Infective endocarditis

Effect of co-treatment with disulfiram and resatorvid on the pyroptosis of monocytes in sepsis

PURPOSE

To evaluate the effects of co-treatment with Disulfiram and Resatorvid on sepsis.

METHODS

Monocytes were isolated from the peripheral blood of sepsis patients with Staphylococcus aureus (S. aureus)-induced infective endocarditis and healthy controls. The expression of Gasdermin D (GSDMD) was analyzed using quantitative polymerase chain reaction (qRT-PCR), Western blotting, and immunofluorescence. An in vitro cellular model of sepsis was established by stimulating monocytes with heat-killed Staphylococcus aureus (HK S. aureus). Cells were pre-treated with Disulfiram and/or Resatorvid. Caspase-1, GSDMD, and interleukin-1 beta (IL-1β) expression were measured by qRT-PCR and Western blotting. A cecal ligation and puncture (CLP) mouse model was used to study in vivo sepsis. Outcomes assessed included survival rate, sickness behavior score, lung wet-to-dry weight ratio, and neutrophil count in the lung.

RESULTS

Compared to healthy controls, GSDMD expression was elevated in monocytes from sepsis patients. Cleaved Caspase-1, N-terminal GSDMD fragments, and secreted IL-1β increased in monocytes were stimulated with HK S. aureus over time. Disulfiram pre-treatment reduced the secretion of IL-1β in HK S. aureus-stimulated monocytes. Resatorvid pre-treatment decreased levels of cleaved Caspase-1, N-terminal GSDMD fragments, and secreted IL-1β. Co-treatment with Disulfiram and Resatorvid resulted in greater reductions in cleaved Caspase-1, N-terminal GSDMD fragments, and IL-1β, and improved outcomes in the CLP mouse model, including higher survival rates, lower sickness behavior scores, reduced lung wet-to-dry weight ratios, and fewer neutrophils in the lung.

CONCLUSION

These findings indicated that pyroptosis of monocytes was activated in sepsis. Disulfiram and Resatorvid pre-treatment effectively suppressed the pyroptosis of monocytes through the Caspase-1/GSDMD/IL-1β signaling pathway. The combination of Disulfiram and Resatorvid showed potential as a therapeutic strategy to mitigate sepsis severity.

A DNA Nanopatch-Bacteriophage System Targeting Streptococcus Gallolyticus for Inflammatory Bowel Disease Treatment and Colorectal Cancer Prevention

Persistent inflammation in inflammatory bowel disease (IBD) increases Streptococcus gallolyticus (Sg) colonization, increasing the risk of colorectal cancer progression via the Sg-activated cyclooxygenase-2 (COX-2) pathway and β-catenin upregulation. This study presents Sg-specific bacteriophages modified with DNA nanopatches (DNPs@P) designed to treat IBD and prevent Sg-induced malignancy. The DNPs are composed of DNA origami nanosheets and phage capture strands. The DNPs scavenge reactive oxygen species, enhancing the therapeutic efficacy of the phages while targeting and lysing pathogenic bacteria. Coating with an enteric polymer, DNPs@P ensures effective delivery in the gastrointestinal tract. These findings demonstrate significant restoration of colonic length, reduced inflammation, and improved gut microbiota diversity compared with current clinical treatments. Additionally, DNPs@P effectively prevents colonic tumourigenesis in mouse models. This approach presents a promising strategy for treating gastrointestinal diseases by remodeling the gut microenvironment, addressing a critical gap in current therapies.

A Contemporary Picture of Coagulase-Negative Staphylococcal Endocarditis: A Nationwide GAMES Cohort Study

BACKGROUND

Coagulase-negative staphylococci (CoNS) are an increasingly common cause of infective endocarditis (IE) and lack recent data from large studies.

OBJECTIVES

Our aim was to describe the epidemiology, clinical characteristics, and outcomes of staphylococcal IE in a contemporary nationwide cohort study, while comparing coagulase-negative staphylococcal IE (CoNSIE) to IE from Staphylococcus aureus (SAIE), and among IE caused by Staphylococcus epidermidis (SE), S. lugdunensis (SL), and other CoNS.

METHODS

We completed a post hoc analysis of a prospectively collected cohort of 4,567 consecutive definitive IE episodes from 44 Spanish centers between 2008 and 2022 (GAMES ["Grupos de Apoyo al Manejo de la Endocarditis Infecciosa en España"] cohort). A total of 842 cases of CoNSIE were compared with 1,109 cases of SAIE. Additionally, 647 episodes caused by SE were compared with 54 caused by SL and 109 caused by 9 other known CoNS species. Multivariate analyses were performed to investigate prognostic factors for in-hospital and 1-year mortality.

RESULTS

Staphylococci accounted for 1,951 (42.7%) episodes of IE. The predominant CoNS etiology was SE (76.8%), followed by SL (6.4%), S. capitis (3.5%), S. haemolyticus (3.2%), S. hominis (3.2%), S. warneri (1.5%), and 5 other species. CoNSIE showed a distinct clinical profile from SAIE (older age, higher rates of prior heart disease, aortic and prosthetic valve involvement, nosocomial acquisition, methicillin resistance, intracardiac complications, and cardiac surgery), while in-hospital mortality was higher in SAIE (32.8% vs 37.1%; P = 0.049), with no significant differences in 1-year mortality. S. lugdunensis displayed a shorter course of infection and higher rates of leaflet perforation/rupture than S. epidermidis and other CoNS, but cardiac surgery rates (60.4% vs 61.1% vs 56.0%; P = 0.850), as well as in-hospital (33.1% vs 37.0% vs 27.5%; P = 0.540) and 1-year mortality rates were high and similar in all groups. Septic shock, heart failure, and cardiac surgery (protective) were consistently identified as independent prognostic factors, whereas none of the staphylococcal species were independently associated with mortality. Last, each 5-year study period was independently associated with a reduction in staphylococcal in-hospital and 1-year mortality.

CONCLUSIONS

CoNSIE was a relatively common (18.4%) and life-threatening entity with particularities by species yet generally high rates of surgery and mortality, although its prognosis improved over time.

Diagnostic Algorithm Using Multimodal Imaging for the Differential Diagnosis of Intra-Cardiac Masses

Cardiac masses are complex clinical conditions that frequently pose diagnostic challenges in cardiology practice. These masses can form within heart chambers or near the pericardium and are generally categorized as either non-neoplastic or neoplastic. These latter are further classified into benign and malignant (primary and secondary or metastatic). Diagnosing these conditions often requires a multiparametric approach that includes both clinical features, such as the patient's and associated clinical conditions, and multimodality imaging. However, histological examination of the resected specimen is often necessary to ascertain the nature of the mass. Given their heterogeneity and the rarity of many cardiac masses, there are no guidelines or consensus on the best diagnostic approach. Modern imaging protocols must be tailored to the specific clinical issues and patient characteristics, given the rapid advancements in technology. Thus, it is imperative to use a multimodality approach, combining different imaging techniques and multidisciplinary teamwork. Hereby, we propose a practical algorithm for evaluating cardiac lesions using a step-by-step implementation of multimodal imaging. Ultimately, the goal is to tailor the most suitable imaging technique to the patient's needs.

Etiological Aspects of Infectious Endocarditis in a Tertiary Hospital in Northeastern Romania

Background and Objectives: Infective endocarditis (IE) is a severe, life-threatening infection of the endocardial surface. Its incidence has shifted towards older, immunocompromised patients and those with cardiac devices. Materials and Methods: This study was conducted at the "Sf. Parascheva" Clinical Hospital of Infectious Diseases in Iasi, Romania, and retrospectively analyzed cases of IE from January 1, 2019, to September 30, 2024. It received ethical approval (Approval No. 7/17 June 2024). Results: The study included 130 patients with infectious endocarditis, predominantly men (75.38%), with a median age of 55 years. The most affected age groups were 50-59 and over 60 years, each representing 30.76% of cases. The most frequently implicated etiological agent was Staphylococcus aureus in 33% of cases. The most common antibiotic regimen combined glycopeptides and fluoroquinolones/polymyxins (27% cases). Conclusions: A multidisciplinary approach involving infectious disease specialists, cardiologists, and cardiovascular surgeons is essential for effective treatment. Immediate combined antibiotic therapy is vital for presumed IE cases. Despite advances in diagnosis and treatment, the high mortality rates highlight the importance of timely intervention. Future research should focus on improving preventive and therapeutic strategies for IE.

Infective Endocarditis Caused by Streptococcus viridans in a Previously Healthy Man: A Case Report

Infective endocarditis (IE) is a rare and potentially fatal infection of the heart valves, often caused by streptococci, staphylococci, and enterococci. This case is particularly significant as it describes IE caused by Streptococcus viridans in a 36-year-old male patient, previously healthy with no known risk factors, who presented with a three-week history of fever, night sweats, and fatigue. Initially, the clinical presentation was attributed to an atypical infection due to his occupational exposure, and he was empirically treated with doxycycline, showing apparent clinical improvement. However, blood cultures were positive for Streptococcus viridans, leading to hospitalization and suspicion of endocarditis. Echocardiography revealed congenital aortic valvulopathy (bicuspid aortic valve) with moderate regurgitation but no evidence of vegetation. A transesophageal echocardiogram identified vegetations, confirming the diagnosis of IE. Treatment with ceftriaxone and gentamicin resulted in a favorable clinical response after four weeks. This case highlights the diagnostic challenges of IE in atypical presentations and the importance of considering IE in patients with fever and positive blood cultures, even in the absence of known cardiac disease or previous risk factors. It also emphasizes the need for timely diagnosis to prevent severe complications associated with endocarditis. The authors aim to underscore the indolent course of IE in this rare clinical presentation.

Long Axial Field of View PET/CT: Technical Aspects in Cardiovascular Diseases

Positron emission tomography / computed tomography (PET/CT) plays a pivotal role in the assessment of cardiovascular diseases (CVD), particularly in the context of ischemic heart disease. Nevertheless, its application in other forms of CVD, such as infiltrative, infectious, or inflammatory conditions, remains limited. Recently, PET/CT systems with an extended axial field of view (LAFOV) have been developed, offering greater anatomical coverage and significantly enhanced PET sensitivity. These advancements enable head-to-pelvis imaging with a single bed position, and in systems with an axial field of view (FOV) of approximately 2 meters, even total body (TB) imaging is feasible in a single scan session. The application of LAFOV PET/CT in CVD presents a promising opportunity to improve systemic cardiovascular assessments and address the limitations inherent to conventional short axial field of view (SAFOV) devices. However, several technical challenges, including procedural considerations for LAFOV systems in CVD, complexities in data processing, arterial input function extraction, and artefact management, have not been fully explored. This review aims to discuss the technical aspects of LAFOV PET/CT in relation to CVD by highlighting key opportunities and challenges and examining the impact of these factors on the evaluation of most relevant CVD.

In Vitro Activity of Ampicillin Plus Ceftriaxone Against Non-faecalis and Non-faecium Enterococcal Isolates With/Without VanC Phenotype: Clinical Implications for Infective Endocarditis

(1) Background: Alternative antibiotics are needed to treat infective endocarditis (IE) caused by non-faecalis/non-faecium enterococci; we aimed to assess the in vitro activity of ampicillin plus ceftriaxone (AMP + CTR) against these enterococci and to describe its clinical efficacy in IE cases. (2) Methods: Time-kill curves with standard (ISI) and high (IHI) inocula were performed to test VanC isolates [3 E. casseliflavus (ECAS) and 1 E. gallinarum (EGALL)] and non-VanC isolates [1 E. durans (EDUR), 1 E. hirae (EHIR) and 1 E. raffinosus (ERAF)]. The narrative literature review of IE cases treated with AMP + CTR was analyzed alongside three study cases. Clinical outcomes were relapse and death. (3) Results: Ampicillin plus gentamicin (AMP + GEN) showed synergistic and bactericidal activity against most isolates. AMP + CTR was synergistic at ISI for EGALL, EDUR, and EHIR and bactericidal against EHIR. At IHI, indifferent activity was observed for all isolates. In IE cases treated with AMP + CTR, it was only effective for EDUR and EHIR. Clinical information for EGALL IE is lacking. For IE caused by ECAS and ERAF, AMP + CTR seems suboptimal or ineffective, respectively. (4) AMP + CTR cannot be recommended for treating IE due to ECAS/ERAF. In contrast, this combination was effective in IE caused by EDUR/EHIR and could be recommended.

Exploring links between oral health and infective endocarditis

Infective endocarditis (IE) is a bacterial infection of the heart's inner lining. A low incidence rate combined with a high mortality rate mean that IE can be difficult to treat effectively. There is currently substantial evidence supporting a link between oral health and IE with the oral microbiome impacting various aspects of IE, including pathogenesis, diagnosis, treatment, and mortality rates. The oral microbiome is highly diverse and plays a crucial role in maintaining oral health by providing protective functions. However, when dysbiosis occurs, conditions such as periodontal or peri-implant disease can arise, offering a pathway for bacteraemia to develop. The role of the oral microbiome as a coloniser, facilitator and driver of IE remains to be uncovered by next-generation sequencing techniques. Understanding the dysbiosis and ecology of the oral microbiome of IE patients will allow improvements into the diagnosis, treatment, and prognosis of the disease. Furthermore, an increased awareness amongst those at high-risk of developing IE may encourage improved oral hygiene methods and lower incidence rates. This narrative review examines current findings on the relationship between oral health and IE. It draws from key studies on both topics, with manuscripts selected for their pertinence to the subject. It highlights the link between the oral microbiome and IE by exploring diagnostic techniques and treatments for IE caused by oral commensals.

Three modes of viral adaption by the heart

Viruses elicit long-term adaptive responses in the tissues they infect. Understanding viral adaptions in humans is difficult in organs such as the heart, where primary infected material is not routinely collected. In search of asymptomatic infections with accompanying host adaptions, we mined for cardio-pathogenic viruses in the unaligned reads of nearly 1000 human hearts profiled by RNA sequencing. Among virus-positive cases (~20%), we identified three robust adaptions in the host transcriptome related to inflammatory nuclear factor κB (NF-κB) signaling and posttranscriptional regulation by the p38-MK2 pathway. The adaptions are not determined by the infecting virus, and they recur in infections of human or animal hearts and cultured cardiomyocytes. Adaptions switch states when NF-κB or p38-MK2 is perturbed in cells engineered for chronic infection by the cardio-pathogenic virus, coxsackievirus B3. Stratifying viral responses into reversible adaptions adds a targetable systems-level simplification for infections of the heart and perhaps other organs.

Infective Endocarditis With Origin in Orbital Vascular Malformation and Maxillary Sinusitis: A Case Report and Review of Four Patients in the Literature

Infective endocarditis is a life-threatening disease and the early diagnosis is crucial for a better outcome. We report an old adult who developed infective endocarditis in association with new-onset maxillary sinusitis as well as proptosis, which was caused by an orbital mass lesion in the background of pre-existing orbital vascular malformation. A 74-year-old woman was found incidentally to have right orbital vascular (venous) malformation by head magnetic resonance imaging when she was hospitalized for left dorsal pontine infarction. No paranasal sinusitis was noted at that time. She was well until half a year later when she developed fatigue and appetite loss for two days. At the same time, she had proptosis on the right side but did not have a fever. Blood examinations showed leukocytosis and a marked increase of C-reactive protein to 22 mg/dL as well as a moderate increase of bilirubin and liver enzymes. Emergency computed tomography scans from the head to abdomen showed nothing to be noted except for maxillary sinusitis and a retrobulbar orbital mass on the right side, which was in the same location as pre-existing vascular malformation. She began to have empirical antibiotics suspected of infective endocarditis. Head magnetic resonance imaging showed ischemic lesions in the right parietal lobe. Transthoracic and transesophageal echocardiography showed mitral valve regurgitation but no apparent vegetation. Streptococcus anginosus was detected by blood culture and the antibiotics were switched to intravenous penicillin G for 32 days. She was discharged in healthy condition with no proptosis. The orbital vascular malformation might serve as a route for infective endocarditis with the infectious origin in maxillary sinusitis. Maxillary sinusitis would be a predisposing factor for the development of infective endocarditis, and proptosis caused by an infectious focus of abnormal vascular channels in the orbit would lead to the early diagnosis of infective endocarditis. The present patient is unique in showing infective endocarditis in association with orbital vascular malformation.

Deficiency of hasB accelerated the clearance of Streptococcus equi subsp. Zooepidemicus through gasdermin d-dependent neutrophil extracellular traps

Streptococcus equi subsp. zooepidemicus (S. zooepidemicus, SEZ) is an essential zoonotic bacterial pathogen that can cause various inflammation, such as meningitis, endocarditis, and pneumonia. UDP-glucose dehydrogenase (hasB) is indispensable in synthesizing SEZ virulence factor hyaluronan capsules. Our study investigated the infection of hasB on mice response to SEZ by employing a constructed capsule-deficient mutant strain designated as the ΔhasB strain. This deficiency was associated with a reduced SEZ bacterial load in the mice's blood and peritoneal lavage fluid (PLF) post-infection. Besides, the ΔhasB SEZ strain exhibited a higher propensity for neutrophil infiltration and release of cell-free DNA (cfDNA) in vivo compared to the wild-type (WT) SEZ strain. In vitro experiments further revealed that ΔhasB SEZ more effectively induced the formation of neutrophil extracellular traps (NETs) containing histone 3 (H3), neutrophil elastase (NE), and DNA, than its WT counterpart. Moreover, the release of NETs was determined to be gasdermin D (GSDMD)-dependent during the infection process. Taken together, these findings underscore that the deficiency of the hasB gene in SEZ leads to enhanced GSDMD-dependent NET release from neutrophils, thereby reducing SEZ's capacity to resist NETs-mediated eradication during infection. Our finding paves the way for the development of innovative therapeutic strategies against SEZ.

Aortic Homografts in Surgical Management of Prosthetic Valve Endocarditis: A Case Series from Greece

BACKGROUND Infective endocarditis (IE) is a severe, life-threatening, and relatively common complication after valve replacement operations, with incidence rates varying between 1.8% and 5.8%, with an in-hospital mortality rate of up to 20%. Common microorganisms are (listed by decreasing incidence) Streptococci, Staphylococcus aureus, Enterococci, bacteria of the HACEK group, and fungi. Treatment of IE is complex, typically involving prolonged courses of antibiotics. However, in cases of aortic prosthetic valve endocarditis, root abscess formation with involvement of the aorto-mitral skeleton is not uncommon and complex surgical intervention is required. One of the notable advancements in surgical management is the use of homografts for aortic root endocarditis. CASE REPORT We report the first case series of 8 patients successfully operated on for prosthetic valve endocarditis with extensive aortic root abscess formation in Greece at Onassis Cardiac Surgery Center with the use of aortic homograft. All cases were redo surgeries and had good outcomes. Interestingly, one of the cases had extensive aortic root involvement with abscess formation extending to the aorto-mitral fibrous skeleton, requiring aortic root replacement with homograft, aorto-mitral skeleton reconstruction with bovine pericardium and mitral valve replacement with a mechanical prosthesis. Two other patients required concomitant coronary bypass grafting of the right coronary artery with reversed saphenous vein grafts. CONCLUSIONS Aortic root replacement with aortic homograft is the preferred choice for prosthetic valve endocarditis with aortic root abscess formation. Despite the technical complexity needed for implantation, this option offers a second chance for survival in patients with this challenging condition.

Mitral valve infective endocarditis as a manifestation of disseminated Cryptococcus neoformans infection: a case report

Infective endocarditis is a disease that affects mainly the endocardial surface of the heart and cardiac valves (native or prosthetic). The main risk factors for developing infective endocarditis are male sex, older age, intracardiac shunts, prosthetic valves, rheumatic, and congenital heart disease, intracardiac devices, intravenous drugs use, immunosuppression, and hemodialysis. Streptococci and Staphylococci spp. have been the most frequent isolated organisms. On the other hand, the most common fungal organism in infective endocarditis is Candida albicans (24-46%), followed by Aspergillus spp. (25%), and a few cases by Cryptococcus neoformans, which are associated with higher rate of mortality. This case provides an interesting case of Cryptococcus neoformans native valve infective endocarditis in a young woman with stage IV chronic kidney disease and severe malnutrition.

Preoperative fibrinogen level predicts the risk and prognosis of patients with native valve infective endocarditis undergoing valve surgery

Aim

The aim of this study was to assess the clinical significance and prognostic value of the preoperative fibrinogen (FBG) level in patients with native valve infective endocarditis (NVIE) who underwent valve surgery.

Methods

This retrospective study included a total of 163 consecutive patients who were diagnosed with NVIE and underwent valve surgery from January 2019 to January 2022 in our hospital. The primary endpoint was all-cause mortality.

Results

All-cause mortality was observed in 9.2% of the patients (n = 15). Body mass index (BMI) was lower in the survival group (p = 0.025), whereas FBG (p = 0.008) and platelet count (p = 0.044) were significantly greater in the survival group than in the death group. Multivariate Cox proportional hazards analysis revealed that FBG (HR, 0.55; 95% CI, [0.32-0.94]; p = 0.029) was an independent prognostic factor for all-cause mortality. Furthermore, Kaplan‒Meier survival curve analysis revealed that patients with low FBG levels (<3.28 g/L) had a significantly greater mortality rate (p = 0.034) than did those with high FBG levels (>3.99 g/L). In the trend analysis, the FBG tertiles were significantly related to all-cause mortality in all three adjusted models, and the p values for trend were 0.017, 0.016, and 0.028, respectively.

Conclusion

Preoperative FBG may serve as a prognostic factor for all-cause mortality, and an FBG concentration less than 3.28 g/L was associated with a greater risk of all-cause mortality in NVIE patients undergoing valve surgery.

Enterococcal-host interactions in the gastrointestinal tract and beyond

The gastrointestinal tract (GIT) is typically considered the natural niche of enterococci. However, these bacteria also inhabit extraintestinal tissues, where they can disrupt organ physiology and cause life-threatening infections. Here, we discuss how enterococci, primarily Enterococcus faecalis, interact with the intestine and other host anatomical locations such as the oral cavity, heart, liver, kidney, and vaginal tract. The metabolic flexibility of these bacteria allows them to quickly adapt to new environments, promoting their persistence in diverse tissues. In transitioning from commensals to pathogens, enterococci must overcome harsh conditions such as nutrient competition, exposure to antimicrobials, and immune pressure. Therefore, enterococci have evolved multiple mechanisms to adhere, colonize, persist, and endure these challenges in the host. This review provides a comprehensive overview of how enterococci interact with diverse host cells and tissues across multiple organ systems, highlighting the key molecular pathways that mediate enterococcal adaptation, persistence, and pathogenic behavior.

Population genomics of Streptococcus mitis in UK and Ireland bloodstream infection and infective endocarditis cases

Streptococcus mitis is a leading cause of infective endocarditis (IE). However, our understanding of the genomic epidemiology and pathogenicity of IE-associated S. mitis is hampered by low IE incidence. Here we use whole genome sequencing of 129 S. mitis bloodstream infection (BSI) isolates collected between 2001-2016 from clinically diagnosed IE cases in the UK to investigate genetic diversity, antimicrobial resistance, and pathogenicity. We show high genetic diversity of IE-associated S. mitis with virtually all isolates belonging to distinct lineages indicating no predominance of specific lineages. Additionally, we find a highly variable distribution of known pneumococcal virulence genes among the isolates, some of which are overrepresented in disease when compared to carriage strains. Our findings suggest that S. mitis in patients with clinically diagnosed IE is not primarily caused by specific hypervirulent or antimicrobial resistant lineages, highlighting the accidental pathogenic nature of S. mitis in patients with clinically diagnosed IE.

Unexpected Infective Endocarditis: Towards a New Alert for Clinicians

Despite the clear indications and worldwide application of specific guidelines, the recognition of Infective Endocarditis (IE) may be challenging in day-to-day clinical practice. Significant changes in the epidemiological and clinical profile of IE have been observed, including variations in the populations at risk and an increased incidence in subjects without at-risk cardiac disease. Emergent at-risk populations for IE particularly include immunocompromised patients with a comorbidity burden (e.g., cancer, diabetes, dialysis), requiring long-term central venous catheters or recurrent healthcare interventions. In addition, healthy subjects, such as skin-contact athletes or those with piercing implants, may be exposed to the transmission of highly virulent bacteria (through the skin or mucous), determining endothelial lesions and subsequent IE, despite the absence of pre-existing at-risk cardiac disease. Emergent at-risk populations and clinical presentation changes may subvert the conventional paradigm of IE toward an unexpected clinical scenario. Owing to its unusual clinical context, IE might be overlooked, resulting in a challenging diagnosis and delayed treatment. This review, supported by a series of clinical cases, analyzed the subtle and deceptive phenotypes subtending the complex syndrome of unexpected IE. The awareness of an unexpected clinical course should alert clinicians to also consider IE diagnosis in patients with atypical features, enhancing vigilance for preventive measures in an emergent at-risk population untargeted by conventional workflows.

Enterococcal quorum-controlled protease alters phage infection

Increased prevalence of multidrug-resistant bacterial infections has sparked interest in alternative antimicrobials, including bacteriophages (phages). Limited understanding of the phage infection process hampers our ability to utilize phages to their full therapeutic potential. To understand phage infection dynamics, we performed proteomics on Enterococcus faecalis infected with the phage VPE25. We discovered that numerous uncharacterized phage proteins are produced during phage infection of E. faecalis. Additionally, we identified hundreds of changes in bacterial protein abundances during infection. One such protein, enterococcal gelatinase (GelE), an fsr quorum-sensing-regulated protease involved in biofilm formation and virulence, was reduced during VPE25 infection. Plaque assays showed that mutation of either the quorum-sensing regulator fsrA or gelE resulted in plaques with a "halo" morphology and significantly larger diameters, suggesting decreased protection from phage infection. GelE-associated protection during phage infection is dependent on the putative murein hydrolase regulator LrgA and antiholin-like protein LrgB, whose expression have been shown to be regulated by GelE. Our work may be leveraged in the development of phage therapies that can modulate the production of GelE thereby altering biofilm formation and decreasing E. faecalis virulence.

Innovative Management of Blood Culture-Negative Endocarditis With Pulmonary Septic Emboli in a Patient With a Biventricular Pacemaker and Implantable Cardioverter Defibrillator (BiV-ICD) and Psychosocial Stressors: A Case Report

Blood culture-negative endocarditis (BCNE) poses significant diagnostic and therapeutic challenges and is associated with notable morbidity and mortality. When presented concurrently with other comorbidities, these challenges and the chances of morbidity and mortality significantly increase. This case presents right-sided BCNE accompanied by pulmonary cavitary lesions in a patient with a history of supraventricular tachycardias (SVT), a biventricular pacemaker and implantable cardioverter-defibrillator (BiV-ICD), alcohol use, and anticoagulant noncompliance. The patient missed follow-up appointments for six months after the death of his wife, leading to increased alcohol use and noncompliance with medications. During this period, his home monitoring device was offline. Once reconnected, it detected several episodes of SVT and ventricular tachycardia (VT), prompting a wellness check. He presented to the cardiology clinic with shortness of breath and a cough producing brown-tinged sputum. Evaluation revealed cavitary lesions in the lingula and left lower lobe, a vegetation on his tricuspid valve, and vegetations on his endocardial leads, despite negative blood cultures. Tuberculosis testing was negative, while sputum cultures were positive for Haemophilus influenzae. After ruling out other possible infectious causes of the cavitary lesions, septic emboli were suspected as the cause. Broad-spectrum antibiotics were begun and surgical intervention was done to replace the tricuspid valve and remove the endocardial leads. This procedure was complicated by fibrosis of the leads at the coronary sinus, necessitating their cutting at the superior vena cava and leaving them inside the patient until laser therapy could be performed for their removal. The patient's history of bradycardia and SVTs required the ongoing use of a pacemaker. Inventory discrepancy during the placement of the new pacemaker epicardial leads lead to complications warranting an alternative approach to lead implantation. A traditionally used epicardial lead was placed on the right ventricle for pacing, and an innovative technique was employed to place an endocardial lead on the right atrium epicardium for sensing. This case underscores the importance of thorough evaluation and collaborative management strategies to optimize outcomes for patients with concomitant cardiac and pulmonary pathologies, particularly in the context of underlying psychosocial stressors. Additionally, it demonstrates solutions to challenges that can arise during surgery and presents an alternative lead placement technique for physicians who have only one epicardial lead available after removing infected endocardial leads. This is illustrated by the innovative use of an endocardial lead as an epicardial sensing lead.

Infective Endocarditis Caused by Carbapenemase-Producing Klebsiella pneumoniae on a Prosthetic Valve: A Case Report and Review of the Literature

Infective endocarditis (IE) is a rare but severe disease due to frequent and serious complications. Healthcare-associated cases often involve Staphylococcus aureus, while Gram-negative bacteria such as Klebsiella pneumoniae, though rare, pose severe challenges due to their resistance profiles. We report a case of a 68-year-old woman with a history of hypertension and mitral valve replacement 12 years ago, who was admitted to the intensive care unit (ICU) for management of non-traumatic, afebrile altered mental status due to intracerebral hemorrhage from anticoagulant overdose. His stay in the ICU revealed septic shock with multi-organ failure caused by carbapenemase (New Delhi metallo-β-lactamase (NDM))-producing K. pneumoniae complicated by IE on the prosthetic mitral valve. Despite treatment with meropenem, colistin, and tigecycline, the patient succumbed to septic shock after 15 days of therapy. This case highlights the importance of close surveillance of nosocomial infections and the need for prompt management strategies integrating medical and surgical approaches to reduce the high mortality associated with such infections.

Role of the Lymphatics in Cardiac Disease

Cardiovascular diseases remain the largest cause of death worldwide with recent evidence increasingly attributing the development and progression of these diseases to an exacerbated inflammatory response. As a result, significant research is now focused on modifying the immune environment to prevent the disease progression. This in turn has highlighted the lymphatic system in the pathophysiology of cardiovascular diseases owing, in part, to its established function in immune cell surveillance and trafficking. In this review, we highlight the role of the cardiac lymphatic system and its potential as an immunomodulatory therapeutic target in selected cardiovascular diseases.

Enterococcal quorum-controlled protease alters phage infection

Increased prevalence of multidrug resistant bacterial infections has sparked interest in alternative antimicrobials, including bacteriophages (phages). Limited understanding of the phage infection process hampers our ability to utilize phages to their full therapeutic potential. To understand phage infection dynamics we performed proteomics on Enterococcus faecalis infected with the phage VPE25. We discovered numerous uncharacterized phage proteins are produced during phage infection of Enterococcus faecalis. Additionally, we identified hundreds of changes in bacterial protein abundances during infection. One such protein, enterococcal gelatinase (GelE), an fsr quorum sensing regulated protease involved in biofilm formation and virulence, was reduced during VPE25 infection. Plaque assays showed that mutation of either the fsrA or gelE resulted in plaques with a "halo" morphology and significantly larger diameters, suggesting decreased protection from phage infection. GelE-associated protection during phage infection is dependent on the murein hydrolase regulator LrgA and antiholin-like protein LrgB, whose expression have been shown to be regulated by GelE. Our work may be leveraged in the development of phage therapies that can modulate the production of GelE thereby altering biofilm formation and decreasing E. faecalis virulence.

CCR2-dependent CX3CR1+ colonic macrophages promote Enterococcus faecalis dissemination

Enterococci are common commensal bacteria that colonize the gastrointestinal tracts of most mammals, including humans. Importantly, these bacteria are one of the leading causes of nosocomial infections. This study examined the role of colonic macrophages in facilitating Enterococcus faecalis infections in mice. We determined that depletion of colonic phagocytes resulted in the reduction of E. faecalis dissemination to the gut-draining mesenteric lymph nodes. Furthermore, we established that trafficking of monocyte-derived CX3CR1-expressing macrophages contributed to E. faecalis dissemination in a manner that was not reliant on CCR7, the conventional receptor involved in lymphatic migration. Finally, we showed that E. faecalis mutants with impaired intracellular survival exhibited reduced dissemination, suggesting that E. faecalis can exploit host immune cell migration to disseminate systemically and cause disease. Our findings indicate that modulation of macrophage trafficking in the context of antibiotic therapy could serve as a novel approach for preventing or treating opportunistic infections by disseminating enteric pathobionts like E. faecalis.

Gut microbiome and resistome characterization of pigs treated with commonly used post-weaning diarrhea treatments

BACKGROUND

The global burden of antimicrobial resistance demands additional measures to ensure the sustainable and conscious use of antimicrobials. For the swine industry, the post-weaning period is critical and for many years, antimicrobials have been the most effective strategy to control and treat post-weaning related infections. Among them, post-weaning diarrhea causes vast economic losses, as it severely compromises piglets' health and growth performance. In this study, 210 piglets were transferred from a farm with recurrent cases of post-weaning diarrhea to an experimental farm and divided into six different treatment groups to determine the effect of the different treatments on the growth performance and survival, the microbiome, and the resistome in a cross-sectional and longitudinal study. The different treatments included antimicrobials trimethoprim/sulfamethoxazole, colistin, and gentamicin, an oral commercial vaccine, a control with water acidification, and an untreated control. An extra group remained at the farm of origin following the implemented amoxicillin routine treatment. A total of 280 fecal samples from pigs at four different sampling times were selected for metagenomics: before weaning-treatment at the farm of origin, and three days, two weeks, and four weeks post-treatment.

RESULTS

The control group with water acidification showed a reduced death risk in the survival analyses and non-significant differences in average daily weight gain in comparison to the antibiotic-treated groups. However, the growth-promoting effect among antibiotic-treated groups was demonstrated when comparing against the untreated control group at the experimental farm. After four weeks of treatment, diversity indexes revealed significantly decreased diversity for the untreated control and the group that remained at the farm of origin treated with amoxicillin. For this last group, impaired microbial diversity could be related to the continuous amoxicillin treatment carried out at the farm. Analysis of the resistome showed that both gentamicin and amoxicillin treatments significantly contributed to the emergence of resistance, while trimethoprim/sulphonamide and colistin did not, suggesting that different treatments contribute differently to the emergence of resistance.

CONCLUSIONS

Overall, this shotgun longitudinal metagenomics analysis demonstrates that non-antibiotic alternatives, such as water acidification, can contribute to reducing the emergence of antimicrobial resistance without compromising pig growth performance and gut microbiome.

Exploring Unusual Cardiac Complications: Chorda Tendinea Rupture and Pulmonary Valve Vegetation in Infective Endocarditis-A Comprehensive Review

Infective endocarditis (IE) is a severe infection of the endocardium, frequently involving heart valves, and is associated with significant morbidity and mortality. At the same time, traditional complications of IE, such as valvular dysfunction and embolic events, are well-documented, and uncommon cardiac manifestations, such as chorda tendinea rupture and pulmonary valve vegetation, present unique diagnostic and management challenges. This comprehensive review explores the pathophysiology, clinical presentation, diagnostic strategies, and management approaches for IE's chorda tendinea rupture and pulmonary valve vegetation. Through a detailed examination of the literature and discussion of clinical scenarios, we highlight the importance of recognizing these rare complications and discuss the implications for clinical practice. Additionally, we identify knowledge gaps and propose areas for future research to enhance further our understanding and management of these unusual cardiac complications in IE. This review aims to provide clinicians with valuable insights to improve patient care and outcomes in the challenging setting of infective endocarditis.

Splenic Embolism in Infective Endocarditis: A Systematic Review of the Literature with an Emphasis on Radiological and Histopathological Diagnoses

Infective endocarditis (IE) is characterised by fever, heart murmurs, and emboli. Splenic emboli are frequent in left-sided IE. A systematic review of the literature published on splenic embolism (SE) between 2000 and 2023 was conducted. Search strategies in electronic databases identified 2751 studies published between 1 January 2000 and 4 October 2023, of which 29 were finally included. The results showed that the imaging tests predominantly used to detect embolisms were computed tomography (CT), magnetic resonance imaging, positron emission tomography (PET)/CT, single-photon emission computed tomography/CT, ultrasound, and contrast-enhanced ultrasound. More recent studies typically used 18F-FDG PET-CT. The proportion of SE ranged from 1.4% to 71.7%. Only seven studies performed systematic conventional CT screening for intra-abdominal emboli, and the weighted mean frequency of SE was 22% (range: 8-34.8%). 18F-FDG PET-CT was performed systematically in seven studies, and splenic uptake was found in a weighted mean of 4.5%. There was a lack of uniformity in the published literature regarding the frequency and management of splenic embolisation. CT scans were the most frequently used method, until recently, when 18F-FDG PET-CT scans began to predominate. More data are necessary regarding the frequency of SE, especially focusing on their impact on IE management and prognosis.

Epidemiology, microbiology, and outcomes of infective endocarditis in a tertiary center in Jordan

BACKGROUND

Infective endocarditis (IE) is a relatively rare but serious and life-threatening disease with substantial mortality and morbidity despite progress in diagnostic and treatment techniques. The aim of this study is to investigate the epidemiology, clinical characteristics, microbiological profile, and outcomes of IE patients in a tertiary care facility in Jordan, the Jordan University Hospital (JUH).

METHODS

This is a retrospective case series study which was conducted at JUH. A total of 23 patients with either definite or possible IE according to the Modified Duke Criteria were included in the study. Medical records were reviewed, and relevant information was collected. Descriptive data analysis was performed.

RESULTS

Our study identified a total of 23 patients with infective endocarditis; 65.2% were males, with a mean age of 40.4 years. The majority of patients had an underlying cardiac disease (60.9%), with the most common being congenital heart diseases (17.4%). The most commonly affected valves were the left-side heart valves, with the mitral valve (52.2%) being the most common followed by the aortic valve (34.8%). The most common organism detected in blood culture was Streptococcus viridans (21.7%) followed by methicillin-resistant Staphylococcus aureus. The most common complications among the patients were heart failure and septic shock, and the mortality rate among the patients was 13%.

CONCLUSION

In patients with endocarditis, Streptococcus viridans is the most common culture-positive bacteria at JUH. One third of our patients needed surgical intervention and the mortality rate was 13%.

Three Modes of Viral Adaption by the Heart

Viruses elicit long-term adaptive responses in the tissues they infect. Understanding viral adaptions in humans is difficult in organs such as the heart, where primary infected material is not routinely collected. In search of asymptomatic infections with accompanying host adaptions, we mined for cardio-pathogenic viruses in the unaligned reads of nearly one thousand human hearts profiled by RNA sequencing. Among virus-positive cases (~20%), we identified three robust adaptions in the host transcriptome related to inflammatory NFκB signaling and post-transcriptional regulation by the p38-MK2 pathway. The adaptions are not determined by the infecting virus, and they recur in infections of human or animal hearts and cultured cardiomyocytes. Adaptions switch states when NFκB or p38-MK2 are perturbed in cells engineered for chronic infection by the cardio-pathogenic virus, coxsackievirus B3. Stratifying viral responses into reversible adaptions adds a targetable systems-level simplification for infections of the heart and perhaps other organs.

Current Knowledge of Enterococcal Endocarditis: A Disease Lurking in Plain Sight of Health Providers

Enterococcus faecalis is a bacterial pathogen that can cause opportunistic infections. Studies indicate that initial biofilm formation plays a crucial regulatory role in these infections, as well as in colonising and maintaining the gastrointestinal tract as a commensal member of the microbiome of most land animals. It has long been thought that vegetation of endocarditis resulting from bacterial attachment to the endocardial endothelium requires some pre-existing tissue damage, and in animal models of experimental endocarditis, mechanical valve damage is typically induced by cardiac catheterisation preceding infection. This section reviews historical and contemporary animal model studies that demonstrate the ability of E. faecalis to colonise the undamaged endovascular endothelial surface directly and produce robust microcolony biofilms encapsulated within a bacterially derived extracellular matrix. This report reviews both previous and current animal model studies demonstrating the resilient capacity of E. faecalis to colonise the undamaged endovascular endothelial surface directly and produce robust microcolony biofilms encapsulated in a bacterially derived extracellular matrix. The article also considers the morphological similarities when these biofilms develop on different host sites, such as when E. faecalis colonises the gastrointestinal epithelium as a commensal member of the common vertebrate microbiome, lurking in plain sight and transmitting systemic infection. These phenotypes may enable the organism to survive as an unrecognised infection in asymptomatic subjects, providing an infectious resource for subsequent clinical process of endocarditis.

The Surgical Treatment of Infective Endocarditis: A Comprehensive Review

Infective endocarditis (IE) is a severe cardiac complication with high mortality rates, especially when surgical intervention is delayed or absent. This review addresses the expanding role of surgery in managing IE, focusing on the variation in surgical treatment rates, the impact of patient demographics, and the effectiveness of different surgical approaches. Despite varying global data, a notable increase in surgical interventions for IE is evident, with over 50% of patients undergoing surgery in tertiary centres. This review synthesizes information from focused literature searches up to July 2023, covering preoperative to postoperative considerations and surgical strategies for IE. Key preoperative concerns include accurate diagnosis, appropriate antimicrobial treatment, and the timing of surgery, which is particularly crucial for patients with heart failure or at risk of embolism. Surgical approaches vary based on valve involvement, with mitral valve repair showing promising outcomes compared to replacement. Aortic valve surgery, traditionally favouring replacement, now includes repair as a viable option. Emerging techniques such as sutureless valves and aortic homografts are explored, highlighting their potential advantages in specific IE cases. The review also delves into high-risk groups like intravenous drug users and the elderly, emphasizing the need for tailored surgical strategies. With an increasing number of patients presenting with prosthetic valve endocarditis and device-related IE, the review underscores the importance of comprehensive management strategies encompassing surgical and medical interventions. Overall, this review provides a comprehensive overview of current evidence in the surgical management of IE, highlighting the necessity of a multidisciplinary approach and ongoing research to optimize patient outcomes.

Elucidating common pathogenic transcriptional networks in infective endocarditis and sepsis: integrated insights from biomarker discovery and single-cell RNA sequencing

Background

Infective Endocarditis (IE) and Sepsis are two closely related infectious diseases, yet their shared pathogenic mechanisms at the transcriptional level remain unclear. This research gap poses a barrier to the development of refined therapeutic strategies and drug innovation.

Methods

This study employed a collaborative approach using both microarray data and single-cell RNA sequencing (scRNA-seq) data to identify biomarkers for IE and Sepsis. It also offered an in-depth analysis of the roles and regulatory patterns of immune cells in these diseases.

Results

We successfully identified four key biomarkers correlated with IE and Sepsis, namely CD177, IRAK3, RNASE2, and S100A12. Further investigation revealed the central role of Th1 cells, B cells, T cells, and IL-10, among other immune cells and cytokines, in the pathogenesis of these conditions. Notably, the small molecule drug Matrine exhibited potential therapeutic effects by targeting IL-10. Additionally, we discovered two Sepsis subgroups with distinct inflammatory responses and therapeutic strategies, where CD177 demonstrated significant classification value. The reliability of CD177 as a biomarker was further validated through qRT-PCR experiments.

Conclusion

This research not only paves the way for early diagnosis and treatment of IE and Sepsis but also underscores the importance of identifying shared pathogenic mechanisms and novel therapeutic targets at the transcriptional level. Despite limitations in data volume and experimental validation, these preliminary findings add new perspectives to our understanding of these complex diseases.

The Trimeric Autotransporter Adhesin EmaA and Infective Endocarditis

Infective endocarditis (IE), a disease of the endocardial surface of the heart, is usually of bacterial origin and disproportionally affects individuals with underlying structural heart disease. Although IE is typically associated with Gram-positive bacteria, a minority of cases are caused by a group of Gram-negative species referred to as the HACEK group. These species, classically associated with the oral cavity, consist of bacteria from the genera Haemophilus (excluding Haemophilus influenzae), Aggregatibacter, Cardiobacterium, Eikenella, and Kingella. Aggregatibacter actinomycetemcomitans, a bacterium of the Pasteurellaceae family, is classically associated with Aggressive Periodontitis and is also concomitant with the chronic form of the disease. Bacterial colonization of the oral cavity serves as a reservoir for infection at distal body sites via hematological spreading. A. actinomycetemcomitans adheres to and causes disease at multiple physiologic niches using a diverse array of bacterial cell surface structures, which include both fimbrial and nonfimbrial adhesins. The nonfimbrial adhesin EmaA (extracellular matrix binding protein adhesin A), which displays sequence heterogeneity dependent on the serotype of the bacterium, has been identified as a virulence determinant in the initiation of IE. In this chapter, we will discuss the known biochemical, molecular, and structural aspects of this protein, including its interactions with extracellular matrix components and how this multifunctional adhesin may contribute to the pathogenicity of A. actinomycetemcomitans.

The Predictive Value of Sepsis Scores for In-Hospital Mortality in Patients with Left-Sided Infective Endocarditis

BACKGROUND

As infective endocarditis has particular characteristics compared to other infectious diseases, it is not clear if sepsis scores are reported with good accuracy in these patients. The aim of this study is to evaluate the accuracy of the qSOFA and SOFA scores to predict mortality in patients with infective endocarditis.

METHODS

Between January 2010 and June 2019, 867 patients with suspected left-sided endocarditis were evaluated; 517 were included with left-sided infective endocarditis defined as "possible" or "definite" endocarditis, according to the Modified Duke Criteria. ROC curves were constructed to assess the accuracy of qSOFA and SOFA sepsis scores for the prediction of in-hospital mortality.

RESULTS

The median age was 57 years, 65% were male, 435 (84%) had pre-existing heart valve disease, and the overall mortality was 28%. The most frequent etiologies were Streptococcus spp. (36%), Enterococcus spp. (10%), and Staphylococcus aureus (9%). The sepsis scores from the ROC curves used to predict in-hospital mortality were qSOFA 0.601 (CI95% 0.522-0.681) and SOFA score 0.679 (CI95% 0.602-0.756). A sub-group analysis in patients with and without pre-existing valve disease for SOFA ≥ 2 showed ROC curves of 0.627 (CI95% 0.563-0.690) and 0.775 (CI95% 0.594-0.956), respectively.

CONCLUSIONS

qSOFA and SOFA scores were associated with increased in-hospital mortality in patients with infective endocarditis. However, as accuracy was relatively lower compared to other sites of bacterial infections, we believe that this score may have lower accuracy when predicting the prognosis of patients with IE, because, in this disease, the patient's death may be more frequently linked to valvular and cardiac dysfunction, as well as embolic events, and less frequently directly associated with sepsis.

Prevalence, Characteristics, and Outcomes of Infective Endocarditis Readmissions in Patients With Variables Associated With Liver Disease in the United States

Infective endocarditis (IE) is common in patients with liver disease. Outcomes of IE in patients with liver disease are limited. We aimed to investigate IE outcomes in patients with variables associated with liver disease in the USA. We used the 2017 National Readmission Database to identify index admission of adults with IE, based on the International Classification of Disease, 10th revision codes. The primary outcome was 30-day readmission. Secondary outcomes were mortality and predictors of hospital readmission. We identified 40,413 IE admissions. Patients who were readmitted were more likely to have a history of HCV (19.4 vs 12.3%, P < .001), hyponatremia (25 vs 21%, P < .001), and thrombocytopenia (20.3 vs 16.3%, P < .001). After adjusting for age, hypertension, heart failure, diabetes mellitus, and end stage renal disease, hyponatremia (odds ratio (OR) 1.25; 95% confidence intervals [CI]: 1.17-1.35; P < .001) and thrombocytopenia (OR 1.16; 95% CI: 1.08-1.24; P < .001) correlated with higher odds of 30-day readmission. Mortality was higher among patients with hyponatremia (29 vs 22%, P < .001), thrombocytopenia (29 vs 17%, P < .001), coagulopathy (12 vs 5%, P < .001), cirrhosis (6 vs 4%, P < .001), ascites (7 vs 3%, P < .001), liver failure (18 vs 3%, P < .001), and portal hypertension (3 vs 1.5%, P < .001).

B-type natriuretic peptide levels at admission predict the prognosis of patients with infective endocarditis undergoing cardiac surgery

Purpose: The objective of this study was to explore the relationship between elevated B-type natriuretic peptide (BNP) levels and the prognosis of patients with infective endocarditis (IE) undergoing cardiac surgery. Methods: In total, 162 IE patients with recorded BNP levels upon admission were included in the present study. The primary end point was all-cause mortality. Results: Multivariate Cox analysis revealed a significant association between log BNP and all-cause mortality. Kaplan-Meier analysis revealed a poorer prognosis for patients with BNP levels ≥ the 75th percentile. Furthermore, the linear trend test indicated a significant link between BNP quartiles and the primary end point within the models. Conclusion: Elevated BNP levels upon admission could predict all-cause mortality in IE patients undergoing cardiac surgery.

Initiation of warfarin is associated with decreased mortality in patients with infective endocarditis: A population-based cohort study

IMPORTANCE

The use of warfarin to prevent thromboembolism in patients with infective endocarditis (IE) remains controversial due to potentially increased bleeding risks.

DESIGN

Population-based retrospective cohort study.

PARTICIPANTS

Patients aged 18 or older and diagnosed with IE in Hong Kong between January 1st, 1997 and August 31st, 2020 were included. Patients with use of any anticoagulant 30 days before IE diagnosis were excluded. Patients initiated on warfarin within 14 days of IE diagnosis and patients without warfarin use were matched for baseline characteristics using 1:1 propensity score matching.

EXPOSURE

Warfarin use within 14 days of IE diagnosis.

MAIN OUTCOMES AND MEASURES

Patients were followed up to 90 days for the outcomes of ischemic stroke, all-cause mortality, intracranial hemorrhage, and gastrointestinal bleeding. Cox regression was used to determine hazard ratios (HRs) [95 % confidence intervals (CIs)] between treatment groups. Fine-Gray competing risk regression with all-cause mortality as the competing event was performed as a sensitivity analysis. In addition to 90-day analyses, landmark analyses were performed at 30 days of follow-up.

RESULTS

The matched cohort consisted of 675 warfarin users (57.0 % male, age 59 ± 16 years) and 675 warfarin non-users (53.5 % male, age 61 ± 19 years). Warfarin users had a 50 % decreased 90-day risk in all-cause mortality (HR:0.50 [0.39-0.65]), without significantly different 90-day risks of ischemic stroke (HR:1.04 [0.70-1.53]), intracranial hemorrhage (HR:1.25 [0.77-2.04]), and gastrointestinal bleeding (HR:1.04 [0.60-1.78]). Thirty-day landmark analysis showed similar results. Competing risk regression showed significantly higher 30-day cumulative incidence of intracranial hemorrhage in warfarin users (sub-HR:3.34 [1.34-8.31]), but not at 90-day (sub-HR:1.63 [0.95-2.81]). Results from Fine-Gray regression were otherwise congruent with those from Cox regression.

CONCLUSIONS AND RELEVANCE

Warfarin initiated within 14 days of IE diagnosis was associated with significantly decreased risks of mortality but higher risks of intracranial hemorrhage, with similar risks of ischemic stroke and gastrointestinal bleeding, compared with non-use of warfarin with 14 days of IE diagnosis.

KEY POINTS

Question: Is warfarin, initiated within 14 days of a diagnosis of infective endocarditis (IE), efficacious and safe?

FINDINGS

In this propensity score-matched, population-based, prospective cohort study from Hong Kong, warfarin use within 14 days of IE diagnosis was associated with a 50 % decrease in the risk of all-cause mortality, albeit with higher risk of intracranial hemorrhage, and without significant differences in the risk of ischaemic stroke and gastrointestinal bleeding. Meaning: In patients with IE, warfarin use within 14 days of diagnosis may have mortality benefits, despite increased risks of intracranial hemorrhage.

Comparison of Blood-Based Shotgun and Targeted Metagenomic Sequencing for Microbiological Diagnosis of Infective Endocarditis

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.

PASTA-kinase-mediated signaling drives accumulation of the peptidoglycan synthesis protein MurAA to promote cephalosporin resistance in Enterococcus faecalis

The bacterial PASTA kinase, IreK, is required for intrinsic cephalosporin resistance in the Gram-positive opportunistic pathogen, Enterococcus faecalis. IreK activity is enhanced in response to cell wall stress, such as cephalosporin exposure. The downstream consequences of IreK activation are not well understood in E. faecalis, but recent work in other low-GC Gram-positive bacteria demonstrated PASTA kinase-dependent regulation of MurAA, an enzyme that performs the first committed step in the peptidoglycan synthesis pathway. Here, we used genetic suppressor selections to identify MurAA as a downstream target of IreK signaling in E. faecalis. Using complementary genetic and biochemical approaches, we demonstrated that MurAA abundance is regulated by IreK signaling in response to physiologically relevant cell wall stress to modulate substrate flux through the peptidoglycan synthesis pathway. Specifically, the IreK substrate, IreB, promotes proteolysis of MurAA through a direct physical interaction in a manner responsive to phosphorylation by IreK. MurAB, a homolog of MurAA, also promotes MurAA proteolysis and interacts directly with IreB. Our results therefore establish a connection between the cell wall stress sensor IreK and one critical physiological output to modulate peptidoglycan synthesis and drive cephalosporin resistance.

Sex Differences in Infective Endocarditis: A Systematic Review

Despite the advancement in medicine, there is still a lack of understanding of the sex disparities in disease onset, progression, treatment, and outcome. In some life-threatening acute conditions, despite most patients with these illnesses being males, females have a significantly higher chance of mortality. This can be due to the differences in disease progression or healthcare disparities in managing the illness between the sexes. Treatment of illnesses tends to be more conservative for women without an explanation, but this disparity is due to the healthcare provider. Infective endocarditis (IE) is an acute life-threatening condition where bacteria latch onto and seed damaged endocardium, with some preliminary information reporting differences between the sexes. This paper aims to evaluate the sex disparities in the incidence, age, comorbidities, etiology, risk factors, manifestations, treatment, and outcomes of IE. From 2003-2023, 21584 articles were found that focused on the sex differences in IE and, through PRISMA guidelines, were narrowed down to 34 publications. There are significant differences between the sexes in IE, such as a significantly higher incidence of IE in males, who also tend to be older and have their native aortic valves involved, compared to younger females who have their mitral valve involved. Comorbidities also vary between the sexes; females tend to have atrial fibrillation, chronic kidney disease, psychiatric disorders, and taking immunosuppressants compared to males who suffer from chronic liver disease, underlying valve disease, and peripheral artery disease, contributing to the ease of developing IE. While the most common microorganism leading to IE is Staphylococcus aureus, females were more likely to have culture-negative IE, and men were more likely to be infected with Streptococcus viridans. Major manifestations in IE are fever and vegetation along the closure of the valves in the heart, where females were more likely to have vegetation on the mitral and aortic valves. At the same time, males were more likely to have it on the tricuspid valve. On par with sex disparities in health, females usually took longer to seek medical help than males despite the advancement of symptoms and deterioration. Females were also treated conservatively through antibiotic management, whereas males were more likely to advance to surgical treatment, leading to a longer hospital stay. While there was no true difference in the in-hospital mortality rate, the 30-day and 1-year mortality were significantly increased in females. These differences provide a range of starting points for various research to further educate physicians on sex disparities, such as why males have a higher incidence of infective endocarditis and determining whether it's hormones and basic metabolites, possibly limiting those who develop the infection. Another important point is treating females with IE; the antibiotic doses are standard, but whether they advance to surgical treatment is mostly up to the provider. Some providers deny surgical treatment despite all indications, but it could also be females denying surgery as they tend to leave against medical advice. This review is crucial in developing the next steps to sex disparity in IE, which may lead to better outcomes for males and females.

Wall Teichoic Acid Mediates Staphylococcus aureus Binding to Endothelial Cells via the Scavenger Receptor LOX-1

The success of Staphylococcus aureus as a major cause for endovascular infections depends on effective interactions with blood-vessel walls. We have previously shown that S. aureus uses its wall teichoic acid (WTA), a surface glycopolymer, to attach to endothelial cells. However, the endothelial WTA receptor remained unknown. We show here that the endothelial oxidized low-density lipoprotein receptor 1 (LOX-1) interacts with S. aureus WTA and permits effective binding of S. aureus to human endothelial cells. Purified LOX-1 bound to isolated S. aureus WTA. Ectopic LOX-1 expression led to increased binding of S. aureus wild type but not of a WTA-deficient mutant to a cell line, and LOX-1 blockage prevented S. aureus binding to endothelial cells. Moreover, WTA and LOX-1 expression levels correlated with the efficacy of the S. aureus-endothelial interaction. Thus, LOX-1 is an endothelial ligand for S. aureus, whose blockage may help to prevent or treat severe endovascular infections.

Vertebral osteomyelitis secondary to infective endocarditis detected by repeated magnetic resonance imaging: a case report

Background

Patients with infective endocarditis (IE) experience various symptoms, a major one being back pain, which is occasionally caused by concomitant vertebral osteomyelitis (VO). Magnetic resonance imaging (MRI) is generally used to detect VO; however, the sensitivity of detection using MRI is very low in the early stages of VO.

Case summary

A 60-year-old man visited our hospital with complaints of fever and persistent back pain over the past 7 days. A holosystolic heart murmur was auscultated, and an echocardiography revealed a vegetation on the posterior mitral leaflet. Blood cultures were positive for Streptococcus sanguinis. He was diagnosed with IE and treated with antimicrobials. A lumbar spine MRI on Day 1 showed no clear signs of vertebral infection, but the back pain continued and gradually worsened. Magnetic resonance imaging retest on Day 8 showed high signal intensity within the lumbar vertebral bodies and the disk on T2-weighted sequences, indicating VO. Intravenous antimicrobial therapy was extended, followed by oral antimicrobials, and a corset was put on to protect the lumbar spine to prevent bone degradation.

Discussion

For persistent back pain in IE patients, repeat MRIs at regular intervals of time can detect possible vertebral infection even if signs of vertebral infection were absent on the initial MRI.

Novel putative biomarkers for infective endocarditis by serum proteomic analysis: a comprehensive review of literature

Infective endocarditis (IE) is a challenging condition with high mortality. Prompt detection of IE has become essential for early and immediate management. The authors aimed to comprehensively review the existing literature on novel putative biomarkers for IE through serum proteomic analysis. The literature reveals high levels of N-terminal-pro-B-type natriuretic peptide (NT-proBNP) levels in IE with staphylococcal etiology, valvular lesions, and when combined with cardiac troponin I (cTnI), had a more significant value for risk stratification. A higher pro-ADM level, copeptin, NT-proBNP, and the monocyte-to-high-density lipoprotein cholesterol ratio (MHR) all impacted mortality during the hospital stay. The biomarker matrix metalloproteinase-9 was utilized to predict new-onset embolic events in patients, thus serving as a predictive marker. Procalcitonin was an important diagnostic marker in IE complicated with severe infection. Interleukin-6 (IL-6), Interleukin-8 (IL-8), Interferon-γ, cTnI, and NT-proBNP were also discovered to be useful as prognostic indicators. Early diagnosis and appropriate treatment are possible using antiphospholipid antibodies as a diagnostic test for definite IE. It is also concluded that antineutrophilic cytoplasmic antibody positive individuals with IE had a lengthier hospital stay. These noninvasive biomarkers can identify patients at risk and provide appropriate and early clinical management. NT-proBNP, Cystatin C, troponins, IL-6, IL-8, S100A11, and AQP9 are examples of possible markers that appear promising for further research. In conclusion, large-scale validation studies should study these biomarkers further to establish their use in clinical settings.

Recent infective endocarditis research findings suggest dentists prescribe prophylactic antibiotics for patients having a bicuspid aortic valve or mitral valve prolapse

BACKGROUND

The scientific validity of the European Society of Cardiology's (ESC) infective endocarditis (IE) guidelines limiting provision of prophylactic antibiotics (AP) only to patients having cardiac anomalies (e.g., prosthetic valves) believed to place them at "high risk" of adverse events when undergoing high risk dental procedures (HRDP) is unclear.

MATERIAL AND METHODS

A systematic review of studies conducted between 2017 and 2022 and catalogued in the PubMed database was undertaken to ascertain if this edict was associated with changes in IE incidence, development of infection in unprotected cardiac anomalies, developing infection and resultant adverse clinical outcomes.

RESULTS

Retrieved were 19 published manuscripts, however of these, 16 were excluded because they did not bare upon the issues of concern. Among the three studies eligible for review were those in the Netherlands, Spain, and England. The results of the Dutch study denoted a significant increase in the incidence of IE cases over the projected historical trend (rate ratio: 1327, 95% CI 1.205-1.462; p<0.001) after the introduction of the ESC guidelines. The findings from the Spanish study evidenced the uniquely high in-hospital IE associated fatality rates suffered by patients having bicuspid aortic valves (BAV); 5.6% or mitral valve prolapse (MVP); 10%. The British study provided evidence that the incidence of fatal IE infection was significantly greater among an "intermediate risk" cohort of patients, (a group likely including those with BAC and MVP for which the ESC guidelines don't recommend AP), than among "high risk" patients (P = 0.002).

CONCLUSIONS

Patients having either a BAV or MVP are at significant risk of developing IE and suffering serious sequelae including death. The ESC guidelines must reclassify these specific cardiac anomalies into the "high risk" category so that AP are recognized as being needed prior to provision of HRDP.

Candida endocarditis: Update on management considerations

The rise in incidence rates of invasive candidiasis warrants an increase in attention and efforts toward preventing and treating this virulent infection. Cardiac involvement is one of the most feared sequelae and has a poor prognosis. Despite the introduction of several novel antifungal agents over the past quarter century, complications and mortality rates due to Candida endocarditis have remained high. Although fungal endocarditis has a mechanism similar to bacterial endocarditis, no specific diagnostic criteria or algorithm exists to help guide its management. Furthermore, recent data has questioned the current guidelines recommending a combined approach of antifungal agents with surgical valve or indwelling prostheses removal. With the emergence of multidrug-resistant Candida auris, a focus on improved prophylactic measures and management strategies is necessary.

Risk of Infective Endocarditis Post-transcatheter Pulmonary Valve Replacement Versus Surgical Pulmonary Valve Replacement: A Systematic Review

Pulmonary valve replacement (PVR) is the most common cardiac operation in adult patients with congenital heart disease (ACHD). It can improve right ventricular outflow tract (RVOT) obstruction, typically due to pulmonary valve stenosis or regurgitation. PVR can be performed surgically (open-heart) and through a transcatheter (percutaneous) method, which is minimally invasive and is associated with shorter hospitalization stays. However, following PVR, infectious endocarditis (IE) can complicate the recovery process and increase mortality in the long term. IE is a rare but deadly multi-organ system condition caused by microorganisms traversing the bloodstream from a specific entry point. It can have many presentations, such as splinter hemorrhages, fevers, and vegetation on valves that lead to stroke consequences. This paper aims to evaluate the differences in the rate, etiology, manifestations, treatment, and outcomes of IE following surgical and transcatheter PVR, as the goal is to perform a procedure with few complications. In both approaches, Staphylococcus aureus was the most common microorganism that affected the valves, followed by Streptococcus viridians. Research has shown that surgical pulmonary valve replacement (SPVR) has a decreased risk of IE following surgery compared to TPVR. However, TPVR is preferred due to the reduced overall risk and complications of the procedure. Despite this, the consensus on mortality rates does differ. Future research should consider the type of valves used for transcatheter pulmonary valve replacement (TPVR), such as Melody valves versus Edward Sapien valves, as their IE rates vary significantly.

Fungal Endocarditis: Pathophysiology, Epidemiology, Clinical Presentation, Diagnosis, and Management

Fungal endocarditis accounts for 1% to 3% of all infective endocarditis cases, is associated with high morbidity and mortality (>70%), and presents numerous challenges during clinical care. Candida spp. are the most common causes of fungal endocarditis, implicated in over 50% of cases, followed by Aspergillus and Histoplasma spp. Important risk factors for fungal endocarditis include prosthetic valves, prior heart surgery, and injection drug use. The signs and symptoms of fungal endocarditis are nonspecific, and a high degree of clinical suspicion coupled with the judicious use of diagnostic tests is required for diagnosis. In addition to microbiological diagnostics (e.g., blood culture for Candida spp. or galactomannan testing and PCR for Aspergillus spp.), echocardiography remains critical for evaluation of potential infective endocarditis, although radionuclide imaging modalities such as 18F-fluorodeoxyglucose positron emission tomography/computed tomography are increasingly being used. A multimodal treatment approach is necessary: surgery is usually required and should be accompanied by long-term systemic antifungal therapy, such as echinocandin therapy for Candida endocarditis or voriconazole therapy for Aspergillus endocarditis.

Acquired Ventricular Septal Defect in Panton-Valentine Leukocidin-Positive Staphylococcus aureus Infective Endocarditis

Infective endocarditis (IE) is life-threatening and can lead to complications if left untreated. A 56-year-old gentleman presented with acute delirium, fever and rigor. Panton-Valentine leukocidin (PVL)-positive Staphylococcus aureus (S. aureus) was isolated in the blood culture and the PR interval was prolonged on the electrocardiogram (ECG). However, the transthoracic echocardiogram (TTE) and transoesophageal echocardiogram (TOE) at presentation were unremarkable with no evidence of intracardiac vegetations. Despite expedient intravenous antibiotics, an acquired ventricular septal defect (VSD) developed, which required urgent cardiothoracic surgical repair. It is imperative to consider early surgical interventions and the use of anti-toxin antibiotics in PVL-positive S. aureus IE.