Enterococcal endocarditis: 107 cases from the international collaboration on endocarditis merged database

Enterococcal endocarditis management and relapses

Introduction

Enterococcus faecalis is the third micro-organism causing endocarditis and is associated with a significant relapse rate. The objective of this study was to describe the management of patients with Enterococcus faecalis endocarditis (EE) and its implication for relapses.

Methods

We conducted a monocentric, retrospective analysis of all patients hospitalized for EE including endocarditis or infection of cardiac implantable electronic device defined by the modified ESC 2015 Duke criteria in a referral centre in Paris, France.

Results

Between October 2016, and September 2022, 54 patients with EE were included, mostly men (n = 40, 74%) with a median age of 75 [68-80] years. A high risk for infective endocarditis (IE) was found in 42 patients (78%), including 14 (26%) previous histories of IE, and 32 (59%) histories of valvular cardiac surgery. The aortic valve was the most frequently affected (n = 36, 67%). Combination therapy was mainly amoxicillin-ceftriaxone during all the curative antibiotic therapy duration (n = 31, 57%). Surgery was indicated for 40 patients (74%), but only 27 (50%) were operated on, mainly due to their frailty. Among the 17 deaths (32%), six (11%) happened during the first hospitalization for EE. A suppressive antibiotic treatment was initiated in 15 (29%) patients, mostly because of not performing surgery. During the 6-year study period an EE relapse occurred in three (6%) patients.

Conclusions

EE is a worrying disease associated with a high risk of relapse and significant mortality. Suppressive antibiotic therapy could be a key treatment to limit the occurrence of relapses.

Comparative study of virulence factor genes, β-hemolysis and biofilm production in invasive and colonizing enterococci

Objectives: In humans, enterococci are among the most important opportunistic pathogens. This study aims to compare invasive isolates obtained from blood cultures of patients with sepsis and endocarditis with colonizing isolates obtained from healthy donors’ stool samples.

Methods: A case-by-case assessment was conducted on invasive infection cases to determine whether enterococci were involved in their pathogenesis. They were tested for the presence of virulence factor genes, β-hemolysis on agars supplemented with human and sheep blood, and biofilm forming capacity.

Results: Three species of enterococci were identified among invasive isolates: Enterococcus faecalis, Enterococcus faecium, and Enterococcus durans. All endocarditis isolates were biofilm producers. Genes esp, gelE, asa1, ace, hyl, cylB, and cylA were present in 7 (41.2%), 11 (64.7%), 11 (64.7%), 13 (76.5%), 0, 3 (17.6%), and 1 (5.9%) invasive isolate, but none of them could be linked to a particular infection (sepsis or endocarditis). Colonizing isolates proved to have had more virulence factor genes, but the differences were not statistically significant. Members of that group produced a greater amount of biofilm when the ace gene was absent ( p = 0.047). The production of β-hemolysis by noninvasive strains was detected more frequently when agar was supplemented with human blood ( p = 0.021). In general, the presence of either cyl gene on that specific agar was in direct connection with the production of β-hemolysis: cylA ( p = 0.047) or cylB ( p = 0.020).

Conclusion: We have been unable to establish any correlation between invasive isolates and any virulence gene carriage and biofilm formation. β-hemolysis was produced significantly more often by colonizing strains when agar had been supplemented with human blood.

Treatment of Enterococcus faecalis Infective Endocarditis: A Continuing Challenge

Today, Enterococcus faecalis is one of the main causes of infective endocarditis in the world, generally affecting an elderly and fragile population, with a high mortality rate. Enterococci are partially resistant to many commonly used antimicrobial agents such as penicillin and ampicillin, as well as high-level resistance to most cephalosporins and sometimes carbapenems, because of low-affinity penicillin-binding proteins, that lead to an unacceptable number of therapeutic failures with monotherapy. For many years, the synergistic combination of penicillins and aminoglycosides has been the cornerstone of treatment, but the emergence of strains with high resistance to aminoglycosides led to the search for new alternatives, like dual beta-lactam therapy. The development of multi-drug resistant strains of Enterococcus faecium is a matter of considerable concern due to its probable spread to E. faecalis and have necessitated the search of new guidelines with the combination of daptomycin, fosfomycin or tigecycline. Some of them have scarce clinical experience and others are still under investigation and will be analyzed in this review. In addition, the need for prolonged treatment (6–8 weeks) to avoid relapses has forced to the consideration of other viable options as outpatient parenteral strategies, long-acting administrations with the new lipoglycopeptides (dalbavancin or oritavancin), and sequential oral treatments, which will also be discussed.

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.

Risk factors for neurological complications in left-sided infective endocarditis

BACKGROUND AND PURPOSE

Neurological complications following infective endocarditis (IE) directly contribute to long-term morbidity. We examined the risk factors for different neurological complications of left-sided IE.

METHODS

Using a database of consecutive adults admitted to a health system with left-sided IE from 2015 to 2019, the frequency of cerebral infarcts, intraparenchymal hemorrhage, cerebral microbleeds (CMB), mycotic aneurysm, and encephalopathy was determined. Variables with significant differences comparing each neurological complication (p < 0.1) were entered into regression models along with age to determine predictors.

RESULTS

211 patients with mean age 54 (±18) years, and 69 (33%) females were included. Infarcts were found in 118 (56%) patients, intraparenchymal hemorrhage was found in 17 (8%) patients, CMB were found in 58 (27%) patients, mycotic aneurysms were found in 22 (10%) patients, and encephalopathy occurred in 16 (8%) patients. In multivariable models, vegetation size ≥15 mm was associated with a higher risk of infarcts (aOR 2.26, 95% CI (1.12-4.57)), and the presence of a mycotic aneurysm was a risk factor for intraparenchymal hemorrhage (aOR 18.79, 95% CI (3.97-88.97)). Prosthetic valves (aOR 2.89, 95% CI (1.11-7.54)) and Staphylococcus aureus infection (aOR 3.50, 95% CI (1.08-11.36)) were associated with CMB. No risk factors emerged as predictors of encephalopathy.

CONCLUSIONS

Large vegetation size is associated with stroke in patients with IE. Mycotic aneurysms are found at a higher frequency in young patients and are the primary cause of intraparenchymal hemorrhage. CMB may be related to prosthetic valves and Staphylococcus aureus infection.

CroR Regulates Expression of pbp4(5) to Promote Cephalosporin Resistance in Enterococcus faecalis

Enterococcus faecalis is an opportunistic pathogen and a major cause of severe nosocomial infections. Treatment options against enterococcal infections are declining due to the resistance of enterococci to numerous antibiotics. A key risk factor for developing enterococcal infections is treatment with cephalosporin antibiotics, to which enterococci are intrinsically resistant. For susceptible organisms, cephalosporins inhibit bacterial growth by acylating the active site of penicillin-binding proteins (PBPs), key enzymes that catalyze peptidoglycan cross-linking. Two specific PBPs of enterococci, Pbp4(5) and PbpA(2b), exhibit low reactivity toward cephalosporins, allowing these PBPs to cross-link peptidoglycan in the presence of cephalosporins to drive resistance in enterococci, but the mechanisms by which these PBPs are regulated are poorly understood. The CroS/R two-component signal transduction system (TCS) is also required for cephalosporin resistance. Activation of CroS/R by cephalosporins leads to CroR-dependent changes in gene expression. However, the specific genes regulated by CroS/R that are responsible for cephalosporin resistance remain largely unknown. In this study, we characterized CroR-dependent transcriptome remodeling by RNA-seq, identifying pbp4(5) as a CroR regulon member in multiple, diverse lineages of E. faecalis. Through genetic analysis of the pbp4(5) and croR promoters, we uncovered a CroR-dependent regulatory motif. Mutations in this motif to disrupt CroR-dependent upregulation of pbp4(5) in the presence of cell wall stress resulted in a reduction of resistance to cephalosporins in E. faecalis, demonstrating that enhanced production of Pbp4(5) and likely other proteins involved in peptidoglycan biogenesis by the CroS/R system drives enterococcal cephalosporin resistance.

Clinical features and antimicrobial susceptibility of oral bacteria isolated from the blood cultures of patients with infective endocarditis

Background/purpose

The epidemiology of infective endocarditis (IE) is under constant change due to the aging society and increases in antimicrobial-resistant pathogens. However, IE remains severe. This study aimed to review the current clinical characteristics of IE and the antimicrobial susceptibility of oral bacteria (OB) isolated from blood cultures to implement appropriate antimicrobial prophylaxis.

Materials and methods

We retrospectively investigated the clinical features of 180 patients with IE in whom OB and pathogens except OB (eOB) were identified as causative microorganisms via blood cultures. The susceptibility of the OB group to eight antibiotics was examined by broth microdilution.

Results

Among causative microorganisms, the isolation rate of staphylococci was slightly higher than that of OB; however, the difference was not significant (36.7% vs. 33.8%, p = 0.3203). The number of patients with underlying cardiac disease was significantly higher in the OB group than in the eOB group (53.7% vs. 34.1%, p = 0.0113). Only one ampicillin-resistant OB was detected (2.0%). OBs were significantly less susceptible to clarithromycin and azithromycin than to ampicillin (98.0% vs. 66.7% and 98.0% vs. 60.0%, p = 0.0003 and p = 0.0003, respectively). Moreover, OBs were significantly less susceptible to clarithromycin and azithromycin than to clindamycin (66.7% vs. 88.2% and 60.0% vs. 88.2%, p = 0.0301 and p = 0.0217, respectively).

Conclusion

OBs were susceptible to ampicillin. However, the susceptibility of OBs to clarithromycin and azithromycin was significantly lower than that to ampicillin and clindamycin. These results are important and should help decisions regarding guide antimicrobial prophylaxis.

Enterococcus gallinarum causing cervical vertebral osteomyelitis: imagery detecting the process of rapid progression of degeneration-like change in 3 months

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Blood stream infection of Enterococcus gallinarum can cause osteomyelitis.

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X-ray images of vertebral osteomyelitis shows degeneration-like change.

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The degeneration-like change develops much faster than true degenerative change.

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Enterococcus gallinarum osteomyelitis might require longer period for development.

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Patients with persistent neck or back pain with fever should undergo blood cultures.

We present a series of images of X-rays and MRI of vertebral osteomyelitis caused by Enterococcus gallinarum in a 65-year-old patient with persistent neck pain and fever accompanied by preceding transient biliary enzymes elevation. Images detected progression of degeneration-like changes of C5–7 in three months, which is too rapid for true degeneration and relatively slow for vertebral osteomyelitis of common pathogens. Though initial imagery evaluation detected merely degenerative change, the patient was followed up monthly because of persistent fever. Three months later, the images detected the typical imagery of vertebral osteomyelitis i.e., the destruction of vertebral bone: narrowing of intervertebral spaces with focal osteosclerosis and osteolysis on C5–7 became prominent. At this point, consultation to general internal medicine was made. With grade 3 regurgitation murmur, transthoracic echocardiography was performed and revealed 14-mm-in-diameter vegetation on aortic valve. Blood cultures detected Enterococcus gallinarum of which suspected entry was biliary tract.

No previous case reports of Enterococcus gallinarum referred to vertebral osteomyelitis. While this case showed a typical clinical course of infective endocarditis, the course of progression of vertebral osteomyelitis and perhaps endocarditis was much slower comparing to common pathogens. This might reflect the relatively non-life-threatening features of this organism. Enterococcus gallinarum shows mild resistance to vancomycin and cephalosporins, initial therapy sometimes fails. Enterococcus gallinarum should be newly added to pathogenic candidates of vertebral osteomyelitis especially when feverish patients shows back or neck pain with preceding biliary tract problems.

Enterococcus durans Cardiac Implantable Electronic Device Lead Infection and Review of Enterococcus durans Endocarditis Cases

Introduction: Cardiac implantable electronic device (CIED) infections present a growing problem in medicine due to a significant increase in the number of implanted devices and the age of the recipient population. Enterococcus spp. are Gram-positive, facultative anaerobic, lactic acid bacteria; they are relatively common pathogens in humans, but uncommon as the cause of CIED lead infections. Only eight cases of Enterococcus durans endocarditis have been reported in the literature thus far; however, there are no reported cases of Enterococcus durans CIED lead infection. Case presentation: A 58-year-old gentleman with a previously implanted St. Jude Medical single-chamber implantable cardioverter–defibrillator (ICD) due to tachy/brady arrhythmias presented with nonspecific constitutional symptoms (i.e., low-grade fevers, chills, fatigue), and was found to have innumerable bilateral pulmonary nodules via computed tomography angiography of the chest. Many of these pulmonary nodules were cavitated and highly concerning for septic pulmonary emboli and infarcts. Within 24 h from presentation, blood cultures in all four culture bottles grew ampicillin- and vancomycin-susceptible Enterococcus durans. Transthoracic echocardiogram confirmed vegetations on the ICD lead in the right ventricle. The patient underwent laser extraction of the ICD lead with generator removal and recovered completely after a 6-week intravenous antibiotic course. Conclusion: To our knowledge, this is the first report of CIED lead infection caused by Enterococcus durans. In this case, management with antibiotics along with ICD lead extraction led to complete recovery. Clinicians should be aware of this rare but potentially devastating infection in patients with native and artificial valves, but also in those with CIEDs.

Potential Advances of Adjunctive Hyperbaric Oxygen Therapy in Infective Endocarditis

Patients with infective endocarditis (IE) form a heterogeneous group by age, co-morbidities and severity ranging from stable patients to patients with life-threatening complications with need for intensive care. A large proportion need surgical intervention. In-hospital mortality is 15-20%. The concept of using hyperbaric oxygen therapy (HBOT) in other severe bacterial infections has been used for many decades supported by various preclinical and clinical studies. However, the availability and capacity of HBOT may be limited for clinical practice and we still lack well-designed studies documenting clinical efficacy. In the present review we highlight the potential beneficial aspects of adjunctive HBOT in patients with IE. Based on the pathogenesis and pathophysiological conditions of IE, we here summarize some of the important mechanisms and effects by HBOT in relation to infection and inflammation in general. In details, we elaborate on the aspects and impact of HBOT in relation to the host response, tissue hypoxia, biofilm, antibiotics and pathogens. Two preclinical (animal) studies have shown beneficial effect of HBOT in IE, but so far, no clinical study has evaluated the feasibility of HBOT in IE. New therapeutic options in IE are much needed and adjunctive HBOT might be a therapeutic option in certain IE patients to decrease morbidity and mortality and improve the long-term outcome of this severe disease.

Ampicillin plus ceftriaxone therapy against Enterococcus faecalis endocarditis: A case report, guidelines considerations, and literature review

Enterococcus faecalis infective endocarditis (EFIE) continues to be a very serious disease, showing considerable morbidity and mortality rates which are influenced by the spread of multi-drug resistant strains occurred in the last decades. Although aminoglycosides were considered the treatment of choice of EIFE, in recent years several studies have investigated alternative therapeutic approaches, including combinations of beta-lactams, mainly because of the aminoglycoside-renowned nephrotoxicity and the widespread development of high-level aminoglycosides resistance (HLAR). In this scenario, we reported a case involving a prosthetic valve infective endocarditis caused by an aminoglycoside-resistant E. faecalis strain which was successfully treated with ampicillin plus ceftriaxone despite the presence of artificial heart valve and the patient’s severe clinical conditions.

Changing spectrum of infective endocarditis in India: An 11-year experience from an academic hospital in North India

Objective

Several studies have demonstrated a shift in the spectrum of infective endocarditis (IE) in the developed world. We aimed to investigate whether demographic and microbiologic characteristics of IE have changed in India.

Design

A retrospective analysis of patients with in north India between 2010 and 2020.

Methods

The clinical and laboratory profiles of 199 IE admitted to an academic hospital patients who met the modified Duke criteria for definite IE were analysed.

Results

The mean age was 34 years, and 84% were males. The main predisposing conditions were injection drug use (IDU) (n = 71, 35.7%), congenital heart disease (n = 46, 21.6%), rheumatic heart disease (n = 25, 12.5%), and prosthetic device (n = 19, 9.5%). 17.1% of patients developed IE without identified predispositions. Among 64.3% culture-positive cases, the most prevalent causative pathogens were Staphylococcus aureus (46.1%), viridans streptococci (7.0%), enterococci (6.0%), coagulase-negative staphylococci (5.5%), gram negative bacilli (5.5%), polymicrobial (5.5%), and Candida (1.0%). The tricuspid (30.3%), mitral (25.6%), and aortic (21.6%) valves were the most common sites of infection, and 60.3% had large vegetations (>10 mm). Systemic embolization occurred in 55.3% of patients at presentation. Cardiac surgery was required for 13.1%. In-hospital mortality was 17.1% and was associated with prosthetic devices (p-value, 0.001), baseline leucocytosis (p-value, 0.036) or acute kidney injury (p-value, 0.001), and a microbial etiology of gram negative bacilli or enterococci (p-value, 0.005).

Conclusion

IDU is now the most important predisposition for IE in India, and S. aureus has become the leading cause of native valve endocarditis with or without IDU.

Ampicillin Plus Ceftriaxone Regimen against Enterococcus faecalis Endocarditis: A Literature Review

Enterococcus faecalis infective endocarditis (EFIE) continues to represent a potentially fatal infectious disease characterized by elevated morbidity and mortality. Despite advances in antimicrobial therapy, changing demographics and the reduced availability of useful antibiotics combined with the dissemination of multi-drug resistant strains, the mortality rate remained unchanged in the last decades. Nowadays, optimizing the antibiotic regimen is still of paramount importance. Historically, aminoglycosides were considered as a cornerstone for treatment even though their use is associated with a high risk of kidney failure. It is against this background that, in recent years, several studies have been carried in order to assess the validity of alternative therapeutic approaches, including combinations of beta-lactams, that, acting synergistically, have yielded useful results in different clinical settings. In this scenario, we searched and critically report clinical studies assessing the efficacy and safety of double beta-lactam therapy in treating EFIE.

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.

Development and validation of a dosing nomogram for amoxicillin in infective endocarditis

BACKGROUND

Amoxicillin is the first-line treatment for streptococcal or enterococcal infective endocarditis (IE) with a dose regimen adapted to weight.

OBJECTIVES

Covariates influencing pharmacokinetics (PK) of amoxicillin were identified in order to develop a dosing nomogram based on identified covariates for individual adaptation.

PATIENTS AND METHODS

Patients treated with amoxicillin administered by continuous infusion for IE were included retrospectively. The population PK analysis was performed using the Pmetrics package for R (NPAG algorithm). Influence of weight, ideal weight, height, BMI, body surface area, glomerular filtration rate adapted to the body surface area and calculated by the CKD-EPI method (mL/min), additional ceftriaxone treatment and serum protein level on amoxicillin PK was tested. A nomogram was then developed to determine the daily dose needed to achieve a steady-state free plasma concentration above 4× MIC, 100% of the time, without exceeding a total plasma concentration of 80 mg/L.

RESULTS

A total of 160 patients were included. Population PK analysis was performed on 540 amoxicillin plasma concentrations. A two-compartment model best described amoxicillin PK and the glomerular filtration rate covariate significantly improved the model when included in the calculation of the elimination constant Ke.

CONCLUSIONS

This work allowed the development of a dosing nomogram that can help to increase achievement of the PK/pharmacodynamic targets in IE treated with amoxicillin.

Prevalence of Virulence Genes and Antibiotic Resistance Pattern in Enterococcus Faecalis Isolated from Urinary Tract Infection in Shahrekord, Iran

Background

This study aims to specify the antimicrobial resistance pattern and virulence genes of Enterococcus faecalis isolated from urinary tract infections in Shahrekord, Iran.

Methods

Urine samples of 1000 people suspected of having urinary tract infections referred to Shahrekord medical diagnostic laboratories were examined. Biofilm assays were performed by microtiter plate test through reading the OD490. Polymerase Chain Reaction (PCR) was applied to study the virulence factors.

Results

Enterococcus faecalis was detected in 60 samples. After performing microbiological tests, all samples were positive in the molecular analysis. Strong, moderate and weak biofilm reactions reported 66.67%, 25%, and 8.33% respectively. The most resistance reported to cotrimoxazole, vancomycin and amikacin and the lowest resistance to nitrofurantoin (8.33%) was reported. Statistical analysis with Fisher's exact test showed a statistically significant relationship between biofilm production and resistance to cotrimoxazole, vancomycin and cefotaxime. Prevalence of efe A, ace, gel E, esp, cyl M, agg, cyl A and cyl B in strong biofilm formation isolates was reported 100%, 87.5%, 82%, 62.5%, 55%, 37.5% 25% and 22.5% respectively. There was a significant relationship between the frequency of efa A and strong biofilm reaction.

Conclusion

The presence of E. faecalis strains resistant to co-trimoxazole and vancomycin and present of some virulence factors is alarming the researchers. Since antibiotic resistance genes are probably transmitted among enterococci, and Staphylococci, controlling infections made by enterococci as well as the appropriate administration of antibiotics could treat the nosocomial infections effectively.

Evolution of epidemiological characteristics of infective endocarditis in Greece

OBJECTIVE

The clinical profile, management and outcome of infective endocarditis (IE) may be influenced by socioeconomic issues.

METHODS

A nationwide prospective study evaluated IE during the era of deep economic crisis in Greece. Epidemiological data and factors associated with 60-day mortality were analyzed through descriptive statistics, logistic and Cox-regression models.

RESULTS

Among 224 patients (male 72.3%, mean age 62.4 years), Staphylococcus aureus (n = 62; methicillin-resistant S. aureus (MRSA) 33.8%) predominated in the young without impact on mortality (p = 0.593), whilst Enterococci (n = 36) predominated in the elderly. Complications of IE were associated with mortality: heart failure [OR 2.415 (95% CI: 1.159-5.029), p = 0.019], stroke [OR 3.206 (95% CI: 1.190-8.632), p = 0.018] and acute kidney injury [OR 2.283 (95% CI: 1.085-4.805), p = 0.029]. A 60-day survival benefit was solely related to cardiac surgery for IE during hospitalization [HR 0.386 (95% CI: 0.165-0.903), p = 0.028] and compliance with antimicrobial treatment guidelines [HR 0.487 (95% CI: 0.259-0.916), p = 0.026]. Compared with a previous country cohort study, history of rheumatic fever and native valve predisposition had declined, whilst underlying renal disease and right-sided IE had increased (p < 0.0001); HIV infection had emerged (p = 0.002). No difference in rates of surgery and outcome was assessed.

CONCLUSIONS

A country-wide survey of IE highlighted emergence of HIV, right-sided IE and predominance of MRSA in the youth during a severe socioeconomic crisis. Compliance with treatment guidelines promoted survival.

Does over a century of aerobic phage work provide a solid framework for the study of phages in the gut?

Bacterial viruses (bacteriophages, phages) of the gut have increasingly become a focus in microbiome studies, with an understanding that they are likely key players in health and disease. However, characterization of the virome remains largely based on bioinformatic approaches, with the impact of these viromes inferred based on a century of knowledge from aerobic phage work. Studying the phages infecting anaerobes is difficult, as they are often technically demanding to isolate and propagate. In this review, we primarily discuss the phages infecting three well-studied anaerobes in the gut: Bifidobacterium, Clostridia and Bacteroides, with a particular focus on the challenges in isolating and characterizing these phages. We contrast the lessons learned from these to other anaerobic work on phages infecting facultative anaerobes of the gut: Enterococcus and Lactobacillus. Phages from the gut do appear to adhere to the lessons learned from aerobic work, but the additional challenges of working on them has required ingenious new approaches to enable their study. This, in turn, has uncovered remarkable biology likely underpinning phage-host relationships in many stable environments.

Role of Cardiac Macrophages on Cardiac Inflammation, Fibrosis and Tissue Repair

The immune system plays a pivotal role in the initiation, development and resolution of inflammation following insult or damage to organs. The heart is a vital organ which supplies nutrients and oxygen to all parts of the body. Heart failure (HF) has been conventionally described as a disease associated with cardiac tissue damage caused by systemic inflammation, arrhythmia and conduction defects. Cardiac inflammation and subsequent tissue damage is orchestrated by the infiltration and activation of various immune cells including neutrophils, monocytes, macrophages, eosinophils, mast cells, natural killer cells, and T and B cells into the myocardium. After tissue injury, monocytes and tissue-resident macrophages undergo marked phenotypic and functional changes, and function as key regulators of tissue repair, regeneration and fibrosis. Disturbance in resident macrophage functions such as uncontrolled production of inflammatory cytokines, growth factors and inefficient generation of an anti-inflammatory response or unsuccessful communication between macrophages and epithelial and endothelial cells and fibroblasts can lead to aberrant repair, persistent injury, and HF. Therefore, in this review, we discuss the role of cardiac macrophages on cardiac inflammation, tissue repair, regeneration and fibrosis.

Late Prosthetic Valve Infective Endocarditis by Enterococcus durans

Enterococcus durans is an extremely rare cause of infective endocarditis. We have reported the first case where a 56-year-old female presented with late prosthetic valve infective endocarditis on a mechanical mitral valve. Medical management failed and eventually lead to the demise of the patient.

Epidemiology and risk factors of infective endocarditis in a tertiary hospital in China from 2007 to 2016

Background

To explore the trends in epidemiology and the risk factors related to the prognosis of infective endocarditis in a tertiary hospital over the past ten years.

Methods

A retrospective cohort study was performed. A total of 407 consecutive patients who were admitted with infective endocarditis were included. The clinical characteristics and the risk factors related to the prognosis of infective endocarditis during this period were analyzed.

Results

A total of 407 patients with infective endocarditis were included, the average age was 48 ± 16 years old with an increasing trend and in-hospital mortality rate was 10.6% and one-year mortality rate was 11.3%. Among patients with underlying heart disease, congenital heart disease was the most common (25.8%), followed by rheumatic heart disease (17.0%) which showed a decreased trend during this period (P < 0.001). There were 222(54.5%) patients with positive blood cultures results and Streptococci (24.6%) was the main pathogens with an increasing trend. There were 403 patients (99%) with surgical indications, but only 235 patients (57.7%) received surgical treatment. Hemodialysis (P = 0.041, OR = 4.697, 95% CI 1.068–20.665), pulmonary hypertension (P = 0.001, OR = 5.308, 95% CI 2.034–13.852), Pitt score ≥ 4 (P < 0.001, OR = 28.594, 95% CI 5.561–148.173) and vegetation length>30 mm (P = 0.011, OR = 13.754, 95% CI 1.832–103.250) were independent risk factors for in-hospital mortality.

Conclusions

There were no significant changes in the overall incidence of infective endocarditis, but the clinical features of infective endocarditis had slightly changed during the past ten years. Streptococci infective endocarditis was still the predominant. Patients with hemodialysis, pulmonary hypertension, Pitt score ≥ 4 and vegetation length>30 mm had an worse in-hospital outcome.

Prevalence of Infective Endocarditis in Enterococcus faecalis Bacteremia

BACKGROUND

Enterococcus faecalis is the third most frequent cause of infective endocarditis (IE). Despite this, no systematic prospective echocardiography studies have examined the prevalence of IE in patients with E. faecalis bacteremia.

OBJECTIVES

This study sought to determine the prevalence of IE in patients with E. faecalis bacteremia. The secondary objective was to identify predictors of IE.

METHODS

From January 1, 2014, to December 31, 2016, a prospective multicenter study was conducted with echocardiography in consecutive patients with E. faecalis bacteremia. Predictors of IE were assessed using multivariate logistic regression with backward elimination.

RESULTS

A total of 344 patients with E. faecalis bacteremia were included, all examined using echocardiography, including transesophageal echocardiography in 74% of the cases. The patients had a mean age of 74.2 years, and 73.5% were men. Definite endocarditis was diagnosed in 90 patients, resulting in a prevalence of 26.1 ± 4.6% (95% confidence interval [CI]). Risk factors for IE were prosthetic heart valve (odds ratio [OR]: 3.93; 95% CI: 1.76 to 8.77; p = 0.001), community acquisition (OR: 3.35; 95% CI: 1.74 to 6.46; p < 0.001), ≥3 positive blood culture bottles (OR: 3.69; 95% CI: 1.88 to 7.23; p < 0.001), unknown portal of entry (OR: 2.36; 95% CI: 1.26 to 4.40; p = 0.007), monomicrobial bacteremia (OR: 2.73; 95% CI: 1.23 to 6.05; p = 0.013), and immunosuppression (OR: 2.82; 95% CI: 1.20 to 6.58; p = 0.017).

CONCLUSIONS

This study revealed a high prevalence of 26% definite IE in patients with E. faecalis bacteremia, suggesting that echocardiography should be considered in all patients with E. faecalis bacteremia.

A Contemporary Picture of Enterococcal Endocarditis

BACKGROUND

Enterococcal endocarditis (EE) is a growing entity in Western countries. However, quality data from large studies is lacking.

OBJECTIVES

The purpose of this study was to describe the characteristics and analyze the prognostic factors of EE in the GAMES cohort.

METHODS

This was a post hoc analysis of a prospectively collected cohort of patients from 35 Spanish centers from 2008 to 2016. Characteristics and outcomes of 516 cases of EE were compared with those of 3,308 cases of nonenterococcal endocarditis (NEE). Logistic regression and Cox proportional hazards regression analysis were performed to investigate risk factors for in-hospital and 1-year mortality, as well as relapses.

RESULTS

Patients with EE were significantly older; more frequently presented chronic lung disease, chronic heart failure, prior endocarditis, and degenerative valve disease; and had higher median age-adjusted Charlson score. EE more frequently involved the aortic valve and prosthesis (64.3% vs. 46.7%; p < 0.001; and 35.9% vs. 28.9%; p = 0.002, respectively) but less frequently pacemakers/defibrillators (1.5% vs. 10.5%; p < 0.001), and showed higher rates of acute heart failure (45% vs. 38.3%; p = 0.005). Cardiac surgery was less frequently performed in EE (40.7% vs. 45.9%; p = 0.024). No differences in in-hospital and 1-year mortality were found, whereas relapses were significantly higher in EE (3.5% vs. 1.7%; p = 0.035). Increasing Charlson score, LogEuroSCORE, acute heart failure, septic shock, and paravalvular complications were risk factors for mortality, whereas prior endocarditis was protective and persistent bacteremia constituted the sole risk factor for relapse.

CONCLUSIONS

Besides other baseline and clinical differences, EE more frequently affects prosthetic valves and less frequently pacemakers/defibrillators. EE presents higher rates of relapse than NEE.

Cardiovascular implantable electronic device infections due to enterococcal species: Clinical features, management, and outcomes

BACKGROUND

Enterococcal cardiovascular implantable electronic device (CIED) infections are not well characterized.

METHODS

Data from the Multicenter Electrophysiologic Device Infection Cohort, a prospective study of CIED infections, were used for descriptive analysis of adults with enterococcal CIED infections.

RESULTS

Of 433 patients, 21 (4.8%) had enterococcal CIED infection. Median age was 71 years. Twelve patients (57%) had permanent pacemakers, five (24%) implantable cardioverter defibrillators, and four (19%) biventricular devices. Median time from last procedure to infection was 570 days. CIED-related bloodstream infections occurred in three patients (14%) and 18 (86%) had infective endocarditis (IE), 14 (78%) of which were definite by the modified Duke criteria. IE cases were classified as follows: valvular IE, four; lead IE, eight; both valve and lead IE, six. Vegetations were demonstrated by transesophageal echocardiography in 17 patients (81%). Blood cultures were positive in 19/19 patients with confirmed results. The most common antimicrobial regimen was penicillin plus an aminoglycoside (33%). Antibiotics were given for a median of 43 days. Only 14 patients (67%) underwent device removal. There was one death during the index hospitalization with four additional deaths within 6 months (overall mortality 24%). There were no relapses.

CONCLUSIONS

Enterococci caused 4.8% of CIED infections in our cohort. Based on the late onset after device placement or manipulation, most infections were likely hematogenous in origin. IE was the most common infection syndrome. Only 67% of patients underwent device removal. At 6 months follow-up, no CIED infection relapses had occurred, but overall mortality was 24%.

Prevalence of colorectal disease in Enterococcus faecalis infective endocarditis: results of an observational multicenter study

INTRODUCTION AND OBJECTIVES

The aim of this study was to determine the prevalence of colorectal disease in Enterococcus faecalis infective endocarditis (EFIE) patients.

METHODS

An observational, retrospective, multicenter study was performed at 4 referral centers. From the moment that a colonoscopy was systematically performed in EFIE in each participating hospital until October 2018, we included all consecutive episodes of definite EFIE in adult patients. The outcome was an endoscopic finding of colorectal disease potentially causing bacteremia.

RESULTS

A total of 103 patients with EFIE were included; 83 (81%) were male, the median age was 76 [interquartile range 67-82] years, and the median age-adjusted Charlson comorbidity index was 5 [interquartile range 4-7]. The presumed sources of infection were unknown in 63 (61%), urinary in 20 (19%), gastrointestinal in 13 (13%), catheter-related bacteremia in 5 (5%), and others in 2 (2%). Seventy-eight patients (76%) underwent a colonoscopy, and 47 (60%) had endoscopic findings indicating a potential source of bacteremia. Thirty-nine patients (83%) had a colorectal neoplastic disease, and 8 (17%) a nonneoplastic disease. Of the 45 with an unknown portal of entry who underwent a colonoscopy, gastrointestinal origin was identified in 64%. In the subgroup of 25 patients with a known source of infection and a colonoscopy, excluding those with previously diagnosed colorectal disease, 44% had colorectal disease.

CONCLUSIONS

Performing a colonoscopy in all EFIE patients, irrespective of the presumed source of infection, could be helpful to diagnose colorectal disease in these patients and to avoid a new bacteremia episode (and eventually infective endocarditis) by the same or a different microorganism.

In search of novel protein drug targets for treatment of Enterococcus faecalis infections

Enterococcus faecalis (Ef) is one of the major pathogens involved in hospital-acquired infections. It can cause nosocomial bacteremia, surgical wound infection, and urinary tract infection. It is important to mention here that Ef is developing resistance against many commonly occurring antibiotics. The occurrence of multidrug resistance (MDR) and extensive-drug resistance (XDR) is now posing a major challenge to the medical community. In this regard, to combat the infections caused by Ef, we have to look for an alternative. Rational structure-based drug design exploits the three-dimensional structure of the target protein, which can be unraveled by various techniques such as X-ray crystallography or nuclear magnetic resonance (NMR) spectroscopy. In this review, we have discussed the complete picture of Ef infections, the possible treatment available at present, and the alternative treatment options to be explored. This study will help in better understanding of novel biological targets against Ef and the compounds, which are likely to bind with these targets. Using these detailed structural informations, rational structure-based drug design is achievable and tight inhibitors against Ef can be prepared.

The Many Faces of Bacterium-Endothelium Interactions during Systemic Infections

A wide variety of pathogens reach the circulatory system during viral, parasitic, fungal, and bacterial infections, causing clinically diverse pathologies. Such systemic infections are usually severe and frequently life-threatening despite intensive care, in particular during the age of antibiotic resistance. Because of its position at the interface between the blood and the rest of the organism, the endothelium plays a central role during these infections. Using several examples of systemic infections, we explore the diversity of interactions between pathogens and the endothelium. These examples reveal that bacterial pathogens target specific vascular beds and affect most aspects of endothelial cell biology, ranging from cellular junction stability to endothelial cell proliferation and inflammation.

Enterococcus gallinarum Causing Native Valve Endocarditis

Endocarditis due to Enterococcus gallinarum is a rare condition, usually affecting older patients. The most frequent source of infection is the gastrointestinal or genitourinary tracts; it frequently involves the aortic valve and tends to produce heart failure.

We present a case of Enterococcus gallinarum endocarditis developing on a normal native heart valve.

Enterococcus gallinarum is intrinsically resistant to vancomycin. Antibiotic susceptibility patterns indicate that most isolates are penicillin and ampicillin-susceptible.

Native aortic versus mitral valve infective endocarditis: a nationwide registry study

Background

Native aortic and mitral valve infective endocarditis (AVE and MVE, respectively) are usually grouped together as left-sided native valve infective endocarditis (LNVE), while the differences between AVE and MVE have not yet been properly investigated. We aimed to compare AVE and MVE in regard to patient characteristics, microbiology and determinants of survival.

Methods

We conducted a retrospective study using the Swedish national registry on infective endocarditis, which contains nationwide patient data. The study period was 2007‒2017, and included cases were patients who had either AVE or MVE.

Results

We included 649 AVE and 744 MVE episodes. Staphylococcus aureus was more often the causative pathogen in MVE (41% vs 31%, p<0.001), whereas enterococci were more often the causative pathogen in AVE (14% vs 7.4%, p<0.001). Perivalvular involvement occurred more frequently in AVE (8.5% vs 3.5%, p<0.001) and brain emboli more frequently in MVE (21% vs 13%, p<0.001). Surgery for IE was performed more often (35% vs 27%, p<0.001) and sooner after diagnosis (6.5 days vs 9 days, p=0.012) in AVE than in MVE. Several risk predictors differed between the two groups.

Conclusions

The microbiology seems to differ between AVE and MVE. The causative pathogen was not associated with mortality in AVE. The between-group differences regarding clinical presentation and predictors of survival indicate that it may be important to differentiate AVE from MVE in the treatment of LNVE.

Management Considerations in Infective Endocarditis: A Review

IMPORTANCE

Infective endocarditis occurs in approximately 15 of 100 000 people in the United States and has increased in incidence. Clinicians must make treatment decisions with respect to prophylaxis, surgical management, specific antibiotics, and the length of treatment in the setting of emerging, sometimes inconclusive clinical research findings.

OBSERVATIONS

Community-associated infective endocarditis remains the predominant form of the disease; however, health care accounts for one-third of cases in high-income countries. As medical interventions are increasingly performed on older patients, the disease incidence from cardiac implanted electronic devices is also increasing. In addition, younger patients involved with intravenous drug use has increased in the past decade and with it the proportion of US hospitalization has increased to more than 10%. These epidemiological factors have led to Staphylococcus aureus being the most common cause in high-income countries, accounting for up to 40% of cases. The mainstays of diagnosis are still echocardiography and blood cultures. Adjunctive imaging such as cardiac computed tomographic and nuclear imaging can improve the sensitivity for diagnosis when echocardiography is not conclusive. Serological studies, histopathology, and polymerase chain reaction assays have distinct roles in the diagnosis of infective endocarditis when blood culture have tested negative with the highest yield obtained from serological studies. Increasing antibiotic resistance, particularly to S aureus, has led to a need for different antibiotic treatment options such as newer antibiotics and combination therapy regimens. Surgery can confer a survival benefit to patients with major complications; however, the decision to pursue surgery must balance the risks and benefits of operations in these frequently high-risk patients.

CONCLUSIONS AND RELEVANCE

The epidemiology and management of infective endocarditis are continually changing. Guidelines provide specific recommendations about management; however, careful attention to individual patient characteristics, pathogen, and risk of sequela must be considered when making therapeutic decisions.

Comparison of Dual β-Lactam therapy to penicillin-aminoglycoside combination in treatment of Enterococcus faecalis infective endocarditis

BACKGROUND

Dual β-lactam therapy and a penicillin-aminoglycoside combination are first line regimens in the treatment of penicillin-susceptible Enterococcus faecalis infective endocarditis (EFIE). Our aim was to compare ampicillin plus ceftriaxone (A+C) to ampicillin plus gentamicin (A+G) in the treatment of EFIE.

METHODS

This was a retrospective cohort study of adults (≥18 years) patients diagnosed with EFIE at Mayo Clinic campuses in Rochester, Minnesota, and Phoenix, Arizona and treated with either A+C or A+G. Main outcome measurements were 1 year mortality, nephrotoxicity, and EFIE relapse rates.

RESULTS

Eighty-five cases of EFIE were included in this investigation. The majority (n=67, 79%) of patients received A+G while 18 (21%) patients received A+C as initial treatment. On admission, patients who received A+C had a higher Charlson Comorbidity Index (median [IQR], 4 [3, 4 vs. 2 [1, 4]; P=.008) and a higher baseline serum creatinine (median [IQR], 1.2 [0.9, 1.6] vs. 0.9 [0.8, 1.2] mg/dL, P=.020). The 1 year mortality rates were similar for both treatment groups, 17% vs. 17%, P=.982. Each group had 1 case of relapsing EFIE. Patients who received A+G had worse kidney function outcome demonstrated by a greater increase in serum creatinine at end of therapy (median [IQR] difference, +0.4 [0.2, 0.8] vs. -0.2 [-0.3, 0.1] mg/dL, P≤.001).

CONCLUSION

A+C appears to be a safe and efficacious regimen in the treatment of EFIE. Patients treated with A+C had lower rates of nephrotoxicity and no differences in relapse rate and 1-year mortality as compared to that of the A+G group.

Mechanistic Features of the Enterococcal pCF10 Sex Pheromone Response and the Biology of Enterococcus faecalis in Its Natural Habitat

Conjugative transfer of plasmids in enterococci is promoted by intercellular communication using peptide pheromones. The regulatory mechanisms that control transfer have been extensively studied in vitro However, the complicated systems that regulate the spread of these plasmids did not evolve in the laboratory test tube, and remarkably little is known about this form of signaling in the intestinal tract, the primary niche of these organisms. Because the evolution of Enterococcus faecalis strains and their coresident pheromone-inducible plasmids, such as pCF10, have occurred in the gastrointestinal (GI) tract, it is important to consider the functions controlled by pheromones in light of this ecology. This review summarizes our current understanding of the pCF10-encoded pheromone response. We consider how selective pressures in the natural environment may have selected for the complex and very tightly regulated systems controlling conjugation, and we pay special attention to the ecology of enterococci and the pCF10 plasmid as a gut commensal. We summarize the results of recent studies of the pheromone response at the single-cell level, as well as those of the first experiments demonstrating a role for pheromone signaling in plasmid transfer and in GI tract competitive fitness. These results will serve as a foundation for further in vivo studies that could lead to novel interventions to reduce opportunistic infections and the spread of antibiotic resistance.

Infective endocarditis in Western Norway: a 20-year retrospective survey

BACKGROUND

To investigate epidemiological trends of infective endocarditis (IE) in western Norway a retrospective study was performed.

METHODS

Characteristics of 706 IE admissions from 1996 to 2005 and 2006 to 2015 were analysed and compared using the Chi-square test for categorical variables and the t-test for age. Survival was analysed by multiple Cox regression and reported by the hazard ratio (HR).

RESULTS

Mean annual incidence rates increased from 4.6 to 7.4 per 100,000 inhabitants (rate ratio: 1.97, 95% confidence interval: 1.52-2.56, p < .001). Non-viridans streptococci, enterococci and Staphylococcus aureus (S. aureus), were all independently associated with increased mortality. The frequency of IE caused by enterococci increased from 3.7 to 13.0% (p < .001). The proportion of intravenous drug users (IVDU) increased from 16.5 to 23.5% (p = .015) and had increasing aortic valve involvement (p = .023). Prosthetic valve endocarditis (PVE) constituted 30% of IE cases in both decades with biological PVE increasing from 9.4 to 22.1% (p < .001) and mechanical PVE decreasing from 18.7 to 8.9% (p < .001). In the last decade, valve replacement surgery was performed in 37.6% of the patients, of which 85.5% received a bioprosthesis.

CONCLUSIONS

The incidence of IE increased significantly. Non-viridans streptococci, enterococci and S. aureus were all significantly associated with increased mortality. The increased number of enterococcal IE and the increased number of IVDUs with left-sided IE constituted new challenges. Biological implants were preferred in a majority of patients requiring surgery.

Stochasticity in the enterococcal sex pheromone response revealed by quantitative analysis of transcription in single cells

In Enterococcus faecalis, sex pheromone-mediated transfer of antibiotic resistance plasmids can occur under unfavorable conditions, for example, when inducing pheromone concentrations are low and inhibiting pheromone concentrations are high. To better understand this paradox, we adapted fluorescence in situ hybridization chain reaction (HCR) methodology for simultaneous quantification of multiple E. faecalis transcripts at the single cell level. We present direct evidence for variability in the minimum period, maximum response level, and duration of response of individual cells to a specific inducing condition. Tracking of induction patterns of single cells temporally using a fluorescent reporter supported HCR findings. It also revealed subpopulations of rapid responders, even under low inducing pheromone concentrations where the overall response of the entire population was slow. The strong, rapid induction of small numbers of cells in cultures exposed to low pheromone concentrations is in agreement with predictions of a stochastic model of the enterococcal pheromone response. The previously documented complex regulatory circuitry controlling the pheromone response likely contributes to stochastic variation in this system. In addition to increasing our basic understanding of the biology of a horizontal gene transfer system regulated by cell-cell signaling, demonstration of the stochastic nature of the pheromone response also impacts any future efforts to develop therapeutic agents targeting the system. Quantitative single cell analysis using HCR also has great potential to elucidate important bacterial regulatory mechanisms not previously amenable to study at the single cell level, and to accelerate the pace of functional genomic studies.

Substance P enhances lactic acid and tyramine production in Enterococcus faecalis V583 and promotes its cytotoxic effect on intestinal Caco-2/TC7 cells

Background

Enterococcus faecalis, generally considered as a saprophytic bowel commensal, has recently emerged as an important nosocomial pathogen causing severe urinary tract infections, surgical wound infections, bacteremia, and bacterial endocarditis. This bacterium is capable of forming biofilms on various surfaces and its high level of antibiotic resistance contributes to its pathogenicity. The aim of this study was to evaluate the effect on E. faecalis, of Substance P (SP), an antimicrobial peptide that is produced in the gut and skin.

Results

We found that SP did not have antibacterial activity against E. faecalis V583 (MIC >1000 µg/ml). Conversely, SP stimulated aggregation, hydrophobicity, lactic acid and tyramine production in this bacterium. The cytotoxicity and bacterial translocation were also accelerated when E. faecalis V583 were pretreated with SP before infection of intestinal Caco-2/TC7 cells.

Conclusion

SP can modulate the physiology of E. faecalis. Extensive studies are now needed to screen within the human microbiota which bacteria are responsive to host molecules, and to identify their sensors.

The role of side stream dark field microvasculature imaging in a rare case of vancomycin-resistant enterococcal endocarditis complicated by heparin-induced thrombocytopenia

Sidestream dark field (SDF) imaging allows direct visualization of microvascular architecture and function. We examine the role of an SDF imaging device in visualizing the sub-lingual microvasculature as a surrogate for splanchnic microperfusion. We demonstrate good correlation between current monitoring techniques and the SDF imaging device in a rare case of vancomycin-resistant enterococcal (VRE) sepsis along with heparin-induced thrombocytopenia (HIT). To the best of our knowledge, VRE endocarditis with concurrent HIT has not been described in literature. The role of SDF imaging may predict the earlier need for escalation of care, improving morbidity and mortality.

Synthesis, in vitro anticancer and antibacterial activities and in silico studies of new 4-substituted 1,2,3-triazole-coumarin hybrids

The 4-substituted 1,2,3-triazole core in designed coumarin hybrids (4-35) with diverse physicochemical properties was introduced by eco-friendly copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition under microwave irradiation. Coumarin-1,2,3-triazole-benzofused heterocycle hybrids emerged as the class of compounds exhibiting the highest antiproliferative activity. The strong relationship between lipophilicity and antiproliferative activities was observed indicating that lipophilic 1,2,3-triazole-coumarin hybrids containing phenylethyl (13), 3,5-difluorophenyl (14), 5-iodoindole (30) and benzimidazole (33 and 35) subunits showed the most potent cytostatic effects. The 7-methylcoumarin-1,2,3-triazole-2-methylbenzimidazole hybrid 33 can be highlighted as a lead that exerted the highest cytotoxicity against hepatocellular carcinoma HepG2 cells with IC₅₀ value of 0.9 μM and high selectivity (SI = 50). This compound induced cell death, mainly due to early apoptosis. Strong antiproliferative effect of 33 could be associated with its inhibition of 5-lipoxygenase (5-LO) activity and perturbation of sphingolipid signaling by interfering with intracellular acid ceramidase (ASAH) activity. Outlined considerable effect of lipophilicity on antiproliferative activity was not observed for antibacterial activity. The compounds with p-pentylphenyl (17), 2-chloro-4-fluorobenzenesulfonamide (23) and dithiocarbamate (27) moiety were endowed with high selectivity against Enterococcus species. Moreover, these compounds were found to be superior in inhibiting the growth of clinically isolated vancomycin-resistant Enterococcus faecium, while the reference antibiotics exhibited the lack of activity. Our findings indicate that coumarin-1,2,3-triazole could be used as the scaffold for structural optimization to develop more potent and selective anticancer agents and encourage further development of novel structurally related analogs of 33 as more effective 5-LO inhibitors.

Incidence of virulence determinants in clinical Enterococcus faecalis and Enterococcus faecium isolates collected in Bulgaria

Objectives

To evaluate the prevalence of some virulence genes among 510 clinical Enterococcus spp. isolates and to assess the association of those genes with the species, infection site, and patient group (inpatients/outpatients).

Methods

Adhesins genes (aggregation substances agg and asa1 of Enterococcus faecalis and Enterococcus faecium, respectively), enterococcal surface protein (esp), endocarditis-specific antigen A (efaA), collagen-binding proteins (ace/acm)); invasins (hyaluronidase (hyl) and gelatinase (gelE)); cytotoxines (activation of cytolysin (cylA) in E. faecalis); and modulators of the host immunity and inflammation (enhanced expression pheromone (eep) in E. faecalis) were detected by polymerase chain reaction.

Results

The overall prevalence was: esp – 44.3%, agg/asa1 – 38.4%, ace/acm – 64.3%, efaA – 85.9%, eep – 69.4%, gelE – 64.3%, hyl – 25.1%, and cylA – 47.1%. E. faecalis isolates had significantly higher frequency of adhesin genes (esp and agg/asa1) and gelatinase in comparison to E. faecium. Multiple virulence genes in E. faecalis were significantly more prevalent than in E. faecium isolates. Domination of E. faecium with or without only one gene compared to the isolates of E. faecalis were found. Enterococcus spp. isolates obtained from outpatients compared to inpatients isolates had significantly higher frequency of agg/asa1, eep, gelE and cylA. Some adhesins genes (esp, agg/asa1 and efaA) had higher prevalence among the non-invasive Enterococcus spp. isolates compared to those causing invasive bacteremia, while ace/acm revealed higher dissemination in isolates causing invasive infections compared to non-invasive isolates.

Conclusion

Most E. faecalis attaches to abiotic surfaces in hospital environment, which correlates with higher prevalence of gene encoding for virulence factors involved in biofilm formation, such as enterococcal surface protein, aggregation substance, and gelatinase. The intestinal tract is an important reservoir for opportunistic enterococcal pathogens and allows them to access infectious sites through different virulence factors, demonstrated in outpatient isolates in this study.

Epidemiology and the prognosis of healthcare-associated infective endocarditis in China: the significance of non-nosocomial acquisition

Limited research has been conducted on healthcare-associated infective endocarditis (HAIE), although it is of increasing importance. The aim of this study is to compare the epidemiology, clinical characteristics, and prognosis of community-acquired IE (CA-IE) with HAIE and non-nosocomial healthcare-associated IE (NNHCA-IE). A retrospective, consecutive case-series analysis was organized and performed during the 20-year study period in Huashan Hospital, Shanghai, China. A total of 154 patients were enrolled, including 126 (81.8%) who had CA-IE and 28 (18.2%) who had HAIE, among whom 20 (71.4%) had non-nosocomial IE. Patients with HAIE compared to patients with CA-IE had poorer clinical conditions (Charlson comorbidity index ≥2: 35.7% vs. 15.1%, P = 0.012; immunosuppressive therapy: 21.4% vs. 4.0%, P = 0.005), underwent more prosthetic valve replacement (35.7% vs. 7.1%, P <0.001), had less streptococcus infection (16.7% vs. 51.1%, P = 0.007) but more atypical bacterial infection (50.0% vs. 21.1%, P = 0.017) and poorer outcomes (17.9% vs. 4.0%, P = 0.019). It is noteworthy that the results were quite similar between the comparison of patients with NNHCA-IE and those with CA-IE. Overall, in-hospital mortality was 6.5%. The IE acquisition site and low serum albumin levels (odds ratio (OR): 0.8; P = 0.04) were significantly associated with an increased risk of mortality. Nosocomial IE patients had an 8.3-fold and NNHCA-IE patients had 6.5-fold increase in the risk of mortality compared to CA-IE patients. In conclusion, HAIE and NNHCA-IE have important epidemiological and prognostic implications. Because NNHCA-IE usually occurs in patients residing in the community, it is suggested that these patients should be identified and treated by the community primary care clinical staff as early as possible.

Enterococcal endocarditis revisited

The Enterococcus species is the third main cause of infective endocarditis (IE) worldwide, and it is gaining relevance, especially among healthcare-associated cases. Patients with enterococcal IE are older and have more comorbidities than other types of IE. Classical treatment options are limited due to the emergence of high-level aminoglycosides resistance (HLAR), vancomycin resistance and multidrug resistance in some cases. Besides, few new antimicrobial alternatives have shown real efficacy, despite some of them being recommended by major guidelines (including linezolid and daptomycin). Ampicillin plus ceftriaxone 2 g iv./12 h is a good option for Enterococcus faecalis IE caused by HLAR strains, but randomized clinical trials are essential to demonstrate its efficacy for non-HLAR EFIE and to compare it with ampicillin plus short-course gentamicin. The main mechanisms of resistance and treatment options are also reviewed for other enterococcal species.

[Multiple pulmonary emboli complicating infective endocarditis in a child with congenital heart disease]

Pulmonary embolism in children is a rare condition, associated with high mortality. Clinical presentation is nonspecific. Pulmonary embolism may present initially similar to bacterial endocarditis of the right heart, septic thrombophlebitis, or osteomyelitis. We report the case of a 6-year-old girl who had dyspnea over the four months before consultation, complicated three months later by hemoptysis. She was diagnosed with subacute bacterial endocarditis secondary to group D Streptococcus, developed upon a ventricular septal defect. Two weeks later, the child had sudden chest pain and tachypnea. Lung scintigraphy showed multiple pulmonary embolisms. The therapeutic approach was to continue antibiotics without anticoagulant treatment. The outcome was favorable with apyrexia and stabilization on the respiratory level. Pulmonary embolism is a rare disease in children with an incidence of 3.7%. Classically, it presents with fever, hemoptysis, and nonspecific infiltrates on chest X-ray. These signs were noted in our patient, although the infiltrates on the chest X-ray were hidden by the pulmonary edema associated with heart failure. The persistence of these left basal opacities after antidiuretic treatment suggested an infectious origin. Subsequently, lung scintigraphy showed that it was a pulmonary infarct. The therapy of septic pulmonary embolism is the same as that for infective endocarditis. Antibiotic treatment alone was maintained without anticoagulants because of the high risk of bleeding at the seat of the pulmonary embolism and the insubstantial significant benefit of this therapy. Pulmonary embolism in children is a rare disease, but its incidence is underestimated. Better knowledge on its actual impact and etiologies in children is necessary. Multicenter studies are needed to establish recommendations.

The catastrophic journey of a retained temporary epicardial pacemaker wire leading to Enterococcus faecalis endocarditis and subsequent stroke

A 52-year-old man underwent triple coronary artery bypass graft (CABG). Three months later, he presented to the emergency room with dizziness and left-sided weakness. Workup revealed right frontal parenchymal haemorrhage; also, two retained temporary epicardial pacemaker wires (TEPW) from his previous CABG were observed, one of which had significantly migrated. One wire was found in the soft tissues below the heart; the other transversed the mediastinum from the expected location of the right atrium, perforating the right atrial appendage, entering the lumen of the ascending aorta and coursing into the mid-descending aorta. There were vegetations (Enterococcus spp) on the migrated TEPW and aortic valve, aortic valve endocarditis and aortic regurgitation. In summary, we suspect the migrated TEPW may be the source of bacteria that seeded the aortic valve, causing endocarditis and contributing to the patient's subsequent stroke. Management involved two 6-week antibiotic courses, wire-extraction, aortic valve replacement and redo CABG.