibiotics per patient. Only one IE relapse was identified and occurred in a patient with NVC. Conclusions Both preoperative antibiotic duration and causative pathogen were associated with PVC. IE relapses were rare and unrelated to PVC. There may be an opportunity to shorten postoperative antibiotic durations following surgical management in patients with IE.

Abstract Background Knowing the prevalence of patent foramen ovale (PFO) and the increasing number of people who inject drugs (PWID) with right-sided infective endocarditis (RSIE), we aimed to better characterize the syndrome of injection drug use, RSIE, and PFO with systemic embolic events. Method A systematic search across multiple databases was independently screened using predefined criteria (from inception until September 2025). Published cases of adult PWID diagnosed with RSIE and ischemic stroke or other systemic embolic event were included, provided they had PFO assessment. Individuals were excluded if they had cardiac implantable electronic device (CIED) infections or any other conditions associated with systemic or paradoxical embolism. Results The review identified 13 studies with 14 young patients, mostly without comorbidities, predominantly infected with Staphylococcus aureus. In most cases, echocardiography revealed large tricuspid valve vegetations. Neuroimaging confirmed multiple ischemic infarcts, while 5 patients showed emboli outside the central nervous system (4 of them as the only systemic embolism). At least 11 (79%) patients had echocardiographic evidence of right-to-left shunting. Management included cardiac surgery in 6 cases that involved valve replacement or repair, percutaneous PFO closure in 2 cases, and percutaneous mechanical aspiration in 1 case. Three patients (21%) died during hospitalization, and only 27.3% patients had outpatient follow-up. Conclusions RSIE with systemic embolism in PWID with PFO has rarely been reported, affects younger patients without sex predominance, and was usually due to S. aureus with large tricuspid vegetations. Right-to-left shunting was characteristic, and outcomes were poor despite combined medical, surgical, and interventional therapies.

Abstract The practice patterns of fluorine 18–labeled fluorodeoxyglucose positron emission tomography/computed tomography ([18F] FDG PET/CT) use in cardiac implantable electronic device infection remain undefined. Among 258 Emerging Infections Network respondents, 69% reported never or rarely using [18F] FDG PET/CT. Limited access and insurance barriers were the most common obstacles.

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 Recent clinical trial evidence supports broader use of partial oral therapy (POT) for infective endocarditis (IE), yet real-world uptake in the U.S. has not been investigated. Methods Adult infectious diseases (ID) physician members of the Infectious Diseases Society of America Emerging Infections Network were surveyed in April–May 2025. A 10-item instrument captured frequency of POT, organism-specific influence, decision factors, barriers, and facilitators. Results Among 1531 members, 516 (34%) responded; 452 (88%) of them managed IE. POT was uncommon: 16% never used, 53% used in ≤10% of cases, and only 10% used in >25% of patients. Frequent POT rose with caseload (23% in physicians treating >50 IE cases year vs ≤9% in lower-volume groups, P < .001) and with fewer years in clinical practice (13% in <5 yrs vs 5% in ≥25 yrs, P = .013). Comfort with POT depended on the pathogen: 66% were comfortable switching for Streptococcus spp., 52% for Gram-negative bacilli, 19% for methicillin-resistant Staphylococcus aureus. Three quarters of those who used POT finished with a single agent. In people who inject drugs, 34% of physicians often or always considered an oral regimen. Availability of an active oral agent (75%) and the pathogen involved (69%) were the leading decision drivers; principal barriers were fear of relapse (72%), adherence concerns (53%), and insufficient evidence (48%). Respondents most desired clearer guidelines (75%) and additional data (71%). Conclusions U.S. adult ID physicians adopt POT for IE sparingly. Updated IE treatment guidelines, additional clinical trial data, and broader access to complex outpatient antimicrobial therapy services may facilitate wider adoption.

Abstract Background The incidence, epidemiology, and clinical characteristics of enterococcal bloodstream infection (BSI) have not previously been studied on a population-based level in the United States. Methods We utilized the Expanded Rochester Epidemiology Project medical records linkage system to conduct a contemporary 5-year, retrospective, population-based study of monomicrobial enterococcal (ME) BSI among adult residents of 8 counties in southeast Minnesota from January 1, 2018 to December 31, 2022. Results A total of 109 cases of ME-BSI were identified. The overall age- and sex-adjusted incidence rate was 6.7 per 100 000 person-years (95% confidence interval, 5.4–7.9). Multivariable analysis revealed that male sex (P < .001) and older age (P < .001) were each independently associated with increased incidence, whereas no temporal association was demonstrated (year effect, P = .475). The median age of incident cases was 76.8 years (interquartile range, 65.0–83.3). Urinary tract source was the most common presumed source (42.2%), and Enterococcus faecalis was the predominant (83.5%) pathogen. Overall, 14.4% of patients met modified Duke criteria for definite infective endocarditis. Cumulative mortality was 28.4% at 12 weeks and 43.1% at 1 year. Conclusions In this population-based study, ME-BSI was significantly associated with older age and male sex. There was a high rate of mortality at 12 weeks and 1 year, with ∼1 out of 7 cases complicated by definite infective endocarditis. These findings underscore the importance of ongoing investigation of this syndrome.

Background: The relationship between vegetation characteristics in Staphylococcus aureus infective endocarditis (IE) and blood culture time to positivity (TTP) has not been investigated. This study evaluates the correlation between vegetation length and TTP in patients with S. aureus IE. Methods: A retrospective cohort study was conducted that included 164 definite cases S. aureus IE. Vegetation length was determined by transesophageal echocardiography (TEE), and TTP was measured in hours from the initial time of blood culture incubation to positivity. Correlations between vegetation characteristics and TTP were analyzed using Spearman’s rank correlation coefficient. Results: A modest but statistically significant negative correlation was observed between vegetation length and TTP (Spearman ρ = −0.18, p = 0.020), suggesting that larger vegetations were associated with shorter TTP. No significant correlations were found for other vegetation characteristics (e.g., vegetation mobility, location, or number) and TTP. Conclusions: Larger vegetation size in S. aureus IE was associated with shorter TTP. These findings highlight the importance of vegetation size in the pathophysiology of S. aureus IE and its role in bacteremia dynamics.

Abstract Background There remains a lack of consensus regarding the postoperative treatment regimen in patients with native valve Staphylococcus aureus infective endocarditis who undergo surgical valve replacement or repair. Methods We conducted a multicenter retrospective review of patients with S aureus native valve endocarditis who underwent surgical valve replacement or repair at Mayo Clinic Enterprise (Minnesota, Florida, Arizona, and Mayo Clinic Health Systems) between 1 January 2012 and 31 December 2022. Postoperative treatment regimens were classified as either monotherapy with a methicillin-sensitive or methicillin-resistant S aureus active agent or combination therapy that included rifampin and/or gentamicin with either active agent. Results Of the 339 patients diagnosed with S aureus native valve endocarditis, 61 underwent surgical valve replacement or repair within the initial 6 weeks of antimicrobial therapy. A total of 12 (20.2%) patients died during the 1-year follow-up period. Between patients postoperatively treated with monotherapy (n = 33) and combination therapy (n = 28), a propensity score–weighted analysis revealed that combination therapy was associated with increased risk of 1-year mortality (P = .039), 6-month relapse (P = .016), and treatment-related adverse events (P < .001). Conclusions Among patients treated for native valve infective endocarditis caused by S aureus after valvular surgical intervention, all study outcomes—adverse events and drug-drug interactions, 6-month infective endocarditis relapse, and 1-year mortality—were higher in the combination therapy group than the monotherapy group.

Abstract The skip phenomenon (SP) is a pattern where blood cultures are intermittently positive before final clearance. We report that one-third of patients with Staphylococcus lugdunensis infective endocarditis experienced the SP. Patients with the SP experienced both a longer duration of bacteremia and hospital stay, with a higher 1-year mortality rate.

Abstract Background Shotgun and targeted metagenomic sequencing have been shown in separate studies to be potentially useful for culture-free pathogen identification in blood and/or plasma of patients with infective endocarditis (IE). However, the 2 approaches have not been directly compared. The aim of this study was to compare shotgun metagenomic sequencing with targeted metagenomic sequencing (tMGS) for organism identification in blood or plasma of patients with IE. Methods Patients with possible or definite IE were prospectively enrolled from October 2020 to July 2021. Shotgun metagenomic sequencing was performed with the Karius test, which uses microbial cell-free DNA (mcfDNA) sequencing to detect, identify, and quantitate DNA-based pathogens in plasma. tMGS was performed using a 16S ribosomal RNA (rRNA) polymerase chain reaction assay targeting the V1 to V3 regions of the 16S rRNA gene. Results were compared using the McNemar test of paired proportions. Results Samples from 34 patients were investigated. The Karius test was positive in 24/34 (71%), including 3/6 (50%) with blood culture–negative endocarditis (BCNE), which was not significantly different from the positivity rate of tMGS (P = .41). Results of the Karius test were concordant with tMGS in 75% of cases. The Karius test detected 2 cases of methicillin-resistant Staphylococcus aureus among the 7 S. aureus detections, in accordance with results of phenotypic susceptibility testing. The combination of blood cultures, the Karius test, and tMGS found a potential causative pathogen in 33/34 (97%), including 5/6 with BCNE. Conclusions The Karius test and tMGS yielded comparable detection rates; however, beyond organism identification, the Karius test generated potentially useful antibiotic resistance data.