Infective endocarditis with or without congenital heart disease: clinical features and outcomes.

BACKGROUND AND AIMS: Patients with congenital heart disease (CHD) form a high-risk subgroup for infective endocarditis (IE), necessitating tailored prevention and treatment strategies. However, comprehensive nationwide data comparing IE characteristics and outcomes in patients with and without CHD, including children, are sparse. This study aims to address this gap in knowledge. METHODS: Using Danish nationwide registries, all patients with IE from 1977 to 2021 were identified and stratified on whether they had a diagnosis of CHD, regardless of its complexity. Characteristics prior to and during admission as well as associated outcomes (i.e. in-hospital mortality, 1-year mortality, and 10-year mortality, and IE recurrence) were compared between groups. RESULTS: In total, 14 040 patients with IE were identified, including 895 (6.4%) with CHD. Patients with vs. without CHD were younger at the time of IE diagnosis (median age 38.8 vs. 70.7 years), less comorbid, and more frequently underwent cardiac surgery during admission (35.7% vs. 23.0%, P < .001). Notably, 76% of patients with IE < 18 years of age had CHD. The IE-related bacteraemia differed between groups: Streptococci (29.9%) were the most common in patients with CHD, and Staphylococcus aureus (29.9%) in patients without CHD. Patients with CHD had a significantly lower cumulative incidence of in-hospital mortality (5.7% vs. 17.0%, P < .001) and 1-year mortality (9.9% vs. 31.8%, P < .001) compared with those without CHD. The 10-year cumulative incidence of IE recurrence was similar between groups (13.0% and 13.9%, P = .61). CONCLUSIONS: Patients with CHD who develop IE exhibit distinct characteristics and improved long-term outcomes compared with patients without CHD. Notably, the majority of children and adolescents with IE have underlying CHD.

A machine learning-based risk score for prediction of infective endocarditis among patients with Staphylococcus aureus bacteraemia - The SABIER score.

BACKGROUND: Early risk assessment is needed to stratify Staphylococcus aureus infective endocarditis (SA-IE) risk among Staphylococcus aureus bacteraemia (SAB) patients to guide clinical management. The objective of this study is to develop a novel risk score independent of subjective clinical judgment and can be used early at the time of blood culture positivity. METHODS: We conducted a retrospective big data analysis from territory-wide electronic data and included hospitalized patients with SAB between 2009 and 2019. We applied a random forest risk scoring model to select variables from an array of parameters, according to the statistical importance of each feature in predicting SA-IE outcome. The data was divided into derivation and validation cohorts. The areas under the curve of the receiver operating characteristic (AUCROC) were determined. RESULTS: We identified 15,741 SAB patients, among them 4.18% had SA-IE. The AUCROC was 0.74 (95%CI 0.70-0.76), with a negative predictive value of 0.980 (95%CI 0.977-0.983). The four most discriminatory features were age, history of infective endocarditis, valvular heart disease, and being community-onset. CONCLUSION: We developed a novel risk score with good performance as compared to existing scores and can be used at the time of SAB and prior to subjective clinical judgment.

Performance of the 2023 Duke-International Society of Cardiovascular Infectious Diseases Diagnostic Criteria for Infective Endocarditis in Relation to the Modified Duke Criteria and to Clinical Management-Reanalysis of Retrospective Bacteremia Cohorts.

BACKGROUND: Revised diagnostic criteria for infective endocarditis (IE), the 2023 Duke-ISCVID criteria, were recently presented and need validation. Here, we compare the 2000 modified Duke criteria for IE with Duke-ISCVID among patients with bacteremia and relate the diagnostic classification to IE treatment. METHODS: We reanalyzed patient cohorts with Staphylococcus aureus, Staphylococcus lugdunensis, non-ß-hemolytic streptococci, Streptococcus-like bacteria, Streptococcus dysgalactiae, Enterococcus faecalis, and HACEK (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella) bacteremia. Episodes were classified as definite, possible, or rejected IE with the modified Duke and Duke-ISCVID criteria. Reclassification included the microbiology criteria, positron emission tomography-computed tomography, and cardiac implanted electronic devices. To calculate sensitivity, patients treated for IE were considered as having IE. RESULTS: In 4050 episodes of bacteremia, the modified Duke criteria assigned 307 episodes (7.6%) as definite IE, 1190 (29%) as possible IE, and 2553 (63%) as rejected IE. Using the Duke-ISCVID criteria, 13 episodes (0.3%) were reclassified from possible to definite IE, and 475 episodes (12%) were reclassified from rejected to possible IE. With the modified Duke criteria, 79 episodes that were treated as IE were classified as possible IE, and 11 of these episodes were reclassified to definite IE with Duke-ISCVID. Applying the decision to treat for IE as a reference standard, the sensitivity of the Duke-ISCVID criteria was 80%. None of the 475 episodes reclassified to possible IE were treated as IE. CONCLUSIONS: The Duke-ISCVID criteria reclassified a small proportion of episodes to definite IE at the expense of more episodes of possible IE. Future criteria should minimize the possible IE group while keeping or improving sensitivity.

Lower specificity of the ESC2023 diagnostic criteria for infective endocarditis when spondylodiscitis is regarded as a vascular phenomenon.

The ESC diagnostic criteria for infective endocarditis (IE) added spondylodiscitis as minor diagnostic criterion. Of patients with Staphylococcus aureus, streptococcal or Enterococcus faecalis bacteremia, 11 of 1807 episodes were reclassified to definite IE of which nine were not treated as IE. Spondylodiscitis as a minor criterion decreases specificity of the criteria.

External Validation of the 2023 Duke-International Society for Cardiovascular Infectious Diseases Diagnostic Criteria for Infective Endocarditis.

BACKGROUND: The 2023 Duke-International Society of Cardiovascular Infectious Diseases (ISCVID) criteria for infective endocarditis (IE) were introduced to improve classification of IE for research and clinical purposes. External validation studies are required. METHODS: We studied consecutive patients with suspected IE referred to the IE team of Amsterdam University Medical Center (from October 2016 to March 2021). An international expert panel independently reviewed case summaries and assigned a final diagnosis of "IE" or "not IE," which served as the reference standard, to which the "definite" Duke-ISCVID classifications were compared. We also evaluated accuracy when excluding cardiac surgical and pathologic data ("clinical" criteria). Finally, we compared the 2023 Duke-ISCVID with the 2000 modified Duke criteria and the 2015 and 2023 European Society of Cardiology (ESC) criteria. RESULTS: A total of 595 consecutive patients with suspected IE were included: 399 (67%) were adjudicated as having IE; 111 (19%) had prosthetic valve IE, and 48 (8%) had a cardiac implantable electronic device IE. The 2023 Duke-ISCVID criteria were more sensitive than either the modified Duke or 2015 ESC criteria (84.2% vs 74.9% and 80%, respectively; P < .001) without significant loss of specificity. The 2023 Duke-ISCVID criteria were similarly sensitive but more specific than the 2023 ESC criteria (94% vs 82%; P < .001). The same pattern was seen for the clinical criteria (excluding surgical/pathologic results). New modifications in the 2023 Duke-ISCVID criteria related to "major microbiological" and "imaging" criteria had the most impact. CONCLUSIONS: The 2023 Duke-ISCVID criteria represent a significant advance in the diagnostic classification of patients with suspected IE.

Cutibacterium species valvular and cardiac device-related infective endocarditis: contemporary data from the GAMES prospective cohort (2008-2023).

BACKGROUND: Information on infective endocarditis (IE) caused by Cutibacterium spp. is limited and new Duke-ISCVID criteria have not yet been properly assessed. We examined clinical characteristics, outcomes and performance of diagnostic tests for Cutibacterium valvular and cardiac implantable electronic device-related IE (CIED-IE). METHODS: Data corresponding to all episodes of Cutibacterium IE recorded from 2008 to 2023 in a prospective national cohort including 46 Spanish hospitals were examined. Possible IE cases were reassessed using the new criteria. The sensitivity of blood cultures, valvular and CIED cultures, and PCR of the 16SrRNA gene and sequencing (16SPCR) was evaluated. RESULTS: There were 67/6,692 (1%) episodes of IE caused by Cutibacterium spp., 85% affecting men. Of these, 50 were valve-related (45 prosthetic, 5 native) and 17 CIED-related. The new criteria identified 8 additional cases and reclassified 15 as definite IE. Intracardiac complications (abscess, pseudoaneurysm, perforation or intracardiac fistula) occurred in 23/50 (46%) valvular IE episodes, leading to 18% mortality, and up to 40% mortality if surgery was indicated but could not be performed. All CIED-IE cases underwent device removal and no deaths were recorded. Positive diagnosis rates for blood cultures, valve/device cultures and 16SPCR were 52%, 70% and 82%, respectively. CONCLUSION: Cutibacterium IE is a rare yet potentially life-threatening condition that warrants a high index of suspicion in men with endovascular prosthetic material. The new Duke-ISCVID criteria and molecular techniques are useful for its diagnosis. Considering a significant complication rate, cardiac surgery and removal of CIEDs play a key role in reducing mortality.

Infective Endocarditis After Transcatheter Versus Surgical Aortic Valve Replacement.

BACKGROUND: Scarce data are available comparing infective endocarditis (IE) following surgical aortic valve replacement (SAVR) and transcatheter aortic valve replacement (TAVR). This study aimed to compare the clinical presentation, microbiological profile, management, and outcomes of IE after SAVR versus TAVR. METHODS: Data were collected from the "Infectious Endocarditis after TAVR International" (enrollment from 2005 to 2020) and the "International Collaboration on Endocarditis" (enrollment from 2000 to 2012) registries. Only patients with an IE affecting the aortic valve prosthesis were included. A 1:1 paired matching approach was used to compare patients with TAVR and SAVR. RESULTS: A total of 1688 patients were included. Of them, 602 (35.7%) had a surgical bioprosthesis (SB), 666 (39.5%) a mechanical prosthesis, 70 (4.2%) a homograft, and 350 (20.7%) a transcatheter heart valve. In the SAVR versus TAVR matched population, the rate of new moderate or severe aortic regurgitation was higher in the SB group (43.4% vs 13.5%; P < .001), and fewer vegetations were diagnosed in the SB group (62.5% vs 82%; P < .001). Patients with an SB had a higher rate of perivalvular extension (47.9% vs 27%; P < .001) and Staphylococcus aureus was less common in this group (13.4% vs 22%; P = .033). Despite a higher rate of surgery in patients with SB (44.4% vs 27.3%; P < .001), 1-year mortality was similar (SB: 46.5%; TAVR: 44.8%; log-rank P = .697). CONCLUSIONS: Clinical presentation, type of causative microorganism, and treatment differed between patients with an IE located on SB compared with TAVR. Despite these differences, both groups exhibited high and similar mortality at 1-year follow-up.

Revisiting the Evidence Base Informing the Use of Adjunctive Therapy for Enterococcus faecalis Endocarditis: A Systematic Review and Meta-Analysis.

BACKGROUND: Current guidelines recommend adjunctive gentamicin for the treatment of Enterococcus faecalis infective endocarditis (EFIE) despite a risk of toxicity. We sought to revisit the evidence for adjunctive therapy in EFIE and to synthesize the comparative safety and effectiveness of adjunctive use of the aminoglycosides versus ceftriaxone by systematic review and meta-analysis. METHODS: For historical context, we reviewed the seminal case series and in vitro studies informing the evolution from penicillin monotherapy to modern-day regimens for EFIE. Next, we searched MEDLINE and Embase from inception to January 16, 2024 for studies of EFIE comparing 1) adjunctive aminoglycosides versus ceftriaxone or 2) adjunctive therapy versus monotherapy. Where possible, clinical outcomes were compared between regimens by random-effects meta-analysis. Otherwise, data were narratively summarized. RESULTS: Results for the systematic review and meta-analysis were limited to 10 observational studies totaling 911 patients. All studies were at high risk of bias. Relative to adjunctive ceftriaxone, gentamicin had similar all-cause mortality (Risk Difference [RD]=-0.8%, 95% Confidence interval [95%CI]=-5.0, 3.5), relapse (RD=-0.1%, 95%CI=-2.4, 2.3), and treatment failure (RD=1.1%, 95%CI=-1.6, 3.7), but higher discontinuation due to toxicity (RD=26.3%, 95%CI=19.8, 32.7). The 3 studies comparing adjunctive therapy to monotherapy included only 30 monotherapy patients and heterogeneity precluded meta-analysis. CONCLUSION: Adjunctive therapy with ceftriaxone appeared to be equally effective and less toxic than gentamicin for the treatment of EFIE. The existing evidence does not clearly establish the superiority of either adjunctive therapy or monotherapy. Pending randomized evidence, if adjunctive therapy is to be used, ceftriaxone appears to be a reasonable option.

Evaluation of the HANDOC Score and the 2023 International Society of Cardiovascular Infectious Diseases and European Society of Cardiology Duke Clinical Criteria for the Diagnosis of Infective Endocarditis Among Patients With Streptococcal Bacteremia.

BACKGROUND: Streptococci are a common cause of infective endocarditis (IE). We aimed to evaluate the performance of the HANDOC score to identify patients at high risk for IE and the Duke clinical criteria of the European Society of Cardiology (ESC; 2015 and 2023 versions) and the 2023 version from the International Society of Cardiovascular Infectious Diseases (ISCVID) in diagnosing IE among patients with streptococcal bacteremia. METHODS: This retrospective study included adult patients with streptococcal bacteremia hospitalized at Lausanne University Hospital. Episodes were classified as IE by the Endocarditis Team. A HANDOC score >2 classified patients as high risk for IE. RESULTS: Among 851 episodes with streptococcal bacteremia, IE was diagnosed in 171 episodes (20%). Among 607 episodes with non-ß-hemolytic streptococci, 213 (35%) had HANDOC scores >2 points; 132 (22%) had IE. The sensitivity of the HANDOC score to identify episodes at high risk for IE was 95% (95% confidence interval [CI], 90%-98%), the specificity 82% (95% CI, 78%-85%), and the negative predictive value (NPV) 98% (95% CI, 96%-99%). 2015 Duke-ESC, 2023 Duke-ISCVID, and 2023 Duke-ESC clinical criteria classified 114 (13%), 145 (17%), and 126 (15%) episodes as definite IE, respectively. Sensitivity (95% CI) for the 2015 Duke-ESC, 2023 Duke-ISCVID, and 2023 Duke-ESC clinical criteria was calculated at 65% (57%-72%), 81% (74%-86%), and 73% (65%-79%), respectively, with specificity (95% CI) at 100% (98%-100%), 99% (98%-100%), and 99% (98%-100%), respectively. CONCLUSIONS: The HANDOC score showed an excellent NPV to identify episodes at high risk for IE. Among the different versions of the Duke criteria, the 2023 Duke-ISCVID version fared better for the diagnosis of IE among streptococcal bacteremia.

Evaluation of the 2023 Duke-ISCVID and 2023 Duke-ESC Clinical Criteria for the Diagnosis of Infective Endocarditis in a Multicenter Cohort of Patients With Staphylococcus aureus Bacteremia.

BACKGROUND: The Duke criteria for infective endocarditis (IE) diagnosis underwent revisions in 2023 by the European Society of Cardiology (ESC) and the International Society for Cardiovascular Infectious Diseases (ISCVID). This study aims to assess the diagnostic accuracy of these criteria, focusing on patients with Staphylococcus aureus bacteremia (SAB). METHODS: This Swiss multicenter study conducted between 2014 and 2023 pooled data from three cohorts. It evaluated the performance of each iteration of the Duke criteria by assessing the degree of concordance between definite S. aureus IE (SAIE) and the diagnoses made by the Endocarditis Team (2018-23) or IE expert clinicians (2014-17). RESULTS: Among 1344 SAB episodes analyzed, 486 (36%) were identified as cases of SAIE. The 2023 Duke-ISCVID and 2023 Duke-ESC criteria demonstrated improved sensitivity for SAIE diagnosis (81% and 82%, respectively) compared to the 2015 Duke-ESC criteria (75%). However, the new criteria exhibited reduced specificity for SAIE (96% for both) compared to the 2015 criteria (99%). Spondylodiscitis was more prevalent among patients with SAIE compared to those with SAB alone (10% vs 7%, P = .026). However, when patients meeting the minor 2015 Duke-ESC vascular criterion were excluded, the incidence of spondylodiscitis was similar between SAIE and SAB patients (6% vs 5%, P = .461). CONCLUSIONS: The 2023 Duke-ISCVID and 2023 Duke-ESC clinical criteria show improved sensitivity for SAIE diagnosis compared to 2015 Duke-ESC criteria. However, this increase in sensitivity comes at the expense of reduced specificity. Future research should aim at evaluating the impact of each component introduced within these criteria.

Compared Performance of the 2023 Duke-International Society for Cardiovascular Infectious Diseases, 2000 Modified Duke, and 2015 European Society of Cardiology Criteria for the Diagnosis of Infective Endocarditis in a French Multicenter Prospective Cohort.

BACKGROUND: The 2023 Duke-International Society for Cardiovascular Diseases (ISCVID) criteria for infective endocarditis (IE) were proposed as an updated diagnostic classification of IE. Using an open prospective multicenter cohort of patients treated for IE, we compared the performance of these new criteria to that of the 2000 Modified Duke and 2015 European Society of Cardiology (ESC) criteria. METHODS: Cases of patients treated for IE between January 2017 and October 2022 were adjudicated as certain IE or not. Each case was also categorized as either definite or possible/rejected within each classification. Sensitivity, specificity, and accuracy were estimated with 95% confidence intervals. RESULTS: Of the 1194 patients analyzed (mean age, 66.1 years; 71.2% males), 414 (34.7%) had a prosthetic valve and 284 (23.8%) had a cardiac implanted electronic device (CIED); 946 (79.2%) were adjudicated as certain IE; 978 (81.9%), 997 (83.5%), and 1057 (88.5%) were classified as definite IE in the 2000 modified Duke, 2015 ESC, and 2023 Duke-ISCVID criteria, respectively. The sensitivity of each set of criteria was 93.2% (95% confidence interval [CI], 91.6-94.8), 95.0% (95% CI, 93.7-96.4), and 97.6% (95% CI, 96.6-98.6), respectively (P < .001 for all 2-by-2 comparisons). Corresponding specificity rates were 61.3% (95% CI, 55.2-67.4), 60.5% (95% CI, 54.4-66.6), and 46.0% (95% CI, 39.8-52.2), respectively. In patients without CIED, sensitivity rates were 94.8% (95% CI, 93.2-96.4), 96.5% (95% CI, 95.1-97.8), and 97.7% (95% CI, 96.6-98.8); specificity rates were 59.0% (95% CI, 51.6-66.3), 56.6% (95% CI, 49.3-64.0), and 53.8% (95% CI, 46.3-61.2), respectively. CONCLUSIONS: Overall, the 2023 Duke-ISCVID criteria had a significantly higher sensitivity but a significantly lower specificity compared with older criteria. This decreased specificity was mainly attributable to patients with CIED.

Evaluation of the Specificity of the 2023 Duke-International Society of Cardiovascular Infectious Diseases Classification for Infective Endocarditis.

BACKGROUND: The 2023 Duke-ISCVID (International Society of Cardiovascular Infectious Diseases) classification is a new diagnostic tool for infective endocarditis, updating the 2000 modified Duke and the 2015 European Society for Cardiology (ESC) classifications. In comparison, its sensitivity is higher; however, its specificity remains to be evaluated and compared to that of the 2 other classifications in endocarditis suspected patients. METHODS: We retrospectively collected the characteristics of patients hospitalized in Bichat University's Hospital, Paris, in 2021, who had been evaluated for clinical suspicion of endocarditis, have had at least a transthoracic echocardiography, 2 pairs of blood cultures, 3-month follow-up and in whom endocarditis diagnosis was finally rejected. All patients were classified by 2000 modified Duke, 2015 ESC and 2023 Duke-ISCVID, as though the endocarditis diagnosis had not been rejected. RESULTS: In total, 130 patients' charts were analyzed. Mean age was 62 years, 84 (64.6%) were male, 39 (30.0%) had prosthetic cardiac valve or valve repair, 21 (16.2%) cardiac implanted electronic device, and 30 (23.1%) other cardiac conditions. Overall, 5, 2, and 5 patients were falsely classified as definite endocarditis with the 2000 modified Duke, 2015 ESC, and 2023 Duke-ISCVID classifications, respectively. The corresponding specificities were 96.2% (95% confidence interval [CI] [90.8%, 98.6%]), 98.5% (95% CI [93.9%, 99.7%]), and 96.2% (95% CI [90.8%, 98.6%]). The rates of possible endocarditis were of 38%, 35%, and 35% in the 3 classifications, respectively. CONCLUSIONS: The 2023 Duke-ISCVID classification is highly specific for ruling out the diagnosis of definite infective endocarditis in patients who had been evaluated for IE.

Comparison of the 2015 and 2023 European Society of Cardiology versions of the Duke criteria among patients with suspected infective endocarditis.

BACKGROUND: Diagnosing infective endocarditis (IE) poses a significant challenge. This study aimed to compare the diagnostic accuracy of the 2015 and 2023 Duke clinical criteria introduced by the European Society of Cardiology (ESC) in a cohort of patients suspected of having IE. METHODS: Conducted retrospectively at two Swiss University Hospitals between 2014-2023, the study involved patients with suspected IE. Each hospitals' Endocarditis Team categorized case as either IE or not IE. The performance of each iteration of the Duke-ESC clinical criteria was assessed based on the agreement between definite IE and the diagnoses made by the Endocarditis Team. RESULTS: Among the 3127 episodes with suspected IE, 1177 (38%) were confirmed to have IE. Using the 2015 Duke-ESC clinical criteria, 707 (23%) episodes were deemed definite IE, with 696 (98%) receiving a final IE diagnosis. With the 2023 Duke-ESC clinical criteria, 855 (27%) episodes were classified as definite IE, of which 813 (95%) were confirmed as IE. The 2015 and 2023 Duke-ESC clinical criteria categorized 1039 (33%) and 1034 (33%) episodes, respectively, as possible IE. Sensitivity for the 2015 Duke-ESC and the 2023 Duke-ESC clinical criteria was calculated at 59% (95% CI: 56-62%), and 69% (66-72%), respectively, with specificity at 99% (99-100%), and 98% (97-98%), respectively. CONCLUSIONS: The 2023 ESC criteria demonstrated significant improvements in sensitivity compared to the 2015 version, although one-third of episodes were classified as possible IE by both versions.

Eyes Wide Shut: A Cohort Study Questioning the Role of Fundoscopy in Infective Endocarditis Diagnosis.

In this retrospective/prospective study, we assessed the role of fundoscopy in 711 episodes with suspected infective endocarditis (IE); 238 (33%) had IE. Ocular embolic events (retinal emboli or chorioretinitis/endophthalmitis) and Roth spots were found in 37 (5%) and 34 (5%) episodes, respectively, but had no impact on IE diagnosis.

Evaluation of the 2023 Duke-International Society of Cardiovascular Infectious Diseases Criteria in a Multicenter Cohort of Patients With Suspected Infective Endocarditis.

BACKGROUND: Since publication of Duke criteria for infective endocarditis (IE) diagnosis, several modifications have been proposed. We aimed to evaluate the diagnostic performance of the Duke-ISCVID (International Society of Cardiovascular Infectious Diseases) 2023 criteria compared to prior versions from 2000 (Duke-Li 2000) and 2015 (Duke-ESC [European Society for Cardiology] 2015). METHODS: This study was conducted at 2 university hospitals between 2014 and 2022 among patients with suspected IE. A case was classified as IE (final IE diagnosis) by the Endocarditis Team. Sensitivity for each version of the Duke criteria was calculated among patients with confirmed IE based on pathological, surgical, and microbiological data. Specificity for each version of the Duke criteria was calculated among patients with suspected IE for whom IE diagnosis was ruled out. RESULTS: In total, 2132 episodes with suspected IE were included, of which 1101 (52%) had final IE diagnosis. Definite IE by pathologic criteria was found in 285 (13%), 285 (13%), and 345 (16%) patients using the Duke-Li 2000, Duke-ESC 2015, or the Duke-ISCVID 2023 criteria, respectively. IE was excluded by histopathology in 25 (1%) patients. The Duke-ISCVID 2023 clinical criteria showed a higher sensitivity (84%) compared to previous versions (70%). However, specificity of the new clinical criteria was lower (60%) compared to previous versions (74%). CONCLUSIONS: The Duke-ISCVID 2023 criteria led to an increase in sensitivity compared to previous versions. Further studies are needed to evaluate items that could increase sensitivity by reducing the number of IE patients misclassified as possible, but without having detrimental effect on specificity of Duke criteria.

Make Modern Microbiology Matter More in the 2023 European Society of Cardiology Guidelines for the Management of Infective Endocarditis.

The European Society of Cardiology (ESC) 2023 guidelines for the management of infective endocarditis (IE) stress that a multidisciplinary approach is needed to manage patients with IE. In our view, the guidelines do not include the relevant perspectives from modern microbiology. The diagnostic criteria for IE were changed in the ESC 2023 guidelines, and many IE-causing pathogens are either not clearly defined. Moreover, an improved understanding of the relationship between bacterial species and the risk for IE has not been implemented. The guidelines give detailed and, in our view, incorrect instructions about diagnostic testing in blood culture-negative IE without presenting proper evidence. Other important diagnostic aspects, such as the value of repeated blood cultures and incubation time for blood cultures, are not discussed. We believe that a multidisciplinary collaboration that include microbiologists would have improved these guidelines, and we hope for a future harmonization of diagnostic criteria for IE.

18F-FDG PET/CT and radiolabeled leukocyte SPECT/CT imaging for the evaluation of cardiovascular infection in the multimodality context: ASNC Imaging Indications (ASNC I2) Series Expert Consensus Recommendations from ASNC, AATS, ACC, AHA, ASE, EANM, HRS, IDSA, SCCT, SNMMI, and STS.

This document on cardiovascular infection, including infective endocarditis, is the first in the American Society of Nuclear Cardiology Imaging Indications (ASNC I2) series to assess the role of radionuclide imaging in the multimodality context for the evaluation of complex systemic diseases with multi-societal involvement including pertinent disciplines. A rigorous modified Delphi approach was used to determine consensus clinical indications, diagnostic criteria, and an algorithmic approach to diagnosis of cardiovascular infection including infective endocarditis. Cardiovascular infection incidence is increasing and is associated with high morbidity and mortality. Current strategies based on clinical criteria and an initial echocardiographic imaging approach are effective but often insufficient in complicated cardiovascular infection. Radionuclide imaging with 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and single photon emission computed tomography/CT leukocyte scintigraphy can enhance the evaluation of suspected cardiovascular infection by increasing diagnostic accuracy, identifying extracardiac involvement, and assessing cardiac implanted device pockets, leads, and all portions of ventricular assist devices. This advanced imaging can aid in key medical and surgical considerations. Consensus diagnostic features include focal/multi-focal or diffuse heterogenous intense 18F-FDG uptake on valvular and prosthetic material, perivalvular areas, device pockets and leads, and ventricular assist device hardware persisting on non-attenuation corrected images. There are numerous clinical indications with a larger role in prosthetic valves, and cardiac devices particularly with possible infective endocarditis or in the setting of prior equivocal or non-diagnostic imaging. Illustrative cases incorporating these consensus recommendations provide additional clarification. Future research is necessary to refine application of these advanced imaging tools for surgical planning, to identify treatment response, and more.

Staphylococcus succinus Infective Endocarditis, France.

Infective endocarditis is a rare condition in humans and is associated with high illness and death rates. We describe a case of infective endocarditis caused by Staphylococcus succinus bacteria in France. We used several techniques for susceptibility testing for this case to determine the oxacillin profile.

C-terminal deletion of RelA protein is suggested as a possible cause of infective endocarditis recurrence with Enterococcus faecium.

Infective endocarditis (IE) caused by Enterococcus spp. represents the third most common cause of IE, with high rates of relapse compared with other bacteria. Interestingly, late relapses (>6 months) have only been described in Enterococcus faecalis, but here we describe the first reported IE relapse with Enterococcus faecium more than a year (17 months) after the initial endocarditis episode. Firstly, by multi locus sequence typing (MLST), we demonstrated that both isolates (EF646 and EF641) belong to the same sequence type (ST117). Considering that EF641 was able to overcome starvation and antibiotic treatment conditions surviving for a long period of time, we performed bioinformatic analysis in identifying potential genes involved in virulence and stringent response. Our results showed a 13-nucleotide duplication (positions 1638-1650) in the gene relA, resulting in a premature stop codon, with a loss of 167 amino acids from the C-terminal domains of the RelA enzyme. RelA mediates the stringent response in bacteria, modulating levels of the alarmone guanosine tetraphosphate (ppGpp). The relA mutant (EF641) was associated with lower growth capacity, the presence of small colony variants, and higher capacity to produce biofilms (compared with the strain EF646), but without differences in antimicrobial susceptibility patterns according to standard procedures during planktonic growth. Instead, EF641 demonstrated tolerance to high doses of teicoplanin when growing in a biofilm. We conclude that all these events would be closely related to the long-term survival of the E. faecium and the late relapse of the IE. These data represent the first clinical evidence of mutations in the stringent response (relA gene) related with E. faecium IE relapse.

Sensitizing methicillin-resistant Staphylococcus aureus (MRSA) to cefuroxime: the synergic effect of bicarbonate and the wall teichoic acid inhibitor ticlopidine.

Methicillin-resistant Staphylococcus aureus (MRSA) strains are a major challenge for clinicians due, in part, to their resistance to most ß-lactams, the first-line treatment for methicillin-susceptible S. aureus. A phenotype termed "NaHCO3-responsiveness" has been identified, wherein many clinical MRSA isolates are rendered susceptible to standard-of-care ß-lactams in the presence of physiologically relevant concentrations of NaHCO3, in vitro and ex vivo; moreover, such "NaHCO3-responsive" isolates can be effectively cleared by ß-lactams from target tissues in experimental infective endocarditis (IE). One mechanistic impact of NaHCO3 exposure on NaHCO3-responsive MRSA is to repress WTA synthesis. This NaHCO3 effect mimics the phenotype of tarO-deficient MRSA, including sensitization to the PBP2-targeting ß-lactam, cefuroxime (CFX). Herein, we further investigated the impacts of NaHCO3 exposure on CFX susceptibility in the presence and absence of a WTA synthesis inhibitor, ticlopidine (TCP), in a collection of clinical MRSA isolates from skin and soft tissue infections (SSTI) and bloodstream infections (BSI). NaHCO3 and/or TCP enhanced susceptibility to CFX in vitro, by both minimum inhibitor concentration (MIC) and time-kill assays, as well as in an ex vivo simulated endocarditis vegetations (SEV) model, in NaHCO3-responsive MRSA. Furthermore, in experimental IE (presumably in the presence of endogenous NaHCO3), pre-exposure to TCP prior to infection sensitized the NaHCO3-responsive MRSA strain (but not the non-responsive strain) to enhanced clearances by CFX in target tissues. These data support the notion that NaHCO3 is acting similarly to WTA synthesis inhibitors, and that such inhibitors have potential translational applications in the treatment of certain MRSA strains in conjunction with specific ß-lactam agents.