Infective endocarditis

Concurrent bacterial endocarditis is associated with worse inpatient outcomes for large vessel occlusions

BACKGROUND

Neurological complications of bacterial endocarditis (BE) are common, including acute ischemic stroke (AIS). Although mechanical thrombectomy (MT) is effective for large vessel occlusion (LVO) stroke, data are limited on MT for LVOs in patients with endocarditis. We assess outcomes in patients treated with thrombectomy for LVOs with concurrent BE.

METHODS

The National Inpatient Sample (NIS) was used. The NIS was queried from October 2015-2019 for patients receiving MT for LVO of the middle cerebral artery. Odds ratios (OR) were calculated using a multivariate logistic regression model.

RESULTS

A total of 635 AIS with BE patients and 57 420 AIS only patients were identified undergoing MT. AIS with BE patients had a death rate of 26.8% versus 10.2% in the stroke alone cohort, and were also less likely to have a routine discharge (10.2% vs 20.9%, both P<0.0001). AIS with BE patients had higher odds of death (OR 3.94) and lower odds of routine discharge (OR 0.23). AIS with BE patients also had higher rates of post-treatment cerebral hemorrhage, 39.4% vs 23.7%, with an OR of 2.20 (P<0.0001 for both analyses). These patients also had higher odds of other complications, including hydrocephalus, respiratory failure, acute kidney injury, and sepsis.

CONCLUSION

While MT can be used to treat endocarditis patients with LVOs, these patients have worse outcomes. Additional investigations should be undertaken to better understand their clinical course, and further develop treatments for endocarditis patients with stroke.

Stroke in Asia

BACKGROUND

There is a significant burden of stroke in Asia. Asia has the largest population in the world in 2023, estimated at 4.7 billion. Approximately 9.5-10.6 million strokes will be anticipated annually in the backdrop of a diverse group of well-developed and less developed countries with large disparities in stroke care resources. In addition, Asian countries are in varying phases of epidemiological transition.

SUMMARY

In this review, we examined recent epidemiological features of ischaemic stroke and intracerebral haemorrhage in Asia with recent developments in hyperacute stroke reperfusion therapy and technical improvements in intracerebral haemorrhage. The article also discussed the spectrum of cerebrovascular diseases in Asia, which include intracranial atherosclerosis, intracerebral haemorrhage, infective aetiologies of stroke, moyamoya disease, vascular dissection, radiation vasculopathy, and cerebral venous thrombosis.

KEY MESSAGES

The review of selected literature and recent updates calls for attention to the different requirements for resources within Asia and highlights the breadth of cerebrovascular diseases still requiring further research and more effective therapies.

Anticoagulation Therapy in a Patient who had two Consecutive Strokes After Antibiotic Therapy for Infective Endocarditis: A Case Report

A 77-year-old male presented with altered mentation and was diagnosed with infective endocarditis. Echocardiography revealed aortic valve vegetations. While receiving inpatient antibiotic therapy, the patient experienced an acute ischemic stroke. Magnetic resonance imaging of the brain showed punctate embolic-appearing infarcts in the right cerebellum and in the left occipital, frontal, and parietal lobes. Anticoagulation was not initiated due to a high risk of hemorrhagic transformation. He was readmitted after being discharged due to another episode of altered mentation. Repeat echocardiography indicated increased size of aortic valve vegetations. The patient was then transferred to our hospital for surgical intervention of enlarging vegetations, however was deemed unsuitable for surgery. During hospitalization, he suffered another embolic stroke in the right frontal lobe. By this time, the patient had completed a full course of antibiotics for infective endocarditis, and additional antibiotics were deemed unnecessary by our infectious disease specialists. Literature review highlighted that residual vegetations carry a higher risk for stroke, but no clear guidelines were found on how to intervene or assess the risk of hemorrhage with anticoagulation in this population. Consequently, a decision was made to initiate anticoagulation, Follow-up imaging revealed no evidence of hemorrhagic transformation. Subsequently, the patient remained stable and was discharged to a rehabilitation center, where he did not experience any further events.

The interplay among a dental procedure, infective endocarditis, and an acute ischemic stroke

BACKGROUND

This case report highlights the rare association among a dental procedure, infective endocarditis, and an acute ischemic stroke.

CASE DESCRIPTION

A 54-year-old woman who experienced an acute ischemic stroke 5 weeks after a tooth extraction is described. The initial symptoms of this patient included mild to moderate word-finding difficulty and right facial droop. Computed tomographic angiography revealed a left M1 segment middle cerebral artery occlusion (thrombolysis in cerebral infarction scale, 0) with reconstitution of the distal middle cerebral branches through arterial collaterals. After initial administration of tissue plasminogen activator, endovascular thrombectomy was successfully performed with thrombolysis in cerebral infarction scale 3 (complete) recanalization. After the procedure, the patient showed improvement in language and neurologic deficits. Imaging showed multifocal, bilateral, cortical, and deep brain hemorrhages. Blood cultures grew Streptococcus mitis, ultimately leading to the diagnosis of endocarditis. Echocardiographic imaging revealed moderate to severe aortic insufficiency, a mitral valve vegetation, and mild mitral valve regurgitation. After evaluation by the cardiothoracic surgery team, the patient was discharged with intravenous antibiotics and short-term outpatient follow-up with the cardiothoracic surgery team.

PRACTICAL IMPLICATIONS

Dental procedures, although generally safe, can introduce oral bacteria into the bloodstream, leading to bacterial seeding of cardiac valves and subsequent infective endocarditis. Recognizing infective endocarditis subsequent to a dental procedure, including a tooth extraction, as a potential cause of an acute ischemic stroke is vital so that prompt treatment can be initiated.

"National survey for preliminary evaluation of neuroradiological protocols in patients with infective endocarditis"

OBJECTIVES

The aim of this study was to identify imaging protocols in patients with infective endocarditis through a nationwide survey.

METHODS

An electronic evolutionary survey was sent to interventional Neuroradiologists among neuroradiological centers, under the aegis of the Société Française de Neuroradiologie. Among 33 contacted centers, 25 completed the survey (21 universitary hospitals and 4 peripheric hospitals).

RESULTS

Most of the centers (88%) used systematic imaging screening in IE patients. MRI was the first imaging method used in 66% of cases, while CT was used in 44%. When no IIA was detectable in CT-scan screening, 6 (54,54%) stopped investigations, while 9 (81,81%) continued with MRI exploration in case of hemorrhage, ischemia or enhancement. Sulcal hemorrhage on MRI was an indication of complementary DSA in 25 centers (100%). Regarding IIA characterization, 12 centers (48%) used systematic DSA, whereas for 10 centers (40%), DSA was conditioned by hemorrhage or patient status.

CONCLUSION

We highlighted large variations in Neuroimaging exploration and follow-up of IE patients in real-world practices. Expert guidelines able to standardize practices are warranted to improve the management of this serious and often misdiagnosed pathology.

Significant increase in mortality and risk of acute ischemic stroke in infective endocarditis patients with subarachnoid hemorrhage secondary to mycotic aneurysms

Infective Endocarditis (IE) patients are known to have a variety of complications with one of the rarest, but serious being cerebral mycotic aneurysm, which can result in subarachnoid hemorrhage (SAH). Using the National In-Patient Sample database, we sought to determine the rate of acute ischemic stroke (AIS) and outcomes in IE- patients with and without SAH. In total, we identified 82,844 IE-patients from 2010 to 2016, of which 641 had a concurrent diagnosis of SAH. IE patients with SAH had a more complicated course, higher mortality rate (OR 4.65 CI 95% 3.9-5.5, P < 0.001), and worse outcomes. This patient population also had a significantly higher rate of AIS (OR 6.3 CI 95% 5.4-7.4, P < 0.001). Overall, 41.5% of IE-patients with SAH had AIS during their hospitalization as compared to 10.1% of IE only patients. IE-patients with SAH were more likely to undergo endovascular treatment (3.6%) with 0.8% of the IE patients with AIS undergoing mechanical thrombectomy. While IE-patients are at risk for various complications, our study suggests a significant increase in the mortality and risk of AIS in those with SAH.

The Use of AngioVac in a Patient With Severe Infective Endocarditis Where Open Heart Surgery Is Contraindicated: A Case Report

Infectious endocarditis of the tricuspid valve (TV) is a common complication of intravenous (IV) drug use. Endocarditis caused by viridans streptococci can lead to heart valve vegetations, which may be life-threatening due to the potential for embolism and obstruction. The management of large valvular vegetations is often difficult due to the risks involved with open heart surgery, especially in patients with comorbid conditions. The AngioVac device (AngioDynamics Inc., Latham, NY) has been shown in rare cases to be effective at debulking vegetations without the need for invasive surgery. We present a 45-year-old male with a history of intravenous heroin use disorder, hepatitis C, spinal abscesses, and chronic anemia who experienced worsening shortness of breath, generalized weakness, bilateral lower extremity edema, dysuria with dark urine, and blood on toilet paper. Workup revealed a 4.39 × 4.35 cm tricuspid valve vegetation, severe tricuspid regurgitation (TR), acute renal failure, acute on chronic anemia, and thrombocytopenia from sepsis-induced disseminated intravascular coagulation (DIC). AngioVac was used to aspirate the vegetation and effectively reduced the size to 3.75 × 2.31 cm. Follow-up blood cultures revealed no growth after five days. This is the largest documented tricuspid valve vegetation with a successful implementation of the AngioVac to date. This therapy, in conjunction with intravenous antibiotics and hemodialysis, successfully sterilized the vegetation, prevented worsening presentation, and averted life-threatening complications, although severe tricuspid regurgitation persisted. Based on the findings of this case, the AngioVac device is a safe and effective treatment option for tricuspid valve endocarditis patients with large vegetation and severe comorbidities, which contraindicate open heart surgery.

Long-term incidence of infective endocarditis among patients with congenital heart disease

BACKGROUND

Patients with congenital heart disease (CHD) are at lifelong high risk of infective endocarditis (IE). The risk of IE presumably differs among different CHD, but little knowledge exists on the area.

METHODS

In this observational cohort study, all CHD-patients born in 1977 to 2018 were identified using Danish nationwide registries and followed from the date of birth until first-time IE, emigration, death, or end of study (December 31, 2018). The comparative risk of IE among CHD-patients vs age- and sex-matched controls from the background population was assessed. The risk of IE was stratified according to the type of CHD and factors associated with IE including sex and relevant time-varying coefficients (ie, cyanosis, cardiac prostheses, diabetes mellitus, chronic kidney disease, and cardiac implantable electronic devices) were examined using Cox-regression analysis.

RESULTS

A total of 23,464 CHD-patients (50.0% men) were identified and matched with 93,856 controls. During a median follow-up of 17.7 years, 217(0.9%) CHD-patients and 4(0.0%) controls developed IE, corresponding to incidence rates of 5.2(95%CI 4.6-6.0) and 0.02(95%CI 0.01-0.1) per 10,000 person-years, respectively. The incidence of IE was greatest among patients with tetralogy of fallot, malformations of the heart chambers (including transposition of the great arteries, univentricular heart, and truncus arteriosus), atrioventricular septal defects, and heart valve defects. Factors associated with IE among CHD-patients included male sex, cyanosis, cardiac prostheses, chronic kidney disease, and cardiac implantable electronic devices.

CONCLUSIONS

CHD-patients have a substantially higher associated incidence of IE than the background population. With the increasing longevity of these patients, relevant guidelines concerning preventive measures are important.

Native and Prosthetic Simultaneously Double Valve Infective Endocarditis with Enterococcus faecalis-Case-Based Review

Infective endocarditis is a severe infective heart disease, commonly involving native or prosthetic valves. It frequently presents with univalvular involvement and simultaneous double valve or multivalvular involvement is rarely described. The third leading cause of infective endocarditis worldwide is Enterococcus faecalis, which is associated with high mortality rates despite important advances in antimicrobial therapy. It develops secondary to enterococcal bacteremia, with its origin from the gastrointestinal or genitourinary tract and predominantly affecting the elderly population with multiple comorbidities. Clinical presentation is usually less typical, and the treatment is challenging. It can be marked by antibiotic resistance, side effects, and subsequent complications. Surgical treatment can be considered if deemed appropriate. To the best of our knowledge, we present the first case-based narrative review of Enterococcus faecalis double valve endocarditis involving both the aortic native and prosthetic mitral valve, highlighting the clinical characteristics, treatment, and complications of this condition.

Endovascular Treatment of Large Vessel Occlusion Strokes Caused by Infective Endocarditis: A Systematic Review, Meta-Analysis, and Case Presentation

Thromboembolic events such as acute ischemic strokes are frequently seen in patients with infective endocarditis (IE). It is generally recommended that the administration of intravenous thrombolytics is avoided in these patients as they might encounter a higher risk of intracranial hemorrhages. In this setting, particularly with a large vessel occlusion (LVO), a mechanical thrombectomy may be an alternative option. In this systematic review and meta-analysis, we aimed to investigate the outcomes and safety of mechanical thrombectomies for LVO stroke patients secondary to IE. A search strategy was developed and we searched PubMed, Scopus, Web of Sciences, and Embase using the words "infective endocarditis", "stroke", and "mechanical thrombectomy". Including 6 studies and 120 patients overall, this study showed that a mechanical thrombectomy might reduce the National Institute of Health Stroke Scale (NIHSS), with a weighted mean difference of -3.06 and a 95% CI of -4.43 to -1.70. The pooled rate of symptomatic intracranial hemorrhages and all-cause mortality were also determined to be 15% (95% CI: 4-47%) and 34% (95% CI:14-61%), respectively. The results of this study showed that a mechanical thrombectomy might be an effective and reasonably safe option for the treatment of LVO strokes caused by IE. However, more large-scale studies are needed to consolidate these results.

Superantigens, a Paradox of the Immune Response

Staphylococcal enterotoxins are a wide family of bacterial exotoxins with the capacity to activate as much as 20% of the host T cells, which is why they were called superantigens. Superantigens (SAgs) can cause multiple diseases in humans and cattle, ranging from mild to life-threatening infections. Almost all S. aureus isolates encode at least one of these toxins, though there is no complete knowledge about how their production is triggered. One of the main problems with the available evidence for these toxins is that most studies have been conducted with a few superantigens; however, the resulting characteristics are attributed to the whole group. Although these toxins share homology and a two-domain structure organization, the similarity ratio varies from 20 to 89% among different SAgs, implying wide heterogeneity. Furthermore, every attempt to structurally classify these proteins has failed to answer differential biological functionalities. Taking these concerns into account, it might not be appropriate to extrapolate all the information that is currently available to every staphylococcal SAg. Here, we aimed to gather the available information about all staphylococcal SAgs, considering their functions and pathogenicity, their ability to interact with the immune system as well as their capacity to be used as immunotherapeutic agents, resembling the two faces of Dr. Jekyll and Mr. Hyde.

Epidemiology, burden, and attributable risks of infective endocarditis in Iran and its provinces: From 1990 to 2019

BACKGROUND

Endocarditis is a potentially life-threatening infectious disease associated with significant morbidity and mortality and an escalating incidence in recent decades. In this study, as a part of the global burden of disease (GBD) 2019 study, we intend to report endocarditis burden in Iran at national and provincial levels from 1990 to 2019.

METHOD

This study was conducted using GBD 2019 study data on endocarditis from 1990 to 2019. We gathered incidence, prevalence, disability-adjusted life years (DALYs), and mortality rates in Iran and its 31 provinces by sex and age groups as epidemiological indices for endocarditis burden. Further decomposition analysis was also performed to delineate the endocarditis new cases trend.

RESULTS

On the country scale, age-standardized incidence rate (ASIR), age-standardized prevalence rate (ASPR), age-standardized mortality rate (ASMR), and age-standardized DALYs rate were (16.5 (95% uncertainty interval 13.7 to 19.8), 3.4 (2.9 to 4.1), 0.6 (0.5 to 0.9), and 14.4 (12.0 to 21.1) in 2019, respectively. Decomposition analysis showed that only 59.2% of the overall new cases increase (114.1%) was caused by the incidence rate change. All estimated age-standardized rates were higher in men in 1990 and 2019 with a ratio of 1.1-1.5.

CONCLUSION

The ASIR and ASPR of endocarditis increased, and the ASMR and age-standardized DALYs rate declined over the past 30 years in Iran, nearly all the provinces followed the same pattern with North Khorasan having the Highest ASIR, ASPR, ASMR, and DALYs rates in both years. High systolic blood pressure (SBP) had the greatest attributed burden among risk factors.

Incidence of Infective Endocarditis Among Patients With Tetralogy of Fallot

Background

Patients with tetralogy of Fallot (ToF) are considered at high risk of infective endocarditis (IE) as a result of altered hemodynamics and multiple invasive procedures, including pulmonary valve replacement (PVR). Data on the long‐term risk of IE are sparse.

Methods and Results

In this observational cohort study, all patients with ToF born from 1977 to 2018 were identified using Danish nationwide registries and followed from date of birth until occurrence of first‐time IE, emigration, death, or end of study (December 31, 2018). The comparative risk of IE among patients with ToF versus age‐ and sex‐matched controls from the background population was assessed. Because of rules on anonymity, exact numbers cannot be reported if the number of patients is <4. A total of 1164 patients with ToF were identified and matched with 4656 controls. Among patients with ToF, 851 (73.1%) underwent early surgical intracardiac repair and 276 (23.7%) underwent PVR during follow‐up. During a median follow‐up of 20.3 years, 41 (3.5%) patients with ToF (comprising 24 [8.7%] with PVR and 17 [1.9%] without PVR) and <4 (<0.8%) controls were admitted with IE. The incidence rates of IE per 10 000 person‐years were 22.4 (95% CI, 16.5–30.4) and 0.1 (95% CI, 0.01–0.7) among patients and controls, respectively. Moreover, PVR was associated with a further increased incidence of IE among patients with ToF (incidence rates per 10 000 person‐years with and without PVR were 46.7 [95% CI, 25.1–86.6] and 2.8 [95% CI 2.0–4.0], respectively).

Conclusions

Patients with ToF are associated with a substantially higher incidence of IE than the background population. In particular, PVR was associated with an increased incidence of IE. With an increasing life expectancy of these patients, intensified awareness, preventive measures, and surveillance of this patient group are decisive.

European Stroke Organisation (ESO) guidelines on intravenous thrombolysis for acute ischaemic stroke

Intravenous thrombolysis is the only approved systemic reperfusion treatment for patients with acute ischaemic stroke. These European Stroke Organisation (ESO) guidelines provide evidence-based recommendations to assist physicians in their clinical decisions with regard to intravenous thrombolysis for acute ischaemic stroke. These guidelines were developed based on the ESO standard operating procedure and followed the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. The working group identified relevant clinical questions, performed systematic reviews and meta-analyses of the literature, assessed the quality of the available evidence, and wrote recommendations. Expert consensus statements were provided if not enough evidence was available to provide recommendations based on the GRADE approach. We found high quality evidence to recommend intravenous thrombolysis with alteplase to improve functional outcome in patients with acute ischemic stroke within 4.5 h after symptom onset. We also found high quality evidence to recommend intravenous thrombolysis with alteplase in patients with acute ischaemic stroke on awakening from sleep, who were last seen well more than 4.5 h earlier, who have MRI DWI-FLAIR mismatch, and for whom mechanical thrombectomy is not planned. These guidelines provide further recommendations regarding patient subgroups, late time windows, imaging selection strategies, relative and absolute contraindications to alteplase, and tenecteplase. Intravenous thrombolysis remains a cornerstone of acute stroke management. Appropriate patient selection and timely treatment are crucial. Further randomized controlled clinical trials are needed to inform clinical decision-making with regard to tenecteplase and the use of intravenous thrombolysis before mechanical thrombectomy in patients with large vessel occlusion.

Transcranial Doppler Emboli Monitoring for Infective Endocarditis

BACKGROUND AND PURPOSE

Ischemic stroke can occur in 20-55% of patients with infective endocarditis (IE) with 75% occurring during the first 2 weeks of treatment. CT or MRI brain can diagnose the sequelae of stroke but transcranial Doppler (TCD) can document active embolization. We undertook a retrospective review of our patient cohort and a systematic review of literature to assess the role of TCD in early diagnosis and management of ischemic stroke in IE.

METHODS

Retrospective chart review and literature review.

RESULTS

We found 89 patients with stroke caused by IE at our institution from December 2011 to April 2018. TCDs were obtained on 26 patients; 16 were abnormal for cerebrovascular abnormalities. Only 4 patients had 30-minute emboli monitoring performed, of which one revealed emboli. We found 3 studies investigating the role of TCDs in IE that showed promise in its use as a predictive tool in stroke risk stratification.

CONCLUSIONS

Presence of embolization in the form of high-intensity transient signals (HITS) detected on TCDs can be used for early diagnosis of IE, assessing efficacy of antibiotic therapy, and stratification of stroke risk in IE. This can aid further research into testing preventative interventions for reducing stroke burden in IE such as earlier valvular surgery or vacuum-assisted vegetation extraction.

Infective Endocarditis: Preliminary Results of a Cohort Study in the Southern Italian Population

Background

Infective endocarditis (IE) is an uncommon disease with an involved interplay of clinical and surgical team management. We aimed to define diagnosis parameters and delineate in-hospital management in patients with IE admitted in a tertiary hospital of Southern Italian.

Materials and methods

Fifty-six consecutive patients (42 males, 14 females; age range: 34-85 years) admitted for IE in the Infectious Diseases, Cardiac Surgery, and Cardiology units, between January 2011 and August 2017, were enrolled. Demographic data, mortality, comorbidities, specimen type, microscopy results, special histological staining performed, and antimicrobial therapy were collected and analyzed. Any comments at the multidisciplinary team meetings were recorded in minutes of and approved.

Results

We found 83.9% of patients with positive blood cultures. The four most common bacteria were methicillin-resistant Staphylococcus aureus (MRSA: 21.3%), methicillin-sensitive Staphylococcus aureus (MSSA: 17%), Streptococci (14.9%), and Enterococci (14.9%). Both in the univariate and multivariate analysis, we observed a significant positive correlation between surgery and complications. Particularly in the univariate analysis only, surgery was positively correlated to males and C-reactive protein (CPR) at baseline. Also, considering the most common bacteria, it resulted in a positive correlation between surgery and MRSA and Streptococci spp. and between complications and MSSA. Finally, the male gender was positively correlated to MSSA and heart complications, major arterial embolism, septic pulmonary emboli, splenic infarction, and cerebral embolism.

Conclusions

A blood culture test remains a critical factor for the diagnosis of IE and the antibiotic treatment of susceptible and emerging resistant bacteria. Male gender and heart complications are red flags for prompt operative management.

Recurrent infective endocarditis versus first-time infective endocarditis after heart valve surgery

OBJECTIVE

Infective endocarditis (IE) may require heart valve surgery. It is well known that heart valve surgery itself and previous IE predispose to IE. However, data are sparse on whether the risk of IE is different among patients undergoing valve surgery due to IE and other causes (i.e. recurrent vs. first-time IE).

METHODS

Using Danish nationwide registries, patients undergoing left-sided heart valve surgery in the course of an IE hospitalization (1996-2017) were identified and matched with controls undergoing left-sided heart valve surgery due to another cause than IE in a 1:1 ratio. Patients were stratified according to type of surgical valve intervention and affected valve. The comparative risk of recurrent vs. first-time IE was assessed by cumulative incidence curves and multivariable Cox regression analyses.

RESULTS

The study population comprised 971 patients with a first-time admission for IE requiring heart valve surgery matched with 971 controls undergoing heart valve surgery due to other causes than IE. The risk of recurrent IE was significantly higher than the risk of first-time IE following heart valve surgery (5.5% and 3.0% by 10 years, hazard ratio (HR) 1.66, 95% confidence interval (CI) 1.02-2.70). The risk of IE recurrence was not significantly different comparing valve replacement and valve repair (5.5% and 5.3%, respectively, HR 1.60, 95% CI 0.71-3.60). Yet, the risk of IE recurrence was significantly higher among patients with biological versus mechanical prostheses (6.3% and 4.6%, respectively, HR 2.00, 95% CI 1.02-3.70).

CONCLUSIONS

Following heart valve surgery, the risk of recurrent IE was significantly higher than the risk of first-time IE.

Comparative analysis of the oral microbiota between iron-deficiency anaemia (IDA) patients and healthy individuals by high-throughput sequencing

Background

The relationship between oral microbiota and IE (infective endocarditis) is well established. Opportunistic pathogens in normal oral flora enter the bloodstream through daily oral cleaning or invasive dental procedures, leading to the occurrence of infective endocarditis. An in vitro iron-deficient condition leads to a drastic community shift in oral microbiota with increasing proportions of taxa related to infective endocarditis. To investigate the relationship among insufficient iron supply, oral microbiota and the risk of IE and to conduct a population amplification study, iron-deficiency anaemia is used as an in vivo model.

Methods

This cross-sectional study enrolled 24 primary iron-deficiency anemia (IDA) patients from 2015.6 to 2016.6 from the hematology department of West China Hospital, Sichuan University, and 24 healthy controls. High-throughput sequencing compared the dental plaque microbiota of 24 IDA (iron-deficiency anaemia) patients and 24 healthy controls.

Results

Sequences were classified into 12 phyla, 28 classes, 50 orders, 161 genera and 497 OTUs (the IDA and control groups shared the same 384 OTUs). Iron deficiency leads to lower internal diversity in the oral flora. The abundances of genera Corynebacterium, Neisseria, Cardiobacterium, Capnocytophaga, and Aggregatibacter were significantly higher in healthy controls, while genera Lactococcus, Enterococcus, Lactobacillus, Pseudomonas and Moraxella showed higher proportions in the IDA group (P < 0.05). The relative abundances of genera Lactococcus, Enterococcus, Pseudomonas and Moraxella were significantly negatively correlated with the concentration of serum ferritin (P < 0.05).

Conclusions

Without an increase of oral streptococci, the main pathogen of IE, it is difficult to determine whether IDA can increase the risk of IE. However, the iron-deficient condition did lead to changes in the oral microbiota community structure. The genera that showed higher proportions in the IDA group were frequently reported as antibiotic-resistant. As antibiotics are commonly recommended to prevent IE before dental procedures, this study offers new ideas of personalized prevention of IE.

Vegetative Valvular Endocarditis and Hepatitis Associated with Helcococcus ovis in a 7-year-old White Leghorn Rooster

Helcococcus ovis is a slow-growing, pyridoxal-dependent, Gram-positive coccus belonging to the Peptostreptococcaceae family. Bacteria belonging to the genus Helcococcus are considered normal inhabitants of keratinized epithelium in humans; however, several reports support their role as pathogens in humans and several animal species. This case report describes the identification of H. ovis in a white leghorn rooster with valvular vegetative endocarditis and hepatitis. In February 2017 one dead, 7-yr-old, white leghorn rooster was submitted to the California Animal Health and Food Safety Turlock laboratory for diagnostic testing. Postmortem and microscopic examination revealed vegetative endocarditis and aortic thrombosis associated with large numbers of Gram-positive cocci. Myocarditis and extensive necrotic hepatitis were also noticed. Helcococcus ovis was isolated in large numbers from the aortic endothelium and confirmed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Bacterial colonies become evident 48 hr postincubation and exhibited a satellite growth around Escherichia coli on blood agar plates. A similar relationship has been described between Helcococcus spp. and Staphylococcus aureus. The primary site of infection in this chicken was not determined. To our understanding this is the first report of H. ovis infection in an avian species. The fastidious nature and nutritional requirements of Helcococcus spp. must be considered in order to allow proper identification and avoid misdiagnosis. Further studies are needed to define pathogenesis, virulence factors, and predisposing conditions associated with this microorganism.

Association between acute ischemic stroke etiology and macroscopic aspect of retrieved clots: is a clot’s color a warning light for underlying pathologies?

Background

Few case reports have considered the chromatic aspect of retrieved clots and the possible association with their underlying etiology.

Objective

The aim of our study was to analyze the frequency of the TOAST ischemic stroke typical (atrial fibrillation, dissection, atheroma) and atypical (infective endocarditis, cancer-related, valve-related thrombi) etiologies depending on the chromatic aspect of retrieved clots.

Methods

A total of 255 anonymized and standardized clot photos of consecutive patients treated by mechanical thrombectomy for acute ischemic stroke were included. A double-blind evaluation was performed by two senior interventional neuroradiologists, who classified the visual aspects of the clots into two main patterns: red/black or white. Main patient characteristics, distribution of underlying stroke etiologies, and outcomes were compared between the two study groups.

Results

The inter-reader agreement for clot colors was excellent (k=0.78). Two hundred and thirty-three patients were classified as having red/black clots and 22 as having white clots. A statistically significant association (p=0.001) between atypical etiologies and white clots was observed.

Conclusions

White clots were significantly associated with atypical etiologies in this cohort,in particular, with infectious endocarditis.

Neurological Complications of Infective Endocarditis

PURPOSE OF REVIEW

The purpose of this narrative review and update is to summarize the current knowledge and provide recent advances on the neurologic complications of infective endocarditis.

RECENT FINDINGS

Neurological complications occur in about one-fourth of patients with infective endocarditis. Brain MRI represents a major tool for the identification of asymptomatic lesions, which occur in most of the patients with infective endocarditis. The usefulness of systematic brain imaging and the preferred treatment of patients with infective endocarditis and silent brain lesions remains uncertain. The basis of treatment of infective endocarditis is early antimicrobial therapy. In stroke due to infective endocarditis, anticoagulation and thrombolysis should be avoided. Endovascular treatment can be useful for both acute septic emboli and mycotic aneurysms, but evidence is still limited. In patients with neurological complications, cardiac surgery can be safely performed early, if indicated. The optimal management of a patients with neurological complications of infective endocarditis needs an individualized case discussion and the participation of a multidisciplinary team including neurologists, cardiologists, cardiothoracic surgeons, neuroradiologists, neurosurgeons, and infectious disease specialists.

Infective Endocarditis in the Intravenous Drug Use Population at a Tertiary Hospital in Melbourne, Australia

BACKGROUND

Infective endocarditis has been associated with underlying cardiac pathology and streptococci infections. Intravenous drug use (IVDU) is increasingly implicated as a contributing factor, resulting in a shift to a younger patient demographic, tricuspid valve involvement, severe staphylococcal infection, and unique management challenges. The objective of this study was to describe the clinical features, management and outcomes of patients with IVDU-associated infective endocarditis in the Australian context.

METHODS

A retrospective review of all episodes of IVDU-associated infective endocarditis at a tertiary hospital in Melbourne, Australia, from 2008 to 2015, was conducted. Included cases met Duke Criteria for 'definite' or 'possible' infective endocarditis, and had a history of IVDU within 3 months of presentation. Demographic data, substance use history, clinical features, surgical intervention, follow-up, and mortality data was collected. We explored factors associated with surgical intervention, recurrence and mortality.

RESULTS

Fifty-five (55) episodes of IVDU-associated infective endocarditis were identified in 46 patients; the median age was 40 years and 58% were male. The tricuspid valve was most commonly affected (38%), and left heart pathology was documented in 53% of cases. Methicillin-sensitive Staphylococcus aureus was the most common pathogen (67%). Thirty-six (36%) per cent of patients underwent surgical intervention, and all patients received antibiotics as a component of treatment, with a median duration of 42 days (IQR 21, 42 days). Heart failure and a vegetation larger than 1 cm were significantly associated with surgical intervention. Total mortality was 14.5%; surgical mortality was 10%. Opioid replacement therapy and the absence of psychiatric co-morbidities were protective factors for surgical intervention and disease recurrence.

CONCLUSIONS

In contrast to common perception, left-sided endocarditis was more common than tricuspid valve endocarditis. Left heart pathology is typically a more severe clinical entity, however, our study determined mortality rates remained similar when compared to right heart pathology. Further research is required to assess rates of left sided disease in the IVDU population, and elucidate the relationship between IVDU and left heart pathology.

Hospitalizations Related To Opioid Abuse/Dependence And Associated Serious Infections Increased Sharply, 2002-12

Serious infection is a recognized complication of intravenous drug abuse and a major cause of morbidity and mortality among intravenous drug users. Trends in rates of serious infection and the associated costs related to opioid abuse/dependence have not been previously investigated in the context of the US opioid use epidemic. Our study, using a nationally representative sample of US inpatient hospitalizations, showed that hospitalizations related to opioid abuse/dependence both with and without associated serious infection significantly increased from 2002 to 2012, respectively, from 301,707 to 520,275 and from 3,421 to 6,535. Additionally, inpatient charges for both types of hospitalizations almost quadrupled over the same time period, reaching almost $15 billion for hospitalizations related to opioid abuse/dependence and more than $700 million for those related to associated infection in 2012. Medicaid was the most common primary payer for both types of hospitalizations. Our results characterize the financial burden on the health care system related to opioid abuse/dependence and one of the more serious downstream complications of this epidemic: serious infection. These findings have important implications for the hospitals and government agencies that disproportionately shoulder these costs and for clinicians, researchers, and policy makers interested in estimating the potential impact of targeted public health interventions on a national level.

Interdisciplinary Treatment of Intracranial Infectious Aneurysms

OBJECTIVE

Intracranial infectious aneurysms (IIAs) are a rare clinical entity without a definitive treatment guideline. In this study, we evaluate the treatment options of these lesions based on our own clinical experience and review the current knowledge of therapy as portrayed in the literature.

METHODS

We conducted a single-center retrospective analysis of all patients with an IIA and performed a systematic review of the literature using the MEDLINE database. We undertook a comprehensive literature search using the OVID gateway of the MEDLINE database (1950-October 2015) using the following keywords (in combination): 'infectious', 'mycotic', 'cerebral aneurysm', 'intracranial aneurysm'. 1,721 potentially relevant abstracts were identified and 63 studies were selected for full review. The studies were analysed regarding ruptured versus unruptured aneurysms, aneurysm localization and treatment, as well as clinical and radiological outcome.

RESULTS

Our institutional series consisted of 6 patients (median age 57 [32-76]) treated between 2011 and 2015. All patients presented with ruptured IIAs located on the middle cerebral artery (MCA, 5 patients) and anterior cerebral artery (ACA, 1 patient). Five patients were treated by clipping and resecting the aneurysm, 1 patient underwent coiling. All patients received antibiotic therapy and 1 patient died. We further identified 814 patients (median age 35.5 [0-81]) in 63 studies. Locations of the aneurysms were mentioned in 55 studies. The most frequent locations of the aneurysms were: MCA (63.5%), posterior cerebral artery (14%), ACA (9.0%) and others (13.5%). Treatment for IIAs was described in 62 studies: antibiotic treatment (56.1%), a combination of antibiotics and surgery (20.9%) or antibiotics and endovascular treatment (23.0%). Outcome was mentioned in 82.4% of the patients with a mortality rate of 16.8%. An evaluation of treatment outcome was limited due to the heterogeneity of patients in the published case series.

CONCLUSION

Antibiotic therapy of patients with IIA is mandatory. However, due to the complexity of the disease and its accompanying comorbidities, a general treatment algorithm could not be defined. Analogous to non-mycotic aneurysms, further treatment decisions require an interdisciplinary approach involving neurosurgeons, interventionists and infectious disease specialists.

Novel Tissue Level Effects of the Staphylococcus aureus Enterotoxin Gene Cluster Are Essential for Infective Endocarditis

Background

Superantigens are indispensable virulence factors for Staphylococcus aureus in disease causation. Superantigens stimulate massive immune cell activation, leading to toxic shock syndrome (TSS) and contributing to other illnesses. However, superantigens differ in their capacities to induce body-wide effects. For many, their production, at least as tested in vitro, is not high enough to reach the circulation, or the proteins are not efficient in crossing epithelial and endothelial barriers, thus remaining within tissues or localized on mucosal surfaces where they exert only local effects. In this study, we address the role of TSS toxin-1 (TSST-1) and most importantly the enterotoxin gene cluster (egc) in infective endocarditis and sepsis, gaining insights into the body-wide versus local effects of superantigens.

Methods

We examined S. aureus TSST-1 gene (tstH) and egc deletion strains in the rabbit model of infective endocarditis and sepsis. Importantly, we also assessed the ability of commercial human intravenous immunoglobulin (IVIG) plus vancomycin to alter the course of infective endocarditis and sepsis.

Results

TSST-1 contributed to infective endocarditis vegetations and lethal sepsis, while superantigens of the egc, a cluster with uncharacterized functions in S. aureus infections, promoted vegetation formation in infective endocarditis. IVIG plus vancomycin prevented lethality and stroke development in infective endocarditis and sepsis.

Conclusions

Our studies support the local tissue effects of egc superantigens for establishment and progression of infective endocarditis providing evidence for their role in life-threatening illnesses. In contrast, TSST-1 contributes to both infective endocarditis and lethal sepsis. IVIG may be a useful adjunct therapy for infective endocarditis and sepsis.

Staphylococcus aureus β-Toxin Mutants Are Defective in Biofilm Ligase and Sphingomyelinase Activity, and Causation of Infective Endocarditis and Sepsis

β-Toxin is an important virulence factor of Staphylococcus aureus, contributing to colonization and development of disease [Salgado-Pabon, W., et al. (2014) J. Infect. Dis. 210, 784-792; Huseby, M. J., et al. (2010) Proc. Natl. Acad. Sci. U.S.A. 107, 14407-14412; Katayama, Y., et al. (2013) J. Bacteriol. 195, 1194-1203]. This cytotoxin has two distinct mechanisms of action: sphingomyelinase activity and DNA biofilm ligase activity. However, the distinct mechanism that is most important for its role in infective endocarditis is unknown. We characterized the active site of β-toxin DNA biofilm ligase activity by examining deficiencies in site-directed mutants through in vitro DNA precipitation and biofilm formation assays. Possible conformational changes in mutant structure compared to that of wild-type toxin were assessed preliminarily by trypsin digestion analysis, retention of sphingomyelinase activity, and predicted structures based on the native toxin structure. We addressed the contribution of each mechanism of action to producing infective endocarditis and sepsis in vivo in a rabbit model. The H289N β-toxin mutant, lacking sphingomyelinase activity, exhibited lower sepsis lethality and infective endocarditis vegetation formation compared to those of the wild-type toxin. β-Toxin mutants with disrupted biofilm ligase activity did not exhibit decreased sepsis lethality but were deficient in infective endocarditis vegetation formation compared to the wild-type protein. Our study begins to characterize the DNA biofilm ligase active site of β-toxin and suggests β-toxin functions importantly in infective endocarditis through both of its mechanisms of action.

Clinical management of infectious cerebral vasculitides

A wide range of infections (virus, bacteria, parasite and fungi) may cause cerebral vasculitides. Headache, seizures, encephalopathy and stroke are common forms of presentation. Infection and inflammation of intracranial vessels may cause pathological vascular remodelling, vascular occlusion and ischemia. Vasculitis in chronic meningitis may cause ischemic infarctions, and is associated with poor outcome. Appropriate neuroimaging (CT-angiography, MR-angiography, conventional 4-vessel angiography) and laboratory testing (specific antibodies in blood and CSF, CSF culture and microscopy) and even brain biopsy are needed to quickly establish the aetiology. Enhancement of contrast, wall thickening and lumen narrowing are radiological signs pointing to an infectious vasculitis origin. Although corticosteroids and prophylactic antiplatelet therapy have been used in infectious cerebral vasculitis, there are no randomized clinical trials that have evaluated their efficacy and safety. Stable mycotic aneurysms can be treated with specific antimicrobial therapy. Endovascular therapy and intracranial surgery are reserved for ruptured aneurysms or enlarging unruptured aneurysms.

Ratiometric imaging of extracellular pH in bacterial biofilms with C-SNARF-4

pH in the extracellular matrix of bacterial biofilms is of central importance for microbial metabolism. Biofilms possess a complex three-dimensional architecture characterized by chemically different microenvironments in close proximity. For decades, pH measurements in biofilms have been limited to monitoring bulk pH with electrodes. Although pH microelectrodes with a better spatial resolution have been developed, they do not permit the monitoring of horizontal pH gradients in biofilms in real time. Quantitative fluorescence microscopy can overcome these problems, but none of the hitherto employed methods differentiated accurately between extracellular and intracellular microbial pH and visualized extracellular pH in all areas of the biofilms. Here, we developed a method to reliably monitor extracellular biofilm pH microscopically with the ratiometric pH-sensitive dye C-SNARF-4, choosing dental biofilms as an example. Fluorescent emissions of C-SNARF-4 can be used to calculate extracellular pH irrespective of the dye concentration. We showed that at pH values of <6, C-SNARF-4 stained 15 bacterial species frequently isolated from dental biofilm and visualized the entire bacterial biomass in in vivo-grown dental biofilms with unknown species composition. We then employed digital image analysis to remove the bacterial biomass from the microscopic images and adequately calculate extracellular pH values. As a proof of concept, we monitored the extracellular pH drop in in vivo-grown dental biofilms fermenting glucose. The combination of pH ratiometry with C-SNARF-4 and digital image analysis allows the accurate monitoring of extracellular pH in bacterial biofilms in three dimensions in real time and represents a significant improvement to previously employed methods of biofilm pH measurement.

Rare Mycotic Aneurysm of the Mitral Valve without Aortic Valve Involvement

Mycotic aneurysms can be a rare, but serious complication of infectious endocarditis. We report the case of a 20-year-old woman who presented with fever and malaise from streptococcal bacteremia and found to have vegetation on the anterior leaflet of the mitral valve. On follow-up visit, the patient was noted to have a mycotic aneurysm of the anterior mitral valve without aortic involvement. Her clinical course was complicated by mitral valve chordal rupture, severe mitral regurgitation, and dyspnea from severe mitral regurgitation for which she underwent successful surgical repair of the mitral valve.