Current patterns of infective endocarditis in congenital heart disease

Pulmonary Valve Endocarditis With Tetralogy of Fallot: A Comprehensive Exploration

Infective endocarditis, a fatal infection with rising morbidity and mortality rates among infants and children, is characterized by microbial infection within the endocardium, the inner lining of the heart including heart valves. The heightened susceptibility to infection in children is attributed to pre-existing pathologies, structural defects, and comorbidities. This report details a case of a one-year-old child with tetralogy of Fallot, showcasing isolated pulmonary valve vegetations as a distinctive manifestation of infective endocarditis.

PepO and CppA modulate Streptococcus sanguinis susceptibility to complement immunity and virulence

Streptococcus sanguinis is a ubiquitous commensal species of the oral cavity commonly involved as an opportunistic pathogen in cardiovascular infections. In this study, we investigated the functions of endopeptidase O (PepO) and a C3-degrading protease (CppA) in the systemic virulence of S. sanguinis. Isogenic mutants of pepO and cppA obtained in strain SK36 showed increased susceptibility to C3b deposition and to opsonophagocytosis by human polymorphonuclear neutrophils (PMN). These mutants differ, however, in their profiles of binding to serum amyloid P component (SAP) and C1q, whereas both showed reduced interaction with C4b-binding protein (C4BP) and/or factor H (FH) regulators as compared to SK36. The two mutants showed defects in ex vivo persistence in human blood, serum-mediated invasion of HCAEC endothelial cells, and virulence in a Galleria mellonella infection model. The transcriptional activities of pepO and cppA, assessed by RT-qPCR in nine wild-type strains, further indicated strain-specific profiles of pepO/cppA expression. Moreover, non-conserved amino acid substitutions were detected among the strains, mostly in CppA. Phylogenetic comparisons with homologues of streptococcal species of the oral and oropharyngeal sites suggested that S. sanguinis PepO and CppA have independent ancestralities. Thus, this study showed that PepO and CppA are complement evasion proteins expressed by S. sanguinis in a strain-specific manner, which are required for multiple functions associated with cardiovascular virulence.

Infective endocarditis in childhood: a single-centre experience of 26 years

The aim of this study was to present the clinical and microbiological characteristics of patients with infective endocarditis.A retrospective evaluation was made of patients diagnosed with infective endocarditis between 1995 and 2021. The clinical and laboratory characteristics of the patients were recorded together with conditions constituting a risk for the development of endocarditis, treatment, and surgical outcomes.Evaluation was made of 68 patients with a mean age of 7.3 years (3 months-17 years), diagnosed with infective endocarditis. An underlying cause of CHD was determined in 47 (69%) patients and rheumatic valve disease in 3 (4.4%). There was no structural heart disease in 18 (26%) patients of whom 13 of them had other risk factors. A causative organism was found in 41 (60%) cases, and the microorganism most often determined was viridans group streptococcus. No difference was determined between the patients diagnosed before and after 2007 in respect of the frequency of viridans streptococcus (p > 0.05). Septic emboli were seen in 18 (26%) patients, of which 17 required surgical treatments. In 5 of 11 (16.6%) patients with mortality, the agent was S. aureus. Of the total 28 (41%) patients were evaluated as hospital-acquired endocarditis. The most frequently determined agents in this group were staphylococcus epidermidis and S. aureus.Although CHDs continue to be the greatest risk factor for endocarditis, there is an increasing frequency of endocarditis in patients with no structural heart disease. Mortality rates are still high in infective endocarditis, especially in S. aureus endocarditis.

Infective Endocarditis at a Referral Children's Hospital During 19-Year Period: Trends and Outcomes

BACKGROUND

We noted a recent increase in cases of infective endocarditis (IE) at our institution. The purpose of the study is to examine the incidence, risk factors, microbiology and outcome of IE in our pediatric population.

METHODS

Retrospective review of IE cases during 2002-2020 at Children's Hospital of Michigan, Detroit.

RESULTS

68 patients with IE were identified. There was a 2-fold increase in incidence during the 2012-2020 (late period) compared to the 2002-2011 (early period). The most common predisposing conditions were congenital heart disease (CHD) in 39 (57.4%) and central venous catheter (CVC) in 19 (27.9%). CHD was more frequent in the late period (29/43, 67.4%) compared to early period (10/25, 40.0%) (p = 0.042). In CHD patients, palliative or corrective cardiac surgery was performed prior to IE diagnosis in 4/25 (16%) in early period and 23/43 (53.5%) in the late period (p = 0.004). S. aureus was the most common causative organism (35.3%) followed by streptococci (22.1%). Valve replacement or valvuloplasty was performed in 22.1% of patients. Complications occurred in 20 (29.4%). Mortality occurred in 7 (10.3%): 3 had CHD, 3 had CVC and underlying conditions and 1 had fulminant MRSA infection.

CONCLUSION(S)

The higher incidence of IE during the late period is likely due to an increase in patients with CHD who had undergone prior cardiac surgery. S. aureus was the predominant pathogen in all patients including those with CHD, followed by streptococci. IE in children continues to be associated with high rates of morbidity and mortality.

Infective Endocarditis among Pediatric Patients with Prosthetic Valves and Cardiac Devices: A Review and Update of Recent Emerging Diagnostic and Management Strategies

Infective endocarditis (IE) is a disease of the endocardium, which leads to the appearance of vegetation on the valves, cardiac structures, or, potentially, vascular endothelium of the heart. The risk of IE can be increased more than 140 times by congenital heart disease (50-59% of all IE), particularly if cyanotic. An increase in mortality may result from IE in patients with a complex cardiac pathology or patients with an implanted prosthetic material, most frequently conduits in a pulmonary position. Cardiac implantable electronic devices (CIED) infective endocarditis is a life-threatening complication representing 10% of all cases of endocarditis. Common signs of presentation are often fever and chills; redness and swelling at the pocket of the pacemaker, including the erosion and exteriorization of the device; and life-threatening sepsis. The use of intracardiac echocardiography for the diagnosis of IE is an innovative method. This may be needed, especially in older children undergoing complex cardiac surgery, when transthoracic echocardiography (TTE) and transesophageal echocardiography (TOE) failed to provide a reliable diagnosis. The 2018 European Heart Rhythm Association (EHRA) experts' consensus statement on transvenous lead extraction recommends complete device removal and antimicrobial therapy for any device-related infection, including CIED-IE. The most detected microorganism was Staphylococcus Aureus. In addition, cardiac surgery and interventional cardiology associated with the placement of prostheses or conduits may increase the risk of IE up to 1.6% for Melody valve implantation. Our manuscript presents a comprehensive review of infective endocarditis associated with cardiac devices and prostheses in the pediatric population, including recent advances in diagnosis and management.

Diversity in Phenotypes Associated With Host Persistence and Systemic Virulence in Streptococcus sanguinis Strains

Streptococcus sanguinis is a pioneer commensal species of dental biofilms, abundant in different oral sites and commonly associated with opportunist cardiovascular infections. In this study, we addressed intra-species functional diversity to better understand the S. sanguinis commensal and pathogenic lifestyles. Multiple phenotypes were screened in nine strains isolated from dental biofilms or from the bloodstream to identify conserved and strain-specific functions involved in biofilm formation and/or persistence in oral and cardiovascular tissues. Strain phenotypes of biofilm maturation were independent of biofilm initiation phenotypes, and significantly influenced by human saliva and by aggregation mediated by sucrose-derived exopolysaccharides (EPS). The production of H2O2 was conserved in most strains, and consistent with variations in extracellular DNA (eDNA) production observed in few strains. The diversity in complement C3b deposition correlated with the rates of opsonophagocytosis by human PMN and was influenced by culture medium and sucrose-derived EPS in a strain-specific fashion. Differences in C3b deposition correlated with strain binding to recognition proteins of the classical pathway, C1q and serum amyloid protein (SAP). Importantly, differences in strain invasiveness into primary human coronary artery endothelial cells (HCAEC) were significantly associated with C3b binding, and in a lesser extent, with binding to host glycoproteins (such as fibrinogen, plasminogen, fibronectin, and collagen). Thus, by identifying conserved and strain-specific phenotypes involved in host persistence and systemic virulence, this study indicates potential new functions involved in systemic virulence and highlights the need of including a wider panel of strains in molecular studies to understand S. sanguinis biology.

Contribution of a ZIP-family protein to manganese uptake and infective endocarditis virulence in Streptococcus sanguinis

Streptococcus sanguinis is an important cause of infective endocarditis. In strain SK36, the ABC‐family manganese transporter, SsaACB, is essential for virulence. We have now identified a ZIP‐family protein, TmpA, as a secondary manganese transporter. A tmpA mutant had no phenotype, but a ΔssaACB ΔtmpA mutant was more attenuated for serum growth and for virulence in a rabbit model than its ΔssaACB parent. The growth of both mutants was restored by supplemental manganese, but the ΔssaACB ΔtmpA mutant required twenty‐fold more and accumulated less. Although ZIP‐family proteins are known for zinc and iron transport, TmpA‐mediated transport of either metal was minimal. While ssaACB appears ubiquitous in St. sanguinis, tmpA was present in a majority of strains and a mntH gene encoding an NRAMP‐family transporter was identified in relatively few, including VMC66. As in SK36, deletion of ssaACB greatly diminished VMC66 endocarditis virulence and serum growth, and deletion of tmpA from this mutant diminished virulence further. Virulence was not significantly altered by deletion of mntH from either VMC66 or its ΔssaACB mutant. This and the accompanying paper together suggest that SsaACB is of primary importance for endocarditis virulence while secondary transporters TmpA and MntH contribute to growth under differing conditions.

Mapping the colorectal tumor microbiota

The gut microbiome in patients with colorectal cancer (CRC) is different than that of healthy controls. Previous studies have profiled the CRC tumor microbiome using a single biopsy. However, since the morphology and cellular subtype vary significantly within an individual tumor, the possibility of sampling error arises for the microbiome within an individual tumor. To test this hypothesis, seven biopsies were taken from representative areas on and off the tumor in five patients with CRC. The microbiome composition was strikingly similar across all samples from an individual. The variation in microbiome alpha-diversity was significantly greater between individuals' samples then within individuals. This is the first study, to our knowledge, that shows that the microbiome of an individual tumor is spatially homogeneous. Our finding strengthens the assumption that a single biopsy is representative of the entire tumor, and that microbiota changes are not limited to a specific area of the neoplasm.

Extensive right-sided infectious endocarditis due to Streptococcus pneumoniae

Streptococcus pneumoniae is a rare cause of infectious endocarditis. Most cases have an acute and aggressive evolution, with a high mortality rate. We report the case of a 36-year-old man, with a history of unrepaired ventricular septal defect, who came to the emergency department with fever, cough and asthenia with 3 months of evolution. Blood cultures were positive for Streptococcus pneumoniae Echocardiogram showed large vegetation on septum, free wall and outflow tract of the right ventricle. Thoracic CT revealed septic pulmonary embolism. Antimicrobial therapy and surgical treatment was performed and the patient presented a favourable evolution.

Intensive Care Unit Management of the Adult with Congenital Heart Disease

PURPOSE

Adults with congenital heart disease (ACHD) are a rapidly growing population with ever-increasing complexity, and intensive care unit (ICU) management is often necessary. This review summarizes common cardiovascular and non-cardiovascular complications in ACHD and provides a framework for ICU care.

RECENT FINDINGS

Heart failure is the leading cause of hospitalization and mortality in ACHD. Varied anatomy and repairs, as well as differing physiological complications, limit generalized application of management algorithms. Recent studies suggest that earlier mechanical support in advanced cases is feasible and potentially helpful. Cardiac arrhythmias are poorly tolerated and often require immediate attention. Other complications requiring intensive care include infections such as endocarditis and COVID-19, pulmonary hypertension, renal failure, hepatic dysfunction, coagulopathy, and stroke. Successful ICU care in ACHD requires a multi-disciplinary approach with careful consideration of anatomy, physiology, and associated comorbidities. Few studies have formally examined ICU management in ACHD and further research is necessary.

The Association Between Periodontitis and Cardiovascular Disease: an Update

PURPOSE OF THE REVIEW

The purpose of this review is to provide an update on the data regarding periodontitis and its association with cardiovascular disease (CVD), as well as a closer look at the connection between periodontitis and valvular heart disease.

RECENT FINDINGS

The body of literature that demonstrates an association between periodontitis and CVD is growing, and there is increasing evidence that periodontal disease (PD) can have negative cardiovascular effects. Far less data is available for the management of periodontitis specifically in those with valvular heart disease. However, recent studies suggest that routine preoperative dental evaluation practices may not be necessary in all patients and, similar to changes in antibiotic prophylaxis, may only be indicated for a select group of individuals. There is a strong association between PD and CVD, although a causal relationship is yet to be elucidated. Further data is needed in this regard, as well as in determining the appropriate management of PD in those with valvular heart disease.

Clinical outcomes for congenital heart disease patients presenting with infective endocarditis

INTRODUCTION

Infective endocarditis (IE) is a life-threatening adverse event for patients with congenital heart disease (CHD). Its incidence has changed little over time despite progress in techniques for diagnosis and treatment, and guidelines for prophylaxis.

AREAS COVERED

The review sought for key-words: 'congenital heart disease,' 'infective endocarditis,' 'microbial diagnosis,' 'imaging diagnosis,' 'surgical techniques,' 'prognosis,' 'prophylaxis.' Objectives were to investigate epidemiology, novel techniques for imaging and microbial diagnosis, therapeutic management and prognosis, and guidelines for prophylaxis in patients with CHD. The incidence of IE is increasing in adults with CHD. Morbidity caused by a broad clinical spectrum of cardiac and extracardiac episode-related complications is high. Surgical management is increasingly required in the early phase of the disease. Despite new techniques for diagnosis and microbiological therapy, mortality rate is still up to 10-20%.

EXPERT OPINION

IE has increased in the growing cohort of adults with complex heart disease, living with residual cardiac lesions and prosthetic materials. Diagnosis is challenging for complex heart defects. Pet-scan technique can provide beneficial information to locate intracardiac lesions and embolic foci. Identification of the microbiological agents is improving. Innovative surgical techniques aim to avoid prosthetic material. Guidelines for prophylaxis currently emphasize oral and skin daily hygiene.

Association of Novel Streptococcus sanguinis Virulence Factors With Pathogenesis in a Native Valve Infective Endocarditis Model

Streptococcus sanguinis (S. sanguinis) is an abundant oral commensal which can cause disseminated human infection if it gains access to the bloodstream. The most important among these diseases is infective endocarditis (IE). While virulence phenotypes of S. sanguinis have been correlated to disease severity, genetic factors mediating these phenotypes, and contributing to pathogenesis are largely uncharacterized. In this report, we investigate the roles of 128 genes in virulence-related phenotypes of S. sanguinis and characterize the pathogenic potential of two selected mutants in a left-sided, native valve IE rabbit model. Assays determining the ability of our mutant strains to produce a biofilm, bind to and aggregate platelets, and adhere to or invade endothelial cells identified sixteen genes with novel association to these phenotypes. These results suggest the presence of many uncharacterized genes involved in IE pathogenesis which may be relevant for disease progression. Two mutants identified by the above screening process – SSA_1099, encoding an RTX-like protein, and mur2, encoding a peptidoglycan hydrolase – were subsequently evaluated in vivo. Wild type (WT) S. sanguinis reliably induced cardiac vegetations, while the SSA_1099 and mur2 mutants produced either no vegetation or vegetations of small size. Splenomegaly was reduced in both mutant strains compared to WT, while pathology of other distal organs was indistinguishable. Histopathology analyses suggest the cardiac lesions and vegetations in this model resemble those observed in humans. These data indicate that SSA_1099 and mur2 encode virulence factors in S. sanguinis which are integral to pathogenesis of IE.

Predictive factors of death associated with infective endocarditis in adult patients with congenital heart disease

AIMS

Infective endocarditis is a severe infection which can occur in adult patients with congenital heart disease. We aimed to determine outcomes and risk factors of death in adult congenital heart disease and to investigate differences with infective endocarditis in non-congenital heart disease.

METHODS AND RESULTS

Between March 2000 and June 2018, 671 consecutive episodes of infective endocarditis in adult patients were retrospectively recorded. Cases were classified according to the modified Duke classification. All adult congenital heart disease cases were managed by infectious disease specialists and adult congenital heart disease cardiologists. During this period, 142 infective endocarditis episodes (21%) occurred in adult congenital heart disease patients with simple (46.5%), moderate (21.1%), or complex (32.4%) congenital heart disease. In-hospital mortality was 12.7%. The strongest predictive factors of in-hospital death in multivariate analysis were complexity of congenital heart disease (odds ratio (OR) 8.02, 95% confidence interval (CI) 1.53-42.07), age (OR 1.05, 95% CI 1.00-1.19) and white blood cell count 12 g/L or greater (OR 8.72, 95% CI 2.42-31.43). Patients with congenital heart disease were significantly younger (median age 36 vs. 67 years, P<0.001), had undergone more redo cardiac surgeries (35.7% vs. 11.3%, P<0.01) and presented with more right-sided infective endocarditis (39.4% vs. 7.9%, P<0.01) than patients without congenital heart disease. Congenital heart disease was associated with two-fold lower in-hospital mortality rates (OR 0.37, 95% CI 0.19-0.74), independently of age, gender, obesity, renal function and side of infective endocarditis.

CONCLUSION

Although mortality associated with infective endocarditis is lower in adult patients with congenital heart disease than patients without congenital heart disease, infective endocarditis mortality is particularly high in patients with complex congenital heart disease. Education and prevention about the risk of infective endocarditis is essential, especially in this group.

Health behaviours reported by adults with congenital heart disease across 15 countries

Background

Health behaviours are essential to maintain optimal health and reduce the risk of cardiovascular complications in adults with congenital heart disease. This study aimed to describe health behaviours in adults with congenital heart disease in 15 countries and to identify patient characteristics associated with optimal health behaviours in the international sample.

Design

This was a cross-sectional observational study.

Methods

Adults with congenital heart disease ( n = 4028, median age = 32 years, interquartile range 25–42 years) completed self-report measures as part of the Assessment of Patterns of Patient-Reported Outcomes in Adults with Congenital Heart disease - International Study (APPROACH-IS). Participants reported on seven health behaviours using the Health Behaviors Scale-Congenital Heart Disease. Demographic and medical characteristics were assessed via medical chart review and self-report. Multivariate path analyses with inverse sampling weights were used to investigate study aims.

Results

Health behaviour rates for the full sample were 10% binge drinking, 12% cigarette smoking, 6% recreational drug use, 72% annual dental visit, 69% twice daily tooth brushing, 27% daily dental flossing and 43% sport participation. Pairwise comparisons indicated that rates differed between countries. Rates of substance use behaviours were higher in younger, male participants. Optimal dental health behaviours were more common among older, female participants with higher educational attainment while sports participation was more frequent among participants who were younger, male, married, employed/students, with higher educational attainment, less complex anatomical defects and better functional status.

Conclusions

Health behaviour rates vary by country. Predictors of health behaviours may reflect larger geographic trends. Our findings have implications for the development and implementation of programmes for the assessment and promotion of optimal health behaviours in adults with congenital heart disease.

Contemporary epidemiology of infective endocarditis in patients with congenital heart disease: A UK prospective study

OBJECTIVES

Infective endocarditis is a life-threatening complication of congenital heart disease (CHD), but there are few studies concerning the contemporary risk profile, preceding invasive procedures and outcomes in this patient population. The aim of this study was to investigate the epidemiology of infective endocarditis (IE) in patients with CHD.

METHODS

Cases of IE in children and adults with CHD were prospectively recorded as part of the UK National Institute for Cardiovascular Outcomes Research (NICOR) National Congenital Heart Disease Audit. Patients were entered into the database between April 2008 and March 2016.

RESULTS

Eight hundred episodes of IE were recorded in 736 patients with CHD. Sixty-five patients (9%) were infants (aged <1 year), 235 (32%) were children (aged 1-15 years), and 436 (59%) were adults (aged >15 years). The most common diagnoses were Tetralogy of Fallot (n = 150, 22.8%), ventricular septal defect (n = 129, 19.6%) and bicuspid aortic valve (n = 70, 10.7%). Dental procedures preceded 67 of 635 episodes (11%) of IE, and non-dental invasive procedures preceded 177 of 644 episodes (27.4%). The most common causative organisms were streptococci, accounting for 40% of cases. Overall in-hospital mortality was 6.7%. On multivariable analysis, adverse factors associated with in-hospital mortality were staphylococcal infection and presence of an underlying atrioventricular septal defect.

CONCLUSIONS

Infective endocarditis in patients with CHD is an ongoing clinical challenge. In contemporary practice in tertiary congenital centers, 1 of 15 patients do not survive to hospital discharge. Streptococci remain the most common causative organism, and antecedent dental or medical procedures were undertaken in a significant minority in the 3 months before diagnosis. The presence of an atrioventricular septal defect or staphylococcal infection is associated with significantly increased risk of early mortality.

Clinical Characteristics of Infective Endocarditis in Children

BACKGROUND

Infective endocarditis (IE) remains a diagnostic and therapeutic challenge associated with high morbidity and mortality. We evaluated the microbial profile and clinical manifestation of IE in children.

METHODS

A retrospective study examining pediatric IE cases treated between 2000 and 2017 at the Department of Pediatric Cardiology, KU Leuven, was conducted. Clinical presentation, treatment, complications, outcome of IE, underlying microorganisms and congenital heart defects were reviewed.

RESULTS

Fifty-three patients were diagnosed with IE. Overall, 19 patients (36%) required cardiac surgery. Seven patients (13%) died. Eighty-seven percent of patients had an underlying congenital cardiac defect. Eighteen (34%) children presented with prosthetic graft IE. A causative organism was found in 49 (92%) cases: viridans group streptococci were identified in 17 (32%), Staphylococcus aureus in 13 (25%) and coagulase-negative staphylococci in 11 (20%) children. Community-acquired (CA) IE increased significantly from 8 (33%) cases in 2000-2007 to 20 (74%) cases in 2008-2017 (P < 0.01). Even with viridans streptococci being significantly more prevalent in the CA group (P < 0.01), we did not observe an increase of streptococcal IE from 2008 to 2017. Seventeen (32%) patients presented with hospital-acquired IE during the first year of life with 14 (82%) children after surgery and a prevalence of coagulase-negative staphylococci (53%).

CONCLUSIONS

The incidence of pediatric IE was similar over the investigated time period with a shift toward CA IE. Streptococci and staphylococci accounted for the majority of cases in both periods. Awareness of IE and its prevention is crucial in patients after implantation of prosthetic grafts.

A rare late finding in corrected tetralogy of Fallot: a case report

Introduction

Isolated pulmonary valve endocarditis is a rare phenomenon. Pulmonary prosthesis endocarditis is even more unusual, with only about 50 descriptions in worldwide literature, and its diagnosis and treatment is a challenge. Due to the increasing number of surgically corrected tetralogy of Fallot (TOF) patients, that often include pulmonary valve implantation, this clinical scenario is likely to become more frequent.

Case presentation

We describe a 37-year-old man with a previously implanted biologic pulmonary prosthesis after a TOF correction that presented to the emergency department with new-onset fever, orthopnoea, and lower limb oedema. Blood cultures were positive for Streptococcus mitis. Transthoracic echocardiography showed a large mobile mass in the right ventricular outflow tract, apparently originating from the pulmonary prosthesis. Transoesophageal echocardiography (TOE) showed the presence of multiple mobile structures arising from the arterial surface of the prosthesis, extending into the right pulmonary artery and causing right ventricular obstruction. Antibiogram guided treatment was administered and surgery was performed, removing a 9 cm vegetation and replacing the valve. Patient recovered well and was discharged 35 days after.

Discussion

In right-sided endocarditis, surgery indications and its timing are much less clear than in left-sided infections, but current literature describes it as associated with a significant morbidity, mortality, and high likelihood of requiring surgery. Large vegetations and clinical signs of haemodynamic impact should prompt consideration of early surgical intervention. The combination of transthoracic and TOE allowed a correct diagnosis and a timely treatment.

Incidence, predictors and outcomes of infective endocarditis in a contemporary adult congenital heart disease population

BACKGROUND

The prevalence of congenital heart disease (CHD) in the adult population is steadily increasing. A substrate of prosthetic material and residual lesions, constantly evolving as surgical techniques change over time, predispose these patients to the potentially devastating complication of infective endocarditis (IE).

METHODS

We retrospectively reviewed 2935 patients in our adult CHD database for all cases of endocarditis between 1991 and 2016. Incidence, clinical course and predictors of outcomes were analysed.

RESULTS

We document 74 episodes in 62 patients, with an incidence of 0.9 cases/1000 patient years (py). IE was more common in complex CHD (1.4 cases/1000py) and ventricular septal defects (VSDs) (1.9 cases/1000py). Prosthetic material was involved in 47% and left-sided infection predominated (66%). The incidence in bicuspid aortic valves post aortic valve replacement (AVR) was significantly higher than in unoperated valves, being 1.8 and 1.1 cases/1000 patient years respectively. Streptococcus was the most frequently implicated causative organism (37%). Emboli occurred in 34% of cases with a cerebral predilection. 46% of patients required surgery during the admission for IE, most frequently to replace a severely regurgitant bicuspid aortic valve. Early endocarditis-related mortality was 15%, associated with cerebral emboli and acute renal failure.

CONCLUSIONS

In a contemporary adult CHD cohort, those with complex underlying lesions, VSDs or an AVR were at higher risk for IE. Mortality remains substantial and is more likely in patients with cerebral emboli and/or acute renal failure.

Incidence, risk factors, and predictors of infective endocarditis in adult congenital heart disease: focus on the use of prosthetic material

Aims

Adult congenital heart disease (ACHD) predisposes to infective endocarditis (IE). Surgical advancements have changed the ACHD population, whereas associated prosthetic material may constitute additional IE targets. We aimed to prospectively determine contemporary incidence, risk factors, and predictors of IE in a nationwide ACHD cohort, focusing on the presence of prosthetics.

Methods and results

We identified 14 224 patients prospectively followed in the CONCOR ACHD registry (50.5% female, median age 33.6years). IE incidence was determined using Poisson regression, risk factors and predictors using Cox regression. Overall incidence was 1.33 cases/1000 person-years (124 cases in 93 562 person-years). For risk-factor analysis, presence of prosthetics was forced-as separate time-updated variables for specific prosthetics-into a model with baseline characteristics univariably associated with IE. Valve-containing prosthetics were independently associated with greater risk both short- and long term after implantation [0-6 months: hazard ratio (HR) = 17.29; 7.34-40.70, 6-12 months: HR = 15.91; 6.76-37.45, beyond 12 months: HR = 5.26; 3.52-7.86], non-valve-containing prosthetics, including valve repair, only in the first 6 months after implantation (HR = 3.34; 1.33-8.41), not thereafter. A prediction model was derived and validated using bootstrapping techniques. Independent predictors of IE were baseline valve-containing prosthetics, main congenital heart defect, multiple defects, previous IE, and sex. The model had fair discriminative ability and provided accurate predictions up to 10 years.

Conclusions

This study provides IE incidence estimates, and determinants of IE risk in a nationwide ACHD cohort. Our findings, essentially informing IE prevention guidelines, indicate valve-containing prosthetics as a main determinant of IE risk whereas other prosthetics, including valve-repair, are not associated with increased risk long term after implantation.

Novel Two-Component System of Streptococcus sanguinis Affecting Functions Associated with Viability in Saliva and Biofilm Formation

Streptococcus sanguinis is a pioneer species of teeth and a common opportunistic pathogen of infective endocarditis. In this study, we identified a two-component system, S. sanguinis SptRS (SptRS _Ss ), affecting S. sanguinis survival in saliva and biofilm formation. Isogenic mutants of sptR_Ss (SKsptR) and sptS_Ss (SKsptS) showed reduced cell counts in ex vivo assays of viability in saliva compared to those of parent strain SK36 and complemented mutants. Reduced counts of the mutants in saliva were associated with reduced growth rates in nutrient-poor medium (RPMI) and increased susceptibility to the deposition of C3b and the membrane attach complex (MAC) of the complement system, a defense component of saliva and serum. Conversely, sptR_Ss and sptS_Ss mutants showed increased biofilm formation associated with higher levels of production of H₂O₂ and extracellular DNA. Reverse transcription-quantitative PCR (RT-qPCR) comparisons of strains indicated a global role of SptRS _Ss in repressing genes for H₂O₂ production (2.5- to 15-fold upregulation of spxB, spxR, vicR, tpk, and ackA in sptR_Ss and sptS_Ss mutants), biofilm formation, and/or evasion of host immunity (2.1- to 11.4-fold upregulation of srtA, pcsB, cwdP, iga, and nt5e). Compatible with the homology of SptR _Ss with AraC-type regulators, duplicate to multiple conserved repeats were identified in 1,000-bp regulatory regions of downstream genes, suggesting that SptR _Ss regulates transcription by DNA looping. Significant transcriptional changes in the regulatory genes vicR, spxR, comE, comX, and mecA in the sptR_Ss and sptS_Ss mutants further indicated that SptRS _Ss is part of a regulatory network that coordinates cell wall homeostasis, H₂O₂ production, and competence. This study reveals that SptRS _Ss is involved in the regulation of crucial functions for S. sanguinis persistence in the oral cavity.

Is SpxA2 involved in hydrogen peroxide production and competence development in Streptococcus sanguinis?

PURPOSE

The objective of the present study was to investigate whether Streptococcus sanguinis SpxA2 plays a role in competence development and endogenous H2O2 generation, and whether the SpxA2 Cys10-XX-Cys13 (CXXC) motif is involved in competence development.

METHODOLOGY

The competence development of wild-type S. sanguinis (SK36) and its derivatives was compared by transformation efficiency assay and real-time RT-PCR. The spx allele mutants, spxA2 (C10A) and spxA2 (C13A), were constructed by site-directed mutagenesis. The Δpox mutant was treated with 1 mM H2O2 to exclude the effect of other Pox products on competence development.

RESULTS

Compared with the wild-type (4.42±0.58×10-4), the ΔspxA2 mutant showed decreased transformation efficiency (0.07±0.03×10-4). Furthermore, there was a 2- to 15-fold reduction in ΔspxA2 mutant com gene expression. SpxA2 was able to down-regulate endogenous H2O2 generation by repressing pox expression. Additionally, endogenous H2O2 negatively regulated competence without affecting spxA2 expression. The Δpox mutant increased com gene expression (2- to 8-fold), but the 1 mM H2O2-treated Δpox mutant showed decreased com gene expression. Interestingly, the ΔspxA2Δpox mutant showed enhanced competence-associated parameters. The fact that spxA2 (C10A) and spxA2 (C13A) behaved like the ΔspxA2 mutant revealed the role of the CXXC motif in competence development.

CONCLUSION

Although the intricate relationship between SpxA2, pox-mediated H2O2 production and competence development was clarified in S. sanguinis, it would be worthwhile to explore further whether H2O2 is involved in competence development through oxidizing the SpxA2 CXXC motif.

Gender-related differences in self-reported dental care in adults with congenital heart disease at increased risk of infective endocarditis

OBJECTIVE

Adults with congenital heart disease (CHD) are at increased risk of infective endocarditis (IE). Women with CHD have a lower IE risk, potentially due to gender-related differences in dental care. We aimed to assess self-reported dental hygiene measures in adults with CHD, and to identify factors associated with good oral hygiene.

METHODS AND RESULTS

Descriptive study includes 187 adults with CHD at increased risk of IE. The patients' IE knowledge was assessed using an adapted version of the Leuven Knowledge Questionnaire for CHD. Their mean age was 34.9±14.9 years, 73 of them (39%) were women, 91 (49%) were at high risk for IE, including 66 (35%) with a prosthetic valve, 14 (7%) with a history of IE and 11 (6%) with cyanotic CHD or residual shunts/valvular regurgitation in the proximity of prosthetic material. The self-defined IE knowledge score did not differ between men and women (21.6±10.0 vs 23.4±10.0; p=0.225). 126 patients (67%) reported to have a good oral hygiene. Female gender (OR 2.4, 95% CI 1.1 to 4.4), and a higher IE knowledge score (OR 1.2, 95% CI 1.1 to 1.5, per 5 points) were the variables independently associated with good oral hygiene.

CONCLUSIONS

In adults with CHD, patients with a higher IE knowledge score and women are more likely to practise dental care as recommended. Gender differences in oral hygiene practise may explain the observed lower female IE incidence rate. Efforts to improve patients' knowledge on IE are encouraged.

Changing Landscape of Congenital Heart Disease

Congenital heart disease is the most frequently occurring congenital disorder affecting ≈0.8% of live births. Thanks to great efforts and technical improvements, including the development of cardiopulmonary bypass in the 1950s, large-scale repair in these patients became possible, with subsequent dramatic reduction in morbidity and mortality. The ongoing search for progress and the growing understanding of the cardiovascular system and its pathophysiology refined all aspects of care for these patients. As a consequence, survival further increased over the past decades, and a new group of patients, those who survived congenital heart disease into adulthood, emerged. However, a large range of complications raised at the horizon as arrhythmias, endocarditis, pulmonary hypertension, and heart failure, and the need for additional treatment became clear. Technical solutions were sought in perfection and creation of new surgical techniques by developing catheter-based interventions, with elimination of open heart surgery and new electronic devices enabling, for example, multisite pacing and implantation of internal cardiac defibrillators to prevent sudden death. Over time, many pharmaceutical studies were conducted, changing clinical treatment slowly toward evidence-based care, although results were often limited by low numbers and clinical heterogeneity. More attention has been given to secondary issues like sports participation, pregnancy, work, and social-related difficulties. The relevance of these issues was already recognized in the 1970s when the need for specialized centers with multidisciplinary teams was proclaimed. Finally, research has become incorporated in care. Results of intervention studies and registries increased the knowledge on epidemiology of adults with congenital heart disease and their complications during life, and at the end, several guidelines became easily accessible, guiding physicians to deliver care appropriately. Over the past decades, the landscape of adult congenital heart disease has changed dramatically, which has to be continued in the future.

Isolation and Characterization of a microRNA-size Secretable Small RNA in Streptococcus sanguinis

MicroRNAs in eukaryotic cells are thought to control highly complex signal transduction and other biological processes by regulating coding transcripts, accounting for their important role in cellular events in eukaryotes. Recently, a novel class of bacterial RNAs similar in size [18-22 nucleotides (nt)] to microRNAs has been reported. Herein, we describe microRNAs, small RNAs from the oral pathogen Streptococcus sanguinis. The bacteria are normally present in the oral cavities and cause endocarditis by contaminating bloodstreams. Small RNAs were analyzed by deep sequencing. Selected highly expressed small RNAs were further validated by real-time polymerase chain reaction and northern blot analyses. We found that skim milk supplement changed the expression of small RNAs S.S-1964 in tandem with the nearby SSA_0513 gene involved in vitamin B₁₂ conversion. We furthermore observed small RNAs secreted via bacterial membrane vesicles. Although their precise function remains unclear, secretable small RNAs may represent an entirely new area of study in bacterial genetics.

Activation of nucleotide-binding domain-like receptor containing protein 3 inflammasome in dendritic cells and macrophages by Streptococcus sanguinis

Streptococcus sanguinis is frequently isolated from the blood of patients with infective endocarditis and contributes to the pathology of this disease through induction of interleukin (IL)-1β responsible for the development of the disease. However, the mechanism of IL-1β induction remains unknown. In this study, S. sanguinis activated a murine dendritic cell (DC) to induce IL-1β and this activity was attenuated by silencing the mRNAs of nucleotide-binding domain-like receptor containing protein 3 (NLRP3) and caspase-1. S. sanguinis induced IL-1β production in murine bone marrow-derived macrophage, but this activity was significantly reduced in bone marrow-derived macrophages from NLRP3-, apoptosis-associated speck-like protein containing a caspase-recruitment domain-, and caspase-1-deficient mice. DC phagocytosed S. sanguinis cells, followed by the release of adenosine triphosphate (ATP). The ATP-degradating enzyme attenuated the release of ATP and IL-1β. The inhibitors for ATP receptor reduced IL-1β release in DC. These results strongly suggest that S. sanguinis has the activity to induce IL-1β through the NLRP3 inflammasome in macrophage and DC and interaction of purinergic receptors with ATP released is involved in expression of the activity.

Streptococcus sanguinis isolated from filler granuloma: Successful treatment with incision and drainage

Filler granuloma is considered to be the result of delayed immune responses; growing evidence suggests that they may be secondary to biofilm formation. Dermal filler is technically a foreign body, and as the development of newer generations of dermal fillers lengthens their duration, it is possible that there is also an increased risk of biofilm formation. Here, we present a case report of a patient with Streptococcus sanguinis isolated from a filler granuloma, suggestive of biofilm formation. This case demonstrates the effective use of antibiotics after incision and drainage on antibiotic resistant biofilm.

Metabolic traits of pathogenic streptococci

Invasive and noninvasive diseases caused by facultative pathogenic streptococci depend on their equipment with virulence factors and on their ability to sense and adapt to changing nutrients in different host environments. The knowledge of the principal metabolic mechanisms which allow these bacteria to recognize and utilize nutrients in host habitats is a prerequisite for our understanding of streptococcal pathogenicity and the development of novel control strategies. This review aims to summarize and compare the central carbohydrate metabolic and amino acid biosynthetic pathways of a selected group of streptococcal species, all belonging to the naso-oropharyngeal microbiome in humans and/or animals. We also discuss the urgent need of comprehensive metabolomics approaches for a better understanding of the streptococcal metabolism during host-pathogen interaction.

The Changing Epidemiology of Pediatric Endocarditis

The epidemiology of infective endocarditis (IE) appears to be related to changes in the management of children with congenital heart disease (CHD) and the virtual disappearance of rheumatic heart disease. To better understand these changes, we divide the history into: I. The pre-surgical era, II. The early years of CHD surgical intervention, correlated with introduction of antibiotics, III. The modern era of cardiac interventions. Microbiologic changes include an early predominance of viridans streptococci and an overtaking by staphylococci. Additionally, there have been advances in imaging that allow earlier detection of IE and a reduction in IE-related mortality.

The causative agents in infective endocarditis: a systematic review comprising 33,214 cases

Infective endocarditis (IE) incidence remains high with considerable fatality rates; guidelines for prophylaxis against IE are currently under review in some settings which highlights the importance of maintaining up-to-date epidemiological estimates about the most common microbial causes. The objective of this systematic review, following PRISMA guidelines, was to identify the most common microbial causes of IE in recent years. Medline was searched from January 1, 2003 to March 31, 2013 for all articles containing the term "infective endocarditis". All relevant studies reporting diagnostic results were included. Special patient subpopulations were assessed separately. A total of 105 studies were included, from 36 countries, with available data on a total of 33,214 cases. Staphylococcus aureus was found to be the most common microorganism, being the most frequent in 54.3 % of studies (N = 57) (and in 55.4 % of studies using Duke's criteria for diagnosis [N = 51]). Viridans group streptococci (VGS), coagulase-negative staphylococci (CoNS), Enterococcus spp and Streptococcus bovis were among the most common causes. S. aureus was the most common pathogen in almost all population subgroups; however, this was not the case in patients with implantable devices, prosthetic valves, or immunocompromised non-HIV, as well as in the sub-group from Asia, emphasizing that a global one-size-fits-all approach to the management of suspected IE is not appropriate. This review provides an evidence-based map of the most common causative agents of IE, highlighting S. aureus as the leading cause in the 21st century. The changing epidemiology of IE in some patient sub-groups in the last decade and the very high number of microbiologically undiagnosed cases (26.6 %) suggest the need to revisit IE prophylaxis and diagnostic strategies.

Reconstruction of a Previously Repaired Aortic Valve Destroyed by Infective Endocarditis: Case Report

Infective endocarditis (IE) is an uncommon condition among patients with congenital heart disease, however it can be life threatening. The usual management includes replacement of the affected valve, especially in patients with aortic valve compromise, and is even more common in previously repaired valves. In this case report, we describe the successful reconstruction of an aortic root destroyed by IE, in a patient with history of ballooning of a congenital aortic stenosis.

Involvement of NADH Oxidase in Competition and Endocarditis Virulence in Streptococcus sanguinis

Here, we report for the first time that the Streptococcus sanguinis nox gene encoding NADH oxidase is involved in both competition with Streptococcus mutans and virulence for infective endocarditis. An S. sanguinis nox mutant was found to fail to inhibit the growth of Streptococcus mutans under microaerobic conditions. In the presence of oxygen, the recombinant Nox protein of S. sanguinis could reduce oxygen to water and oxidize NADH to NAD(+) The oxidation of NADH to NAD(+) was diminished in the nox mutant. The nox mutant exhibited decreased levels of extracellular H2O2; however, the intracellular level of H2O2 in the mutant was increased. Furthermore, the virulence of the nox mutant was attenuated in a rabbit endocarditis model. The nox mutant also was shown to be more sensitive to blood killing, oxidative and acid stresses, and reduced growth in serum. Thus, NADH oxidase contributes to multiple phenotypes related to competitiveness in the oral cavity and systemic virulence.

Extra-cardiac manifestations of adult congenital heart disease

Advancement in correction or palliation of congenital cardiac lesions has greatly improved the lifespan of congenital heart disease patients, resulting in a rapidly growing adult congenital heart disease (ACHD) population. As this group has increased in number and age, emerging science has highlighted the systemic nature of ACHD. Providers caring for these patients are tasked with long-term management of multiple neurologic, pulmonary, hepatic, renal, and endocrine manifestations that arise as syndromic associations with congenital heart defects or as sequelae of primary structural or hemodynamic abnormalities. In this review, we outline the current understanding and recent research into these extra-cardiac manifestations.

Intrauterine device infection causing concomitant streptococcal toxic shock syndrome and pelvic abscess with Actinomyces odontolyticus bacteraemia

Intrauterine devices (IUDs) are rarely associated with serious infections. We report an unusual concomitant infection of group A Streptococcus (GAS) causing toxic shock syndrome and pelvic abscess with Actinomyces odontolyticus associated with an IUD in a healthy 50-year-old patient. The IUD was subsequently removed and the patient recovered on the appropriate antibiotics. This case highlights the importance of clinicians' high index of suspicion of an IUD infection and prompt removal of the infected foreign body to obtain source control.

SpxB-mediated H2 O2 induces programmed cell death in Streptococcus sanguinis

Streptococcus sanguinis (S. sanguinis) is a commensal oral streptococci that produces hydrogen peroxide (H2 O2 ), and this production is dependent on pyruvate oxidase (SpxB) activity. In addition to its well-known role in intraspecies or interspecies competitions, recent studies have shown that H2 O2 produced by S. sanguinis under aerobic conditions not only upregulates biofilm formation and eDNA release but also regulates cell death without obvious cell lysis. Here, we report that S. sanguinis exhibits characteristic hallmarks of eukaryotic apoptosis when it encounters endogenous and exogenous H2 O2 . As the most common mode of programmed cell death (PCD), apoptosis is accompanied by a series of biochemical and morphological events, including DNA fragmentation, chromosome condensation, membrane potential depolarization, phosphatidylserine (PS) exposure, and caspase substrate binding protein activity changes. In addition, we also provide genetic evidence that there is decreased expression of the related DNA repair genes comEA, recA, dnaC, dinG, and pcrA in the wild-type compared to the isogenic spxB mutant in S. sanguinis. Our data suggest that endogenous H2 O2 is the most important agent in this development process in S. sanguinis.

[Infective endocarditis in adult patients with congenital heart disease. Experience from a reference centre]

INTRODUCTION

A growing number of patients with congenital heart disease (CHD) will reach adulthood. Infective endocarditis (IE) is a major complication in this population. The aim of this study was to describe the features of IE in adults with CHD treated in a reference centre.

METHODS

A retrospective review was performed on a cohort of patients over 16 years of age with CHD who presented with IE (defined by the modified Duke criteria) between 1996 and 2014. Only the first episode from each patient was considered for the descriptive analysis.

RESULTS

IE was observed in 27 patients. The median age at diagnosis of IE was 27.7 years, and 63% were male. Comorbidity was low (median Charlson index was 0). IE was mostly community-acquired (78%). The most frequent CHD were ventricular septal defect (33%). A repair was performed in 48% of patients, and 19% received palliative treatment. Forty-one percent of patients had some type of prosthesis. A residual defect was observed in 81%. The IE was detected in the right side of 44% of the patients. The most frequent aetiological agents were viridans group streptococci (41%) and Staphylococcus epidermidis (30%). Surgery was required to treat IE in 37% of patients. There were five re-infections and three relapses. Two patients died, both as a result of recurrence.

CONCLUSIONS

IE in adults with CHD occurred in young patients, and almost all of them carried some prosthetic material or a residual defect. The IE is frequently right-sided. Although surgical treatment was required in many cases, mortality was low, except in the case of relapses.

Common long-term complications of adult congenital heart disease: avoid falling in a H.E.A.P

Advances in cardiology and cardiac surgery have transformed the outlook for patients with congenital heart disease (CHD) so that currently 85% of neonates with CHD survive into adult life. Although early surgery has transformed the outcome of these patients, it has not been curative. Heart failure, endocarditis, arrhythmias and pulmonary hypertension are the most common long term complications of adults with CHD. Adults with CHD benefit from tertiary expert care and early recognition of long-term complications and timely management are essential. However, it is as important that primary care physicians and general adult cardiologists are able to recognise the signs and symptoms of such complications, raise the alarm, referring patients early to specialist adult congenital heart disease (ACHD) care, and provide initial care. In this paper, we provide an overview of the most commonly encountered long-term complications in ACHD and describe current state of the art management as provided in tertiary specialist centres.

Changing profile of infective endocarditis: a clinicopathologic study of 220 patients in a single medical center from 1998 through 2009

The epidemiologic profile of infective endocarditis has changed substantially over the past few years, especially in industrialized countries. Our study evaluates the clinical and pathologic characteristics of infective endocarditis patients treated by cardiac surgery in China during a 12-year period. We retrospectively evaluated 220 surgically treated infective endocarditis patients and analyzed their changes from the beginning of 1998 through 2009. The mean age of the patients increased from 36.9 to 42.7 years during those 12 years (P=0.036). The chief predisposing disease was congenital heart disease (32.8%), rather than rheumatic heart disease (13.2%); this rate did not change significantly during the 12 years. The prevalent congenital lesion was bicuspid aortic valve, the rate of which (55.6%) increased significantly over the 3 time intervals studied (P=0.016). The frequency of infective endocarditis after non-dental surgical and nonsurgical intervention was significantly greater (23.3%) during 1998 through 2001, compared with the 2 intervals that followed (9%; P=0.019). Streptococcus viridans was the most frequent causative agent overall (25.6%). Forty-seven of the 220 patients (21.4%) carried the clinical diagnosis of some other form of heart disease before surgery, but at surgery they were found to have infective endocarditis as the fundamental disease process. Of 47 patients, 33 (70.2%) had either very small or no vegetations but had focal necrosis and inflammation of valve tissue that supported the diagnosis of infective endocarditis.

Underlying heart disease and microbiological spectrum of adult infective endocarditis in one Chinese university hospital: a 10-year retrospective study

BACKGROUND AND AIM

To identify the underlying heart disease and microbiological pathogen associated with infective endocarditis (IE) in Chinese patients in one university hospital over a 10-year period.

METHODS

We recruited 115 adult patients admitted to Peking University First Hospital from 2002 to 2011 who were diagnosed with definite IE. Statistical analysis was performed to analyse data on demographics, clinical and laboratory findings, as well as microbiological pathogens.

RESULTS

The most common underlying heart diseases for IE were congenital heart disease (24.3%) followed by degenerative valvular disease (17.4%). Aortic (44.3%) and mitral (43.5%) valves were most frequently affected. The right-sided IE cases were all found in patients with congenital heart disease. The age of patients was younger in right-sided cases than that in left-sided ones (P = 0.001). There was no difference in the mortality among groups with different underlying heart disease (P = 0.841). Forty-four (38.3%) patients were infected with viridans group streptococci. The isolation rate of staphylococci in right-sided IE was higher than that in the left-sided IE group (P = 0.021). More than 85% of streptococci were susceptible to β-lactams.

CONCLUSIONS

Congenital heart disease and degenerative valvular disease have overtaken rheumatic heart disease as the major underlying heart diseases associated with IE. Viridans group streptococci are the most common microbial cause of IE.