Prevalence of Infective Endocarditis in Enterococcus faecalis Bacteremia

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.

Benzothiazole-Containing Analogues of Triclocarban with Potent Antibacterial Activity

Triclocarban (TCC) is a polychlorinated, aromatic, antimicrobial agent commercially used since the 1950s in personal care products for the prevention of spoilage and infections. Humans are frequently exposed to TCC due to its widespread use, leading to its substantial release into the aquatic environment. With the recent ban of TCC from some personal care products, implemented in 2016, many replacement antimicrobial compounds have been studied by researchers. Herein, we report the synthesis and biological activity of a series of diarylureas, analogues of TCC that bear the benzothiazole nucleus as one of the two aryl moieties. Among the studied compounds, 2bF and 2eC showed the highest antimicrobial activity against Staphylococcus aureus, being also more active than TCC, with MIC values of 8 µg/mL versus 16 µg/mL of TCC. Moreover, compound 2bB was much more active than TCC against Enterococcus faecalis, a Gram-positive bacterium that is, unfortunately, strongly responsible for nosocomial infections. Finally, interesting results were found for compound 2bG that, even though less active than the others, exerts an interesting bactericidal action.

Infective Endocarditis: A Focus on Oral Microbiota

Infective endocarditis (IE) is an inflammatory disease usually caused by bacteria entering the bloodstream and settling in the heart lining valves or blood vessels. Despite modern antimicrobial and surgical treatments, IE continues to cause substantial morbidity and mortality. Thus, primary prevention and enhanced diagnosis remain the most important strategies to fight this disease. In this regard, it is worth noting that for over 50 years, oral microbiota has been considered one of the significant risk factors for IE. Indeed, among the disparate recommendations from the American heart association and the European Society of Cardiology, there are good oral hygiene and prophylaxis for high-risk patients undergoing dental procedures. Thus, significant interest has grown in the role of oral microbiota and it continues to be a subject of research interest, especially if we consider that antimicrobial treatments can generate drug-resistant mutant bacteria, becoming a severe social problem. This review will describe the current knowledge about the relationship between oral microbiota, dental procedures, and IE. Further, it will discuss current methods used to prevent IE cases that originate from oral pathogens and how these should be focused on improving oral hygiene, which remains the significant persuasible way to prevent bacteremia and systemic disorders.

Enterococcus faecalis in blood cultures-a prospective study on the role of persistent bacteremia

Enterococcus faecalis can cause infective endocarditis and other complicated infections. We prospectively investigate the incidence of persistent bacteremia with E. faecalis. Of 50 episodes with monomicrobial E. faecalis bacteremia the control blood culture after 48 to 72 hours was positive in 5 episodes (10%) of which 4 had a complicated focal infection.

The Different Facets of Triclocarban: A Review

In the late 1930s and early 1940s, it was discovered that the substitution on aromatic rings of hydrogen atoms with chlorine yielded a novel chemistry of antimicrobials. However, within a few years, many of these compounds and formulations showed adverse effects, including human toxicity, ecotoxicity, and unwanted environmental persistence and bioaccumulation, quickly leading to regulatory bans and phase-outs. Among these, the triclocarban, a polychlorinated aromatic antimicrobial agent, was employed as a major ingredient of toys, clothing, food packaging materials, food industry floors, medical supplies, and especially of personal care products, such as soaps, toothpaste, and shampoo. Triclocarban has been widely used for over 50 years, but only recently some concerns were raised about its endocrine disruptive properties. In September 2016, the U.S. Food and Drug Administration banned its use in over-the-counter hand and body washes because of its toxicity. The withdrawal of triclocarban has prompted the efforts to search for new antimicrobial compounds and several analogues of triclocarban have also been studied. In this review, an examination of different facets of triclocarban and its analogues will be analyzed.

Short time to blood culture positivity in Enterococcus faecalis infective endocarditis

Time to blood culture positivity (TTP) is an indirect measure of bacterial concentration in blood. A short TTP has been linked to the presence of infective endocarditis (IE) and to poor prognosis in Staphylococcus aureus bacteremia. We analyze factors influencing TTP in bacteremia with Enterococcus faecalis. This retrospective observational study of medical records included adults diagnosed with monomicrobial E. faecalis bacteremia between 2015 and 2018 in the Skåne region (Sweden). For each episode, the shortest TTP was recorded. Median TTP was compared between patients grouped based on age, sex, comorbidity, site of acquisition, and focus of infection. Using a dichotomized TTP (shorter or longer than 12 h), a multivariable logistic regression for factors associated to TTP was performed. The association between TTP and IE or mortality was evaluated. Three hundred sixty-seven episodes with monomicrobial E. faecalis bacteremia with the corresponding TTP were identified. Median TTP for the entire cohort was 11.6 (IQR 9.9–14.1) h and a significantly shorter TTP was noted for episodes which represented IE (n = 55, 9.4 (IQR 6.4–10.6) h). Only IE remained associated with a short TTP (≤ 12 h) in binary logistic regression analysis. Factors associated with IE were investigated and TTP was associated with IE also when adjusted for age, gender, comorbidity, and nosocomial acquisition. There was no association between TTP and mortality. A low TTP is associated with IE in E. faecalis bacteremia and could be used as a help in determining the need for echocardiography in patients with this condition.

Secular trends in the epidemiology and clinical characteristics of Enterococcus faecalis infective endocarditis at a referral center (2007-2018)

The aim of the study was to analyze the epidemiological and clinical changes in EFIE. All definite IE episodes treated at a referral center between 2007 and 2018 were registered prospectively, and a trend test was used to study etiologies over time. EFIE cases were divided into three periods, and clinical differences between them were analyzed. All episodes of E. faecalis monomicrobial bacteremia (EFMB) between 2010 and 2018 and the percentage of echocardiograms performed were retrospectively collected. Six hundred forty-eight IE episodes were studied. We detected an increase in the percentage of EFIE (15% in 2007, 25.3% in 2018, P = 0.038), which became the most prevalent causative agent of IE during the last study period. One hundred and eight EFIE episodes were analyzed (2007-2010, n = 30; 2011-2014, n = 22; 2015-2018, n = 56). The patients in the last period were older (median 70.9 vs 66.5 vs 76.3 years, P = 0.015) and more frequently had an abdominal origin of EFIE (20% vs 13.6% vs 42.9%, P = 0.014), fewer indications for surgery (63.3% vs 54.6% vs 32.1%, P = 0.014), and non-significantly lower in-hospital mortality (30% vs 18.2% vs 12.5%, P = 0.139). There was an increase in the percentage of echocardiograms performed in patients with EFMB (30% in 2010, 51.2% in 2018, P = 0.014) and EFIE diagnoses (15% in 2010, 32.6% in 2018, P = 0.004). E. faecalis is an increasing cause of IE in our center, most likely due to an increase in the percentage of echocardiograms performed. The factors involved in clinical changes in EFIE should be thoroughly studied.

Temporal Trends and Outcomes of Percutaneous and Surgical Aortic Valve Replacement in Patients With Atrial Fibrillation

Objectives: The aim of this study was to evaluate the temporal trends of transcatheter aortic valve replacement (TAVR) in severe aortic stenosis (AS) patients with atrial fibrillation (AF) and to compare the in-hospital outcomes between TAVR and surgical aortic valve replacement (SAVR) in patients with AF.

Background: Data comparing TAVR to SAVR in severe AS patients with AF are lacking.

Methods: National inpatient sample database in the United States from 2012 to 2016 were queried to identify hospitalizations for severe aortic stenosis patients with AF who underwent isolated aortic valve replacement. A propensity score-matched analysis was used to compare in-hospital outcomes for TAVR vs. SAVR for AS patients with AF.

Results: The analysis included 278,455 hospitalizations, of which 124,910 (44.9%) were comorbid with AF. Before matching, TAVR had higher in-hospital mortality than SAVR (3.1 vs. 2.2%, p < 0.001); however, there was a declining trend during the study period (Ptrend < 0.001). After matching, TAVR and SAVR had similar in-hospital mortality (2.9 vs. 2.9%, p < 0.001) and stroke. TAVR was associated with lower rates of acute kidney injury, new dialysis, cardiac complications, acquired pneumonia, sepsis, mechanical ventilation, tracheostomy, non-routine discharge, and shorter length of stay; however, TAVR was associated with more pacemaker implantation and higher cost. Of the patients receiving TAVR, the presence of AF was associated with an increased rate of complications and increased medical resource usage compared to those without AF.

Conclusions: In-hospital mortality and stroke for TAVR and SAVR in AF, AS are similar; however, the in-hospital mortality in TAVR AF is declining and associated with more favorable in-hospital outcomes.

How do I manage a patient with enterococcal bacteraemia?

BACKGROUND

Enterococcal bacteraemia (EB) is common, particularly in the nosocomial setting, and its management poses a challenge for clinicians and microbiologists.

OBJECTIVES

The aim was to summarize the more relevant features of EB and to provide a practical state-of-the-art on the topics that more directly affect its management.

SOURCES

Pubmed articles from inception to 31 May 2020.

CONTENT

The following topics are covered: epidemiological, clinical and microbiological characteristics and factors associated with prognosis of EB; diagnosis and work-up, including the use of echocardiography to rule out endocarditis; antibiotic management with special focus on antimicrobial resistance and complicated EB; and the role of infectious disease consultation and the use of bundles in EB. In addition, three clinical vignettes are presented to illustrate the practical application of the guidance provided, and major gaps in the current evidence supporting EB management are discussed.

IMPLICATIONS

EB is associated with large burdens of morbidity and mortality, particularly among fragile and immunosuppressed patients presenting complicated bacteraemia due to multidrug-resistant enterococci. Most cases of EB are caused by Enterococcus faecalis, followed by E. faecium. EB often presents as polymicrobial bacteraemia. Rapidly identifying patients at risk of EB is crucial for timely application of diagnostic techniques and empiric therapy. Early alert systems and rapid diagnostic techniques, such as matrix-assisted desorption ionization-time of flight mass spectrometry, especially if used together with infectious disease consultation within bundles, appear to improve management and prognosis of EB. Echocardiography is also key in the work-up of EB and should probably be more extensively used, although its exact indications in EB are still debated. Multidisciplinary approaches are warranted due to the complexity and severity of EB.

Risk for infective endocarditis in bacteremia with Gram positive cocci

PURPOSE

Infective endocarditis (IE) is a serious complication of bacteremia and is most often caused by Gram positive cocci. We investigated the prevalence of IE in patients where echocardiography was encouraged when bacteremia with Gram positive cocci was present.

METHODS

The study included patients with Gram positive cocci bacteremia hospitalized at two Danish hospitals between March and December 2016. Information concerning echocardiography, demographics and bacterial species was collected from the patients' medical files. Patients without echocardiography were followed for 6 months in order to confirm or reject possible IE.

RESULTS

The study included 585 patients with Gram positive cocci bacteremia, and echocardiography was performed in 414 (71%) of them. The prevalence of IE in patients with high risk bacteremia, i.e. Staphylococcus aureus, non-beta-hemolytic streptococci, Enterococcus faecalis, and coagulase-negative staphylococci was 16%. Patients with Enterococcus faecalis had the highest prevalence of IE (33%) followed by non-beta-hemolytic streptococci (23%) and Staphylococcus aureus (12%). Among low risk bacteremia the prevalence of IE was 1%. The mean age of patients with IE was 74 years (SD 12.9) and 71% were male.

CONCLUSION

These findings strongly support routine echocardiography in patients with high risk bacteremia and non-performance of echocardiography in patients with low risk bacteremia.

Antimicrobial, antibiofilm and cytotoxic effects of a colloidal nanocarrier composed by chitosan-coated iron oxide nanoparticles loaded with chlorhexidine

OBJECTIVES

This study evaluated the antimicrobial and antibiofilm effects of a colloidal nanocarrier for chlorhexidine (CHX) on Candida glabrata and Enterococcus faecalis, as well as tested its cytotoxic effect on murine fibroblasts.

METHODS

Iron oxide nanoparticles (IONPs) were coated with chitosan (CS) and loaded with CHX at 31.2, 78 and 156 μg/mL. Antimicrobial effects were assessed by determining the minimum inhibitory concentration (MIC), using the broth microdilution method, and fractional inhibitory concentration index (FICI). Preformed biofilms (48 h) were treated with different concentrations of the nanocarrier (24 h) and quantified by colony-forming units (CFUs), total biomass and metabolic activity. For cytotoxicity, the viability of L929 cells was evaluated by MTT assay after 24 and 48 h of exposure to the nanocarrier. Data were submitted to ANOVA and Fisher LSD or Tukey post-hoc tests (α = 0.05).

RESULTS

MIC and FICI results showed an indifferent interaction among the components of the nanocarrier for all strains evaluated. CHX alone and nanocarrier containing 156 μg/mL CHX did not differ from each other in reducing the number of CFUs. However, the nanocarrier containing 156 μg/mL CHX promoted the highest reductions in total biofilm biomass and metabolism, surpassing the effect of CHX alone. After 24 and 48 h of exposure, the nanocarrier reduced CHX toxicity to the L929 cell at low concentrations.

CONCLUSION

These findings suggest that the CHX nanocarrier has potential to be used in the control of oral diseases associated with C. glabrata and E. faecalis.

CLINICAL RELEVANCE

CHX has improved the antibiofilm effect and reduced the cytotoxicity (at low concentrations) when conjugated to CS-coated IONPs. This new colloidal formulation has potential as an alternative antimicrobial agent to pure CHX for the control of biofilm-related oral diseases, such as oral candidiasis and endodontic infections.

Prevalence of Infective Endocarditis in Streptococcal Bloodstream Infections Is Dependent on Streptococcal Species

BACKGROUND

Streptococci frequently cause infective endocarditis (IE), yet the prevalence of IE in patients with bloodstream infections (BSIs) caused by different streptococcal species is unknown. We aimed to investigate the prevalence of IE at species level in patients with streptococcal BSIs.

METHODS

We investigated all patients with streptococcal BSIs, from 2008 to 2017, in the Capital Region of Denmark. Data were crosslinked with Danish nationwide registries for identification of concomitant hospitalization with IE. In a multivariable logistic regression analysis, we investigated the risk of IE according to streptococcal species adjusted for age, sex, ≥3 positive blood culture bottles, native valve disease, prosthetic valve, previous IE, and cardiac device.

RESULTS

Among 6506 cases with streptococcal BSIs (mean age 68.1 years [SD 16.2], 52.8% men) the IE prevalence was 7.1% (95% CI, 6.5-7.8). The lowest IE prevalence was found with Streptococcus pneumoniae (S pneumoniae) 1.2% (0.8-1.6) and Spyogenes 1.9% (0.9-3.3). An intermediary IE prevalence was found with Sanginosus 4.8% (3.0-7.3), Ssalivarius 5.8% (2.9-10.1), and Sagalactiae 9.1% (6.6-12.1). The highest IE prevalence was found with Smitis/oralis 19.4% (15.6-23.5), Sgallolyticus (formerly Sbovis) 30.2% (24.3-36.7), Ssanguinis 34.6% (26.6-43.3), Sgordonii 44.2% (34.0-54.8), and Smutans 47.9% (33.3-62.8). In multivariable analysis using S pneumoniae as reference, all species except S pyogenes were associated with significantly higher IE risk, with the highest risk found with S gallolyticus odds ratio (OR) 31.0 (18.8-51.1), S mitis/oralis OR 31.6 (19.8-50.5), S sanguinis OR 59.1 (32.6-107), S gordonii OR 80.8 (43.9-149), and S mutans OR 81.3 (37.6-176).

CONCLUSIONS

The prevalence of IE in streptococcal BSIs is species dependent with S mutans, S gordonii, S sanguinis, S gallolyticus, and S mitis/oralis having the highest IE prevalence and the highest associated IE risk after adjusting for IE risk factors.

Impact on Mortality of a Bundle for the Management of Enterococcal Bloodstream Infection

Objective

In this study, we evaluated the effectiveness of a management bundle for Enterococcus spp bloodstream infection (E-BSI).

Method

This was a single-center, quasi-experimental (pre/post) study. In the prephase (January 2014 to December 2015), patients with monomicrobial E-BSI were retrospectively enrolled. During the post- or intervention phase (January 2016 to December 2017), all patients with incident E-BSI were prospectively enrolled in a nonmandatory intervention arm comprising infectious disease consultation, echocardiography, follow-up blood cultures, and early targeted antibiotic treatment. Patients were followed up to 1 year after E-BSI. The primary outcome was 30-day mortality.

Results

Overall, 368 patients were enrolled, with 173 in the prephase and 195 in the postphase. The entire bundle was applied in 15% and 61% patients during the pre- and postphase, respectively (P < .001). Patients enrolled in the postphase had a significant lower 30-day mortality rate (20% vs 32%, P = .0042). At multivariate analysis, factors independently associated to mortality were age (hazard ratio [HR], 1.03; 95% confidence interval [CI], 1.00–1.05), intensive care unit admission (HR, 2.51; 95% CI, 1.18–3.89), and healthcare-associated (HR, 2.32; 95% CI, 1.05–5.16) and hospital-acquired infection (HR, 2.85; 95% CI, 1.34–4.76), whereas being enrolled in the postphase period (HR, 0.49; 95% CI, 0.32–0.75) was associated with improved survival. Results were consistent also in the subgroups with severe sepsis (HR, 0.37; 95% CI, 0.16–0.90) or healthcare-associated infections (HR, 0.53; 95% CI, 0.31–0.93). A significantly lower 1-year mortality was observed in patients enrolled in the postphase period (50% vs 68%, P < .001).

Conclusions

The introduction of a bundle for the management of E-BSI was associated with improved 30-day and 1-year survival.