Prevalence of Infective Endocarditis in Enterococcus faecalis Bacteremia

Evaluation of Sequential Oral Versus Intravenous Antibiotic Treatment of Enterococcus faecalis Bloodstream Infections

BACKGROUND

Intravenous (IV) antibiotics have historically been considered standard of care for treatment of bloodstream infections (BSIs). Recent literature has shown sequential oral (PO) therapy to be noninferior to IV antibiotics for certain pathogens and disease states. However, a gap exists in the literature for BSI caused by Enterococcus faecalis.

OBJECTIVE

To compare outcomes of definitive sequential PO therapy to definitive IV therapy in patients with E faecalis BSI.

METHODS

Multicenter, retrospective, matched cohort study of adult patients with at least one blood culture positive for E faecalis from January 2017 to November 2022. Patients with polymicrobial BSI, concomitant infections requiring prolonged IV antibiotic therapy, those who did not receive antibiotic therapy, and those who died within 72 hours of index culture were excluded. Subjects were matched based on source of infection in a 2:1 (IV:PO) ratio. The primary outcome was a composite of all-cause mortality and treatment failure. Secondary outcomes included hospital length of stay (LOS), antibiotic duration, and 30-day readmission rate.

RESULTS

Of the 186 patients who met criteria for inclusion, there was no statistically significant difference in the primary composite outcome for PO compared to IV therapy (14.5% vs 21.8%; OR 0.53 [0.23-1.25]) or 30-day readmission (17.5% vs 29%; OR 0.53 [0.25-1.13]). Hospital LOS was significantly longer in patients receiving IV-only therapy (6 days vs 14 days; P < 0.001).

CONCLUSION AND RELEVANCE

Sequential oral therapy for E faecalis BSI had similar outcomes compared to IV-only treatment and may be considered in eligible patients.

Infective endocarditis is rare in patients with hematologic malignancy and neutropenia

BACKGROUND

Infective endocarditis (IE) is a serious complication of bloodstream infections (BSIs) that occurs at variable rates depending on the pathogen and clinical setting. There is a paucity of data describing the risk of IE in patients with hematologic malignancy who develop bacteremia while neutropenic.

METHODS

Adult patients on the hematology ward from January 2018 to December 2020 with hematologic malignancy and bacteremia were evaluated retrospectively for endocarditis by applying the 2023 Duke-ISCVID criteria. Charts of possible cases were evaluated 90 days after the initial BSI for new infectious complications that could indicate missed IE. Descriptive statistics compared patients admitted for hematopoietic stem cell transplantation (HSCT) to those admitted for alternative reasons (non-HSCT).

RESULTS

Among the 1005 positive blood cultures initially identified, there were 66 episodes in 65 patients with hematologic malignancy and at least grade 3 neutropenia for a mean duration of 11.4 days during their admission. Transthoracic echocardiography (TTE) was performed in 34.8% of BSIs, and transesophageal echocardiography (TEE) in 6.1%. There were no new infectious complications in possible cases 90 days after their initial BSI. No cases of endocarditis were identified.

CONCLUSIONS

Endocarditis is rare amongst patients with hematologic malignancy, bacteremia, and neutropenia, and no cases were identified in this cohort. The use of routine TTE in this setting seems unwarranted, and the addition of TEE is unlikely to improve patient-centered outcomes.

Role of echocardiography in the diagnosis and clinical management of infective endocarditis

Infective endocarditis (IE) is a deadly disease, constituting both diagnostic and treatment challenges. A positive outcome requires rapid and accurate diagnosis, and for that, echocardiography unequivocally remains the cornerstone. Transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) have complementary roles and have been markedly improved during the last decades. The transthoracic modality is the recommended first-line approach but may only be sufficient in patients where the probability of IE is low and/or with clear acoustic windows, especially in patients with right-sided IE. The transesophageal modality is superior to TTE in most aspects and is recommended for all other patients. Both TTE and TEE may delineate vegetation location and size, assess for paravalvular extension of infection, and have the added advantage of defining the hemodynamic effects of valvular or device infection. However, echocardiography still has significant limitations, and novel imaging techniques are increasingly being exploited to improve diagnostic potential. Cardiac computed tomography (CT) performs better than TEE in the detection of abscess or pseudoaneurysm, while magnetic resonance imaging (MRI) has limited value in the diagnostic phase of IE but adds knowledge to the evaluation of extracardiac events. Nuclear molecular techniques are evolving as key supplementary methods in difficult-to-diagnose cases. Although newer imaging modalities are undergoing preliminary evaluation and multimodal imaging will play an increasing role in IE, echocardiography will continue to be pivotal in patients with IE for the foreseeable future.

Evaluation of the 2023 Duke-International Society of Cardiovascular Infectious Diseases Criteria in a Multicenter Cohort of Patients With Suspected Infective Endocarditis

BACKGROUND

Since publication of Duke criteria for infective endocarditis (IE) diagnosis, several modifications have been proposed. We aimed to evaluate the diagnostic performance of the Duke-ISCVID (International Society of Cardiovascular Infectious Diseases) 2023 criteria compared to prior versions from 2000 (Duke-Li 2000) and 2015 (Duke-ESC [European Society for Cardiology] 2015).

METHODS

This study was conducted at 2 university hospitals between 2014 and 2022 among patients with suspected IE. A case was classified as IE (final IE diagnosis) by the Endocarditis Team. Sensitivity for each version of the Duke criteria was calculated among patients with confirmed IE based on pathological, surgical, and microbiological data. Specificity for each version of the Duke criteria was calculated among patients with suspected IE for whom IE diagnosis was ruled out.

RESULTS

In total, 2132 episodes with suspected IE were included, of which 1101 (52%) had final IE diagnosis. Definite IE by pathologic criteria was found in 285 (13%), 285 (13%), and 345 (16%) patients using the Duke-Li 2000, Duke-ESC 2015, or the Duke-ISCVID 2023 criteria, respectively. IE was excluded by histopathology in 25 (1%) patients. The Duke-ISCVID 2023 clinical criteria showed a higher sensitivity (84%) compared to previous versions (70%). However, specificity of the new clinical criteria was lower (60%) compared to previous versions (74%).

CONCLUSIONS

The Duke-ISCVID 2023 criteria led to an increase in sensitivity compared to previous versions. Further studies are needed to evaluate items that could increase sensitivity by reducing the number of IE patients misclassified as possible, but without having detrimental effect on specificity of Duke criteria.

Performance of the 2023 Duke-International Society of Cardiovascular Infectious Diseases Diagnostic Criteria for Infective Endocarditis in Relation to the Modified Duke Criteria and to Clinical Management-Reanalysis of Retrospective Bacteremia Cohorts

BACKGROUND

Revised diagnostic criteria for infective endocarditis (IE), the 2023 Duke-ISCVID criteria, were recently presented and need validation. Here, we compare the 2000 modified Duke criteria for IE with Duke-ISCVID among patients with bacteremia and relate the diagnostic classification to IE treatment.

METHODS

We reanalyzed patient cohorts with Staphylococcus aureus, Staphylococcus lugdunensis, non-β-hemolytic streptococci, Streptococcus-like bacteria, Streptococcus dysgalactiae, Enterococcus faecalis, and HACEK (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella) bacteremia. Episodes were classified as definite, possible, or rejected IE with the modified Duke and Duke-ISCVID criteria. Reclassification included the microbiology criteria, positron emission tomography-computed tomography, and cardiac implanted electronic devices. To calculate sensitivity, patients treated for IE were considered as having IE.

RESULTS

In 4050 episodes of bacteremia, the modified Duke criteria assigned 307 episodes (7.6%) as definite IE, 1190 (29%) as possible IE, and 2553 (63%) as rejected IE. Using the Duke-ISCVID criteria, 13 episodes (0.3%) were reclassified from possible to definite IE, and 475 episodes (12%) were reclassified from rejected to possible IE. With the modified Duke criteria, 79 episodes that were treated as IE were classified as possible IE, and 11 of these episodes were reclassified to definite IE with Duke-ISCVID. Applying the decision to treat for IE as a reference standard, the sensitivity of the Duke-ISCVID criteria was 80%. None of the 475 episodes reclassified to possible IE were treated as IE.

CONCLUSIONS

The Duke-ISCVID criteria reclassified a small proportion of episodes to definite IE at the expense of more episodes of possible IE. Future criteria should minimize the possible IE group while keeping or improving sensitivity.

An Unusual Presentation of an Enterococcus faecalis Endocarditis With Wrist and Forearm Infection: A Case Report

In this case, an unusual presentation of Enterococcus faecalis (E.faecalis) endocarditis and clinical signs of wrist and forearm infection are reported. Before the patient was diagnosed with E.faecalis endocarditis, the patient managed to be treated with both prednisolone, various antibiotics, and colchicine on suspicion of gout, erysipelas, and deep tissue infection. Growth of E.faecalis in blood cultures raised the suspicion of endocarditis, and transesophageal echocardiography revealed vegetations on the aortic and the mitral valves with a perforation of the anterior mitral leaflet. Since the patient responded well to antibiotic treatment and there was no progression of the size of the vegetations or the perforation, it was decided by the endocarditis team to refrain from surgery. E. faecalis endocarditis can be difficult to diagnose because the patients are often elderly, and symptoms may be subtle and misleading. In the present case, the diagnostic process was based on the Danish IE guidelines, which state that E. faecalis is a typical IE bacterium. Accepting E. faecalis as a typical infective endocarditis bacterium may lead to an earlier diagnosis and treatment.

Sex differences in infective endocarditis: a Danish nationwide study

PURPOSE

Sex differences in infective endocarditis (IE) are reported, but patient characteristics are sparse and conflicting findings on the association between sex and short-term outcomes demand further research. We aimed to characterize sex differences in IE in terms of patient characteristics, frailty, microbiology, socioeconomic status, management and outcome on a nationwide scale.

METHODS

Between 2010 and 2020, we used Danish national registries to characterize patients with IE according to sex using ICD codes and microbiological lab reports. Frailty was assessed with the Hospital Frailty Risk Score. Mortality was reported with Kaplan-Meier estimates. Logistic regression and Cox regression were used for adjusted analyses.

RESULTS

We included 6259 patients with IE with 2047 (32.7%) female patients and 4212 (67.3%) male patients. Female patients were older (median age 75.0 years (64.3-82.2) vs. 71.7 (61.7-78.9)) and more frail (Intermediate frailty: 36.5% vs. 33.1%, High frailty: 11.4% vs. 9.2%). Staphylococcus aureus-IE were most common in both sexes (34.6% vs. 28.8%), but fewer female patients had Enterococcus-IE (10.5% vs. 18.1%). Female patients were less surgically treated (14.0% vs. 21.2%). Female sex was associated with increased in-hospital mortality (adj. OR 1.33, 95% CI 1.16-1.52), but no statistically significant difference in associated 1- and 5-year mortality from hospital discharge were identified (adj. HR 1.09, 95% CI 0.95-1.24 and 1.02, 95% CI 0.92-1.12, respectively).

CONCLUSION

Female sex is associated with increased in-hospital mortality, but not in long-term mortality as compared with male patients. Female patients have a lower prevalence of Enterococcus-IE and rates of surgery. Further research is needed to understand these differences.

Genome-based taxonomic identification and safety assessment of an Enterococcus strain isolated from a homemade dairy product

The aim of this study was to explore the taxonomic identification and evaluate the safety of a bacterium, Enterococcus lactis IDCC 2105, isolated from homemade cheese in Korea, using whole genome sequence (WGS) analysis. It sought to identify the species level of this Enterococcus spp., assess its antibiotic resistance, and evaluate its virulence potential. WGS analysis confirmed the bacterial strain IDCC 2105 as E. lactis and identified genes responsible for resistance to erythromycin and clindamycin, specifically msrC, and eatAv, which are chromosomally located, indicating a minimal risk for horizontal gene transfer. The absence of plasmids in E. lactis IDCC 2105 further diminishes the likelihood of resistance gene dissemination. Additionally, our investigation into seven virulence factors, including hemolysis, platelet aggregation, biofilm formation, hyaluronidase, gelatinase, ammonia production, and β-glucuronidase activity, revealed no detectable virulence traits. Although bioinformatic analysis suggested the presence of collagen adhesion genes acm and scm, these were not corroborated by phenotypic virulence assays. Based on these findings, E. lactis IDCC 2105 presents as a safe strain for potential applications, contributing valuable information on its taxonomy, antibiotic resistance profile, and lack of virulence factors, supporting its use in food products.

Bacteraemia with gram-positive bacteria-when and how do I need to look for endocarditis?

BACKGROUND

Patients with bacteraemia caused by gram-positive bacteria are at risk for infective endocarditis (IE). Because IE needs long antibiotic treatment and sometimes heart valve surgery, it is very important to identify patients with IE.

OBJECTIVES

In this narrative review we present and discuss how to determine which investigations to detect IE that are needed in individual patients with gram-positive bacteraemia.

SOURCES

Published original studies and previous reviews in English, within the relevant field are used.

CONTENT

First, the different qualities of the bacteraemia in relation to IE risk are discussed. The risk for IE in bacteraemia is related to the species of the bacterium but also to monomicrobial bacteraemia and the number of positive cultures. Second, patient-related factors for IE risk in bacteraemia are presented. Next, the risk stratification systems to determine the risk for IE in gram-positive bacteraemia caused by Staphylococcus aureus, viridans streptococci, and Enterococcus faecalis are presented and their use is discussed. In the last part of the review, an account for the different modalities of IE-investigations is given. The main focus is on echocardiography, which is the cornerstone of IE-investigations. Furthermore, 18F-fluorodesoxyglucose positron emission tomography/computed tomography and cardiac computed tomography are presented and their use is also discussed. A brief account for investigations used to identify embolic phenomena in IE is also given. Finally, we present a flowchart suggesting which investigations to perform in relation to IE in patients with gram-positive bacteraemia.

IMPLICATIONS

For the individual patient as well as the healthcare system, it is important both to diagnose IE and to decide when to stop looking for IE. This review might be helpful in finding that balance.

Antibiotic Resistance Profile of Clinical Strains of Enterococci from Secondary/Persistent Endodontic Infections: What do We Know? A Systematic Review of Clinical Studies

INTRODUCTION

Enterococcus faecalis is the most common enterococcal species associated with infective endocarditis and 1 of the most commonly detected bacteria in cases of secondary/persistent endodontic infection (SPEI). Antimicrobial resistance is a global public health concern. This review aimed to answer the following research question: "Is there a change in the antibiotic resistance profile in clinical strains of E. faecalis over the years?". P (population) - patients with SPEI, I (intervention) -endodontic retreatment, C (comparison) -not included, O (outcome) - profile of Enterococci resistance and susceptibility to systemic antibiotics used.

METHODS

Two authors independently performed study selection, data extraction, and risk of bias assessment. The literature search was conducted using the following electronic databases: PubMed, Scopus, EMBASE, Web of Science, and Medline. Clinical studies in which Enterococci strains were isolated to assess their antimicrobial resistance were included.

RESULTS

Eleven clinical trials were included. Overall, E. faecalis isolated from teeth with SPEI presented an intermediate resistance to 16 antibiotics. In recent years, E. faecalis showed a little resistance to amoxicillin (without clavulanate) and benzylpenicillin. Erythromycin and rifampicin presented an increase in the intermediate-resistance status between the first and the last studies. E. faecium presented intermediate-resistance results.

CONCLUSION

The most effective drugs remain the combination of amoxicillin and clavulanate, followed by amoxicillin and benzylpenicillin. In patients allergic to penicillin derivatives, moxifloxacin and azithromycin may be indicated with caution. The antibiotics with the highest pattern of resistance against E. faecalis are clindamycin, gentamicin, metronidazole, and rifampicin and are therefore, contraindicated in cases of SPEI. Very few clinical studies using a microbiological approach in teeth with endodontic failure have been carried out to improve the efficacy of prophylactic regimens. However, as bacteria periodically develop resistance to the main drugs used, regular studies should be carried out on the action of these drugs in infection control.

Enterococcus faecalis Endocarditis of All Four Native Valves: A Case Report

Enterococcus faecalis is commonly implicated in Infective Endocarditis (IE), resulting in remarkable morbidity and mortality. We present an unusual case documenting the clinical course and outcome of an elderly female patient who developed quadruple valve endocarditis due to Enterococcus faecalis infection. She presented with altered mental status, resulting in hospitalization, and was found to have bacteremia complicated by endocarditis, epidural abscess, discitis, and splenic infarction. Urinalysis was consistent with bacterial infection two days before being admitted to the hospital. Unfortunately, despite aggressive therapeutic regimens, the patient died.  This is one of the few documented endocarditis cases involving all heart valves. It reviews the importance of maintaining a high index of clinical suspicion for assessing IE, with a low threshold for performing a transesophageal echocardiogram as a diagnostic tool.

State-of-the-Art Review: Persistent Enterococcal Bacteremia

Persistent enterococcal bacteremia is a commonly encountered and morbid syndrome without a strong evidence base for optimal management practices. Here we highlight reports on the epidemiology of enterococcal bacteremia to better describe and define persistent enterococcal bacteremia, discuss factors specific to Enterococcus species that may contribute to persistent infections, and describe a measured approach to diagnostic and therapeutic strategies for patients with these frequently complicated infections. The diagnosis of persistent enterococcal bacteremia is typically clinically evident in the setting of repeatedly positive blood culture results; instead, the challenge is to determine in an accurate, cost-effective, and minimally invasive manner whether any underlying nidus of infection (eg, endocarditis or undrained abscess) is present and contributing to the persistent bacteremia. Clinical outcomes for patients with persistent enterococcal bacteremia remain suboptimal. Beyond addressing host immune status if relevant and pursuing source control for all patients, management decisions primarily involve the selection of the proper antimicrobial agent(s). Options for antimicrobial therapy are often limited in the setting of intrinsic and acquired antimicrobial resistance among enterococcal clinical isolates. The synergistic benefit of combination antimicrobial therapy has been demonstrated for enterococcal endocarditis, but it is not clear at present whether a similar approach will provide any clinical benefit to some or all patients with persistent enterococcal bacteremia.

Bacteraemia caused by non-faecalis and non-faecium Enterococcus species-a retrospective study of incidence, focus of infection, and prognosis

BACKGROUND/AIM

Enterococcus faecalis and Enterococcus faecium cause human infections including bacteraemia and infective endocarditis (IE). Only few studies describing non-faecalis and non-faecium Enterococcus (NFE) infections have been conducted. We aimed to describe the incidence, prognosis, and focus of infection of bacteraemia with NFE.

METHODS

This retrospective population-based study included all episodes of patients having a blood culture with growth of NFE between 2012 and 2019 in Region Skåne, Sweden. Information was collected from medical records. Episodes of bacteraemia caused by NFE were compared to episodes of bacteraemia caused by E. faecalis and E. faecium.

RESULTS

During the study period, 136 episodes with NFE bacteraemia were identified corresponding to an incidence of NFE bacteraemia of 16 cases per 1,000,000 person-years among adults. Enterococcus casseliflavus (n=45), Enterococcus gallinarum (n=34), and Enterococcus avium (n=29) were the most common species. The most common foci of infection were biliary tract infections (n=17) followed by gastrointestinal infections (n=7). Urinary tract infections were not commonly caused by NFE (n=1), and no episodes of IE were caused by NFE. Polymicrobial bacteraemia was more common with NFE (73%) than with E. faecalis (35%) and E. faecium (42%). Community acquired infections were more common in bacteraemia with NFE compared to E. faecium. 30- and 90-day survival rates were 76% and 68%, respectively, and recurrent NFE bacteraemia was seen after 3% of the episodes.

CONCLUSION

Bacteraemia caused by NFE is rare and is often polymicrobial. Biliary tract focus is common in NFE bacteraemia whereas IE and urinary tract focus are uncommon.

Enterococcus faecalis bacteraemia and infective endocarditis - what are we missing?

Introduction

Enterococcus faecalis is an increasingly common cause of infective endocarditis, with a recent study by Dahl et al demonstrating a prevalence of 26% of IE when transoesophageal echo was routinely undertaken. Another study undertaken by Østergaard et al found that 16.7% of patients with E. faecalis bacteraemia developed endocarditis. Based on these findings we examined the rates of IE diagnosed in our own health board to determine if our current practice is potentially missing cases of IE and if we could improve our management of these bacteraemias.

Methods

All blood cultures in patients over 18 which were positive for E. faecalis from October 2017 to March 2022 were reviewed. We analysed the patient characteristics, clinical outcomes and included a follow up period of 6 months to assess for recrudescence and treatment failure.

Results

The rate of patients with E. faecalis bacteraemia diagnosed with IE was 7.1%. If polymicrobial blood cultures were excluded this rose to 13.0%. Community acquisition, patient cardiac or immune risk factors, monomicrobial culture and multiple positive blood cultures all were associated with IE. 62.1% of patients with E. faecalis bacteraemia did not have an echocardiogram during their admission, due to a variety of reasons.

Discussion

The lower reported rate of IE in our cohort may be explained by higher proportion of CVC related infections. However, given the low rates of echocardiography and poor correlation of echocardiography use with IE risk factors, it is likely that cases of IE are being missed, particularly in those with multiple risk factors. Despite this, there was no difference in one-year survival between those diagnosed with IE vs without IE. We have delivered education sessions and introduced a multidisciplinary team meeting to discuss infective endocarditis cases to address these issues.

Enterococcus faecalis in secondary apical periodontitis: Mechanisms of bacterial survival and disease persistence

Enterococcus faecalis is a commensal bacterium commonly found in the human gastrointestinal tract. However, in individuals with compromised immune systems, the pathogen can lead to severe illness. This opportunistic pathogen is associated with secondary apical diseases and is adept at resisting antibiotics and other forms of treatment because of its numerous virulence factors. Enterococcus faecalis is capable of disrupting the normal functions of immune cells, thereby hindering the body's ability to eradicate the infection. However, intensive research is needed in further understanding the adverse immunomodulatory effects of E. faecalis. Potential strategies specific for eradicating E. faecalis have proven beneficial in the treatment of persistent secondary apical periodontitis.

Risk and Outcome of Infective Endocarditis in Streptococcal Bloodstream Infections according to Streptococcal Species

This study aimed to identify which streptococcal species are closely associated with infective endocarditis (IE) and to evaluate risk factors for mortality in patients with streptococcal IE. We performed a retrospective cohort study of all patients with streptococcal bloodstream infection (BSI) from January 2010 to June 2020 in a tertiary hospital in South Korea. We compared clinical and microbiological characteristics of streptococcal BSIs according to the diagnosis of IE. We performed multivariate analysis to evaluate the risk of IE according to streptococcal species and risk factors for mortality in streptococcal IE. A total of 2,737 patients were identified during the study period, and 174 (6.4%) were diagnosed with IE. The highest IE prevalence was in patients with Streptococcus mutans BSI (33% [9/27]) followed by S. sanguinis (31% [20/64]), S. gordonii (23% [5/22]), S. gallolyticus (16% [12/77]), and S. oralis (12% [14/115]). In multivariate analysis, previous IE, high-grade BSI, native valve disease, prosthetic valve, congenital heart disease, and community-onset BSI were independent risk factors for IE. After adjusting for these factors, S. sanguinis (adjusted OR [aOR], 7.75), S. mutans (aOR, 5.50), and S. gallolyticus (aOR, 2.57) were significantly associated with higher risk of IE, whereas S. pneumoniae (aOR, 0.23) and S. constellatus (aOR, 0.37) were associated with lower risk of IE. Age, hospital-acquired BSI, ischemic heart disease, and chronic kidney disease were independent risk factors for mortality in streptococcal IE. Our study points to significant differences in the prevalence of IE in streptococcal BSI according to species. IMPORTANCE Our study of risk of infective endocarditis in patients with streptococcal bloodstream infection demonstrated that Streptococcus sanguinis, S. mutans, and S. gallolyticus were significantly associated with higher risk of infective endocarditis. However, when we evaluated the performance of echocardiography in patients with streptococcal bloodstream infection, patients with S. mutans and S. gordonii bloodstream infection had a tendency of low performance in echocardiography. There are significant differences in the prevalence of infective endocarditis in streptococcal bloodstream infection according to species. Therefore, performing echocardiography in streptococcal bloodstream infection with a high prevalence of, and significant association with, infective endocarditis is desirable.

Ampicillin Stability in a Portable Elastomeric Infusion Pump: A Step Forward in Outpatient Parenteral Antimicrobial Therapy

Outpatient parenteral antimicrobial therapy (OPAT) with continuous infusion pumps is postulated as a very promising solution to treat complicated infections, such as endocarditis or osteomyelitis, that require patients to stay in hospital during extended periods of time, thus reducing their quality of life and increasing the risk of complications. However, stability studies of drugs in elastomeric devices are scarce, which limits their use in OPAT. Therefore, we evaluated the stability of ampicillin in sodium chloride 0.9% at two different concentrations, 50 and 15 mg/mL, in an elastomeric infusion pump when stored in the refrigerator and subsequently in real-life conditions at two different temperatures, 25 and 32 °C, with and without the use of a cooling device. The 15 mg/mL ampicillin is stable for up to 72 h under refrigeration, allowing subsequent dosing at 25 °C for 24 h with and without a cooling device, but at 32 °C its concentration drops below 90% after 8 h. In contrast, 50 mg/mL ampicillin only remains stable for the first 24 h under refrigeration, and subsequent administration at room temperature is not possible, even with the use of a cooling system. Our data support that 15 mg/mL AMP is suitable for use in OPAT if the volume and rate of infusion are tailored to the dosage needs of antimicrobial treatments.

Risk of Cardiac Implantable Electronic Device Infection in Patients with Bloodstream Infection: Microbiologic Effect in the Era of Positron Emission Tomography-Computed Tomography

PURPOSE OF REVIEW

Bloodstream infection (BSI) in patients with cardiac implantable electronic devices (CIEDs) is common and can prompt challenges in defining optimal management. We provide a contemporary narrative review of this topic and propose a pathogen-dependent clinical approach to patient management.

RECENT FINDINGS

BSI due to staphylococci, viridans group streptococci, and enterococci is associated with an increased risk of underlying CIED infection, while the risk of CIED infection due to other organisms is poorly defined. There is growing evidence that positron emission tomography-computed tomography may be helpful in some patients with BSI and underlying CIED. Twenty studies were included to examine the impact of microbiologic findings on the risk of CIED infection among patients with BSI. Diagnosis of CIED infection in patients with BSI without pocket findings is often difficult, necessitating the use of novel diagnostic tools to help guide the clinician in subsequent patient management.

Recurrent bacteremia with Enterococcus faecalis, the clinical findings predicting endocarditis, and genomic characterization of the isolates: a retrospective cohort study

Multiple episodes of Enterococcus faecalis bacteremia (EfsB) may indicate a relapse and be due to an undiagnosed infective endocarditis (IE). The aims were to study the clinical presentation of patients with EfsB with focus on the risk of recurrent infection and IE, identify potential improvements of the management, and to investigate whether E. faecalis isolates from different episodes in the same patient were identical. In a retrospective study, a cohort of patients with monomicrobial (M) EfsB episodes was analyzed. Clinical data from medical records were collected. Furthermore, blood culture isolates from patients with multiple episodes were subjected to whole genome sequencing and multilocus sequence typing. In 666 episodes of MEfsB, 69 patients with IE and 43 with recurrent infections were found. Patients without IE, but with a following episode diagnosed as IE, were compared to those without a following episode. Variables significantly correlated with IE were long duration of symptoms, growth in all blood cultures, unknown origin of infection, heart murmur, and predisposition for IE. Transesophageal echocardiography, all negative, was done in 4 out of 11 episodes during the first episodes, later diagnosed with IE. In 28 of 31 patients with two or more EfsB episodes, isolates with identical sequence type were found. Episodes of EfsB in patients later diagnosed with IE showed features of IE already during the first episodes, were not adequately evaluated, are due to identical isolates, and most likely represent true relapses. Risk factor analysis should guide the use of echocardiography.

Guidelines for Diagnosis and Management of Infective Endocarditis in Adults: A WikiGuidelines Group Consensus Statement

Importance

Practice guidelines often provide recommendations in which the strength of the recommendation is dissociated from the quality of the evidence.

Objective

To create a clinical guideline for the diagnosis and management of adult bacterial infective endocarditis (IE) that addresses the gap between the evidence and recommendation strength.

Evidence Review

This consensus statement and systematic review applied an approach previously established by the WikiGuidelines Group to construct collaborative clinical guidelines. In April 2022 a call to new and existing members was released electronically (social media and email) for the next WikiGuidelines topic, and subsequently, topics and questions related to the diagnosis and management of adult bacterial IE were crowdsourced and prioritized by vote. For each topic, PubMed literature searches were conducted including all years and languages. Evidence was reported according to the WikiGuidelines charter: clear recommendations were established only when reproducible, prospective, controlled studies provided hypothesis-confirming evidence. In the absence of such data, clinical reviews were crafted discussing the risks and benefits of different approaches.

Findings

A total of 51 members from 10 countries reviewed 587 articles and submitted information relevant to 4 sections: establishing the diagnosis of IE (9 questions); multidisciplinary IE teams (1 question); prophylaxis (2 questions); and treatment (5 questions). Of 17 unique questions, a clear recommendation could only be provided for 1 question: 3 randomized clinical trials have established that oral transitional therapy is at least as effective as intravenous (IV)-only therapy for the treatment of IE. Clinical reviews were generated for the remaining questions.

Conclusions and Relevance

In this consensus statement that applied the WikiGuideline method for clinical guideline development, oral transitional therapy was at least as effective as IV-only therapy for the treatment of IE. Several randomized clinical trials are underway to inform other areas of practice, and further research is needed.

Therapeutics for Vancomycin-Resistant Enterococcal Bloodstream Infections

Vancomycin-resistant enterococci (VRE) are common causes of bloodstream infections (BSIs) with high morbidity and mortality rates. They are pathogens of global concern with a limited treatment pipeline. Significant challenges exist in the management of VRE BSI, including drug dosing, the emergence of resistance, and the optimal treatment for persistent bacteremia and infective endocarditis. Therapeutic drug monitoring (TDM) for antimicrobial therapy is evolving for VRE-active agents; however, there are significant gaps in the literature for predicting antimicrobial efficacy for VRE BSIs. To date, TDM has the greatest evidence for predicting drug toxicity for the three main VRE-active antimicrobial agents daptomycin, linezolid, and teicoplanin. This article presents an overview of the treatment options for VRE BSIs, the role of antimicrobial dose optimization through TDM in supporting clinical infection management, and challenges and perspectives for the future.

Ampicillin and Ceftobiprole Combination for the Treatment of Enterococcus faecalis Invasive Infections: "The Times They Are A-Changin"

BACKGROUND

Enterococcus faecalis is responsible for a large variety of severe infections. This study is a case series reporting our experience in the treatment of E. faecalis invasive infections with ampicillin in combination with ceftobiprole (ABPR).

METHODS

We retrospectively analyzed all the medical records of patients admitted to the University Hospital of Udine from January to December 2020 with a diagnosis of infective endocarditis or primary or non-primary complicated or uncomplicated bacteremia caused by E. faecalis.

RESULTS

Twenty-one patients were included in the final analysis. The clinical success rate was very high, accounting for 81% of patients, and microbiological cure was obtained in 86% of patients. One relapse was recorded in one patient who did not adhere to the partial oral treatment prescribed. Therapeutic drug monitoring (TDM) was always performed for ampicillin and ceftobiprole, and serum concentrations of both drugs were compared to the MICs of the different enterococcal isolates.

CONCLUSIONS

ABPR is a well-tolerated antimicrobial regimen with anti-E. faecalis activity. TDM can help clinicians optimize medical treatments to achieve the best possible efficacy with fewer side effects. ABPR might be a reasonable option for the treatment of severe invasive infections caused by E. faecalis due to the high level of enterococcal penicillin-binding protein (PBP) saturation.

Treatment and outcome of gram-positive bacteremia in patients receiving extracorporeal membrane oxygenation

BACKGROUND

While guidance exists for management of blood stream infections with various invasive devices, there are currently limited data to guide antibiotic selection and duration for bacteremia in patients receiving extracorporeal membrane oxygenation (ECMO).

OBJECTIVE

To evaluate the treatment and outcomes of thirty-six patients with Staphylococcus aureus and Enterococcus bacteremia on ECMO support.

METHODS

Blood culture data was retrospectively analyzed from patients with Staphylococcus aureus bacteremia (SAB) or Enterococcus bacteremia who underwent ECMO support between March 2012 and September 2021 at Brooke Army Medical Center.

RESULTS

Of the 282 patients who received ECMO during this study period, there 25 (9%) patients developed Enterococcus bacteremia and 16 (6%) developed SAB. SAB occurred earlier in ECMO as compared to Enterococcus (median day 2 IQR (1-5) vs. 22 (12-51), p = 0.01). The most common duration of antibiotics was 28 days after clearance for SAB and 14 days after clearance for Enterococcus. 2 (5%) patients underwent cannula exchange with primary bacteremia, and 7 (17%) underwent circuit exchange. 1/3 (33%) patients with SAB and 3/10 (30%) patients with Enterococcus bacteremia who remained cannulated after completion of antibiotics had a second episode of SAB or Enterococcus bacteremia.

CONCLUSION

This single center case series is the first to describe the specific treatment and outcomes of patients receiving ECMO complicated by SAB and Enterococcus bacteremia. For patients who remain on ECMO after completion of antibiotics, there is a risk of a second episode of Enterococcus bacteremia or SAB.

Enterococcus faecalis endocarditis resulting in annular rupture: a case report

Enterococcus faecalis is the third most common organism to cause infective endocarditis and is associated with high rates of morbidity and mortality. E. faecalis infective endocarditis often presents with a subacute course and with nonspecific constitutional symptoms. Complications related to E. faecalis infective endocarditis are common and include embolic events, abscess formation and pseudoaneurysm formation. Contained annular rupture is a complication of E. faecalis infective endocarditis that, to the authors knowledge, has not been previously described in the literature. Herein, we present an unusual case of a 62-year-old male presenting with classical symptoms of E. faecalis infective endocarditis which resulted in an unusual complication of this condition, a contained annular rupture and the surgical management undertaken to correct this condition.

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.

Infective endocarditis of quadricuspid aortic valve

BACKGROUND

Infective endocarditis of the aortic valve is a relatively common disease presentation, with surgical intervention a mainstay of treatment in severe cases. Quadricuspid aortic valves are a rare spontaneous developmental anomaly that are more likely to be asymptomatic, and less likely to require a full valve replacement than their hypocuspid counterparts. However, there is very little literature addressing infective endocarditis of this valve variant.

CASE PRESENTATION

This case report presents a case of infective endocarditis of a quadricuspid aortic valve that required replacement with a surgical bioprosthetic valve. The patient is a 30 year old male with a history of polysubstance use, upper extremity aneurysm, and prior tricuspid valve endocarditis. Surgical aortic valve replacement was performed with a 25 mm tissue valve via median sternotomy.

CONCLUSIONS

The patient made a full recovery after surgical aortic valve replacement and a course of antibiotics and was discharged home without any complications. This supports that surgical aortic valve replacement is feasible and safe in patients with polycuspid aortic valve endocarditis.

Temporal trends of mortality in patients with infective endocarditis: a nationwide study

AIMS

Little is known about the mortality for patients with infective endocarditis (IE) on a nationwide scale, and previous studies have been conducted in selected cohorts from tertiary centers. We aimed to investigate temporal trends in mortality using nationwide Danish registries.

METHODS AND RESULTS

We identified patients with first-time IE between 1999-2018, and they were grouped by calendar periods (1999-2003, 2004-2008, 2009-2013, 2014-2018). One-year mortality was estimated using Kaplan-Meier estimates. For calendar periods, odds ratios (ORs) and hazard ratios (HRs) were computed using multivariable adjusted logistic regression and Cox proportional Hazards analyses for in-hospital and one-year mortality, respectively. We identified 8804 patients with IE. Age and proportions of men were: 66.7 (25th-75th percentile: 53.4-76.7) years and 59.9% in 1999-2003 and 72.8 (25th-75th percentile: 63.4-80.3) and 65.8% in 2014-2018. In-hospital mortality was 1999-2003: 24.5%, 2004-2008: 22.8%, 2009-2013: 18.8%, and 2014-2018: 18.3%. Relative to 1999-2003, adjusted likelihoods of in-hospital mortality were: OR = 0.81 (95% CI: 0.69-0.96) in 2004-2008, OR = 0.59 (95% CI: 0.50-0.69) in 2009-2013, and OR = 0.51 (95% CI: 0.43-0.60) in 2014-2018. By calendar periods, crude risks of one-year mortality were: 34.4% (95% CI: 32.0-36.8%), 33.5% (95% CI: 31.5-35.6%), 32.1% (95% CI: 30.2-34.0%), and 33.1% (95% CI: 31.3-34.8%). Relative to 1999-2003, adjusted rates of one-year mortality were: HR = 0.88 (95% CI 0.79-0.99) in 2004-2008, HR = 0.76 (95% CI: 0.68-0.86) in 2009-2013, and HR = 0.72 (95% CI: 0.64-0.81) in 2014-2018.

CONCLUSION

In this nationwide study of patients with first-time IE between 1999-2018, both short- and long-term survival has improved over time when accounting for changes in patient characteristics.

ONE-SENTENCE SUMMARY

When accounting for patient characteristics, both short- and long-term mortality have improved in patients with first-time infective endocarditis.

Bacteremia due to Non-Staphylococcus aureus Gram-positive Cocci and Risk of Cardiovascular Implantable Electronic Device Infection

Background

Cardiovascular implantable electronic device (CIED) infection carries significant morbidity and mortality with bacteremia being a possible marker of device infection. A clinical profile of non-Staphylococcus aureus gram-positive cocci (non-SA GPC) bacteremia in patients with CIED has been limited.

Objective

To examine characteristics of patients with CIED who developed non-SA GPC bacteremia and risk of CIED infection.

Methods

We reviewed all patients with CIED who developed non-SA GPC bacteremia at the Mayo Clinic between 2012 and 2019. The 2019 European Heart Rhythm Association Consensus Document was used to define CIED infection.

Results

A total of 160 patients with CIED developed non-SA GPC bacteremia. CIED infection was present in 90 (56.3%) patients, in whom 60 (37.5%) were classified as definite and 30 (18.8%) as possible. This included 41 (45.6%) cases of coagulase-negative Staphylococcus (CoNS), 30 (33.3%) cases of Enterococcus, 13 (14.4%) cases of viridans group streptococci (VGS), and 6 (6.7%) cases of other organisms. The adjusted odds of CIED infection in cases due to CoNS, Enterococcus, and VGS bacteremia were 19-, 14-, and 15-fold higher, respectively, as compared with other non-SA GPC. In patients with CIED infection, the reduction in risk of 1-year mortality associated with device removal was not statistically significant (hazard ratio 0.59; 95% confidence interval 0.26-1.33; P = .198).

Conclusions

The prevalence of CIED infection in non-SA GPC bacteremia was higher than previously reported, particularly in cases due to CoNS, Enterococcus species, and VGS. However, a larger cohort is needed to demonstrate the benefit of CIED extraction in patients with infected CIED due to non-SA GPC.

Sign of the Times: Updating Infective Endocarditis Diagnostic Criteria to Recognize Enterococcus faecalis as a Typical Endocarditis Bacterium

The modified Duke criteria requires that Enterococcus faecalis bacteremia must be both community-acquired and without known focus in order to be considered a microbiological "Major" diagnostic criterion in the diagnosis of infective endocarditis. We believe that the microbiological diagnostic criteria should be updated to regard E. faecalis as a "typical" endocarditis bacterium as is currently the case, for example, viridans group streptococci and Staphylococcus aureus. Using data from a prospective study of 344 patients with E. faecalis bacteremia evaluated with echocardiography, we demonstrate that designating E. faecalis as a "typical" endocarditis pathogen, regardless the place of acquisition or the portal of entry, improved the sensitivity to correctly identify definite endocarditis from 70% (modified Duke criteria) to 96% (enterococcal adjusted Duke criteria).

Impact of Enterococcus faecalis Endocarditis Treatment on Risk of Relapse

BACKGROUND

Enterococcus faecalis infective endocarditis (EFIE) is characterized by a higher frequency of relapses than other infective endocarditis. The role of the treatment on its occurrence remains poorly understood. The aim of this study was to investigate whether the antibiotic regimen could impact the risk of relapse in EFIE.

MATERIALS

This was a multicenter retrospective study of patients diagnosed with definite EFIE between 2015 and 2019 in 14 French hospitals. The primary endpoint was the occurrence of relapses within the year following endocarditis diagnosis. As death was a competing risk for relapse, Fine and Gray models were used for studying risk factors and impact of treatment.

RESULTS

Of the 279 patients included, 83 (29.7%) received the amoxicillin-gentamicin (A-G) combination, 114 (40.9%) amoxicillin-ceftriaxone (A-C), 63 (22.6%) A-G and A-C (A-G/A-C) sequentially, 9 (3.2%) amoxicillin (A), and 10 received other treatments. One-year-relapse rate was 9.3% (26 patients). Relapse occurred after a median delay of 107 days from EFIE diagnosis; 6 occurred after 6 months, and 6 were diagnosed by blood cultures in asymptomatic patients. In multivariate analysis, surgery during treatment was a protective factor against one-year relapse and death.The cumulative incidence of relapse 1 year after endocarditis was 46.2% for patients treated with amoxicillin, 13.4% with A-G, 14.7% with A-C, and 4.3% with A-G/A-C (P≥.05 in multivariate analysis).

CONCLUSIONS

Relapses after treatment of EFIE are frequent, frequently asymptomatic, and may occur more than 6 months after the initial episode.

Measuring Epidemiologic Effects of Enterococcal Bacteremia and Outcomes From a Nationwide Inpatient Sample Database

Introduction

Enterococcus is a gram-positive, non-sporing, facultative anaerobe. It is a common cause of nosocomial infections in the United States. Enterococcal bacteremia is primarily a nosocomial infection in the medical intensive care unit (ICU), with a preference for elderly patients with multiple comorbidities. 

Material and methods

This is a retrospective cohort study using the publicly accessible National (Nationwide) Inpatient Sample (NIS) database from October 2015 to December 2017. We examined data from 75,430 patients aged 18 years and older in the NIS who developed enterococcal bacteremia, as identified from the ICD-10 CM codes (B95), to discuss the epidemiologic effects and outcomes of enterococcal bacteremia. Patients were classified based on demographics, and comorbidities were identified. Three primary outcomes were studied: in-hospital mortality, length of stay, and healthcare cost. The secondary outcome was identifying any comorbidities associated with enterococcal bacteremia. Length of stay was defined as days from admission to discharge or death. Healthcare costs were estimated from the hospital perspective from hospital-level ratios of costs-to-charges. SAS 9.4 (2013; SAS Institute Inc., Cary, North Carolina, United States) was used for univariate and multivariate analyses. For data analysis, mortality was modeled using logistic regression. Length of stay and costs were modeled using linear regression, controlling for patient and hospital characteristics. Statistical analyses were performed using SAS. Statistical significance was defined as P<0.05.

Results

A total of 75,430 patients with enterococcal bacteremia were included in the study. Of this, 44,270 were males and 31,160 females. A total of 50,270 (68.67%) were Caucasians, 11,210 (15.31%) were African Americans, 6,445 (8.80%) were Hispanic and 2,025 (2.77%) were native Americans. Important comorbidities were congestive heart failure (25.91%), valvular disease (8.08%), neurological complications (11.87%), diabetes mellitus with complications (18.89%), renal failure (28.52%), and obesity (11.61%). In-hospital mortality was 11.07%, length of stay was 13.8 days, and a healthcare cost of 41,232.6 USD. 

Conclusions

Enterococcal bacteremia is a nosocomial infection with a preference for the elderly with renal failure, cardiac failure, cardiac valvular diseases, stroke, obesity, and diabetes with complications. Further studies are needed to see whether the mortality caused by enterococcal bacteremia is attributable to comorbidities or to the bacteremia. It is associated with a more extended hospital stay and higher healthcare expenditure. Implementing contact precautions to contain the spread of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus(VRE) has also checked the spread of enterococci. Further prospective studies can be planned using chart-based data.

Unusual Presentation of Infective Endocarditis Following a Prostatic Urethral Lift

Infective endocarditis is a serious inflammation of the inner lining of the heart. It is caused by pathogens entering the bloodstream and infecting the endocardium. We demonstrate a unique presentation of infective endocarditis following a prostatic urethral lift. The low index of suspicion and atypical symptoms prevented early diagnosis of the disease, leading to life-threatening complications and valve replacement surgery. Understanding unusual presentations of infective endocarditis can increase the index of suspicion in outpatient settings, leading to early diagnosis and preventing fatal complications.

Enterococcus faecalis bacteremia, cardiac implantable electronic device, extraction, and the risk of recurrence

PURPOSE

In all patients with cardiac implantable electronic devices (CIED) and Enterococcus faecalis bacteremia (EfsB), endocarditis (IE) and CIED infection should be suspected. Guidelines recommend extraction of the CIED when CIED infection or IE is diagnosed. Whether extraction of the CIED should be done in other situations with EfsB is not known. We aimed to describe the management and outcome of patients with CIED and monomicrobial EfsB, in relation to extraction and recurrent EfsB.

METHODS

A population-based cohort of patients with monomicrobial EfsB from January 2014 to November 2020 was identified through microbiology registers in the Region Skåne, Sweden. Data on CIED and other clinical features were collected from medical records.

RESULTS

Among 1087 episodes of EfsB, 72 patients with CIED and monomicrobial EfsB were identified. Five of these patients were diagnosed with IE (7%), three of whom had echocardiographic changes on the CIED. Four CIED were extracted (6%). Recurrences were found in seven of 68 patients (10%) not subjected to extraction and in none of the extracted. In the group of patients without extraction, community acquisition and predisposition for IE were significantly associated with recurrent infection in univariate analyses. No infections involving the CIED were diagnosed during the recurrences.

CONCLUSIONS

In patient with monomicrobial EfsB, it seems safe to omit extraction if no structural changes are found on the CIED.

Impact of infectious diseases consultation on the outcome of patients with enterococcal bacteremia: a systematic literature review and meta-analysis

Background

Enterococcal bacteremia carries significant mortality. While multiple studies have evaluated the impact of infectious disease consultation (IDC) on this condition, these studies were limited by the low numbers of patients enrolled. This systemic literature review and meta-analysis were conducted to determine whether IDC was associated with a mortality benefit among patients with enterococcal bacteremia.

Methods

We performed a systematic literature search using 5 databases for studies evaluating IDC among patients with enterococcal bacteremia. We conducted a meta-analysis to assess whether IDC was associated with reduced mortality. Random-effect models were used to calculated pooled odds ratios (pORs). Heterogeneity was evaluated using I2 estimation and the Cochrane Q statistic test.

Results

The systemic literature review revealed 6496 reports, from which 18 studies were evaluated in the systemic literature review and 16 studies in the meta-analysis. When all studies were pooled, the association between IDC and mortality was not statistically significant with a pOR of 0.81 (95% CI, 0.61-1.08) and there was substantial heterogeneity (I2=58%). When the studies were limited to those reporting multivariate analysis including IDC, there was a significant protective effect of IDC (pOR=0.40; 95% CI, 0.24-0.68) without heterogeneity (I2=0%). Some studies also showed additional benefits to IDC, including appropriate antibiotic therapy, and improved diagnostic use.

Conclusions

IDC was associated with 60% lower odds of mortality when patients were well-matched, potentially through improvement in the care for patients with enterococcal bacteremia. IDC should be considered a part of routine care for patients with enterococcal bacteremia.

Mechanism of cooperative N-glycan processing by the multi-modular endoglycosidase EndoE

Bacteria produce a remarkably diverse range of glycoside hydrolases to metabolize glycans from the environment as a primary source of nutrients, and to promote the colonization and infection of a host. Here we focus on EndoE, a multi-modular glycoside hydrolase secreted by Enterococcus faecalis, one of the leading causes of healthcare-associated infections. We provide X-ray crystal structures of EndoE, which show an architecture composed of four domains, including GH18 and GH20 glycoside hydrolases connected by two consecutive three α-helical bundles. We determine that the GH20 domain is an exo-β-1,2-N-acetylglucosaminidase, whereas the GH18 domain is an endo-β-1,4-N-acetylglucosaminidase that exclusively processes the central core of complex-type or high-mannose-type N-glycans. Both glycoside hydrolase domains act in a concerted manner to process diverse N-glycans on glycoproteins, including therapeutic IgG antibodies. EndoE combines two enzyme domains with distinct functions and glycan specificities to play a dual role in glycan metabolism and immune evasion.

EndoE is a multi-domain glycoside hydrolase of the human pathogen Enterococcus faecalis. Here, the authors present crystal structures of EndoE and provide biochemical insights into the molecular basis of EndoE’s substrate specificity and catalytic mechanism.

Phalloplasty Complicated by Penile Artery Thrombosis, Recurrent Extended-Spectrum Beta-Lactamase (ESBL) Urinary Tract Infection (UTI), Colovesical Fistula, and Enterococcus Faecalis Endocarditis

Enterococcus faecalis is an enteric microorganism that, if introduced into the vasculature, is an uncommon cause of infective endocarditis. Timely diagnosis, appropriate treatment measures, and close follow-up are key to therapeutic success. Antibiotic therapy is the mainstay of therapy, and surgical intervention is sometimes indicated. Here we present a novel case of a 45-year-old transgender male with Factor V Leiden deficiency who was found to have Enterococcus faecalis mitral valve endocarditis due to the postoperative complications of colovesical fistula formation leading to extended-spectrum beta-lactamase (ESBL) urinary tract infection (UTI) and E. faecalis bacteremia in the setting of recent phalloplasty, mastectomy, and vaginal eversion.

The First Reported Case of Post-Atrioventricular Node Ablation Enterococcus Faecalis Bacteremia in a Patient With Colonic Tubular Adenomas and Chronic Steroid Use

We present the case of a 73-year-old immunosuppressed male with a history of multiple benign, colonic adenomas who was admitted to our hospital with Enterococcus faecalis (E. faecalis) bacteremia. The patient also had a prior history of dual-chamber pacemaker placement for sick sinus syndrome. Two days before the admission, the patient had undergone radiofrequency ablation of the atrioventricular (AV) node for refractory atrial flutter without receiving any peri-procedural antibiotic prophylaxis. Despite high-grade bacteremia and a high NOVA (Number of positive blood cultures, Origin of the bacteremia, previous Valve disease, Auscultation of heart murmur) score, there was no evidence of infective endocarditis on transesophageal echocardiogram (TEE). The patient was treated successfully with appropriate intravenous antibiotics, and he recovered well.

To the best of our knowledge, this is the first reported case of post-AV node ablation E. faecalis bacteremia. We conclude that the presence of colonic lesions and immunosuppression can increase the risk of peri-procedural E. faecalis bacteremia, and clinicians should consider antibiotic prophylaxis in this high-risk patient group.

Diagnostic value of 18F-FDG PET/CT in infective endocarditis

INTRODUCTION

18F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG-PET/CT) is not routinely recommended for the diagnosis of infective endocarditis (IE) due to the lack of clinical impact.

MATERIALS AND METHODS

Between January 2016 and January 2020, clinical data from patients with a possible diagnosis of IE were reviewed retrospectively to evaluate the value of ¹⁸F-FDG-PET/CT in the diagnosis of IE. ¹⁸F-FDG PET/CT scan was performed as an additional diagnostic tool in possible IE when echocardiography was inconclusive or in patients with definite IE to identify extracardiac complications. Cases were classified according to modified Duke criteria as rejected, definite or possible.

RESULTS

313 patients with suspected IE were included. 72 (23%) patients underwent 18F-FDG PET/CT. ¹⁸F-FDG PET/CT resulted in a reclassification of Duke criteria in 29/72 (40%) patients, from "possible" to "definite" (n, 10) and to "rejected" (n, 19). Patients who benefited from a Duke criteria reclassification following ¹⁸F-FDG PET/CT were more frequently classified as possible IE at inclusion or had a non-conclusive baseline echocardiography (100% vs 58%; p 0.001) and had more likely a prosthetic metallic valve replacement (59% vs 21%; p 0.001). Abnormal perivalvular uptake was identified in 46 patients (71% prosthetic vs 50% native; p 0.118). ¹⁸F-FDG PET/CT identified extracardiac uptake consistent with septic emboli in 14/72 (19%) patients. In addition, extracardiac uptake indicative of an alternative diagnosis was identified in 5 patients (2% prosthetic vs 17% native; p 0.039).

CONCLUSION

The use of ¹⁸F-FDG-PET/CT has shown to be useful in the diagnosis of IE, particularly in prosthetic IE and may provide additional value in the detection of septic emboli and/or the identification of an alternative diagnosis different from IE.

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

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

Enterococcus faecalis bloodstream infection: does infectious disease specialist consultation make a difference?

PURPOSE

To evaluate the relationship between mortality or relapse of bloodstream infection (BSI) due to Enterococcus faecalis and infectious diseases specialist consultation (IDC) and other factors potentially associated with outcomes.

METHODS

In a tertiary-care center, consecutive adult patients with E. faecalis BSI between January 1, 2016 and January 31, 2019, were prospectively followed. The management of E. faecalis BSI was evaluated in terms of adherence to evidence-based quality-of-care indicators (QCIs). IDC and other factors potentially associated with 90-day-mortality or relapse of E. faecalis BSI were analyzed by multivariate logistic regression.

RESULTS

A total of 151 patients with a median age of 68 years were studied. IDC was performed in 38% of patients with E. faecalis BSI. 30 cases of endocarditis (20%) were diagnosed. All-cause in-hospital mortality was 23%, 90-day mortality was 37%, and 90-day relapsing E. faecalis BSI was 8%. IDC was significantly associated with better adherence to 5 QCIs. Factors significantly associated with 90-day mortality or relapsing EfB in multivariate analysis were severe sepsis or septic shock at onset (HR 4.32, CI 2.36e7.88) and deep-seated focus of infection (superficial focus HR 0.33, CI 0.14e0.76).

CONCLUSION

Enterococcus faecalis bacteremia is associated with a high mortality. IDC contributed to improved diagnostic and therapeutic management.

Carbohydrate Metabolism Affects Macrophage-Mediated Killing of Enterococcus faecalis

Enterococcus faecalis, an opportunistic pathogen that causes severe community-acquired and nosocomial infections, has been reported to resist phagocyte-mediated killing, which enables its long-term survival in the host. Metabolism, especially carbohydrate metabolism, plays a key role in the battle between pathogens and hosts. However, the function of carbohydrate metabolism in the long-term survival of E. faecalis in phagocytes has rarely been reported. In this study, we utilized transposon insertion sequencing (TIS) to investigate the function of carbohydrate metabolism during the survival of E. faecalis in RAW264.7 cells. The TIS results showed that the fitness of carbohydrate metabolism-related mutants, especially those associated with fructose and mannose metabolism, were significantly enhanced, suggesting that the attenuation of carbohydrate metabolism promotes the survival of E. faecalis in macrophages. The results of our investigation indicated that macrophages responded to carbohydrate metabolism of E. faecalis and polarized to M1 macrophages to increase nitric oxide (NO) production, leading to the enhancement of macrophage-mediated killing to E. faecalis. Meanwhile, E. faecalis automatically decreased carbohydrate metabolism to escape from the immune clearance of macrophages during intracellular survival. The shift of primary carbon resources for macrophages affected the ability to clear intracellular E. faecalis. In summary, the results of the present study demonstrated that carbohydrate metabolism affects the macrophage-mediated killing of E. faecalis.

IMPORTANCEE. faecalis has become a major pathogen leading to a variety of infections around the world. The metabolic interaction between E. faecalis and its host is important during infection but is rarely investigated. We used transposon insertion sequencing coupled with transcriptome sequencing to explore the metabolic interaction between E. faecalis and macrophages and uncovered that the shift of carbohydrate metabolism dramatically affected the inflammatory response of macrophages. In addition, E. faecalis attenuated carbohydrate metabolism to avoid the activation of the immune response of macrophages. This study provides new insights for the reason why E. faecalis is capable of long-term survival in macrophages and may facilitate the development of novel strategies to treat infectious diseases.

Prosthetic valve endocarditis after transcatheter aortic valve replacement in low-risk patients

OBJECTIVES

We sought to report details of the incidence, organisms, clinical course, and outcomes of prosthetic valve endocarditis (PVE) after transcatheter aortic valve replacement (TAVR) in low-risk patients.

BACKGROUND

PVE remains a rare but devastating complication of aortic valve replacement. Data regarding PVE after TAVR in low-risk patients are lacking.

METHODS

We performed a detailed review of all patients in the low-risk TAVR trials who underwent TAVR from 2016 to 2020 and were adjudicated to have definitive PVE by the independent Clinical Events Committee.

RESULTS

We analyzed 396 low-risk patients who underwent TAVR (including 72 with bicuspid valves). PVE occurred in 11 patients at a median 379 days (210, 528) from TAVR. The incidence within the first 30 days was 0%; days 31-365, 1.5%; and after day 365, 2.8%. The most common organism identified was Streptococcus (n = 4/11). Early PVE (≤ 365 days) occurred in five patients, of whom three demonstrated evidence of embolic stroke and two underwent surgical aortic valve re-intervention. Late PVE (> 365 days) occurred in six patients, of whom thee demonstrated evidence of embolic stroke and only one underwent surgical aortic valve re-intervention. Of the six patients with evidence of embolic stroke, two died, two were discharged to rehabilitation, and two were discharged home with home care.

CONCLUSIONS

PVE was infrequent following TAVR in low-risk patients but was associated with substantial morbidity and mortality. Embolic stroke complicated the majority of PVE cases, contributing to worse outcomes in these patients. Efforts must be undertaken to minimize PVE in TAVR.

Enterococcal Endocarditis: Hiding in Plain Sight

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

Proposal for the use of echocardiography in bloodstream infections due to different streptococcal species

Background

Infective endocarditis (IE) is diagnosed in 7–8% of streptococcal bloodstream infections (BSIs), yet it is unclear when to perform transthoracic (TTE) and transoesophageal echocardiography (TOE) according to different streptococcal species. The aim of this sub-study was to propose a flowchart for the use of echocardiography in streptococcal BSIs.

Methods

In a population-based setup, we investigated all patients admitted with streptococcal BSIs and crosslinked data with nationwide registries to identify comorbidities and concomitant hospitalization with IE. Streptococcal species were divided in four groups based on the crude risk of being diagnosed with IE (low-risk < 3%, moderate-risk 3–10%, high-risk 10–30% and very high-risk > 30%). Based on number of positive blood culture (BC) bottles and IE risk factors (prosthetic valve, previous IE, native valve disease, and cardiac device), we further stratified cases according to probability of concomitant IE diagnosis to create a flowchart suggesting TTE plus TOE (IE > 10%), TTE (IE 3–10%), or “wait & see” (IE < 3%).

Results

We included 6393 cases with streptococcal BSIs (mean age 68.1 years [SD 16.2], 52.8% men). BSIs with low-risk streptococci (S. pneumoniae, S. pyogenes, S. intermedius) are not initially recommended echocardiography, unless they have ≥3 positive BC bottles and an IE risk factor. Moderate-risk streptococci (S. agalactiae, S. anginosus, S. constellatus, S. dysgalactiae, S. salivarius, S. thermophilus) are guided to “wait & see” strategy if they neither have a risk factor nor ≥3 positive BC bottles, while a TTE is recommended if they have either ≥3 positive BC bottles or a risk factor. Further, a TTE and TOE are recommended if they present with both. High-risk streptococci (S. mitis/oralis, S. parasanguinis, G. adiacens) are directed to a TTE if they neither have a risk factor nor ≥3 positive BC bottles, but to TTE and TOE if they have either ≥3 positive BC bottles or a risk factor. Very high-risk streptococci (S. gordonii, S. gallolyticus, S. mutans, S. sanguinis) are guided directly to TTE and TOE due to a high baseline IE prevalence.

Conclusion

In addition to the clinical picture, this flowchart based on streptococcal species, number of positive blood culture bottles, and risk factors, can help guide the use of echocardiography in streptococcal bloodstream infections. Since echocardiography results are not available the findings should be confirmed prospectively with the use of systematic echocardiography.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06391-2.

Enterococcus faecalis endocarditis: what's next?

Enterococcus faecalis infective endocarditis (EFIE) is a complex entity in rapid evolution. Although largely relevant findings from recent studies have advanced the knowledge on EFIE and led to some changes in clinical guidelines, there are still a number of gaps to be filled. Coordinated, international, multicenter efforts are needed to obtain quality data that rend the health systems and scientific community prepared enough to understand and handle this infection. In this Perspective, some of the most relevant aspects concerning the epidemiology, clinical presentation and outcomes, diagnostic approaches and antibiotic therapy of EFIE are addressed. Also, several potential future clinical developments in the field are discussed.