Infective Endocarditis Research Articles

Temporal Trends in Etiology of Aortic Valvular Diseases for Patients Undergoing Surgical Valve Replacement: A Report From 40 Years Pathological Experience.

Although aortic valvular disease has various etiologies, recently, calcific aortic valve stenosis has been increasing. We analyzed the trends in the pathological characteristics of aortic valvular disease in the past four decades in Japan. The pathology department data for aortic valvular disease operated in our hospital documented 4508 patients from 1978 to 2022. Subsequently, trend analyses were performed over four periods: Period 1, 1978-1989 (618 cases); Period 2, 1990-1999 (903 cases); Period 3, 2000-2010 (1179 cases); and Period 4, 2011-2022 (1808 cases). We reviewed the pathological characterization of the resected aortic valves and categorized them based on the representative etiology of aortic valvular disease as congenital bicuspid, chronic rheumatic change, infective endocarditis, degenerative calcific change, and myxoid change. Our pathologic analysis revealed a significant decrease in the proportion of chronic rheumatic disease from 47% to 14%, an increase in the congenital bicuspid valve from 8% to 24%, and a rise of the degenerative calcific change of the aortic valve from 4% to 27% (p < 0.001), especially significant increases in aortic stenosis. Calcification of the aortic valve may result from an active process similar to atherosclerosis, leading to aortic stenosis with increasing dyslipidemia in Japanese patients in 40 years.

The ArcAB two-component system is associated with the susceptibility of Aggregatibacter actinomycetemcomitans to superoxide and hydrogen peroxide.

Aggregatibacter actinomycetemcomitans is a Gram-negative facultative anaerobe and is associated with periodontal disease. This bacterium is exposed to environmental stresses, such as osmotic pressure, temperature shifts, pH shifts, and antimicrobial substances, including reactive oxygen species (ROS), in the human oral cavity. The bacterial two-component system ArcAB modulates gene expression in response to environmental changes, primarily by sensing oxygen pressure in several pathogens belonging to the γ-proteobacteria. It is also known to provide adaptation to ROS stress; however, its function in A. actinomycetemcomitans remains unclear. In this study, we found that the expression of sod, which encodes superoxide dismutase, was increased in the inactivated mutant of arcA, which encodes a response regulator. The mutant exhibited reduced susceptibility to superoxide and hydrogen peroxide (H2O2). Additionally, this strain showed reduced susceptibility to H2O2 from Streptococcus sanguinis and increased survival in macrophages. Since ArcB is the cognate histidine kinase of ArcA, the inactivated mutant of arcB was analyzed for its phenotypes. The arcB mutant exhibited reduced susceptibility to superoxide and H2O2. Compared to wild type, the phosphorylation level of ArcA in the arcB mutant was decreased. These results suggest that the ArcA response regulator receives phosphate groups from ArcB histidine kinase and negatively regulates the expression of sod, thereby affecting bacterial survival in response to ROS produced by oral commensals and host immune cells.IMPORTANCEAggregatibacter actinomycetemcomitans is an oral pathogen that is known to be a highly virulent periodontal pathogen, showing strong adherence to periodontal tissue and toxin production, which leads to aggressive periodontitis. This bacterium is associated not only with oral infections but also with systemic infections, such as infective endocarditis and brain abscesses. Therefore, elucidating the adaptation mechanisms of this bacterium is important for human health. Bacterial two-component systems (TCSs) have been studied as attractive targets for elucidating bacterial fitness and pathogenicity in the host. This study characterized a TCS in A. actinomycetemcomitans, ArcAB, which is associated with susceptibility to ROS produced by host cells or oral commensals. Our findings provide insights into the bacterial adaptation mechanism against oxidative stress, which is crucial for understanding the survival strategies of the periodontal pathogen.

Russian conduit: a new approach in aortic root and ascending aortic surgery. Immediate and mid-term results in a single center

Background. There was a trend towards valve-sparing techniques in aortic root surgery in recent decades. This approach can significantly improve the quality of life and do not require anticoagulation. There is a question on surgical strategy for patients with native aortic leaflets not suitable for reconstruction. We describe an alternative technique of aortic root replacement with certain advantages in mid-term period compared to standard Bio Bentall procedure. Material and methods. The study included 50 patients who underwent surgery for aortic root and ascending aorta lesions between 2014 and 2022. Mean follow-up was 31.0±17.9 months in the group «Russian conduit» and 39.2±22.7 months in the group 2 «BioBentall» (p=0.159). In the 1st group, patients (n=28) underwent a combined Bentall-De Bono procedure and aortic valve neocuspidization with autologous pericardium. In the 2nd group (n=22), surgery was performed using synthetic composite conduit containing biological aortic root stented prosthesis. Results. In the 1st group, there were no conversions to standard Bentall or BioBentall procedure. Cumulative freedom from MACE (delayed all-cause mortality, acute myocardial infarction, stroke, infective endocarditis) after 12, 24, and 48 months was similar (92.59±5.04% versus 100% (p=0.367), 88.7±6.1% versus 93.3±6.4% (p=0.534) and 88.7±6.1% versus 86.7±8.8% (p=0.864)). Freedom from redo surgeries throughout 48 months was 92.59±5.04% and 92.3±7.4%, respectively (p=0.734). Indexed effective orifice area in mid-term period was significantly larger in the 1st group (1.36±0.23 versus 0.93±0.1 cm2, p&lt;0.01). Conclusion. Aortic root and ascending aortic replacement using Russian conduit technique demonstrates comparable results regarding freedom from redo surgeries compared to standard BioBentall technique and better hemodynamic parameters (mean pressure gradient and effective orifice area) in mid-term period. This approach may be successfully used for aortic root disease if reconstruction of native cusps is not possible.

Predicting in-hospital mortality in infective endocarditis: insights from the Naples prognostic score

Background Infective Endocarditis (IE) is a severe and potentially life-threatening infection of the heart valves, necessitating a comprehensive understanding of factors influencing patient outcomes. Objective The study aims to investigate the relationship between NPS and in-hospital mortality in patients diagnosed with Infective Endocarditis (IE). Methods A total of 153 IE patients were included in the study, with 32 (20,9%) experiencing in-hospital mortality. Patients were categorised into survivors and non-survivors, and detailed clinical and demographic characteristics were recorded. The final endpoint of the study was determined as in-hospital mortality. Regression analyses were conducted to identify the independent variables, and Kaplan-Meier estimates were created to determine survival outcomes, using a significance level of p < 0.05 for all statistical analyses. Results The non-survivor group exhibited a significantly higher NPS compared to the survivor group (28 (87.5) vs. 56 (46.3); p < 0.001). ROC curve analysis, utilising NPS, the neutrophil-to-lymphocyte ratio (NLR), the lymphocyte-to-monocyte ratio (LMR), albumin, and total cholesterol values, identified NPS as the most robust parameter, with an area under the curve of 0.704 (95% CI: 0.612–0.797; p < 0.001). Multivariate regression analysis revealed Septic shock (p = 0.001), NPS (p = 0.004), and Age (p = 0.012) as independent determinants of in-hospital mortality in IE patients. Conclusions This study demonstrated a strong correlation between NPS and mortality in IE. This novel score, as it reflects both the level of inflammation and nutrition, can be used to predict the prognosis in IE.

The prognostic role of vegetation size in pediatric infective endocarditis: a retrospective study using decision curve and dose-response analysis

ObjectiveTo explore the predictive value of vegetation size on the prognosis of pediatric infective endocarditis (IE).MethodsA total of 27 children diagnosed with IE who were admitted to Kunming Children’s Hospital from January 2014 to June 2024 were included. The good prognosis group comprised 10 cases, while the bad prognosis group comprised 17 cases. The receiver operating characteristic (ROC) curve, restricted cubic spline model, and decision curve analysis were utilized to assess the predictive value of vegetation size on the prognosis of pediatric IE.ResultsThere were statistically significant differences in vegetation size, hemoglobin, platelet count, and prothrombin time between the two groups (P < 0.05). The ROC curve demonstrated that vegetation size had a high predictive accuracy for the prognosis of pediatric IE (AUC = 0.841, 95% CI: 0.775–0.924). Decision curve analysis indicated that vegetation size held substantial clinical value for predicting the prognosis of pediatric IE. The restricted cubic spline analysis revealed a linear dose-response relationship between vegetation size and prognosis of pediatric IE (nonlinear test, P = 0.084).ConclusionSignificant differences were observed in vegetation size, hemoglobin, platelet count, and prothrombin time between different prognosis of pediatric IE. Limited evidence indicates that vegetation size is a critical factor in predicting the prognosis of pediatric IE. However, studies with larger sample sizes are needed to confirm the accuracy of these conclusions.

Infective endocarditis: it takes a team.

Infective endocarditis: it takes a team.

The Dilemma of Surgical Timing in Acute Aortic Valve Endocarditis: Does Early Surgery Improve Risks or Prognosis?

Background: Acute aortic valve infective endocarditis (IE) presents a critical surgical timing dilemma. This study investigates whether early surgical intervention (within seven days of targeted antibiotic therapy initiation) affects mortality and clinical outcomes compared to delayed/conventional surgery. Methods: A retrospective, multicenter analysis of 204 patients with aortic IE was conducted, excluding emergency cases requiring immediate intervention. Patients were stratified into EARLY (≤7 days) and LATE (&gt;7 days) surgical groups. Primary endpoints included in-hospital mortality and major adverse events, while secondary endpoints assessed long-term survival, recurrence, and reintervention rates. Results: No significant differences in in-hospital mortality were observed between groups (16% in both). The LATE group exhibited a trend toward increased permanent pacemaker implantation (16% vs. 8.2%; p = 0.100) and a higher incidence of postoperative atrial fibrillation (36% vs. 24%, p = 0.048). Infective endocarditis recurrence and long-term survival did not significantly differ between groups. Predictors of one-year mortality included chronic kidney disease, annular abscess, extracorporeal membrane oxygenation (ECMO) use, and prolonged mechanical ventilation. Conclusions: These findings suggest that early surgery, following a short course of antibiotics, does not compromise outcomes nor increase recurrence risk, challenging the conventional preference for delayed intervention in non-emergency IE cases.

Clinical features and medical-surgical management overweight the inoculum effect and genotypic characteristics of MSSA in infective endocarditis.

MSSA remains the leading cause of infective endocarditis (IE) and is responsible for significant mortality. While clinical factors tied to mortality are well documented, possible contributing strain-specific characteristics have not been extensively explored. This study investigates MSSA phenotypic and genotypic characteristics and medical-surgical data related to Day-90 mortality in IE. We included all patients enrolled in a monocentric prospective cohort (2016-23), with definite or probable MSSA IE. Cefazolin and oxacillin MICs and inoculum effects were determined by broth microdilution. Genotyping analysis and BlaZ typing were obtained from WGS. Phenotypic and genotypic characteristics of strains and clinical risk factors were confronted with Day-90 mortality. Eighty-eight patients with MSSA IE were included. The most frequent clinical presentations were left-sided native valve IE (25/88), left-sided prosthetic valve IE (12/88) and right-sided IE (19/88). Day-90 mortality rate was 39% (34/88). Most patients were treated with antistaphylococcal penicillin as a primary antibiotic (60/88). The main MSSA clonal complexes identified were CC398 (17/88), CC30 (13/88) and CC5 (13/88). Cefazolin inoculum effect was observed in 18/88 strains, and oxacillin inoculum effect in 13/88. Overall, 15/88 isolates exhibited an inoculum effect on primary antibiotic therapy. Factors independently associated with improved outcomes included cardiac surgery [hazard ratio (HR) 0.34, 95% CI (0.13-0.89)] and source control [HR 0.21, 95% CI (0.03-0.53)]. Neither genetic background, blaZ carriage, nor in vitro inoculum effect to the primary antibiotherapy was associated with Day-90 mortality. This cohort of MSSA IE did not find any microbiological factors correlated with Day-90 mortality. Clinical features and infection management appear to be the main factors in the prognosis of MSSA IE.

Right Heart Bypass Without an Oxygenator as an Alternative Technique for Surgical Management of Right-sided Heart Problems: a Case Report

Introduction: lead-related infective endocarditis is a rare complication with a high mortality rate that needs to be addressed immediately. In most cases, surgery is mandatory in addition to medical treatment. Alternative techniques to conventional cardiopulmonary bypass have been developed to reduce the inflammatory response and post-operative complications. Case presentation: A 29-year-old male patient with dual chamber implantable cardioverter defibrillator presented to our hospital with infective endocarditis. Early evaluation of the patient revealed a large mobile 6*2 cm vegetation attached to the leads and tricuspid valve and the right atrium. Due to large size of the vegetation the patient got prepared for surgical removal of the vegetation. The patient underwent right heart bypass with cannulation of inferior and superior vena cava and the pulmonary artery. Discussion: The inflammatory response subsequent to cardiopulmonary bypass, plays an important role in postoperative complications such as pulmonary complication including transient hypoxemia or even more severe complication like Acute Respiratory Distress Syndrome. Additionally, the ascending aorta manipulation may result in postoperative cerebral atheroembolism and stroke. In selected patients the right heart bypass is a better option, as the cardioplegic arrest is not needed in this technique, and less post-operative inflammatory response is expected due to absence of long tubes, an oxygenator and aortic clamping. Conclusion: Right heart bypass could be a less complicated, safer, and cost-benefit alternative to conventional cardiopulmonary bypass in the case of right sided heart problems. This technique allows effective decompression of right heart and adequate oxygenation without postoperative complications, usually seen in routine cardiopulmonary bypass.

Change of Heart: Can Artificial Intelligence Transform Infective Endocarditis Management?

Artificial intelligence (AI) has emerged as a promising adjunct in the diagnosis and management of infective endocarditis (IE), a disease characterized by diagnostic complexity and significant morbidity. Machine learning (ML) models such as SABIER and SYSUPMIE have demonstrated strong predictive accuracy for early IE diagnosis, embolic risk stratification, and postoperative mortality, surpassing traditional clinical scoring systems. In imaging, AI-enhanced echocardiography and advanced modalities like FDG-PET/CT offer improved sensitivity, specificity, and reduced inter-observer variability, potentially transforming clinical decision making. Additionally, AI-powered microbiological techniques, including MALDI-TOF mass spectrometry combined with ML and neural network-based metagenomic classifiers, show promise in rapidly identifying pathogens and predicting antimicrobial resistance. Despite encouraging early results, widespread adoption faces barriers, including data limitations, interpretability issues, ethical concerns, and the need for robust validation. Future directions include leveraging generative AI as clinical consultative tools, provided their capabilities and limitations are carefully managed. Ultimately, collaborative efforts addressing these challenges could transform IE care, enhancing diagnostic accuracy, clinical outcomes, and patient safety.

Serum lactate dehydrogenase level as a predictor of 28-day mortality in critically ill patients with infective endocarditis: a retrospective cohort study from MIMIC IV database.

Serum lactate dehydrogenase level as a predictor of 28-day mortality in critically ill patients with infective endocarditis: a retrospective cohort study from MIMIC IV database.

Implications of pacemaker implantation after aortic valve surgery for endocarditis: a nationwide study.

Infective endocarditis (IE) is associated with a high risk of atrioventricular block and surgery adds to the risk of receiving a permanent pacemaker. The clinical impact of pacemaker implantation in IE patients is insufficiently studied. Our objective was to analyse long-term clinical outcomes in patients who receive a permanent pacemaker after IE surgery. We conducted a nationwide observational cohort study, including all patients undergoing surgery for aortic valve IE in Sweden 1997-2022. The exposure group was patients who received a permanent pacemaker within 30 days of surgery. We used inverse probability of treatment weighting to account for inter-group differences and flexible parametric models to estimate hazards and cumulative incidences. Outcomes were all-cause mortality, heart failure, and reinfection in the prosthetic valve. Among 2175 patients who underwent surgery for aortic valve endocarditis, 168 (8%) received a permanent pacemaker. The mean age was 59 years; 18% were female. During a mean follow-up of 8.0 years (maximum 26 years), 822 patients (38%) died. At 15 years, the cumulative incidence of all-cause mortality was 60% versus 50% in the pacemaker versus the no pacemaker group; for heart failure, it was 21% versus 16%. We found no association of pacemaker implantation with mortality (HR 1.17., 95% CI: 0.86-1.58), heart failure (HR 1.42, 95% CI: 0.89-2.29), or reinfection (HR 0.85, 95% CI: 0.50-1.45). Pacemaker implantation after surgery for aortic valve IE is common but was not associated with an increased risk of death, heart failure, or reinfection. Although pacemaker need suggests more advanced disease, these results show that lifesaving surgery is not importantly jeopardised by need for a pacemaker.

The Impact of Brain MRI on the Management of Infective Endocarditis (IE) at a Large Urban Safety-Net Hospital (P11-10.004)

The Impact of Brain MRI on the Management of Infective Endocarditis (IE) at a Large Urban Safety-Net Hospital (P11-10.004)

Factors associated with persistent bacteraemia among patients with suspected infective endocarditis

Abstract Purpose To ascertain the predictors of persistent bacteraemia among patients with suspected infective endocarditis (IE) and those with IE. Methods Retrospective study. Setting This study conducted at a Swiss university hospital (2015–2023) included adult patients with bacteraemia and suspected IE. Persistent bacteraemia was defined as continued positive blood cultures with the same microorganism for at least 48 h from antibiotic treatment initiation. Endocarditis Team classified cases as IE or not IE. Results Among 2312 episodes of suspected IE, S. aureus was the most common pathogen (1045 episodes; 45%). IE (644; 28%) was the most prevalent infection type. Persistent bacteraemia was observed in 480 (21%) episodes and was independently associated with S. aureus, ≥ 2 positive sets of index blood cultures, resistant bacterium, sepsis, IE, central venous catheter-associated bacteraemia, and acute native bone and joint infections (BJIs), while, streptococcal bacteraemia, appropriate initial antimicrobial treatment and, performance of source control interventions within 48 h were associated with rapid blood culture clearance. Of the 644 IE episodes, persistent bacteraemia was observed in 196 (30%) and was associated with obesity, S. aureus, ≥ 2 positive sets of index blood cultures, resistant bacterium, acute native BJIs, immunologic phenomena, thoracic embolic events, while streptococcal bacteraemia and performance of source control interventions within 48 h were associated with rapid clearance of blood cultures. Conclusions Persistent bacteraemia was associated with S. aureus and BJI. Delaying source control interventions may increase the risk of persistent bacteraemia. No specific intracardiac lesion was associated with persistent bacteraemia in IE episodes.

Infective endocarditis in surgical versus transcatheter aortic valve implantation. Same incidence and same prognosis?

Infective endocarditis in surgical versus transcatheter aortic valve implantation. Same incidence and same prognosis?

Single- versus multiple-sampling strategy for blood cultures in the diagnosis of infective endocarditis: the prospective multicenter UniEndo study.

Single-sampling strategy (SSS) for blood cultures (BC) has not been evaluated in infective endocarditis (IE). We assessed the diagnostic performance of SSS vs conventional multi-sampling strategy (MSS) in IE diagnosis. Patients suspected of IE were prospectively enrolled in 8 tertiary-care centers. Five BC bottle pairs were sampled from each patient. Pairs 1, 2 and 3 were sampled simultaneously, followed by 2 additional separate pairs (4 and 5) sampled more than one hour later. Pairs 1, 2, and 3 emulated SSS and pairs 1, 4, and 5 emulated MSS. The sensitivity and specificity of the major microbiologic criterion of the 2015-ESC IE diagnostic criteria, based on the SSS and MSS BC results, were calculated using the endocarditis team's diagnosis as the gold standard. An IE was diagnosed in 101 (39.4%) of the 256 patients enrolled. Sensitivity rates of SSS and MSS were 50.5% (95%CI [40.7-60.2]) and 45.5% (95%CI [35.8-55.3]), respectively (p = 0.063), while specificity rates were 94.8% (95%CI [91.4-98.3]) and 95.5% (95%CI [92.2-98.8]), respectively (p = 1). In IE patients, SSS as compared to MSS accurately upgraded the diagnosis from possible to definite IE in one patient and downgraded it in none. Using SSS to define the major microbiologic criterion was as sensitive and specific as using MSS for diagnosing IE. Using SSS instead of MSS BC results did not lead to erroneous changes in diagnostic class according to the 2015 ESC criteria. Consequently, SSS may be regarded as standard practice for IE diagnosis.

Fulminant infective endocarditis with toxin-negative Corynebacterium diphtheriae in people with substance use experiencing homelessness, England, 2024 to 2025.

Between July 2024 and January 2025, five male patients in their early 20s to early 50s were confirmed with infective endocarditis associated with non-toxigenic Corynebacterium diphtheriae in England. Three were known to have experienced homelessness. All five used non-intravenous recreational drugs. Disease progression was rapid, four patients required surgical intervention, one died. Whole-genome sequencing and multilocus sequence type (MLST) analysis identified four individuals as ST559. Clinicians and substance use services have been alerted and enhanced surveillance implemented. A prevalence study is planned.

Population pharmacokinetics and optimized prophylaxis dosing of cefazolin during transcatheter aortic valve implantation.

Transcatheter aortic valve implantation (TAVI) is a less invasive alternative to surgical valve replacement for aortic stenosis. Infective endocarditis, most often caused by enterococci, is a significant post-procedural complication. Cefazolin has been the most frequently utilized agent for TAVI procedural prophylaxis, although recent guidelines suggest addition of an agent with enterococcal activity. Optimizing antimicrobial prophylaxis is important but little is known about antibiotic pharmacokinetics (PK) in this procedure. To define the population PK profile of prophylactic cefazolin in TAVI procedures and determine appropriateness for use. Adult patients receiving cefazolin prophylaxis for TAVI were enrolled. Serum was collected at four timepoints periprocedurally for analysis of cefazolin concentrations. Population PK analysis and Monte Carlo simulation was performed. Fractional target attainment (FTA) against MIC distributions for common pathogens was performed. Three hundred and fifty-nine plasma cefazolin concentrations (188 total, 171 unbound) from 50 participants were used for model development. PTA for a 2 g dose of cefazolin and a procedure of 2 h duration was >90% for organisms with an MIC up to 8 mg/L. FTA was 100% for MSSA at all examined procedure durations and estimated glomerular filtration rate levels. FTAs for Staphylococcus epidermidis and Enterococcus faecalis, based on limited MIC data, were predominantly subthreshold. This study found a 2 g dose of cefazolin achieved target exposure for MSSA but was subthreshold for other pathogens.

Infective Endocarditis Caused by Abiotrophia defectiva: A Unique Case Complicated by Mitral Valve Perforation.

Abiotrophia defectiva, a nutritionally variant streptococcus, represents a rare yet serious cause of infective endocarditis (IE), accounting for 1%-2% of the total IE cases. It affects native valves in 10% of patients, and it is implicated in catastrophic complications. A 33-year-old medically free male presented with a persistent nonproductive cough for 4 months. It was associated with unintentional weight loss (10 kg); however, he denied any other symptoms. His symptoms started after he had a dental implant. Physical examination was unremarkable except for a systolic murmur. Upon further investigations, a blood culture showed Abiotrophia defectiva, and echocardiography demonstrated severe mitral regurgitation originating from the perforation site located on the posterior leaflet measuring 10 × 4 mm, in addition to 2 masses suggestive of vegetations, the largest measuring 10 × 6 mm. The patient was hospitalized as a case of IE and acute mitral valve regurgitation. In light of mitral valve perforation, large vegetation, and bacteremia, an urgent multidisciplinary decision to proceed with mitral valve replacement was made, and the patient received a total of 6 weeks of antibiotics. Physicians should remain highly vigilant for IE, its rare causes, and associated complications. In addition, managing complex cases of IE necessitates a multidisciplinary team approach between cardiology, infectious diseases, and cardiac surgery teams.

Infective endocarditis and the association to income as a proxy for socioeconomic position - A Danish nationwide register-based cohort study.

Infective endocarditis and the association to income as a proxy for socioeconomic position - A Danish nationwide register-based cohort study.