Acute infective endocarditis

Spectrum of Thoracic Imaging Findings in the Setting of Substance Abuse

ABSTRACT

Substance abuse continues to be prevalent nationwide and can lead to a myriad of chest pathologies. Imaging findings are vast and can include nodules, masses, ground-glass opacities, airspace disease, and cysts. Radiologists with awareness of these manifestations can assist in early identification of disease in situations where information is unable to be obtained from the patient. This review focuses on thoracic imaging findings associated with various forms of substance abuse, which are organized by portal of entry into the thorax: inhalation, ingestion, and injection.

Insights into microorganisms, associated factors, and the oral microbiome in infective endocarditis patients

Introduction

Infective Endocarditis (IE) is a rare, life-threatening infection of the endocardium with multisystem effects. Culprit microorganisms derived from different niches circulate through the bloodstream and attach to the endocardium, particularly the heart valves. This study aimed to investigate culprit microorganisms among a cross-sectional cohort of IE patients, their associated factors, and to explore the potential relationship to the oral microbiome.

Methods

In this observational study, we undertook a cross-sectional analysis of 392 medical records from patients diagnosed with IE. The primary outcome of this study was to analyse the association between the IE culprit microorganisms and the underlying anatomical types of IE (native valve (NVE), prosthetic valve (PVE), or cardiac device-related (CDE)). Secondary outcomes encompassed a comparative analysis of additional factors, including: the treatment approaches for IE, and the categorisation of blood cultures, extending to both genus and species levels. Additionally, we cross-referenced and compared the species-level identification of IE bacteraemia outcome measures with data from the expanded Human Oral Microbiome Database (eHOMD).

Results

A culprit microorganism was identified in 299 (76.28%) case participants. Staphylococcal infections were the most common (p < 0.001), responsible for 130 (33.16%) hospitalisations. There were 277 (70.66%) cases of NVE, 104 (26.53%) cases of PVE, and 11 (2.81%) cases of CDE. The majority of PVE occurred on prosthetic aortic valves (78/104, 75%), of which 72 (93.5%) were surgical aortic valve replacements (SAVR), 6 (7.8%) were transcatheter aortic valve implants, and one transcatheter pulmonary valve implant. Overall, underlying anatomy (p = 0.042) as well as the treatment approaches for IE (p < 0.001) were significantly associated with IE culprit microorganisms. Cross-reference between IE bacteraemia outcomes with the eHOMD was observed in 267/392 (68.11%) cases.

Conclusions

This study demonstrated that IE patients with a history of stroke, smoking, intravenous drug use, or dialysis were more likely to be infected with Staphylococcus aureus. CDE case participants and patients who had previous SAVR were most associated with Staphylococcus epidermidis. IE patients aged 78+ were more likely to develop enterococci IE than other age groups. Oral microorganisms indicated by the eHOMD are significantly observed in the IE population. Further research, through enhanced dental and medical collaboration, is required to correlate the presence of oral microbiota as causative factor for IE.

Publication Trends on Infective Endocarditis: Comprehensive Bibliometric Analysis and Visualization Between 1892 and 2022

BACKGROUND

In recent years, studies reported that the incidence of infective endocarditis (IE) has increased despite the decrease in rheumatic heart diseases, great advances in medical and surgical treatment methods, and prophylactic antibiotic therapies. However, there is no bibliometric analysis based on the visual mapping method in the literature. In the study, we aimed to analyze the hot topics in IE, the distribution of publications in terms of country, institution, journal, author, and their relationships by assessing IE articles published in the 130 years between 1892 and 2022.

METHODS

Publications before 2023 were analyzed using the keywords 'infective' and 'endocarditis' in the Scopus database.

RESULTS

Approximately 25% of the publications on IE were from the USA followed by Japan, France, and the UK. A total of 116 keywords were used at least 15 times and the keywords were categorized into 9 clusters by the VOSviewer program. The keywords used more than 100 times except 'infective endocarditis' were 'echocardiography,' 'mortality,' 'surgery,' 'Staphylococcus aureus,' 'cardiac surgery,' 'epidemiology,' and 'prognosis' 247, 191, 152, 142, 130, 122, and 119 times, respectively. To the best of our knowledge, the study is the most comprehensive study globally on IE with the widest time range including the visual mapping method.

CONCLUSION

Since our study reveals the changes in the literature related to infective endocarditis, we think that it will be a guide in planning new research studies. We believe that periodic repetition of bibliometric analyses and keyword mapping studies will contribute to the quantitative and qualitative development of scientific productivity globally.

Proteomics-based vaccine targets annotation and design of multi-epitope vaccine against antibiotic-resistant Streptococcus gallolyticus

Streptococcus gallolyticus is a non-motile, gram-positive bacterium that causes infective endocarditis. S. gallolyticus has developed resistance to existing antibiotics, and no vaccine is currently available. Therefore, it is essential to develop an effective S. gallolyticus vaccine. Core proteomics was used in this study together with subtractive proteomics and reverse vaccinology approach to find antigenic proteins that could be utilized for the design of the S. gallolyticus multi-epitope vaccine. The pipeline identified two antigenic proteins as potential vaccine targets: penicillin-binding protein and the ATP synthase subunit. T and B cell epitopes from the specific proteins were forecasted employing several immunoinformatics and bioinformatics resources. A vaccine (360 amino acids) was created using a combination of seven cytotoxic T cell lymphocyte (CTL), three helper T cell lymphocyte (HTL), and five linear B cell lymphocyte (LBL) epitopes. To increase immune responses, the vaccine was paired with a cholera enterotoxin subunit B (CTB) adjuvant. The developed vaccine was highly antigenic, non-allergenic, and stable for human use. The vaccine's binding affinity and molecular interactions with the human immunological receptor TLR4 were studied using molecular mechanics/generalized Born surface area (MMGBSA), molecular docking, and molecular dynamic (MD) simulation analyses. Escherichia coli (strain K12) plasmid vector pET-28a ( +) was used to examine the ability of the vaccine to be expressed. According to the outcomes of these computer experiments, the vaccine is quite promising in terms of developing a protective immunity against diseases. However, in vitro and animal research are required to validate our findings.

Reduced graphene oxide coated alginate scaffolds: potential for cardiac patch application

BACKGROUND

Cardiovascular diseases, particularly myocardial infarction (MI), are the leading cause of death worldwide and a major contributor to disability. Cardiac tissue engineering is a promising approach for preventing functional damage or improving cardiac function after MI. We aimed to introduce a novel electroactive cardiac patch based on reduced graphene oxide-coated alginate scaffolds due to the promising functional behavior of electroactive biomaterials to regulate cell proliferation, biocompatibility, and signal transition.

METHODS

The fabrication of novel electroactive cardiac patches based on alginate (ALG) coated with different concentrations of reduced graphene oxide (rGO) using sodium hydrosulfite is described here. The prepared scaffolds were thoroughly tested for their physicochemical properties and cytocompatibility. ALG-rGO scaffolds were also tested for their antimicrobial and antioxidant properties. Subcutaneous implantation in mice was used to evaluate the scaffolds' ability to induce angiogenesis.

RESULTS

The Young modulus of the scaffolds was increased by increasing the rGO concentration from 92 ± 4.51 kPa for ALG to 431 ± 4.89 kPa for ALG-rGO-4 (ALG coated with 0.3% w/v rGO). The scaffolds' tensile strength trended similarly. The electrical conductivity of coated scaffolds was calculated in the semi-conductive range (~ 10-4 S/m). Furthermore, when compared to ALG scaffolds, human umbilical vein endothelial cells (HUVECs) cultured on ALG-rGO scaffolds demonstrated improved cell viability and adhesion. Upregulation of VEGFR2 expression at both the mRNA and protein levels confirmed that rGO coating significantly boosted the angiogenic capability of ALG against HUVECs. OD620 assay and FE-SEM observation demonstrated the antibacterial properties of electroactive scaffolds against Escherichia coli, Staphylococcus aureus, and Streptococcus pyogenes. We also showed that the prepared samples possessed antioxidant activity using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assay and UV-vis spectroscopy. Histological evaluations confirmed the enhanced vascularization properties of coated samples after subcutaneous implantation.

CONCLUSION

Our findings suggest that ALG-rGO is a promising scaffold for accelerating the repair of damaged heart tissue.

Impact of routine brain imaging on the prognosis of patients with left-sided valve infective endocarditis without neurological manifestations

BACKGROUND

There are limited data on the impact of routine use of brain magnetic resonance imaging (MRI) on the prognosis of neurologically asymptomatic patients with left-sided infective endocarditis (IE).

METHODS

Among patients diagnosed with possible or definite IE in two tertiary referral centers between January 2005 and March 2019, we identified 527 left-sided IE patients without neurological symptoms or signs at the time of diagnosis. Patients who underwent brain MRI within 1 week after the IE diagnosis were classified as the routine brain imaging group (n = 216), and the rest were categorized as the control group (n = 311). All-cause mortality at 3 months, attributable mortality (defined as death directly related to IE), and fatal neurological events compared after adjustment using inverse probability of treatment weighting (IPTW).

RESULTS

During a median follow-up of 57 months, the routine brain imaging group had a similar risk of 3-month all-cause mortality to the control group in the multivariate analysis (hazard ratio [HR], 0.53; 95% confidence interval [CI], 0.24-1.14) and IPTW-adjusted cohort (HR, 0.59; 95% CI, 0.25-1.42). The risks of attributable mortality and fatal neurological events were also similar between the two groups in the multivariable analysis and IPTW-adjusted cohort. In the subgroup analysis, the routine brain imaging group showed more favorable outcomes in cases of large vegetation (> 10 mm) or acute-onset microorganisms.

CONCLUSIONS

Routine use of brain MRI in left-sided IE patients without neurological manifestations is not associated with improved clinical outcomes. However, routine brain imaging in appropriate clinical settings could improve clinical outcomes.

Potential of graphene-based nanomaterials for cardiac tissue engineering

Cardiovascular diseases are the primary cause of death worldwide. Despite significant advances in pharmacological treatments and surgical interventions to restore heart function after myocardial infarction, it can progress to heart failure due to the restricted inherent potential of adult cardiomyocytes to self-regenerate. Hence, the evolution of new therapeutic methods is critical. Nowadays, novel approaches in tissue engineering have assisted in restoring biological and physical specifications of the injured myocardium and, hence, cardiac function. The incorporation of a supporting matrix that could mechanically and electronically support the heart tissue and stimulate the cells to proliferate and regenerate will be advantageous. Electroconductive nanomaterials can facilitate intracellular communication and aid synchronous contraction via electroactive substrate creation, preventing the issue of arrhythmia in the heart. Among a wide range of electroconductive materials, graphene-based nanomaterials (GBNs) are promising for cardiac tissue engineering (CTE) due to their outstanding features including high mechanical strength, angiogenesis, antibacterial and antioxidant properties, low cost, and scalable fabrication. In the present review, we discuss the effect of applying GBNs on angiogenesis, proliferation, and differentiation of implanted stem cells, their antibacterial and antioxidant properties, and their role in improving the electrical and mechanical properties of the scaffolds for CTE. Also, we summarize the recent research that has applied GBNs in CTE. Finally, we present a concise discussion on the challenges and prospects.

Patterns of Infectious Disease Associated With Injection Drug Use in Massachusetts

BACKGROUND

Since 2014, multiple outbreaks of human immunodeficiency virus (HIV) among people who inject drugs have occurred across the United States along with hepatitis C virus (HCV), skin and soft tissue infections (SSTIs), and infective endocarditis (IE), creating a converging public health crisis.

METHODS

We analyzed the temporal patterns of infectious disease and overdose using a hierarchical Bayesian distributed lag logistic regression model examining the probability that a given geographic area experienced at least 1 HIV case in a given month as a function of the counts/rates of overdose, HCV, SSTI, and IE and associated medical procedures at different lagged time periods.

RESULTS

Current-month HIV is associated with increasing HCV cases, abscess incision and drainage, and SSTI cases, in distinct temporal patterns. For example, 1 additional HCV case occurring 5 and 7 months previously is associated with a 4% increase in the odds of observing at least 1 current-month HIV case in a given locale (odds ratios, 1.04 [90% credible interval {CrI}: 1.01-1.10] and 1.04 [90% CrI: 1.00-1.09]). No such associations were observed for echocardiograms, IE, or overdose.

CONCLUSIONS

Lagged associations in other infections preceding rises in current-month HIV counts cannot be described as predictive of HIV outbreaks but may point toward newly discovered epidemics of injection drug use and associated clinical sequalae, prompting clinicians to screen patients more carefully for substance use disorder and associated infections.

Infective endocarditis and oral surgery input before cardiac surgery: time to prick the paradigm of pre-cardiac surgery assessments?

Purpose To review current practice regarding oral surgery input for patients awaiting cardiac valvular surgery and who are at risk of infective endocarditis (IE) in the context of the COVID-19 pandemic, and to stimulate debate around the indications for pre-operative oral surgery assessment. It also opens the way to developing a new research-based approach which is patient-centred, safe, effective and efficient.Methods A desk-top based patient review was undertaken between 27 March 2020 and 1 July 2022 to record the outcome of patients undergoing cardiac valvular surgery in Northern Ireland, following the revision of the referral guidelines for oral surgery intervention. Data were collected for all cardiac referrals to the oral surgery on-call service in the Royal Victoria Hospital, Belfast. Complications were recorded at two weeks, two months, and six months post-surgery, using Northern Ireland Electronic Care Records.Results In total, 67 cardiac patients were identified between 27 March 2020 and 1 July 2022: 65.7% of patients were male and had an average age of 68, while the female patients had an average age of 61. The mean interval of date of cardiology referral to surgery date was 9.7 working days, with 36% of patients referred within five days of the planned surgery date. Moreover, 39% had valvular surgery in combination with another type of cardiac surgery. No complications linked to dental aetiology were noted.Conclusions This paper raises questions about the advisability of oral surgery input before cardiac surgery for anything other than pain relief, management of acute dental sepsis, or IE whose source has been identified as an oral commensal. The COVID-19 pandemic has presented an opportunity to review current practice and open the way to developing a new approach which is patient-centred, safe, effective and efficient.

Pneumonia, Arthritis, and Liver Injury: A Cardiac Diagnostic Conundrum

A 40-year-old intravenous cocaine user presented with non-specific symptoms, including fever, headache, myalgias, and fatigue. After being provisionally diagnosed with rhinosinusitis and discharged on antibiotics, the patient returned with shortness of breath, dry cough, and persistent high-grade fevers. Initial workup showed multifocal pneumonia, acute liver injury, and septic arthritis. Blood cultures were positive for methicillin-sensitive staphylococcus aureus (MSSA) which led to the evaluation of endocarditis with a transthoracic echocardiogram (TTE) and transesophageal echocardiogram (TEE). TEE was performed as the initial diagnostic imaging test, and it did not show any evidence of valvular vegetation. However, given the persistence of the patient's symptoms and clinical suspicion of infective endocarditis, TTE was performed which showed a 3.2 cm vegetation on the pulmonic valve with severe insufficiency, leading to a diagnosis of pulmonic valve endocarditis. The patient was treated with antibiotics and underwent a pulmonic valve replacement surgery, which showed a large vegetation on the ventricle portion of the pulmonic valve that was replaced with an interspersed tissue valve. The patient was discharged in stable condition after improvement of symptoms and normalization of liver function enzymes. It is important to note that TTE should be considered initially as a diagnostic tool in such cases. Sometimes, a TEE may not be required if the TTE provides a sufficient assessment.

Structural vaccinology-based design of multi-epitopes vaccine against Streptococcus gordonii and validation using molecular modeling and immune simulation approaches

Streptococcus gordonii is an oral bacterium colonizing the dental cavity and leading to plaque formation. This pervasive colonizer is also the etiologic agent of bacterial endocarditis and has a major role in infective endocarditis. The bacteria reach the heart through oral bleeding, leading to inflammation of cardiovascular valves. Over the past 50 years, it has shown a significant pathogenic role in immunocompromised and neutropenic patients. Since antibiotic resistance has created prophylaxis failure towards infective endocarditis, a potent therapeutic candidate is needed. Therefore, multi-epitopes vaccine offers advantages over the other approaches. Thus, herein, numerous molecular-omics tools were exploited to mine immunogenic peptides, i.e., T-cell and B-cell epitopes, and construct a vaccine sequence. Our findings revealed a total of 24 epitopes, including CTL, HTL, and B-cell are responsible for imparting immune responses, which were combined with the help of different linkers, and MEVC was constructed. Multifactorial validation of the candidate vaccine was performed to minimize the risk factors. The final sequence was docked with TLR2 to validate its conformation compatibility with receptor and long-term interactions stability. Our analysis revealed that the vaccine construct is immunogenic and non-allergenic. The construct also established various contacts with the immune receptor. Finally, the vaccine sequence was reverse-translated, optimized for codon usage, and analyzed for expression in the Escherichia coli K12 strain. Maximum expression was noted with a CAI score of 0.95. In silico immune simulation revealed that the antigen was neutralized on the 3rd day after injection. In conclusion, the current study warrants validation of the vaccine construct both in in vitro and in vivo models for accurate therapeutic intervention.

Native Valve Endocarditis Caused by Nocardia asteroides in an Immunocompetent Host: A Case Report and a Review of the Literature

Nocardia species are a rare cause of infective endocarditis (IE). We describe a case of native valve endocarditis caused by Nocardia asteroides in a 38-year-old Hispanic male with no apparent environmental exposures or risk factors for IE. Transesophageal echocardiography revealed severe mitral regurgitation, prompting emergent replacement of the valve. Nocardia asteroides were isolated from the tissue culture of the mitral valve. MRI of the brain also demonstrated innumerable micronodular intra-axial lesions throughout the brain, consistent with disseminated nocardiosis. The patient was treated with intravenous trimethoprim/sulfamethoxazole, meropenem, and amikacin for a six-week course, followed by oral trimethoprim/sulfamethoxazole and minocycline for 12 months. Follow-up after 18 months revealed no evidence of relapse. Although several cases of endocarditis due to Nocardia asteroides have been reported in immunocompromised hosts, to the best of our knowledge we believe the present case is the first to describe native valve endocarditis by Nocardia asteroides in an immunocompetent host with no apparent risk factors for IE.

Rare Proteus mirabilis Aortic Valve Infective Endocarditis without a Urinary Tract Infection

Proteus mirabilis infective endocarditis is a rare disease with only 17 reported cases. It is typically associated with urinary tract infections (UTIs), staghorn calculi, and/or asymptomatic bacteriuria. We present a case of a 73-year-old male who presented with positive blood cultures for Proteus mirabilis but with a negative urinalysis and urine culture. He presented with acute renal failure and required hemodialysis. TTE was remarkable for a 30% ejection fraction, and no vegetations were visualized. TEE demonstrated a small vegetation on the left aortic valve. The initial urine culture remained negative throughout his hospitalization. He was treated with IV antibiotics and discharged without hemodialysis.

Clinical Efficacy of Percutaneous Vegetectomy in Tricuspid and Right-Heart Indwelling Device Infective Endocarditis

Several studies have analyzed the efficacy of AngioVac for percutaneous intracardiac vegetectomy, but impact on surgical candidacy or clinical efficacy for infectious endocarditis (IE) is currently unknown. This is a single-arm, retrospective study on IE vegetectomy with impact on surgical risk scores. Analysis included 32 patients who underwent AngioVac vegetectomy for right heart IE at a single institution. The primary endpoint was improvement in the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) scores. Secondary endpoints included technical success, improved leukocytosis, procedural safety, 30-day mortality, and 60-day mortality. Findings demonstrate 90.6% (n = 29) technically successful debulking. There was improvement in mean NSQIP scores from 34.6 to 27.9 ( P = .007). Zero cases of 30-day all-cause mortality. One patient experienced a major post-procedural complication of pneumothorax, a Class D Adverse Event. 20.5% (n = 5) of valvular vegetation patients went on to have surgical tricuspid valve repair. All indwelling intracardiac devices were removed. Findings suggest that percutaneous vegetectomy improves surgical candidacy, as measured by ACS NSQIP scores, in patients with IE and right heart vegetations and is associated with low complication rates.

Efficacy and safety of outpatient parenteral antibiotic therapy in patients with infective endocarditis: a meta-analysis

OBJECTIVE

To investigate the clinical outcome of patients with infective endocarditis (IE) during and after outpatient parenteral antimicrobial treatment (OPAT), and to further clarify the safety and efficacy of OPAT for IE patients.

METHODS

Through December 20, 2021, a total of 331 articles were preliminarily searched in Pubmed, Web of Science, Cochrane Library and Embase, and 9 articles were eventually included in this study.

RESULTS

A total of 9 articles comprising 1,116 patients were included in this study. The overall mortality rate of patients treated with OPAT was 0.04 (95% CI, 0.02-0.07), that means 4 deaths per 100 patients treated with OPAT. Separately, mortality was low during the follow-up period after OPAT treatment, with an effect size (ES) of 0.03 (95%CI, 0.02-0.07) and the mortality of patients during OPAT treatment was 0.04 (95% CI, 0.01-0.12). In addition, the readmission rate was found to be 0.14 (95% CI, 0.09-0.22) during the follow-up and 0.18 (95% CI, 0.08-0.39) during treatment, and 0.16 (95% CI, 0.10-0.24) for patients treated with OPAT in general. Regarding the relapse of IE in patients, our results showed a low overall relapse rate, with an ES of 0.03 (95% CI, 0.01-0.05). In addition, we found that the incidence of adverse events was low, with an ES of 0.26 (95% CI, 0.19-0.33).

CONCLUSIONS

In general, the incidence of adverse events and mortality, readmission, and relapse rates in IE patients treated with OPAT are low both during treatment and follow-up period after discharge, indicating that OPAT is safe and effective for IE patients. However, our study did not compare routine hospitalization as a control group, so conclusions should be drawn with caution. In order to obtain more scientific and rigorous conclusions and reduce clinical risks, it is still necessary to conduct more research in this field and improve the patient selection criteria for OPAT treatment, especially for IE patients. Finally, clinical monitoring and follow-up of OPAT-treated patients should be strengthened.

Aortic valve endocarditis in patients with bicuspid and tricuspid aortic valves

Objective

To determine the long-term survival and rate of reoperation after surgical treatment of infective endocarditis (IE) in patients with a bicuspid aortic valve (BAV) and patients with a tricuspid aortic valve (TAV).

Methods

Between 1997 and 2017, 210 patients underwent surgical treatment for native aortic valve endocarditis, including 51 patients with BAV (24%) and 159 patients with TAV (76%). Data were obtained from the Society of Thoracic Surgeons data warehouse and hospital medical record review, supplemented with surveys and national death index data for more complete follow-up.

Results

Compared with the TAV IE group, the BAV IE group was significantly younger (42 years vs 54 years) and had lower incidence rates of hypertension, coronary artery disease, and congestive heart failure (CHF). There were no significant between-group differences in postoperative stroke, sepsis, pacemaker requirement, or in-hospital mortality (2.0% vs 4.4%). Liver disease was a risk factor for operative mortality (odds ratio [OR], 13; 95% CI, 3.3-30; P = .0002). The 10-year survival rate was 64% for the BAV group versus 46% for the TAV group (P = .0191). Significant risk factors for long-term mortality were intravenous drug use (hazard ratio [HR], 4.5; P < .0001), preoperative renal failure requiring dialysis (HR, 4.13; P < .0001), CHF (HR, 1.7; P = .04), and liver disease (HR, 2.6; P = .02). The HR for BAV was 0.67 (95% confidence interval [CI], 0.3-1.4). The 10-year postoperative cumulative incidence of reoperation was significantly higher in the BAV patients compared with the TAV patients (5.7% vs 4.5%; P = .045) with an HR of 2.4 (95% CI, 0.8-7.1; P = .11) for BAV.

Conclusions

BAV patients develop IE requiring surgery at a younger age than TAV patients, but have significantly better long-term survival. Early detection of BAV is important to prevent IE and provide aggressive surgical treatment should IE occur.

Enterococcus faecalis colonizes and forms persistent biofilm microcolonies on undamaged endothelial surfaces in a rabbit endovascular infection model

Infectious endocarditis (IE) is an uncommon disease with significant morbidity and mortality. The pathogenesis of IE has historically been described as a cascade of host-specific events beginning with endothelial damage and thrombus formation and followed by bacterial colonization of the nascent thrombus. Enterococcus faecalis is a Gram-positive commensal bacterial member of the gastrointestinal tract microbiota in most terrestrial animals and a leading cause of opportunistic biofilm-associated infections, including endocarditis. Here, we provide evidence that E. faecalis can colonize the endocardial surface without pre-existing damage and in the absence of thrombus formation in a rabbit endovascular infection model. Using previously described light and scanning electron microscopy techniques, we show that inoculation of a well-characterized E. faecalis lab strain in the marginal ear vein of New Zealand White rabbits resulted in rapid colonization of the endocardium throughout the heart within 4 days of administration. Unexpectedly, ultrastructural imaging revealed that the microcolonies were firmly attached directly to the endocardium in areas without morphological evidence of gross tissue damage. Further, the attached bacterial aggregates were not associated with significant cellular components of coagulation or host extracellular matrix damage repair (i.e. platelets). These results suggest that the canonical model of mechanical surface damage as a prerequisite for bacterial attachment to host sub-endothelial components is not required. Furthermore, these findings are consistent with a model of initial establishment of stable, endocarditis-associated E. faecalis biofilm microcolonies that may provide a reservoir for the eventual valvular infection characteristic of clinical endocarditis. The similarities between the E. faecalis colonization and biofilm morphologies seen in this rabbit endovascular infection model and our previously published murine gastrointestinal colonization model indicate that biofilm production and common host cell attachment factors are conserved in disparate mammalian hosts under both commensal and pathogenic contexts.

"To Fix a Broken Heart": An Unusual Case of Infective Endocarditis Involving the Mitral Valve With Perforation and Hemodynamic Instability

Infective endocarditis (IE), commonly caused by Staphylococcus aureus, can affect multiple cardiac structures and lead to significant morbidity and mortality. We present a case of IE with extensive mitral valve involvement causing perforation and hemodynamic compromise. A 66-year-old Caucasian female presented to the emergency department for progressive altered mental status and lethargy. The patient and family denied history of intravenous drug use (IVDU) on interview. Physical exam revealed tachypnea, tachycardia, lethargy, and fluctuance in the right antecubital fossa draining serous fluid. Initial studies revealed a urinary tract infection, patchy bilateral opacities on chest x-ray, hypoxic respiratory failure, elevated lactate and cardiac markers, leukocytosis, and positive urine toxicology for opioid and benzodiazepine. She was intubated and admitted to the ICU, and later developed acute respiratory distress syndrome with requirement for vasopressors. Antibiotics were started, and blood cultures ultimately grew methicillin-sensitive S. aureus. Coronavirus disease 2019 (COVID-19) results were negative. Cardiology was consulted for elevated cardiac markers that were due to myocardial injury in the setting of septic shock. A transthoracic echocardiogram showed a large mobile mass on the anterior mitral leaflet. Further evaluation with transesophageal echocardiogram revealed a large, mobile, and centrally necrotic vegetation on the medial portion of the mitral annulus extending to both the anterior and posterior leaflets. Doppler of the valve showed holosystolic retrograde ejection into the left atrium confirming a perforation. The patient was transferred urgently to a cardiothoracic surgery capable center for operative intervention on the mitral valve. IE is most commonly caused by S. aureus and seen in highest rates among patients with a prosthetic valve, congenital heart disease, and intracardiac device. However, roughly 50% of IE occurs in patients without any valvular disease. Other risk factors include IVDU, valvular disease, and prior history of endocarditis. Clinical diagnosis of IE is made using the Duke's criteria, with echocardiogram and bacteremia playing a major role. The initial management involves empiric antibiotics until a pathogen is identified. Surgical consult is also suggested, and indications for surgery include heart failure due to valve dysfunction, uncontrolled infection, prevention of embolism, and hemodynamic compromise. Prompt recognition and intervention is crucial in the prevention of mortality in patients with IE leading to mitral perforation and hemodynamic compromise.

Enterococcal Endocarditis: Hiding in Plain Sight

Enterococcus faecalis is a major opportunistic bacterial pathogen of increasing clinical relevance. A substantial body of experimental evidence suggests that early biofilm formation plays a critical role in these infections, as well as in colonization and persistence in the GI tract as a commensal member of the microbiome in most terrestrial animals. Animal models of experimental endocarditis generally involve inducing mechanical valve damage by cardiac catheterization prior to infection, and it has long been presumed that endocarditis vegetation formation resulting from bacterial attachment to the endocardial endothelium requires some pre-existing tissue damage. Here we review both historical and contemporary animal model studies demonstrating the robust ability of E. faecalis to directly attach and form stable microcolony biofilms encased within a bacterially-derived extracellular matrix on the undamaged endovascular endothelial surface. We also discuss the morphological similarities when these biofilms form on other host tissues, including when E. faecalis colonizes the GI epithelium as a commensal member of the normal vertebrate microbiome - hiding in plain sight where it can serve as a source for systemic infection via translocation. We propose that these phenotypes may allow the organism to persist as an undetected infection in asymptomatic individuals and thus provide an infectious reservoir for later clinical endocarditis.

Genome-Based Drug Target Identification in Human Pathogen Streptococcus gallolyticus

Streptococcus gallolysticus (Sg) is an opportunistic Gram-positive, non-motile bacterium, which causes infective endocarditis, an inflammation of the inner lining of the heart. As Sg has acquired resistance with the available antibiotics, therefore, there is a dire need to find new therapeutic targets and potent drugs to prevent and treat this disease. In the current study, an in silico approach is utilized to link genomic data of Sg species with its proteome to identify putative therapeutic targets. A total of 1,138 core proteins have been identified using pan genomic approach. Further, using subtractive proteomic analysis, a set of 18 proteins, essential for bacteria and non-homologous to host (human), is identified. Out of these 18 proteins, 12 cytoplasmic proteins were selected as potential drug targets. These selected proteins were subjected to molecular docking against drug-like compounds retrieved from ZINC database. Furthermore, the top docked compounds with lower binding energy were identified. In this work, we have identified novel drug and vaccine targets against Sg, of which some have already been reported and validated in other species. Owing to the experimental validation, we believe our methodology and result are significant contribution for drug/vaccine target identification against Sg-caused infective endocarditis.

The Dynamics of Infectious Diseases Associated With Injection Drug Use in Lawrence and Lowell, Massachusetts

Background

There are a wide variety of infectious complications of injection drug use. Understanding the trajectory of these complications might inform the development of an early warning system for human immunodeficiency virus (HIV) outbreaks that occur regularly among people who inject drugs (PWID).

Methods

A distributed lag Poisson regression model in the Bayesian setting was used to examine temporal patterns in the incidence of injection-associated infectious diseases and their association with HIV cases in Lawrence and Lowell, Massachusetts between 2005 and 2018.

Results

Current-month HIV counts are associated with fatal overdoses approximately 8 months prior, cases of infective endocarditis 10 months prior, and cases of skin and soft tissue infections and incision and drainage procedures associated with these infections 12 months prior.

Conclusions

Collecting data on these other complications associated with injection drug use by public health departments may be important to consider because these complications may serve as input to a sentinel system to trigger early intervention and avert potential outbreaks of HIV.

Non-18F-FDG/18F-NaF Radiotracers Proposed for the Diagnosis and Management of Diseases of the Heart and Vasculature

¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) and ¹⁸F-sodium fluoride (¹⁸F-NaF) are front-runners in PET. However, these tracers have limitations in the imaging of diseases in the heart. A multitude of other radiotracers have been identified as potentially useful PET agents in the identification of cardiovascular disease. This critical review examines recent studies with the use of non-¹⁸F-FDG/¹⁸F-NaF radiotracers in the identification and surveillance of cardiovascular diseases. We highlight the need for further investigation into alternative PET radiotracers to demonstrate their clinical value in the management of these pathologies.

PET/CT Imaging for Personalized Management of Infectious Diseases

Positron emission tomography combined with computed tomography (PET/CT) is a nuclear imaging technique which is increasingly being used in infectious diseases. Because infection foci often consume more glucose than surrounding tissue, most infections can be diagnosed with PET/CT using 2-deoxy-2-[18F]fluoro-D-glucose (FDG), an analogue of glucose labeled with Fluorine-18. In this review, we discuss common infectious diseases in which FDG-PET/CT is currently applied including bloodstream infection of unknown origin, infective endocarditis, vascular graft infection, spondylodiscitis, and cyst infections. Next, we highlight the latest developments within the field of PET/CT, including total body PET/CT, use of novel PET radiotracers, and potential future applications of PET/CT that will likely lead to increased capabilities for patient-tailored treatment of infectious diseases.

Multiorgan emboli due to an intraluminal thrombus from frozen elephant trunk

The impact of kinking of the nonstented part of a frozen elephant trunk on the development of adverse effects is unclear. We report a case of an infected thrombus within the kinked nonstented portion of the frozen elephant trunk that resulted in multiorgan embolization. A 45-year-old man presented with a 1-month history of high-grade fever and fatigue. He had undergone emergent total arch replacement and frozen elephant trunk implantation for type A acute aortic dissection 7 years previously. Computed tomography showed an intraluminal thrombus within the kinked nonstented portion of the frozen elephant trunk. An autopsy also showed an intraluminal thrombus within the graft and diffuse microembolization in the abdominal organs. Therefore, in this case, kinking of the nonstented part of the frozen elephant trunk had resulted in an infected intraluminal thrombus, which subsequently caused multiorgan embolization.

Predictors of mortality and adverse events in patients with infective endocarditis: a retrospective real world study in a surgical centre

Purpose

Mortality in infective endocarditis (IE) is still high, and the long term prognosis remains uncertain. This study aimed to identify predictors of long-term mortality for any cause, adverse event rate, relapse rate, valvular and ventricular dysfunction at follow-up, in a real-world surgical centre.

Methods

We retrospectively analyzed 363 consecutive episodes of IE (123 women, 34%) admitted to our department with a definite diagnosis of non-device-related IE. Median follow-up duration was 2.9 years. Primary endpoints were predictors of mortality, recurrent endocarditis, and major non-fatal adverse events (hospitalization for any cardiovascular cause, pace-maker implantation, new onset of atrial fibrillation, sternal dehiscence), and ventricular and valvular dysfunction at follow-up.

Results

Multivariate analysis independent predictors of mortality showed age (HR per unit 1.031, p < 0.003), drug abuse (HR 3.5, p < 0.002), EUROSCORE II (HR per unit 1.017, p < 0.0006) and double valve infection (HR 2.3, p < 0.001) to be independent predictors of mortality, while streptococcal infection remained associated with a better prognosis (HR 0.5, p < 0.04). Major non-fatal adverse events were associated with age (HR 1.4, p < 0.022). New episodes of infection were correlated with S aureus infection (HR 4.8, p < 0.001), right-sided endocarditis (HR 7.4, p < 0.001), spondylodiscitis (HR 6.8, p < 0.004) and intravenous drug abuse (HR 10.3, p < 0.001). After multivariate analysis, only drug abuse was an independent predictor of new episodes of endocarditis (HR 8.5, p < 0.001). Echocardiographic follow-up, available in 95 cases, showed a worsening of left ventricular systolic function (p < 0.007); severe valvular dysfunction at follow-up was reported only in 4 patients, all of them had mitral IE (p < 0.03).

Conclusions

The present study highlights some clinical, readily available factors that can be useful to stratify the prognosis of patients with IE.

Tricuspid Valve Endocarditis: A Disguise In Multifocal Septic Arthritis

Infective endocarditis (IE) is a rare cause of multifocal septic arthritis. We report a patient who presented with oligo-articular septic arthritis as a complication of tricuspid valve endocarditis, a rare condition. A 69-year-old female presented to the emergency department with complaints of fever, myalgia, right shoulder, and right knee pain. Initial investigation elaborated on elevated C-reactive protein, erythrocyte sedimentation rate (ESR), and white blood cell. Imaging studies, including X-ray, were unrevealing. Blood cultures came out positive for Methicillin-sensitive Staphylococcus aureus (MSSA) bacteremia. Magnetic resonance imaging (MRI) of the right shoulder and right knee showed joint effusion with soft tissue swelling. Diagnostic arthroscopic washout of right shoulder and right knee showed neutrophilic pleocytosis, and the cultures were positive for MSSA. Despite adequate antibiotic coverage for MSSA bacteremia with oligo-articular/multifocal septic arthritis, the patient's fever did not resolve. Initial transthoracic echocardiography (TTE) was negative for any vegetation. Transesophageal echocardiography (TEE) showed vegetations on the tricuspid valve with tricuspid regurgitation and was diagnosed with acute bacterial IE. A multi-disciplinary approach was adopted. She underwent tricuspid valve repair with annuloplasty and was treated with nafcillin for six weeks. She successfully recovered from MSSA bacteremia, and follow-up TEE was negative for any vegetations.

Tricuspid valve diseases: Interventions on the forgotten heart valve

Over the past few decades, the tricuspid valve (TV) interventions have been relatively lower compared to other cardiac valvular disease in terms of pathophysiology and management, especially regarding surgical intervention and therapy. However, recent crucial advances in assessment and management of the TV disease have resulted in a renewed interest in the "forgotten valve." The medical treatment aims to cure the underlying disease and address the presentation of the right heart failure. Surgical interventions have proven to yield good outcomes for those for whom surgery is indicated. For those who are not suitable for surgery, transcatheter surgery may prove to be a suitable replacement. Best practice with regard to surgical techniques is still in question due to limited data. This has been slowing the introduction of transcatheter interventions into common practical guidelines. The aim of this literature review is to discuss new insights on the pathophysiology, diagnosis, and interventions of TV disease, highlighting the surgical management and emerging transcatheter therapies. In addition, this review will provide an overview of the current state of the literature surrounding TV interventions and providing suggestions for future directives.

Outpatient Antimicrobial Therapy for Infective Endocarditis is Safe

Infective endocarditis (IE) is common and is associated with significant mortality, morbidity and health care burden. Outpatient antimicrobial therapy in carefully selected patients, supported by a multidisciplinary team is safe and beneficial for both the patient and the health care system. In this article, we review current literature of outpatient antimicrobial therapy in infective endocarditis and propose that most patients with IE should be considered and appropriate pathways developed to facilitate this.

Infected Right Ventricle Thrombus as a Cause of Persistent Sepsis

The presentation of fevers in a patient with active intravenous (IV) drug use is often challenging, as there is a wide range of both infectious and noninfectious disorders that can cause fevers. A thorough diagnostic workup is essential in identifying the etiology of these fevers. We report a rare case of an infected right ventricular (RV) thrombus as a cause of persistent fever and sepsis in a 46-year-old patient with IV drug use. The patient continued to have persistent bacteremia inspite of appropriate IV antibiotics. Hence, the patient warranted a cardiothoracic surgical excision of the infected RV thrombus following which the patient showed remarkable improvement.

A Case Report of Cardiobacterium hominis Endocarditis in a Pregnant Woman

Infective endocarditis (IE) is an infrequent endovascular disease, which can result in significant mortality and morbidity. Staphylococcus aureus and viridans streptococci remain the most common etiological agent. Cardiobacterium hominis, a member of the HACEK (Haemophilus species, Aggregatibacter species, Cardiobacterium hominis, Eikenella corrodens, and Kingella species) group of fastidious gram-negative bacillus, is a part of normal upper respiratory flora and a rare cause implicated in IE. Cases of Cardiobacterium hominis endocarditis are being increasingly reported in last few years due to advancement in automated blood culture system such as BacT/ALERT Virtuo^® and identification system such as MALDI-TOF MS (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry). We herein report a first case of Cardiobacterium hominis endocarditis in a pregnant woman at 20 weeks of gestation. Following spontaneous abortion and evacuation of the fetus, appropriate surgical intervention under heparinized condition and pathogen-directed medical intervention was initiated in this patient. This case report highlights the importance of appropriate antimicrobial therapy, which augments earlier resolution of the disease.

Heart Infection Prognosis Analysis by Two-dimensional Spot Tracking Imaging

Cardiovascular death is one of the leading causes worldwide; an accurate identification followed by diagnosing the cardiovascular disease increases the chance of a better recovery. Among different demonstrated strategies, imaging on cardiac infections yields a visible result and highly reliable compared to other analytical methods. Two-dimensional spot tracking imaging is the emerging new technology that has been used to study the function and structure of the heart and test the deformation and movement of the myocardium. Particularly, it helps to capture the images of each segment in different directions of myocardial strain values, such as valves of radial strain, longitudinal strain, and circumferential strain. In this overview, we discussed the imaging of infections in the heart by using the two-dimensional spot tracking.

Mitral Valve Aneurysm in Mitral Valve Endocarditis:A Case Report

Mitral valve aneurysm (MVA) is an ominous complication of infective endocarditis (IE), with worse outcomes seen among patients with preexisting valvular disease or intravenous drug use. Valve aneurysms can perforate or lead to rupture of the chordae tendineae, with the consequent development of severe mitral regurgitation and acute pulmonary edema. We present a case of a 54-year-old woman with hypertension, obesity, diabetes mellitus, hyperlipidemia, chronic obstructive pulmonary disease, peptic ulcer disease, obstructive sleep apnea, gastroesophageal reflux disease, intravenous drug abuse and bipolar disorder who developed MVA one month after being discharged for IE. Decline in the clinical status of patients with IE is a troubling sign that may indicate an IE complication such as MVA. Physicians should diligently monitor patients with IE for changes in signs and symptoms, as early recognition and surgical intervention are key to prevent further morbidity and mortality.

The distinct effects of aspirin on platelet aggregation induced by infectious bacteria

Bacteria induce platelet aggregation triggered by several mechanisms. The goal of this work was to characterize platelet aggregates induced by different bacterial strains and to quantify the effect of aspirin treatment using aggregation tests, as well as a novel approach based on confocal analysis. Blood samples were obtained from either healthy donors (n = 27) or patients treated with long-term aspirin (n = 15). The bacterial species included were Staphylococcus aureus, Enterococcus faecalis, and Streptococcus sanguinis. The different aggregate's ultrastructures depending on the bacterial strain were analyzed using Scanning electron microscopy. Quantification of the size of the platelet aggregates, their mean number as well as the bacterial impregnation within the aggregates was performed using confocal laser scanning light microscopy. Light Transmission Aggregometry was also performed. Our results reported distinct characteristics of platelet aggregates depending on the bacterial strain. Using confocal analysis, we have shown that aspirin significantly reduced platelet aggregation induced by S. aureus (p = .003) and E. faecalis (p = .006) with no effect in the case of S. sanguinis (p = .529). The results of the aggregometry were concordant with those of the confocal technique in the case of S. aureus and S. sanguinis. Interestingly, aggregation induced by E. faecalis was detected only with confocal analysis. In conclusion, our confocal scanning microscopy allowed a detailed study of the platelet aggregation induced by bacteria. We showed that aspirin acts on bacterial-induced platelet aggregation depending on the species. These results are in favor of the use of aspirin considering the species and the bacterial strain involved.

Infective endocarditis and the heavily restored dentition: are clinicians becoming more complacent regarding prevention?

The use of antibiotic prophylaxis to reduce the risk of infective endocarditis (IE) in susceptible individuals is a topic which has historically prompted many controversial debates. In the past, dentists have been understandably unwilling to prescribe antibiotic prophylaxis for fear of deviating from the National Institute for Health and Care Excellence (NICE) guidelines. However, in 2016, NICE altered the wording of these guidelines. The subtle change in wording implied that the clinician could use their clinical judgement, alongside advice from cardiologists, to deem their patient high-risk enough to prescribe antibiotics. In this article we discuss the implications of the NICE guidelines, and present the case of a patient who historically received antibiotic prophylaxis due to a history of rheumatic fever. Following the old NICE guidelines of 2008 he no longer received this prescription. As a consequence, he went on to suffer from IE from an unexpected cause due to ineffective preventative advice.

Rare case report of infective endocarditis due to Kocuria kristinae in a patient with ventricular septal defect

Background

Infective endocarditis (IE) is an uncommon but life-threatening infection. It is commonly associated with diseased or damaged valves. Patients with congenital heart disease are more prone to getting IE than the general population. The typical organisms that cause IE include Staphylococcus, Coagulase-negative Staphylococcus, Streptococcus viridians and Enterococci. However, the importance of rare micro-organisms like Kocuria kristinae should not be underestimated especially when isolated from multiple blood cultures in patients suspected of IE.

Case presentation

We report a rare case of right-sided infective endocarditis due to K. kristinae in a young non-diabetic, non-addict female of low socioeconomic class who presented with undiagnosed fever for 1 year. She was investigated and treated for fever by several general practitioners without relief. Later on, she was diagnosed by a local cardiologist to have perimembranous ventricular septal defect with a small pulmonary valve vegetation. She was referred to a tertiary care cardiac hospital in Rawalpindi, Pakistan for further management. Transthoracic and transesophageal echocardiography confirmed IE secondary to preexisting congenital heart disease complicated with a small pulmonary vegetation. Her blood cultures yielded growth of K. kristanae, a rare micro-organism to cause IE. The patient responded to the antibiotic therapy.

Conclusion

Clinicians should have a high index of suspicion for K. kristanae IE as a possible cause of a prolonged fever especially in the presence of congenital heart disease. Antibiotic susceptibility is required for adequate therapy.

Targeting of Nanotherapeutics to Infection Sites for Antimicrobial Therapy

Bacterial infections cause a wide range of host immune disorders, resulting in local and systemic tissue damage. Antibiotics are pharmacological interventions for treating bacterial infections, but increased antimicrobial resistance and the delayed development of new antibiotics have led to a major global health threat, the so-called "superbugs". Bacterial infections consist of two processes: pathogen invasion and host immune responses. Developing nanotherapeutics to target these two pathways may be effective for eliminating bacteria and restoring host homeostasis, thus possibly finding new treatments for bacterial infections. This review offers new approaches for developing nanotherapeutics based on the pathogenesis of infectious diseases. We have discussed how nanoparticles target infectious microenvironments (IMEs) and how they target phagocytes to deliver antibiotics to eliminate intracellular pathogens. We also review a new concept-host-directed therapy for bacterial infections, such as targeting immune cells for the delivery of anti-inflammatory agents and vaccine developments using bacterial membrane-derived nanovesicles. This review demonstrates the translational potential of nanomedicine for improving infectious disease treatments.

Obesity as a Risk Factor Among Hospitalized Patients with Infective Endocarditis

Objective

Obesity contributes to diagnostic and management challenges for many hospitalized patients. The impact of obesity on in-hospital outcomes in patients with infective endocarditis has not been studied and was the focus of this investigation.

Method

We used the 2013 and 2014 Nationwide Inpatient Sample to identify adults ≥18 years of age with a principle diagnosis of endocarditis. We divided the sample into 2 groups based on presence of absence of obesity. Multivariate linear and logistic regression analysis was used to compare in-hospital mortality, valvular replacement, length of stay (LOS), and hospitalization charges.

Results

A total of 24 494 adults 18 years and older were hospitalized with infective endocarditis, of which 2625 were classified as obese. Patients with obesity were older (mean age, 57.8 ± 0.3 vs 54.3 ± 0.6 years; P < .01), more likely to be female (50.1% vs 36.1%; P < .01), and had more comorbidities (Charlson comorbidity score ≥ 3, 50.6% vs 28.8%; P < .01). Multivariate regression analysis found no differences between the 2 groups for mortality or repairs or replacements for any valve. On evaluation of resource utilization, patients with obesity had longer average LOS (13.9 days; confidence interval [CI], 12.7–15.1 vs 12.4 days; CI, 12.0–12.8; P = .016) and higher total hospital charges (US $160 789.90; CI, $140.922.40–$180 657.50 vs US $130 627.20; CI, $123 916.70–$137 337.70; P <.01). After adjustment for LOS for total hospital charges, there was no observed difference $11436.26 (CI, -$6649.07–$29521.6; P = .22).

Conclusions

. Obesity does not significantly impact in-hospital mortality or surgical valvular interventions among patients hospitalized with infective endocarditis, but obesity is associated with increased utilization of hospital resources.

Gemella endocarditis: A case report and a review of the literature

Infective endocarditis (IE) remains a prevalent disease with a high rate of morbidity and mortality. Recent changes have been noted in the profile of causative microorganisms. In this report, we describe a case of Gemella-related endocarditis and review the related literature. Our patient was an 81-year-old man who presented with dyspnea and fatigue. His initial examination revealed a new systolic murmur. Echocardiogram revealed moderate mitral regurgitation with 1-cm mass on the anterior mitral leaflet, and blood cultures grew Gemella haemolysans. Penicillin and gentamicin were initiated, and workup for possible source was positive for a colonic polyp with high-grade dysplasia. The patient subsequently developed cardiogenic shock and severe pulmonary edema. Comfort care measures were initiated, and he passed away thereafter. We reviewed PubMed for cases of Gemella-related endocarditis. We found 65 documented cases and added our patient's case to the analysis. Seventy-two percent of the cases occurred in men. The mean age was 51 years and 42% of the patients were older than 60 years. Fever was the most common presenting symptom and most of the cases presented subacutely. The mitral valve was the most affected site and 50% of the patients required surgical intervention. G. morbillorum was the most common subtype and a total of four cases were found to be associated with colorectal neoplasm. As a conclusion, Gemella species rarely cause IE. The absence of a clear source of bacteremia warrants further evaluation for a gastrointestinal source. The infection can be destructive and must be promptly treated to avoid complications.

Antimicrobial Activity of Exebacase (Lysin CF-301) against the Most Common Causes of Infective Endocarditis

Exebacase, a recombinantly produced lysin (cell wall hydrolase), and comparator antibiotics were tested by the broth microdilution method against strain sets of Staphylococcus and Streptococcus spp., which are the most common causes of infective endocarditis in humans. Exebacase was active against all Staphylococcus spp. tested, including S. aureus and coagulase-negative staphylococci (MIC_50/90, 0.5/1 μg/ml). Activity against Streptococcus spp. was variable, with S. pyogenes, S. agalactiae, and S. dysgalactiae (MIC_50/90, 1/2 μg/ml) among the most susceptible.

Portraying infective endocarditis: results of multinational ID-IRI study

Infective endocarditis is a growing problem with many shifts due to ever-increasing comorbid illnesses, invasive procedures, and increase in the elderly. We performed this multinational study to depict definite infective endocarditis. Adult patients with definite endocarditis hospitalized between January 1, 2015, and October 1, 2018, were included from 41 hospitals in 13 countries. We included microbiological features, types and severity of the disease, complications, but excluded therapeutic parameters. A total of 867 patients were included. A total of 631 (72.8%) patients had native valve endocarditis (NVE), 214 (24.7%) patients had prosthetic valve endocarditis (PVE), 21 (2.4%) patients had pacemaker lead endocarditis, and 1 patient had catheter port endocarditis. Eighteen percent of NVE patients were hospital-acquired. PVE patients were classified as early-onset in 24.9%. A total of 385 (44.4%) patients had major embolic events, most frequently to the brain (n = 227, 26.3%). Blood cultures yielded pathogens in 766 (88.4%). In 101 (11.6%) patients, blood cultures were negative. Molecular testing of vegetations disclosed pathogens in 65 cases. Overall, 795 (91.7%) endocarditis patients had any identified pathogen. Leading pathogens (Staphylococcus aureus (n = 267, 33.6%), Streptococcus viridans (n = 149, 18.7%), enterococci (n = 128, 16.1%), coagulase-negative staphylococci (n = 92, 11.6%)) displayed substantial resistance profiles. A total of 132 (15.2%) patients had cardiac abscesses; 693 (79.9%) patients had left-sided endocarditis. Aortic (n = 394, 45.4%) and mitral valves (n = 369, 42.5%) were most frequently involved. Mortality was more common in PVE than NVE (NVE (n = 101, 16%), PVE (n = 49, 22.9%), p = 0.042).

[Infective Endocarditis Causing Native and Prosthetic Heart Valve Dysfunction]

Infective endocarditis (IE) is the disease that has high inhospital mortality. Heart valves dysfunction - both native and prosthetic - is the primary IE complication requiring a surgical intervention. The IE causes and its course have been discussed in this review. In particular, the role of concomitant infectious foci in the formation and development of IE have been considered, the mechanisms of mutual transition of subacute and acute clinical forms have been described. Modern diagnostic principles and methods based on the Duke criteria system have been mentioned, as well as the difficulties that follow the patient's clinical status evaluation. The normobiotic microbiota participation, as well as the possibilities for their identification using blood culture and PCR technique, have been closely reviewed. According to modern researches and publications, there have been made the conclusion about the contribution of obligate anaerobic bacteria, fungi and viruses to the development of endocarditis. There have been described the hypothesis about the presumptive strategy for the cardiac dysfunction formation as a result of the IE causative agents cells metabolic activity based on a literature data analysis in the article: vegetation formed by Staphylococcus aureus can lead to the heart valve stenosis, and the influence of hyaluronidases, collagenases on a heart valve structure can lead to regurgitation. The pathogens cells ability to avoid the human immune system response is caused by the biofilms, fibrin vegetations formation and the enzymes production - cytotoxins (streptolysins, leukocidin, etc.). It has been suggested that the mediators of inflammation and leukocyte cells participate in the destruction of native and prosthetic tissues due to an IE pathogens inaccessibility for immunocompetent cells.

Probiotic supplements might not be universally-effective and safe: A review

Last few decades have witnessed the unprecedented growth in the application of probiotics for promoting the general gut health as well as their inception as biotherapeutics to alleviate certain clinical disorders related to dysbiosis. While numerous studies have substantiated the health-restoring potentials for a restricted group of microbial species, the marketed extrapolation of a similar probiotic label to a large number of partially characterized microbial formulations seems biased. In particular, the individuals under neonatal stages and/or those with some clinical conditions including malignancies, leaky gut, diabetes mellitus, and post-organ transplant convalescence likely fail to reap the benefits of probiotics. Further exacerbating the conditions, some probiotic strains might take advantage of the weak immunity in these vulnerable groups and turn into opportunistic pathogens engendering life-threatening pneumonia, endocarditis, and sepsis. Moreover, the unregulated and rampant use of probiotics potentially carry the risk of plasmid-mediated antibiotic resistance transfer to the gut infectious pathogens. In this review, we discuss the safety perspectives of probiotics and their therapeutic interventions in certain at-risk population groups. The embodied arguments and hypotheses certainly will shed light on the fact why probiotic usage should be treated with caution.

Embolization of Endocardial Vegetation With Stroke Presentation

This case report details the unique cause of death of a 37-year-old Caucasian woman with a history significant for intravenous drug abuse. Before her death, she complained of extremity weakness and pain. Although her death was discovered to be the result of endocarditis, her symptoms were similar to that of a stroke. Autopsy revealed a large endocardial vegetation infecting both the tricuspid and mitral valves and a patent foramen ovale. The subsequent embolization of this vegetation caused blockages in the lungs, liver, and brain. An acute embolization of these vegetations to the bilateral middle cerebral arteries is the cause of the stroke presentation. Other comorbidities, such as cardiomegaly, microscopic evidence of myocardial infarction, and atherosclerotic disease, also contributed to the cause of death. As the opioid crisis continues in the United States, it is important to review cases involving the effects of drug use. The multiple interactions between endocarditis and the aforementioned conditions are documented to not only serve as references for future autopsies but also for the treatment of patients who have similar symptoms and comorbidities.

An unusual cause of breathlessness and profuse micronodules

We describe a 21-year-old male with a history of smoking and subacute onset of breathlessness with normal cardiorespiratory examination. The presence of "track marks" and digital infarcts prompted evaluation for infective endocarditis and confrontational history taking revealed anorexia, weight loss over 3 months along with intravenous drug abuse of reconstituted tablets of tapentadol. Echocardiography was normal and blood cultures were sterile; computed tomography showed bilateral, diffuse, small centrilobular nodules with "tree-in-bud" appearance. In this clinicopathologic conference, we discuss the clinical and radiological differential diagnosis of centrilobular nodules, lung biopsy findings, and management options for patients with such a presentation.

Pseudomonas aeruginosa Invades Human Aortic Endothelial Cells and Induces Cell Damage in vitro

BACKGROUND

Cardiovascular diseases such as endocarditis are the second most common cause of death worldwide. Infective Endocarditis (IE) is the most severe infection of the heart associated with significant mortality and morbidity. The binding and invasion of Human Aortic Endothelial Cells (HAECs) by pathogenic microbes can play an important role in the pathogenesis of IE.

OBJECTIVE

Pseudomonas aeruginosa is an emerging pathogen that has been associated with IE. However, it is not known whether P. aeruginosa can bind and interact with HAECs. The aim of this study was to determine whether P. aeruginosa can bind and colonize HAECs.

METHODS

The invasion of HAECs by P. aeruginosa was assessed by gentamicin protection assay. Cytokine levels were determined by enzyme-linked Immunosorbent Assay (ELISA) kits. Cell damage was determined by Lactate Dehydrogenase (LDH) assay.

RESULTS

P. aeruginosa can bind and invade HAECs. Infection of HAECs with P. aeruginosa induces TNF-α IL-1β, IL-6 and IL-8 cytokine production leading to the generation of inflammatory milieu that can cause tissue damage as observed in human clinical cases of IE. We also observed that P. aeruginosa induces cell damage in HAECs.

CONCLUSION

In this study, we demonstrate for first time that P. aeruginosa can invade and survive inside HAECs. This cell culture model can be of immense importance to determine the efficacy of drug targets against IE.

Group B Streptococcal Tricuspid Endocarditis: Case Report and Systematic Review

Infective Endocarditis (IE), the microbial infection of the endocardial surface, is categorized by anatomy, microbiology, and valve nativity. Infective endocarditis generally affects older adults, and more commonly presents as a Left-sided IE (LSIE) affecting the mitral or aortic valves. Right-sided IE (RSIE) typically affects younger patients with less pre-existing valvular disease. RSIE is also more commonly associated with intravenous drug use (IVDU) and intra-cardiac instrumentation, such as pacemakers or defibrillators. While Staphylococcus aureus is the most common microorganism responsible for both LSIE and RSIE, Streptococcos agalactiae, or Group B Streptococcus (GBS), accounts for a very small percentage of IE, and, in such instances, rates of tricuspid endocarditis are dramatically lower than LSIE. GBS endocarditis usually affects patients with particular comorbidites, such as diabetes mellitus (DM) and cirrhosis. We present a case of GBS tricuspid endocarditis in a female patient without the typical risk factors for GBS endocarditis. We also present a systematic review of case reports and case series of GBS tricuspid endocarditis highlighting the risk factors, presentation and clinical characteristics, as well as up-to-date outcomes, and mortality rates of GBS endocarditis, a potentially fatal disease entity.

Triple-Valve Endocarditis in a Diabetic Patient: Case Report and Literature Review

BACKGROUND

Despite major advancements since its first description in the 19th century, infective endocarditis remains a significant medical challenge. Although commonly involving a single valve, multiple valve involvement may occur, complicating matters even further. Triplevalve endocarditis is a very rare phenomenon. Poorly studied and described only a handful of times in the literature, little is known about the optimal therapeutic and management options in dealing with this complex entity.

CONCLUSION

In this paper we describe the case of a 48-year-old male who was diagnosed with triple-valve endocarditis and provide a review of the literature to delineate what is already known and improve our understanding of this rare phenomenon.