Pathogen Of Infective Endocarditis Research Articles

Infective endocarditis caused by Gemella – a retrospective registry-based study

Purpose Infective endocarditis (IE) is diagnosed using the Duke criteria, which were updated in 2023. In the Duke-ISCVID 2023 criteria, Gemella was recognised as a typical IE pathogen. This study investigates the impact of this change and compares the clinical characteristics of Gemella IE to IE caused by other pathogens. Methods Data on IE caused by Gemella species and other pathogens was retrieved from the Swedish Registry of Infective Endocarditis (SRIE). Clinical characteristics of Gemella IE were compared to episodes of IE caused by non-beta haemolytic streptococci, by Staphylococcus aureus and by enterococci. Results In the SRIE, 29 episodes of Gemella IE were identified among a total of 7677 registered episodes, corresponding to 0.4% of all cases. The most common species were Gemella morbillorum (47%) and Gemella bergerii (27%). The proportion of episodes meeting the criteria for definite IE increased from 13 (45%) with the modified Duke criteria to 21 (72%) with the Duke-ISCVID criteria. Median age of patients with Gemella IE was 70 years, 40% were females and 90% hade native valve IE. One third of the patients underwent heart valve surgery and only one patient (3%) died. Many clinical aspects of IE caused by Gemella resembled those of IE caused by non-beta haemolytic streptococci. Conclusions Gemella IE is a rare condition and shares several characteristics with IE caused by non-beta haemolytic streptococci. The prognosis of IE caused by Gemella appears to be relatively favourable.

Pathogenic spectrum of infective endocarditis and analysis of prognostic risk factors following surgical treatment in a tertiary hospital in China

BackgroundThis study aimed to summarize the pathogenic spectrum of infective endocarditis (IE) and analyze the risk factors for poor prognosis in surgical patients in a tertiary hospital in China.MethodsWe retrospectively included patients diagnosed with IE between January 2013 and January 2022. The pathogenic spectrum was summarized; the risk factors for early postoperative mortality and embolic events were analyzed using multivariate logistic regression.ResultsAmong 630 patients who underwent blood cultures, the positivity rate was 56.83%. The most prevalent pathogens were viridans streptococci, Staphylococcus aureus, enterococci, and coagulase-negative staphylococci (CoNS). The prevalence of viridans streptococci significantly increased in the surgically treated group, compared to the medically treated group (50.80% vs. 27.78%, P < 0.001), while that of CoNS decreased (5.60% vs. 12.04%, P = 0.034). There has been a declining trend in the blood culture positivity in recent years compared to earlier years (2018–2022 vs. 2013–2017 = 60.95% vs. 47.30%, P = 0.037), with an increasing trend in viridans streptococci and a decreasing trend in CoNS. Multivariate logistic regression analysis identified male gender, coronary artery disease, platelet count < 100 × 109/L, albumin < 35 g/L, elevated creatinine, and prosthetic valve as independent risk factors for early postoperative mortality. Risk factors for embolic events included recent cerebral infarction within 3 months, history of peripheral vasculopathy, and hemoglobin (Hb) < 90 g/L.ConclusionsViridans streptococci predominates as the most common IE pathogen, with its incidence rising recently, especially among surgical patients. Blood culture positivity is decreasing. Understanding risk factors for early postoperative mortality and embolic events is crucial for optimizing patient management and prognosis.Clinical trial numberNot applicable.

Epidemiology, clinical characteristics, and outcome of infective endocarditis due to Abiotrophia and Granulicatella in a Tertiary Hospital in China, 2015–2023: a retrospective study

BackgroundAbiotrophia (ABI) and Granulicatella (GRA) are rare causative pathogens in infective endocarditis (IE). This study aims to describe the epidemiology, clinical characteristics, and outcome of ABI/GRA-IE. The main features of ABI/GRA-IE were compared with Viridans group streptococci (VGS) IE.MethodsFrom January 2015 to December 2023, a total of 1531 definite IE in Zhongshan Hospital, Fudan University, Shanghai, China were retrospectively enrolled in this study. Clinical and laboratory data were collected.ResultsForty-five ABI/GRA-IE cases were identified, representing 2.9% of all IE cases in Zhongshan Hospital between 2015 and 2023, compared to 20.1% of VGS-IE. ABI and GRA IE shared similar clinical characteristics. Congenital valvulopathy was reported in 21 (46.7%) ABI/GRA-IE and 85 (28.8%) VGS-IE (P = 0.025). Pulmonary valve was more frequently affected in ABI/GRA-IE (6 [13.3%]) than VGS-IE (7 [2.4%]) (P = 0.002). Congestive heart failure was observed in 30 (66.7%) ABI/GRA-IE and 103 (34.9%) VGS-IE (P < 0.001). Systemic embolization excluding central nervous system (CNS) occurred in 13 (28.9%) ABI/GRA-IE and 39 (13.2%) VGS-IE (P = 0.012). In-hospital mortality was reported as 4.4% in ABI/GRA-IE and 3.7% in VGS-IE (P = 0.854).ConclusionGRA/ABI-IE was approximately one-seventh as prevalent as VGS-IE. Congestive heart failure and systemic embolization (excluding CNS) were more frequent in GRA/ABI-IE compared to VGS-IE. Mortality of ABI/GRA-IE in this study was comparable to that of VGS-IE and lower than previously reported results.

MICROBIOLOGICAL SPECTRUM OF INFECTIVE ENDOCARDITIS COMPLICATED BY HEART FAILURE

Resume. Infective endocarditis (IE) is a serious disease that can lead to severe complications and death. The study of the microbiological spectrum of pathogens in such patients is great importance for optimizing treatment and increasing the effectiveness treatment. The spectrum of IE pathogens has changed significantly over the past decades. A positive microbiological blood test remains the cornerstone in diagnosis and etiotropic antimicrobial therapy of IE. Considering the global mobility of the population and the growing resistance of microorganisms to antibiotics, it is necessary to update our knowledge about the microbiological spectrum of infective endocarditis constantly. THE AIM was to investigate the microbiological spectrum of pathogens in patients with infective endocarditis complicated by heart failure. Materials and methods. Clinical data of 120 patients with active infective endocarditis who underwent treatment at the SE «Amosov National Institute of Cardiovascular Surgery» National Academy of Medical Sciences of Ukraine from 01.01.2019 to 06.30.2020 were enrolled in the study. The diagnosis of IE was established in accordance with Duke's criteria. The average age of the studied patients was 48.1±1.37 (19-77) years. Results. The rate of gram-positive and gramnegative microorganisms was 69 (93.2 %) cases and 5 (6.8 %) cases respectively. Gram-positive microorganisms were found – Staphylococcus spp. in 42 (56.8 %) cases and Enterococcus spp. in 20 (27.0 %) cases. A high level of oxacillin-resistant (p=0.072) and vancomycin-resistant (p=0.027) strains of microorganisms were found in the group of patients with preoperative heart failure. Conclusions: The microbiological spectrum of IE pathogens in patients with heart failure is characterized by the predominance of gram-positive strains that are resistant to oxacillin and vancomycin. Positive results of bacteriologic blood tests were found in 74 cases out of the total number, which is 61.7 %. Of these, gram-positive microorganisms were detected in 69 cases (93.2 %), while gram-negative microorganisms were detected in only 5 cases (6.8 %). The most common gram-positive microorganisms were Staphylococcus spp. (56.8 %) and Enterococcus spp. (27.0%). There was also found that risk factors such as nosocomial infections, hypothermia and drug abuse can contribute to the development of UI. The overall frequency of nosocomial factors in the development of the disease was 36.7 %. Urological interventions (12.5 %) and general surgical interventions (20.8 %) were among the most common. Our study included patients with active UI who had positive bacteriologic blood tests and signs of a systemic inflammatory response. In these patients, the mean body temperature at hospitalization was 38.3 °C, and the mean heart rate was 91.0 beats/min. The organ dysfunction detected in patients with complicated IE was also confirmed by high levels of creatinine (168.2 mcg/L) and urea (13.3 mmol/L). A comparative analysis of laboratory results also revealed a high level of resistant strains of microorganisms in the group of patients with complicated IE. Thus, the data obtained confirm the seriousness of the problem of infective endocarditis and emphasize the need for further research to develop effective strategies for the diagnosis and treatment of this disease, especially in patients with complicated course.

Silent Aortic Valve Perforation in a Patient with S. Salivarius Infective Endocarditis

Streptococcus salivarius is a commensal bacterium of the oral and gut flora and is rarely implicated in infective endocarditis (IE). Herein, we present a case of a 69-year-old male who presented with fatigue, weight loss, and no fever, ultimately diagnosed with IE complicated by severe aortic regurgitation. Initial investigations revealed leukocytosis, anemia, hyperkalemia, and elevated troponins. Imaging studies revealed bilateral common iliac artery aneurysms and atrophic kidneys with renal cysts. Transthoracic and transesophageal echocardiograms revealed mobile aortic vegetation, severe aortic regurgitation, and valve perforation. Blood cultures identified Streptococcus salivarius/vestibularis. The patient underwent aortic valve replacement, resulting in clinical improvement and negative blood cultures. The discussion highlights the rarity of S. salivarius causing IE and emphasizes the challenges in management, including the need for timely surgical intervention and multidisciplinary care in complicated IE cases. This case underscores the importance of considering atypical pathogens in IE and the complexities involved in its diagnosis and management. Further research is warranted to elucidate such cases' clinical implications and optimal management strategies.

Novel Diagnostic Methods for Infective Endocarditis.

Infective endocarditis (IE) remains a dangerous disease and continues to have a high mortality rate. Unfortunately, despite continuous improvements in diagnostic methods, in many cases, blood cultures remain negative, and the pathogen causing endocarditis is unknown. This makes targeted therapy and the selection of appropriate antibiotics impossible. Therefore, we present what methods can be used to identify the pathogen in infective endocarditis. These are mainly molecular methods, including PCR and MGS, as well as imaging methods using radiotracers, which offer more possibilities for diagnosing IE. However, they are still not widely used in the diagnosis of IE. The article summarizes in which cases we should choose them and what we are most hopeful about in further research into the diagnosis of IE. In addition, registered clinical trials that are currently underway for the diagnosis of IE are also presented.

2411. Association between Causative Pathogen and Occurrence of Infection-Related Glomerulonephritis in Infective Endocarditis

Abstract Background Infection-related glomerulonephritis (IRGN) is an uncommon complication of infective endocarditis (IE). We have noticed that this complication occurs unusually frequently among patients with IE caused by Bartonella spp. The purpose of this study was to investigate the association between causative pathogen and the occurrence of IRGN in patients with IE. Methods This was a retrospective case-control study. Episodes of pathologically-proven IE with a single causative pathogen, among patients admitted from July 1, 2007, through Jan 1, 2022 were identified from the Cleveland Clinic Infective Endocarditis Registry. Those with definite IRGN (proven by renal biopsy) or probable IRGN (hematuria, proteinuria, elevated creatinine, and depleted serum complement levels) were considered case subjects. Four control subjects were selected for each case subject from patients without definite, probable, or possible IRGN (hematuria, proteinuria, elevated creatinine, or hematuria, proteinuria, depleted serum complement levels), by propensity score matching on age, gender, admission year, and IE category (native or prosthetic), using the nearest neighbor method. The association between pathogen and occurrence of IRGN was examined using logistic regression. Results Forty-eight case subjects (IE with IRGN) were matched to 192 control subjects (IE without IRGN). Of the 48 case subjects with IRGN, 17 (35%) had definite IRGN and 13 (27%) had prosthetic valve endocarditis. Bartonella was the causative pathogen in 9 (3.75%) subjects and of these, 8 had IRGN. There was a very strong association between Bartonella being the causative pathogen in IE and the occurrence of IRGN (OR 47.8, 95% C.I. 11.5 – 323.9, p-value &amp;lt; 0.001). A significant association with IRGN was not found for Staphylococcus aureus, viridans group streptococci, Enterococcus, coagulase-negative staphylococci, or fungi. Conclusion Bartonella being the causative pathogen in IE is very strongly associated with the occurrence of IRGN. Acute glomerulonephritis in a person with clinical or echocardiographic features suspicious for IE, and negative blood cultures, should prompt specific testing for the presence of Bartonella infection by blood PCR or serology. Disclosures Leal Herlitz, MD, Chemocentryx: Advisor/Consultant|Novartis: Advisor/Consultant

2405. Extended Incubation of Blood Cultures in the Identification of Cutibacterium acnes as the Causative Pathogen in Infective Endocarditis

Abstract Background Cutibacterium acnes is an uncommon cause of infective endocarditis (IE). Blood cultures are sometimes held for extended incubation (beyond the standard 5 days) with an expectation that such incubation might allow C. acnes to grow. Extended incubation of blood cultures consumes resources, and a justification of such extension requires a demonstration that it increases the likelihood of identifying a causative pathogen. The purpose of this study was to examine the association between extended incubation of blood cultures and the identification of C acnes as the causative pathogen in patients with IE possibly caused by C. acnes. Methods This was a retrospective case-control study. Episodes of surgically treated IE among patients admitted from July 1, 2007, through Jan 1, 2022 were identified from the Cleveland Clinic Infective Endocarditis Registry, were screened for inclusion in the study. Patients with C. acnes IE were case subjects. Controls were selected from patients without an identified pathogen, by propensity score matching on age, gender, admission year, and IE category (native valve endocarditis or prosthetic valve endocarditis), using the nearest neighbor method, from among episodes of IE for whom a causative pathogen was not identified. Extended incubation was defined as incubation of blood cultures for longer than 5 days. The association between extended incubation of blood cultures and C. acnes identification was examined using logistic regression. Results Thirty-five subjects with C. acnes IE were matched to 35 control subjects. Nine of 35 subjects in the C. acnes group had at least 1 blood culture held for &amp;gt;5 days compared to only 1 of 35 controls. Five (50%) of those held for extended incubation grew C. acnes. Extended incubation was associated with a significantly higher odds of identification of C. acnes as the cause of IE (OR 11.8, 95% C.I. 2.0 – 224.1, p-value 0.02). Conclusion Among patients with possible C. acnes IE, extended incubation of blood cultures is associated with 12-fold higher odds of identifying C. acnes. Disclosures All Authors: No reported disclosures

Host-Bacterium Interaction Mechanisms in Staphylococcus aureus Endocarditis: A Systematic Review.

Staphylococci sp. are the most commonly associated pathogens in infective endocarditis, especially within high-income nations. This along with the increasing burden of healthcare, aging populations, and the protracted infection courses, contribute to a significant challenge for healthcare systems. A systematic review was conducted using relevant search criteria from PubMed, Ovid's version of MEDLINE, and EMBASE, and data were tabulated from randomized controlled trials (RCT), observational cohort studies, meta-analysis, and basic research articles. The review was registered with the OSF register of systematic reviews and followed the PRISMA reporting guidelines. Thirty-five studies met the inclusion criteria and were included in the final systematic review. The role of Staphylococcus aureus and its interaction with the protective shield and host protection functions was identified and highlighted in several studies. The interaction between infective endocarditis pathogens, vascular endothelium, and blood constituents was also explored, giving rise to the potential use of antiplatelets as preventative and/or curative agents. Several factors allow Staphylococcus aureus infections to proliferate within the host with numerous promoting and perpetuating agents. The complex interaction with the hosts' innate immunity also potentiates its virulence. The goal of this study is to attain a better understanding on the molecular pathways involved in infective endocarditis supported by S. aureus and whether therapeutic avenues for the prevention and treatment of IE can be obtained. The use of antibiotic-treated allogeneic tissues have marked antibacterial action, thereby becoming the ideal substitute in native and prosthetic valvular infections. However, the development of effective vaccines against S. aureus still requires in-depth studies.

Microbiologic diagnostics and pathogen spectrum in infective endocarditis of surgically treated patients: a five-year, retrospective, monocentric study.

The spectrum of causative organisms in infective endocarditis (IE) has changed significantly in the last decades. Reliable pathogen detection is crucial for appropriate antimicrobial therapy for IE. The aim of the study was to evaluate the diagnostic value of microbiological methods for detecting the causative microorganism of IE and to analyze the spectrum of pathogens. A total of 224 cases (211 unique patients, some with multiple surgeries) were included into this retrospective study. Patients were diagnosed with IE according to the modified Duke criteria from January 2016 to July 2021 and underwent heart valve surgery in a tertiary hospital. Pathogen detection was performed by blood culture, microbiological culture and 16S rDNA PCR of explanted heart valve material. A causative pathogen of IE was detected in 95.5% (n = 214) of cases. Blood cultures were positive in 83.3%, while a pathogen in the examined heart valve samples was identified in 32.6% by culture and in 88.2% by 16S rDNA PCR. A microorganism was identified by 16S rDNA PCR in 61.1% of blood culture negative cases but only in 19.4% by heart valve culture. The most common pathogens were Staphylococcus aureus (27%), viridans group streptococci (20%), enterococci (19%) and coagulase-negative staphylococci (CoNS 8%). Cutibacterium acnes (7%) was detected in prosthetic valve IE cases only. Blood culture as a comparatively non-invasive and straightforward technique remains an important and reliable method for initial detection of the causative organism in IE. Diagnostic stewardship programs should broadly emphasize proper collection of blood cultures, particularly sampling prior to any antibiotic treatment. Additionally, molecular testing using 16S rDNA tissue PCR can be used with culture techniques to increase the diagnostic yield, especially in the case of a negative blood culture.

Complex pathogens in infective endocarditis

Infective endocarditis (IE) is a complex disease whose prognosis depends on the causative microorganism, among other factors. The latter can be difficult to identify and/or treat. In this narrative review, we identify knowledge gaps in the diagnosis and antimicrobial treatment of IE, and attempt to shed light on current questions. Specifically, we: (1) analyze the factors that may hinder the microbiological diagnosis of blood culture-negative IE, as well as the role of new imaging techniques, such as 18F-fluorodeoxyglucose ([18F]FDG PET/CT), in the diagnostic capacity of this disease, understanding their advantages and assuming their limitations; (2) discuss the therapeutic approach to various difficult-to-treat microorganisms. In particular, we focus on the treatment of staphylococcal IE since, at present, staphylococci are the most frequent cause of IE in developed countries and staphylococcal IE is one of those with the highest short- and long-term mortality. We critically evaluate the current evidence on combination therapy and address the occurrence of serious side effects, an aspect that is often overlooked owing to the severity of the infection; and (3) emphasize the need for home antimicrobial treatment of patients with IE, as these are fragile people who benefit from an early return to their environment. This poses undoubted logistical challenges and requires robust evidence to ensure the best short- and long-term outcomes.

Utility of Metagenomic Next-Generation Sequencing in Infective Endocarditis: A Systematic Review.

Blood cultures have been the gold standard for identifying pathogens in infective endocarditis (IE). Blood culture-negative endocarditis (BCNE), however, occurs in 40% or more of IE cases with the bulk of them due to recent antibiotic exposure prior to obtaining blood cultures. Increasingly, molecular techniques are being used for pathogen identification in cases of BCNE and more recently has included metagenomic next-generation sequencing (mNGS). We therefore performed a literature search on August 31, 2022, that assessed the mNGS in IE and 13 publications were identified and included in a systematic review. Eight (61.5%) of them focused only on IE with mNGS performed on cardiac valve tissue in four studies, plasma in three studies and cardiac implantable electronic devices (CIED) in one study. Gram-positive cocci, including Staphylococcus aureus (n = 31, 8.9%), coagulase-negative staphylococci (n = 61, 17.6%), streptococci (n = 130, 37.5%), and Enterococcus&amp;nbsp;faecalis (n = 23, 6.6%) were the predominant organisms identified by mNGS. Subsequent investigations are needed to further define the utility of mNGS in BCNE and its impact on patient outcomes. Despite some pitfalls, mNGS seems to be of value in pathogen identification in IE cases, particularly in those with BCNE. This study was registered and on the Open Science Framework platform.

The Clinical Course of Infective Endocarditis and Independent Predictors of In-Hospital Mortality

Introduction: Despite advances in prevention, medical, and surgical treatment, the global prevalence of infective endocarditis (IE) has been gradually rising over the last two decades. However, the profile of IE varies by continent, geographic region, and hospital type. In this study, we aimed to investigate the epidemiological and clinical features of IE and to determine the factors predicting in-hospital mortality. Patients and Methods: This retrospective study was carried out at a single tertiary health care hospital in Türkiye. A total of 104 consecutive patients (&gt;18 years old) who were hospitalized with IE between January 2016 and August 2021 were included. Modified Duke criteria were used to diagnose IE. Demographic information (age and gender), underlying heart diseases, comorbidities, causative microorganisms, blood culture results, echocardiographic findings, cardiac and extracardiac complications, surgical requirements, and in-hospital mortality were all examined. Results: The study included 104 IE cases (mean age: 57.2 ± 15.9 years; 59.6% males). Fifty-six patients (53.9%) had native valve IE, 37 patients (35.6%) had prosthetic valve IE, and four patients (3.8%) had devicerelated IE. Blood cultures were negative in 62 cases (59.6%). Staphylococcus aureus was the most common responsible microorganism in 17 patients [methicillin-sensitive Staphylococcus aureus in 13 (12.5%), methicillin-resistant Staphylococcus in four (3.8%)]. The overall in-hospital mortality rate was 30.8%. White blood cell count (OR= 1.002, 95% CI= 1.001-1.003) creatinine (OR= 1.45, 95% CI= 1.08-2.00), acute renal failure (OR= 8.60, 95% CI= 2.27-37.81), and cerebrovascular accidents (OR= 4.58, 95% CI= 1.21-18.85) were independent predictors of in-hospital mortality. Conclusion: In line with developed countries, the epidemiology and causative pathogens of IE in Türkiye have been changing. Investigating these epidemiological and clinical changes may serve as a basis for strategies to be developed for the prevention and treatment of IE.

Microbial Cell-Free DNA Identifies the Causative Pathogen in Infective Endocarditis and Remains Detectable Longer Than Conventional Blood Culture in Patients with Prior Antibiotic Therapy.

The diagnosis of infective endocarditis (IE) can be difficult, particularly if blood cultures fail to yield a pathogen. This study evaluates the potential utility of microbial cell-free DNA (mcfDNA) as a tool to identify the microbial etiology of IE. Blood samples from patients with suspected IE were serially collected. mcfDNA was extracted from plasma and underwent next-generation sequencing. Reads were aligned against a library containing DNA sequences belonging to >1400 different pathogens. mcfDNA from organisms present above a statistical threshold were reported and quantified in molecules per milliliter (MPM). Additional mcfDNA was collected on each subject every 2-3 days for a total of 7 collections or until discharge. Of 30 enrolled patients with suspected IE, 23 had definite IE, 2 had possible IE, and IE was rejected in 5 patients by modified Duke Criteria. Only the 23 patients with definite IE were included for analysis. Both mcfDNA and blood cultures achieved a sensitivity of 87%. The median duration of positivity from antibiotic treatment initiation was estimated to be approximately 38.1 days for mcfDNA versus 3.7 days for blood culture (proportional odds, 2.952; P = .02771), using a semiparametric survival analysis. mcfDNA (log10) levels significantly declined (-0.3 MPM log10 units, 95% credible interval -0.45 to -0.14) after surgical source control was performed (pre- vs postprocedure, posterior probability >0.99). mcfDNA accurately identifies the microbial etiology of IE. Sequential mcfDNA levels may ultimately help to individualize therapy by estimating a patient's burden of infection and response to treatment.

Clinical Characteristics and Risk Factors for in-Hospital Mortality in 240 Cases of Infective Endocarditis in a Tertiary Hospital in China: A Retrospective Study.

PurposeThis study aimed (i) to investigate the clinical characteristics and risk factors related to in-hospital mortality in patients with infective endocarditis (IE) and (ii) to compare the differences in three age groups.MethodsA total of 240 IE cases diagnosed using the modified Duke criteria between January 2016 and December 2019 were included and retrospectively studied. Patients were stratified into three age groups: < 50 y, 50–65 y, and > 65 y.ResultsThe mean age of the patients was 51 ± 14 y, and 154 patients (64.2%) were male. In addition, 136 (56.7%) patients with IE had no previous cardiac disease. Congenital heart disease (CHD, 21.3%) was the most common underlying heart disease, followed by rheumatic heart disease (RHD, 8.8%). Streptococcus was found in 55 (22.9%) patients and was the most common causative pathogen, comprising 52.9% of all positive blood cultures. Echocardiography showed the presence of vegetations in 88.3% of cases and the predominant involvement of the left heart valves. Fever and cardiac murmur were the most frequent presentations, with no significant differences among age groups. Compared with younger patients, elderly patients had a lower operation rate and higher in-hospital mortality. The independent risk factors of in-hospital mortality were age > 65 y, intracranial infection, splenic embolization, cerebral hemorrhage, NYHA class III–IV, and prosthetic valve infection.ConclusionCHD replaces RHD as the most common underlying heart disease in IE patients. Patients without previous cardiac disease are at increased risk of IE. Streptococcus is still the primary causative pathogen of IE. Elderly patients present with more comorbidities and complications, in addition to a more severe prognosis than younger patients. Age older than 65 y, intracranial infection, splenic embolization, cerebral hemorrhage, NYHA class III–IV, and prosthetic valve infection showed poorer in-hospital outcomes.

694. Prediction Tool for Infective Endocarditis in Beta-hemolytic Streptococcal Bacteremia

BackgroundAlthough beta-hemolytic streptococci (BHS) is a rare causative pathogen of infective endocarditis (IE), IE is a serious condition and it is important to predict IE in BHS bacteremia (BHS-IE). The purpose of this study was to develop a predictive score for BHS-IE.MethodsWe conducted a retrospective study comparing the clinical features of BHS-IE and BHS-non infective endocarditis (BHS-nIE) in adult patients with BHS bacteremia at a 520-bed tertiary hospital in Tokyo, Japan from 2004 to 2020. IE was diagnosed according to modified Duke's criteria, and both “Definite” and “Possible” were included. Univariate and multivariable analyses were conducted using logistic regression.ResultsAmong 250 patients with BHS bacteremia, 47 (19%) were diagnosed with BHS-IE. The median (IQR) patient age was 71 (59, 84) years and 121 (68%) were male. The proportions of A, B, C/G groups were 14%, 38.4%, and 47.6%, respectively. Five predictors, either independently associated with BHS-IE or clinically relevant, were used to develop the prediction score: C-reactive protein ≥ 10 mg/dl (2 points); Group B Streptococci (1 point); Auscultation of heart murmur (1 point); Platelet count < 150 /µl (1 point); and Hypotension (systolic blood pressure < 90 mmHg or on vasopressor) (1 point). In a receiver operating characteristic analysis, the area under the curve was 0.74 (95% confidence interval [CI]: 0.66 - 0.82). The cut-point was 2. A score ≥2 had a sensitivity of 87% (95%CI: 0.743 - 0.952), a specificity of 37% (95%CI: 0.308 - 0.445), a positive predictive value of 24%, and a negative predictive value of 93%, respectively.ConclusionWe developed the score to help clinicians rule out IE in BHS bacteremia. Further research is warranted for validation.Disclosures All Authors: No reported disclosures

#2: Use of Plasma Metagenomic Next Generation Sequencing for Pathogen Identification in Pediatric Endocarditis

Abstract Background Pediatric infective endocarditis (IE) incurs significant morbidity and most commonly occurs among children with underlying heart disease. Identification of causative pathogens on blood culture allows for more targeted antibiotic therapy, optimizing patient outcomes. However, standard diagnostic testing has limited sensitivity. As a result, there is an opportunity to explore alternative methods to identify pathogens in IE using cell-free plasma next generation sequencing (mNGS). mNGS utilizes a high-throughput approach that is culture-independent and non-invasive to detect microbial DNA. We describe a single center retrospective case series of children with IE in whom plasma mNGS was sent as part of the diagnostic evaluation. Methods In this case series, we evaluated the impact of mNGS on the clinical management of IE by conducting a retrospective chart review of children hospitalized with IE from January 1, 2017 to January 17, 2020. Inclusion criteria included subjects 0–21 years of age who had a diagnosis of IE based on admission diagnosis and problem list. Demographics, echocardiography and diagnostics were obtained by chart review. Results We identified 14 children who were diagnosed with IE, 10 of whom had mNGS sent for diagnostic testing. mNGS detected an organism in 8 of 10 (80%) children as compared to standard of care blood cultures and 16S PCR which identified an organism in only 5 of 10 (30%). Out of 8 subjects with organisms identified by mNGS, clinical management was impacted in 4 of 8 subjects and 3 subjects were only diagnosed through mNGS. Conclusion Although blood and tissue cultures are the historical gold standard for organism identification in IE, new diagnostic modalities such as mNGS may be more sensitive. This could lead to more targeted and possibly more effective therapeutic regimens in cases when empiric antibiotic therapy may hinder pathogen identification. In at least one instance, a change in antibiotic choice to penicillin to target Corynebacterium diphtheriae resulted in a clinical cure that may not have otherwise been achieved. As a result of mNGS, three other subjects also had changes in management that resulted in narrowing of antibiotic choice or adjustments to the antibiotic regimen. Our observations suggest that mNGS is more sensitive than standard blood cultures and that the clinical utility of mNGS may be beneficial to the management of infective endocarditis in children.

GEMELLA MORBILLORUM: A RARE CAUSE OF INFECTIVE ENDOCARDITIS

SESSION TITLE: Medical Student/Resident Chest Infections Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Gemella morbillorum is a Gram-positive coccus, catalase negative facultative anaerobe that is normal flora in the oropharynx and gastrointestinal and genitourinary tracts. It is a rare pathogen in infective endocarditis, accounting for <1% of cases. CASE PRESENTATION: A 23 year old male presented to the emergency department complaining of a three day history of nocturnal cough producing bloody, yellow sputum. He denied fever, intravenous drug use, significant past medical history or ill contacts. He had immigrated from Guatemala to Colorado eight months before presentation to work as a painter. In the ED, he developed respiratory failure, presumed a result of pneumonia, and rapidly decompensated into cardiogenic and distributive shock. A transthoracic echocardiogram showed a bicuspid aortic valve and large vegetations on the mitral and aortic leaflets, severe mitral and aortic regurgitation with perforated leaflets, findings consistent with infective endocarditis. Blood cultures were positive with Gram positive cocci in clusters. His tenuous condition required urgent cardiothoracic surgery to replace both mitral and aortic valves. G.morbillorum was identified employing matrix-assisted laser desorption/ionization using time-of-flight mass spectroscopy (MALDI-TOF MS). Consequently, he began intravenous gentamicin and ampicillin. The source of infection was identified on dental panorex as a lucency in his left lateral incisor; on subsequent questioning, the patient disclosed a history of dental carie with filling that fell out and was replaced before arriving in the US. His postoperative course was complicated by recurrent pneumothoraces, complete heart block, atrial fibrillation with rapid ventricular response, and cardiac arrest due to torsades de pointe and ventricular fibrillation ultimately requiring pacemaker/defibrillator implantation prior to discharge. The aforementioned antibiotics were completed over his 31-day hospitalization. DISCUSSION: This case highlights pre-disposing factors associated with endocarditis: male sex, a congenital bicuspid aortic valve, and recent dental work. G. morbillorum is not easily identified with traditional microbiologic methods and requires more sophisticated techniques utilizing mass spectroscopy and advanced PCR. Biofilm production and downregulation of Interleukin-12 / Interferon-γ support this organism’s opportunistic pathogenicity. A recent case series from Cleveland Clinic identified this Gemella species in <1% of endocarditis patients in their registry. CONCLUSIONS: G. morbillorum, although normal flora, may become pathogenic and cause endocarditis in patients with underlying risk factors such as valvular abnormalities, intravenous drug use and prosthetic heart valves. Utilization of advanced identification microbiologic technology facilitates identification and consequent treatment with appropriate antibiotics. Reference #1: A.Ramanathan, S.M.Gordon and N.K.Shrestha, Acaseseries of patients with Gemellaendocarditis, Diagnostic Microbiology&Infectious Disease (2020),https://doi.org/10.1016/j.diagmicrobio.2020.115009 Reference #2: Nagy, E., Becker, S., Kostrzewa, M., Barta Noémi, & Urbán Edit. (2012). The value of MALDI-TOF MS for the identificationof clinically relevant anaerobic bacteria in routinelaboratories. Journal of Medical Microbiology, 61(10), 1393–1400. doi: 10.1099/jmm.0.043927-0 Reference #3: Benedetti, M., Rassu, M., Branscombe, M., Sefton, A., & Giampietro,P. (2009). Gemella morbillorum: an underestimated aetiology of central nervous system infection. Journal of Medical Microbiology. 58, 1652-1656. doi:10.1099/jmm.0.013367-0 DISCLOSURES: No relevant relationships by Geoffrey Blossom, source=Web Response No relevant relationships by Lauren Spaeth, source=Web Response

GROUP B STREPTOCOCCUS AGALACTIAE INFECTIVE ENDOCARDITIS COMPLICATED BY AORTO-CAVITARY FISTULA IN A POSTPARTUM FEMALE

SESSION TITLE: Medical Student/Resident Cardiothoracic Surgery Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Infective Endocarditis (IE) can have many devastating complications and it is prudent to keep in mind even the rarest of sequela, including aorto-cavitary fistula (ACF). The following case describes an ACF, masked as tricuspid regurgitation, in the setting of native valve IE. The pathogen was Group B streptococcus (GBS) agalactiae, an uncommon culprit, but noteworthy given recent pregnancy. CASE PRESENTATION: A 34-year-old female, postpartum 10 months, was evaluated for 3 weeks of intermittent fevers, chills and dyspnea. Labs were unremarkable, but examination revealed a murmur. A transthoracic echocardiogram (TTE) showed severe aortic regurgitation (AR) with vegetation. At the cardiologist’s office, she endorsed presyncope and had a wide pulse pressure with a loud systolic murmur throughout the precordium and right upper sternum diastolic murmur. Bedside TTE in the ED showed additional severe tricuspid regurgitation. Cardiothoracic surgery was immediately consulted and she was quickly triaged to the ICU. Initial labs showed elevated lactate (19) with acute liver and renal failure. Continuous veno-venous hemodialysis and broad-spectrum antibiotics were started. She developed bradycardia with new left bundle branch block requiring pressors. Swan ganz catheter showed cardiac output of 7-8 L/min with an oxygenation step up in right atrium (68%) to pulmonary artery (90%), suggestive of ACF. Intraoperative transesophageal echo exposed a large aortic to right atria fistula, severe AR with vegetation and a normal tricuspid valve. She underwent aortic valve replacement, ACF repair, coronary artery bypass and intra-aortic balloon pump placement. Central venoarterial extracorporeal membrane oxygenation was initiated, however it was complicated by persistent thrombosis of the arterial cannula and the patient expired. Blood cultures, aortic and tricuspid valve tissue samples grew GBS agalactiae. DISCUSSION: ACF in IE occurs more readily in prosthetic valves IE versus native with an in-hospital mortality of roughly 40%. The primary culprit is classically coagulase negative staphylococcus and staphylococcus aureus. GBS is much less common, but can be a normal part of vaginal and rectal flora with colonization in 10-30% of pregnancies. GBS bacteremia is highly prevalent during pregnancy and can remain present in up to one third of patients 6 weeks postpartum. It is unclear if bacterial translocation during the birthing process may have resulted in bacteremia and sub-acute IE. CONCLUSIONS: Streptococcus agalactiae is an uncommon pathogen in infective endocarditis associated with high mortality and morbidity and even more ominous when coupled with an aorto-right atrial fistula. The result of this combination was an extremely critical and complex patient presentation that demanded emergent multidisciplinary attention. Reference #1: Ignasi Anguera et al, Aorto-cavitary Fistula in Endocarditis Working Group, Aorto-cavitary fistulous tract formation in infective endocarditis: European Heart Journal, Volume 26, Issue 3, February 2005, Pages 288–297. Reference #2: Patras, Kathryn A, and Victor Nizet. “Group B Streptococcal Maternal Colonization and Neonatal Disease: Molecular Mechanisms and Preventative Approaches.” Frontiers in pediatrics vol. 6 27. 22 Feb. 2018. Reference #3: Muller AE, Oostvogel PM, Steegers EA, Dorr PJ. Morbidity related to maternal group B streptococcal infections. Acta Obstet Gynecol Scand (2006) 85(9):1027–37. DISCLOSURES: No relevant relationships by Fastina Khan, source=Web Response No relevant relationships by Michaela Murphy, source=Web Response No relevant relationships by Sarah Upson, source=Web Response

Characteristics of Species Composition of Causative Agents in Infective Endocarditis

&#x0D; Introduction. The frequency of infective endocarditis (IE) in children with congenital heart disease (CHD) is 15– 140 times higher than that in the overall population and varies from 2 to 18% according to different authors.&#x0D; The aim. To define the main groups of causative agents of infective endocarditis in children and adults in order to build up an antibiotic treatment algorithm.&#x0D; Materials and methods. The analysis of examination findings and treatment outcomes in 124 patients was conducted from 2014 to 2019. These patients received medical treatment at the Ukrainian Children`s Cardiac Center (UCCC), Kyiv. The patients were divided into two groups by age: group 1 included children aged from 6 days to 18 years (62 [50.0%]), group 2 comprised adults aged from 18 to 79 years (62 [50.0%]).&#x0D; Results and discussion. Forty-nine isolates were recovered from 124 patients during the analysis of microbiological study results. The frequency of bacterial IE causative agents was 26 (41.9%) in group 1, and 17 (27.4%) in group 2. Comparative analysis of the spectrum of IE pathogens revealed differences in the two study groups. Coagulase-negative staphylococcus was the most common causative agent in group 1 (46.7% of all isolated strains; n = 12) and in group 2 (44.4%; n = 8). Staphylococcus aureus in children was detected in 5 (8.1%) cases, whereas in adults only in 2 (11.1%) cases. Pathogens of the Enterococcus spp. family (E. faecalis) were recovered in both study groups: in 6.5% (n = 2) and 16.6% (n = 3) of the patients, respectively. Gram-negative flora was detected in 3 (9.7%) patients of group 1 and, in 2 (11.1%) patients of group 2. Fungal flora was more commonly found in children (7 [22.6%] cases represented by the Candida family), whereas in adults only 1 (5.6%) case represented by the Mucor family was revealed.&#x0D; Conclusions. Etiological structure of the infective endocarditis pathogens in both groups was represented mainly by gram-positive bacteria, with S. epidermidis (24.5%) being the most essential. The changes were revealed in the species composition of the pathogens in group 1 with fungal microflora dominance: Candida parapsilosis in 9.7%, C. albicans and C. famata in 6.5% of the total number of plated cultures in this group. The difference in surgical operations due to possible IE in both groups was established based on the specific features of operations determined by the age factor.