A Contemporary Picture of Enterococcal Endocarditis

Epidemiological and microbial trends of infective endocarditis in western Norway: a 7-year prospective observational study

BACKGROUND

In this prospective, observational study, we aimed to investigate epidemiologic and microbial trends of infective endocarditis in western Norway.

METHODS

Clinical and microbiological characteristics of 497 cases of infective endocarditis from 2016 through 2022 were investigated. Categorical data were analysed using Chi-squared tests. Survival data were analysed using multiple Cox regression and reported using hazard ratios.

RESULTS

The mean age was 67 years, and 74% were men. The annual incidence rates varied from 10.4 to 14.1 per 100,000 inhabitants per year. Infective endocarditis on native valves was observed in 257 (52%) of the cases, whereas infective endocarditis on prosthetic valves and/or cardiac implantable electronic devices was observed in 240 (48%) of the cases: infection on surgically implanted bioprostheses was observed in 124 (25%) of the patients, infection on transcatheter aortic valve implantation was observed in 47 (10%) patients, and infection on mechanical valves was observed in 34 (7%) cases. Infection related to cardiac implantable electronic devices was observed in a total of 50 (10%) cases. Staphylococcus aureus and viridans streptococci were the most common microbial causes, and isolated in 145 (29%) and 130 (26%) of the cases, respectively. Enterococcal endocarditis showed a rising trend during the study period and constituted 90 (18%) of our total cases of infective endocarditis, and 67%, 47%, and 26% of the cases associated with prosthetic material, transcatheter aortic valve implantation and cardiac implantable electronic devices, respectively. There was no significant difference in 90-day mortality rates between the native valve endocarditis group (12%) and the group with infective endocarditis on prosthetic valves or cardiac implants (14%), p = 0.522. In a model with gender, age, people who inject drugs, microbiology and type of valve affected, only advanced age was significantly associated with fatal outcome within 90 days.

CONCLUSIONS

The incidence of infective endocarditis, and particularly enterococcal endocarditis, increased during the study period. Enterococci appeared to have a particular affinity for prosthetic cardiac material. Advanced age was the only independent risk factor for death within 90 days.

Prosthetic Valve Endocarditis: A Retrospective Cohort Study Conducted at "Dr. Carol Davila" Central Military Emergency University Hospital in Bucharest

OBJECTIVE

To evaluate patients with prosthetic valves who developed infective endocarditis by comparing treatment outcomes in both early- and late-onset IE episodes following prosthetic valve replacement surgery. This study sought to conduct a comprehensive assessment of the efficacy of these methodologies. The insights derived from this assessment can be utilized to enhance the quality of care for individuals with infective endocarditis who have undergone prosthetic valve replacement surgery.

RESULTS

During the period of investigation (January 2017-December 2022), 78 patients diagnosed with infective endocarditis (IE) on a prosthetic valve were admitted to the Infectious Diseases Department of the "Dr. Carol Davila" Central Military Emergency University Hospital in Bucharest. In 28 patients (35.8%), the onset of PVE occurred within 12 months of surgery (early onset), whereas in 50 patients (64.2%), the onset occurred more than 12 months after surgery (late onset). The mortality rate was 35.9% (53.6% among the early onset patients and 26% among the late-onset patients). Among patients who received surgical and medical therapy, the mortality rate was 29.6%, whereas among those who received only medical therapy, a 39.2% mortality rate was reported. According to the extracted data, antibiotic therapy was successful in 72.6% of the patients. In contrast, a combination of surgical and drug-based approaches resulted in a cure in 76.1% of patients. The most common etiological agent was Staphylococcus aureus (38.5%), followed by Enterococcus faecalis (26.9%) and Streptococcus mitis (10.3%). The mortality rate of patients infected with S. aureus was 29.2%, indicating the severity of this infectious agent.

CONCLUSIONS

Prosthetic valve endocarditis (PVE) is a serious condition associated with a high mortality rate both in the short and long term. Regardless of the therapy used, the risk of death remains high.

Enterococcal Infective Endocarditis - Post discharge treatment with continuous benzylpenicillin and ceftriaxone: A retrospective cohort study

BACKGROUND

Enterococcal Infective Endocarditis (EIE) is usually treated with the combination of penicillin/ampicillin with gentamicin or ampicillin with ceftriaxone. To enable prolonged outpatient treatment, a combination of benzylpenicillin and ceftriaxone has been suggested. This study aimed to describe the incidence and characteristics of EIE and to determine the outcome of EIE cases treated with benzylpenicillin and ceftriaxone.

METHODS

This was a retrospective single-center study including all patients diagnosed with infective endocarditis (IE) during 2016-2021, comparing EIE with IE caused by other pathogens. We described the outpatient treatment of patients with EIE, comparing those treated of benzylpenicillin - ceftriaxone with other regimes.

RESULTS

Among 222 patients with IE, 44 (20%) were diagnosed with EIE. Those were older, had a male predominance (p = 0.035), and were more disabled (p = 0.004). The incidence of EIE reached 30% towards the last year, becoming the leading etiology. Twenty-six patients received outpatient treatment, five of whom were discharged with benzylpenicillin and ceftriaxone. Adding patients from this cohort to the scarce data available, revealed similar recurrence and mortality rates compared to other treatment regimes.

CONCLUSIONS

EIE is becoming a more frequent cause of IE, involving older, more disabled patients with male predominance. Our experience and existing literature suggest that the combination of benzylpenicillin and ceftriaxone is as safe as more conventional regimes, although further research is needed.

Trends in epidemiology, surgical management, and prognosis of infective endocarditis during the XXI century in Spain: A population-based nationwide study

BACKGROUND

Few population-based studies have evaluated the epidemiology of infective endocarditis (IE). Changes in population demographics and guidelines on IE may have affected both the incidence and outcomes of IE. Therefore, the aim of our study is to provide contemporary population-based epidemiological data of IE in Spain.

METHODS

Retrospective nationwide observational study using data from the Spanish National Health System Discharge Database. We included all patients hospitalized with IE from January 2000 to December 2019.

RESULTS

A total of 64,550 IE episodes were included. The incidence of IE rose from 5.25 cases/100,000 person-year in 2000 to 7.21 in 2019, with a 2% annual percentage change (95% CI 1.3-2.6). IE incidence was higher among those aged 85 or older (43.5 cases/100.000 person-years). Trends across the study period varied with sex and age. Patients with IE were progressively older (63.9 years in 2000-2004 to 70.0 in 2015-2019, p < 0.001) and had more frequent comorbidities and predispositions, including, previous valvular prosthesis (12.1% vs 20.9%, p < 0.001). After adjustment, a progressive reduction in mortality was noted including in 2015-2019 compared to 2010-2014 (adjusted odds ratio 0.93, 95% confident interval 0.88-0.99, p = 0.023)., which was associated with more frequent cardiac surgery in recent years (15.1% in 2010-2014 vs 19.9% in 2015-2019).

CONCLUSIONS

In Spain, the incidence of IE has increased during the XXI century, with a more pronounced increase in elderly individuals. Adjusted-mortality decreased over the years, which could be related to a higher percentage of surgery. Our results highlight the changing epidemiology of IE.

Differential in vitro susceptibility to ampicillin/ceftriaxone combination therapy among Enterococcus faecalis infective endocarditis clinical isolates

OBJECTIVES

To investigate the genomic diversity and β-lactam susceptibilities of Enterococcus faecalis collected from patients with infective endocarditis (IE).

METHODS

We collected 60 contemporary E. faecalis isolates from definite or probable IE cases identified between 2018 and 2021 at the University of Pittsburgh Medical Center. We used whole-genome sequencing to study bacterial genomic diversity and employed antibiotic checkerboard assays and a one-compartment pharmacokinetic-pharmacodynamic (PK/PD) model to investigate bacterial susceptibility to ampicillin and ceftriaxone both alone and in combination.

RESULTS

Genetically diverse E. faecalis were collected, however, isolates belonging to two STs, ST6 and ST179, were collected from 21/60 (35%) IE patients. All ST6 isolates encoded a previously described mutation upstream of penicillin-binding protein 4 (pbp4) that is associated with pbp4 overexpression. ST6 isolates had higher ceftriaxone MICs and higher fractional inhibitory concentration index values for ampicillin and ceftriaxone (AC) compared to other isolates, suggesting diminished in vitro AC synergy against this lineage. Introduction of the pbp4 upstream mutation found among ST6 isolates caused increased ceftriaxone resistance in a laboratory E. faecalis isolate. PK/PD testing showed that a representative ST6 isolate exhibited attenuated efficacy of AC combination therapy at humanized antibiotic exposures.

CONCLUSIONS

We find evidence for diminished in vitro AC activity among a subset of E. faecalis IE isolates with increased pbp4 expression. These findings suggest that alternate antibiotic combinations against diverse contemporary E. faecalis IE isolates should be evaluated.

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.

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

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

Factors Related to the Development of Infective Endocarditis in Hemodialysis Patients in a Third-Level Hospital in Panama

INTRODUCTION

Venous access for hemodialysis (HD) makes patients more susceptible to transient bacteremia, predisposing them to the development of infective endocarditis (IE). Among the risk factors observed in this population are temporary access to HD, hypoalbuminemia, diabetes mellitus, female gender, anemia, and colonization by methicillin-resistant Staphylococcus aureus (MRSA).

METHODOLOGY

A retrospective case-control study with a one-to-two ratio was carried out on patients with chronic kidney disease (CKD) undergoing renal replacement therapy with at least one vascular access for HD at Complejo Hospitalario Dr. Arnulfo Arias Madrid (CHDrAAM) from 2010 to 2020. Sociodemographic variables, past medical history, and data on current HD were studied. The odds ratio (OR) and adjusted odds ratio (aOR) were calculated for the collected variables.

RESULTS

No statistically significant differences between the groups were observed in sociodemographic variables. In terms of past medical history, the cases showed a predominance of coronary disease (47.6% vs 4.8%; OR: 37.27), valvular disease (23.8% vs 0%), and heart failure (33.3% vs 4.8%; OR: 10). In the cases, the use of a temporary catheter was more prevalent (61.9% vs 33.3%; OR: 3.25), and subclavian access was more frequently recorded (28.6% vs 2.4%; OR: 14.4). A short duration of venous access (<30 days) was found in a greater proportion of cases (23.8% vs 4.8%; OR: 6.25). The main pathogen isolated was S. aureus (33.3%), and the most affected valve was the aortic valve (59.1%). Fever was found in 100% of the reported cases, and up to 47.6% presented with a recent murmur.

DISCUSSION

Similar to previous studies conducted in other countries, we identified a history of pre-existing valve disease, the use of a temporary catheter, and recent venous access as risk factors. Contrary to what has been reported in the literature, this study did not find female sex, diabetes mellitus, and hypoalbuminemia as risks.

CONCLUSION

Factors such as a history of coronary artery disease, heart failure, preexisting valvular disease, the use of a temporary catheter, subclavian venous access, and short duration of venous access (<30 days) were identified as risk factors for the development of IE in patients with CKD on HD.

Healthcare-associated infective endocarditis: source of infection and burden of previous healthcare exposure

Objective

Prevention of healthcare-associated infective endocarditis (HAIE) is based on characterization of underlying factors. Our object was to describe the source of infection, microbiological etiology, and healthcare-related risk factors for HAIE.

Design

Retrospective population-based study.

Patients

Adult patients diagnosed with HAIE during 2013-2017 who resided in the study area in Southern Finland with adult population of 0.9 million.

Results

Ninety-five HAIE episodes were included. Ten episodes were related to cardiac surgery. Of the remaining 85 episodes, 11 were classified as nosocomial (ie, acquired and diagnosed during ongoing hospitalization) and 74 as non-nosocomial HAIE. Staphylococcus aureus caused 45% of nosocomial episodes, but only 16% of non-nosocomial episodes (P = 0.039). Most common sources of infection in non-nosocomial HAIE were previous hospitalization (24%), dialysis (18%), and urologic procedures (15%). Enterococcus spp. caused 23% of non-nosocomial HAIE, and more than half of them were associated with urologic or gastrointestinal procedures. Two-thirds of the non-nosocomial HAIE patients had recent hospitalization or invasive procedure. We counted previous healthcare-related risk factors for IE and those who had two or more of them had higher in-hospital and one-year mortality.

Conclusion

Our study indicates the importance of non-nosocomial acquisition of HAIE and S. aureus as the major pathogen in nosocomial episodes. Enterococcal infections dominate in non-nosocomial cases and further studies are needed to identify patients at risk for enterococcal IE after urological or gastrointestinal procedure.

Clinical presentation, microbiology, and prognostic factors of prosthetic valve endocarditis. Lessons learned from a large prospective registry

BACKGROUND

Prosthetic valve endocarditis (PVE) is a serious infection associated with high mortality that often requires surgical treatment.

METHODS

Study on clinical characteristics and prognosis of a large contemporary prospective cohort of prosthetic valve endocarditis (PVE) that included patients diagnosed between January 2008 and December 2020. Univariate and multivariate analysis of factors associated with in-hospital mortality was performed.

RESULTS

The study included 1354 cases of PVE. The median age was 71 years with an interquartile range of 62-77 years and 66.9% of the cases were male. Patients diagnosed during the first year after valve implantation (early onset) were characterized by a higher proportion of cases due to coagulase-negative staphylococci and Candida and more perivalvular complications than patients detected after the first year (late onset). In-hospital mortality of PVE in this series was 32.6%; specifically, it was 35.4% in the period 2008-2013 and 29.9% in 2014-2020 (p = 0.031). Variables associated with in-hospital mortality were: Age-adjusted Charlson comorbidity index (OR: 1.15, 95% CI: 1.08-1.23), intracardiac abscess (OR:1.78, 95% CI:1.30-2.44), acute heart failure related to PVE (OR: 3. 11, 95% CI: 2.31-4.19), acute renal failure (OR: 3.11, 95% CI:1.14-2.09), septic shock (OR: 5.56, 95% CI:3.55-8.71), persistent bacteremia (OR: 1.85, 95% CI: 1.21-2.83) and surgery indicated but not performed (OR: 2.08, 95% CI: 1.49-2.89). In-hospital mortality in patients with surgical indication according to guidelines was 31.3% in operated patients and 51.3% in non-operated patients (p<0.001). In the latter group, there were more cases of advanced age, comorbidity, hospital acquired PVE, PVE due to Staphylococcus aureus, septic shock, and stroke.

CONCLUSIONS

Not performing cardiac surgery in patients with PVE and surgical indication, according to guidelines, has a significant negative effect on in-hospital mortality. Strategies to better discriminate patients who can benefit most from surgery would be desirable.

Carbonic Anhydrase Inhibition as a Target for Antibiotic Synergy in Enterococci

Enterococcus faecalis is a hospital-associated opportunistic pathogen that can cause infections with high mortality, such as infective endocarditis. With an increasing occurrence of multidrug-resistant enterococci, there is a need for alternative strategies to treat enterococcal infections. We isolated a gentamicin-hypersusceptible E. faecalis strain from a patient with infective endocarditis that carried a mutation in the alpha-carbonic anhydrase (α-CA) and investigated how disruption of α-CA sensitized E. faecalis to killing with gentamicin. The gentamicin-hypersusceptible α-CA mutant strain showed increased intracellular gentamicin uptake in comparison to an isogenic strain encoding full-length, wild-type α-CA. We hypothesized that increased gentamicin uptake could be due to increased proton motive force (PMF), increased membrane permeability, or both. We observed increased intracellular ATP production in the α-CA mutant strain, suggesting increased PMF-driven gentamicin uptake contributed to the strain's gentamicin susceptibility. We also analyzed the membrane permeability and fatty acid composition of isogenic wild-type and α-CA mutant strains and found that the mutant displayed a membrane composition that was consistent with increased membrane permeability. Finally, we observed that exposure to the FDA-approved α-CA inhibitor acetazolamide lowered the gentamicin MIC of eight genetically diverse E. faecalis strains with intact α-CA but did not change the MIC of the α-CA mutant strain. These results suggest that α-CA mutation or inhibition increases PMF and alters membrane permeability, leading to increased uptake of gentamicin into E. faecalis. This connection could be exploited clinically to provide new combination therapies for patients with enterococcal infections. IMPORTANCE Enterococcal infections can be difficult to treat, and new therapeutic approaches are needed. In studying an E. faecalis clinical strain from an infected patient, we found that the bacteria were rendered hypersusceptible to aminoglycoside antibiotics through a mutation that disrupted the α-CA. Our follow-on work suggested two different ways that α-CA disruption causes increased gentamicin accumulation in E. faecalis: increased proton motive force-powered uptake and increased membrane permeability. We also found that a mammalian CA inhibitor could sensitize a variety of E. faecalis strains to killing with gentamicin. Given that mammalian CA inhibitors are frequently used to treat conditions such as glaucoma, hypertension, and epilepsy, our findings suggest that these "off-the-shelf" inhibitors could also be useful partner antibiotics for the treatment of E. faecalis infections.

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.

Stability of Ampicillin plus Ceftriaxone Combined in Elastomeric Infusion Devices for Outpatient Parenteral Antimicrobial Therapy

Currently, ampicillin plus ceftriaxone (AC) is one of the preferred treatments for Enterococcus faecalis infective endocarditis. However, there is a lack of stability data for the combination of both drugs in elastomeric devices, so the inclusion of AC in Outpatient Parenteral Antimicrobial Therapy (OPAT) programs is challenging. The objective of the study was to determine the stability of AC in elastomeric pumps when stored at 8 ± 2 °C, 25 ± 2 °C, 30 ± 2 °C and 37 ± 2 °C using LC-MS/MS. The combination was diluted in 0.9% sodium chloride and the final concentrations were ampicillin 24 g/L plus ceftriaxone 8 g/L. Physical and chemical stability were evaluated at 12, 20, 24, 36 and 48 h after preparation. Stability was met at each time point if the percentage of intact drug was ≥90% of its respective baseline concentration and color and clearness remained unchanged. The drug combination was stable for 48 h when it was kept at 8 ± 2 °C. At 25 ± 2 °C and 30 ± 2 °C, they were stable for 24 h of storage. At 37 ± 2 °C, the stability criterion was not met at any time point. These results prove that AC could be included in OPAT programs using elastomeric infusion devices for the treatment of E. faecalis infections.

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

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

Impact of Enterococcus faecalis Endocarditis Treatment on Risk of Relapse

BACKGROUND

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

MATERIALS

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

RESULTS

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

CONCLUSIONS

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

A retrospective study of Enterococcus faecalis infective endocarditis: comparison of clinical characteristics and outcomes associated with treatment

Introduction

A synergistic antibiotic combination of a penicillin and gentamicin (AG) or ceftriaxone (AC) is used in the management of Enterococcus faecalis infective endocarditis (EFIE). We compare the treatment outcomes between AG and AC, including low and high dose ceftriaxone (1 and 2 g 12 hourly).

Methods

A retrospective cohort study of patients treated for EFIE at single tertiary centre (2012–2019). Outcome measures examined were 90- and 180-day mortality, treatment associated adverse events and relapse of bacteraemia (within 1 year).

Results

39 patients were enrolled [61.6% given (AC) (n = 24), 24% received ACL (n = 10) and 34% received ACN (n = 14)], 38.4% received AG (n = 15). We noted a difference in the mortality outcomes at 90 and 180 days between those treated with AG and AC overall (6.7% and 33.3%, respectively) although this did not reach statistical significance (P = 0.114, P = 0.061). No significant difference was noted between these groups in incidence of relapsed bacteraemia with two cases noted in the AC cohort (8.3%, 2/24) and none observed (0/15) in the AG cohort (P = 0.662, P = 0.414). A greater number of adverse events was observed in the AG group (11/15, 73.3%) compared to the overall AC group (6/24, 25.0%) (P = 0.009), with no difference between the high and low dose ceftriaxone groups (P = 0.05).

Conclusion

Combination treatment of EFIE with AC is associated with a reduced number of adverse events in comparison to AG groups. Although increased mortality was observed in the AC group, this did not reach statistical significance, and reflects the greater comorbidities and reduced capacity for surgical source control in this cohort.

Penicillin plus Ceftriaxone versus Ampicillin plus Ceftriaxone Synergistic Potential against Clinical Enterococcus faecalis Blood Isolates

Penicillin plus ceftriaxone is a promising alternative to ampicillin plus ceftriaxone for the treatment of Enterococcus faecalis infective endocarditis. Limited data is available supporting the utilization of penicillin plus ceftriaxone. A total of 20 E. faecalis isolates; one wild-type strain (JH2-2) and 19 clinical blood strains were assessed for penicillin plus ceftriaxone and ampicillin plus ceftriaxone synergy using a 24-h time-kill experiment. Susceptibility was determined by broth microdilution. Differences in bactericidal, bacteriostatic, or inactivity, as well as synergy between treatments were assessed by chi-square or Fisher exact test. All E. faecalis isolates were considered susceptible to ampicillin and penicillin. Ampicillin plus ceftriaxone versus penicillin plus ceftriaxone similarly demonstrated synergy. Bactericidal activity was more commonly observed for ampicillin plus ceftriaxone versus penicillin plus ceftriaxone. Among isolates with a penicillin MIC of 4 μg/mL (n = 7), synergistic activity for both combinations was less common compared to isolates with a penicillin MIC ≤ 2 μg/mL (n = 13). Ampicillin plus ceftriaxone and penicillin plus ceftriaxone demonstrate similar synergistic potential against E. faecalis clinical blood isolates, but strains with higher penicillin and ceftriaxone MICs less frequently demonstrated synergy. Further research is warranted to determine the role of the penicillin plus ceftriaxone therapy and the penicillin MIC in clinical practice. IMPORTANCE Penicillin plus ceftriaxone demonstrates similar synergistic activity against Enterococcus faecalis to ampicillin plus ceftriaxone. Isolates with a penicillin MIC of 4 mg/L and a ceftriaxone MIC of 512 or higher, lack penicillin plus ceftriaxone synergy despite the penicillin susceptibility MIC breakpoint of 8 mg/L.

Clinical and microbiological characteristics of bloodstream infections caused by Enterococcus spp. within internal medicine wards: a two-year single-centre experience

Enterococcal bloodstream infections (E-BSI) constitute the second cause of Gram-positive bacterial BSI in Europe with a high rate of in-hospital mortality. Furthermore, E-BSI treatment is still challenging because of intrinsic and acquired antibiotic resistances. We conducted a retrospective, 2-year, observational, single-centre study to evaluate clinical outcome and risk factors for E-BSI mortality in internal medicine wards. 201patients with E-BSI were included in the analysis. Infection rate was 2.4/1000 days of hospital admission. Most E-BSI were hospital acquired (78.1%). The median age was 68 years. Charlson Comorbidity Index, adjusted for age, was 5 (range 4-6). Patients with E-BSI frequently had at least one invasive device, predominantly a central venous (73%) or a bladder catheter (61.7%). Enterococcus faecium accounted for 47.94% of E-BSI (resistance rate to ampicillin or vancomycin was 22.2 and 23.3%, respectively) and Enterococcus faecalis for 52.08% (resistance rate to ampicillin or vancomycin was 3.1 and 2.2%, respectively). Among all E-BSI, 25% of patients received appropriate therapy. In total, 59% of E-BSI underwent echocardiography. At the multivariate analysis, resistance to vancomycin (OR 2.09, p = 0.025), sepsis (OR 2.57, p = 0.003) and septic shock (OR 3.82, p = 0.004) was a predictor of mortality. No difference in 28-day survival was observed between appropriate or inappropriate treatment, except for endocarditis. However, E-BSI sources in clinical practices are not always properly investigated, including the rule-out of intracardiac vegetations. We did not demonstrate a difference in mortality for inappropriate therapy in the absence of endocarditis in comorbid patients with a long history of medicalization.

Clinical profile and outcome of recurrent infective endocarditis

AIMS

Purpose of this study is to compare the clinical course and outcome of patients with recurrent versus first-episode infective endocarditis (IE).

METHODS

Patients with recurrent and first-episode IE enrolled in the EUROpean ENDOcarditis (EURO-ENDO) registry including 156 centres were identified and compared using propensity score matching. Recurrent IE was classified as relapse when IE occurred ≤6 months after a previous episode or reinfection when IE occurred >6 months after the prior episode.

RESULTS

3106 patients were enrolled: 2839 (91.4%) patients with first-episode IE (mean age 59.4 (±18.1); 68.3% male) and 267 (8.6%) patients with recurrent IE (mean age 58.1 (±17.7); 74.9% male). Among patients with recurrent IE, 13.2% were intravenous drug users (IVDUs), 66.4% had a repaired or replaced valve with the tricuspid valve being more frequently involved compared with patients with first-episode IE (20.3% vs 14.1%; p=0.012). In patients with a first episode of IE, the aortic valve was more frequently involved (45.6% vs 39.5%; p=0.061). Recurrent relapse and reinfection were 20.6% and 79.4%, respectively. Staphylococcus aureus was the microorganism most frequently observed in both groups (p=0.207). There were no differences in in-hospital and post-hospitalisation mortality between recurrent and first-episode IE. In patients with recurrent IE, in-hospital mortality was higher in IVDU patients. Independent predictors of poorer in-hospital and 1-year outcome, including the occurrence of cardiogenic and septic shock, valvular disease severity and failure to undertake surgery when indicated, were similar for recurrent and first-episode IE.

CONCLUSIONS

In-hospital and 1-year mortality was similar in patients with recurrent and first-episode IE who shared similar predictors of poor outcome.

Relationship among Streptococcus gallolyticus Subsp. gallolyticus, Enterococcus faecalis and Colorectal Neoplasms in Recurrent Endocarditis: A Historical Case Series

Objectives: The role of colorectal neoplasms (CRN) as a common potential source of recurrent Streptococcus gallolyticus subsp. gallolyticus (SGG) and Enterococcus faecalis (EF) endocarditis remains unstudied. We aimed to investigate what proportion of episodes of recurrent endocarditis are caused by a succession of SGG and EF, or vice versa, and to assess the role of a colonic source in such recurrent episodes. Methods: we conducted a retrospective analysis of two prospective endocarditis cohorts (1979–2019) from two Spanish hospitals, providing descriptive analyses of the major features of the endocarditis episodes, colonoscopy findings, and histologic results. Results: among 1552 IE episodes, 204 (13.1%) were caused by EF and 197 (12.7%) by SGG, respectively. There were 155 episodes (10%) of recurrent IE, 20 of which (12.9%) were due to a succession of SGG/EF IE in 10 patients (the first episode caused by SGG in eight cases, and by EF in two cases). The median follow-up was 86 (interquartile range 34–156) months. In 8/10 initial episodes, the causative microorganism was SGG, and all patients were diagnosed with CRN either during the initial episode or during follow-up. During the second episode of IE or follow-up, colonoscopies revealed CRN in six patients. Conclusions: There seems to be an association between SGG and EF in recurrent endocarditis that warrants further investigation. Our findings reinforce the need for systematically performing colonoscopy in the event of endocarditis caused by both microorganisms.

Anesthesia Considerations in Infective Endocarditis

The management of infective endocarditis is complex and inherently requires multidisciplinary cooperation. About half of all patients diagnosed with infective endocarditis will meet the criteria to undergo cardiac surgery, which regularly takes place in urgent or emergency settings. The pathophysiology and clinical presentation of infective endocarditis make it a unique disorder within cardiac surgery that warrants a thorough understanding of specific characteristics in the perioperative period. This includes, among others, echocardiography, coagulation, bleeding management, or treatment of organ dysfunction. In this narrative review article, the authors summarize the current knowledge on infective endocarditis relevant for the clinical anesthesiologist in perioperative management of respective patients. Furthermore, the authors advocate for the anesthesiologist to become a structural member of the endocarditis team.

Ampicillin Plus Ceftriaxone Combined Therapy for Enterococcus faecalis Infective Endocarditis in OPAT

Ampicillin plus ceftriaxone (AC) is a well-recognized inpatient regimen for Enterococcus faecalis infective endocarditis (IE). In this regimen, ceftriaxone is usually administered 2 g every 2 h (AC12). The administration of AC in outpatient parenteral antibiotic treatment (OPAT) programs is challenging because multiple daily doses are required. AC regimens useful for OPAT programs include once-daily high-dose administration of ceftriaxone (AC24) or AC co-diluted and jointly administered in bolus every 4 h (ACjoined). In this retrospective analysis of prospectively collected cases, we aimed to assess the clinical effectivity and safety of three AC regimens for the treatment of E. faecalis IE. Fifty-nine patients were treated with AC combinations (AC12 n = 32, AC24 n = 17, and ACjoined n = 10). Six relapses occurred in the whole cohort: five (29.4%) treated with AC24 regimen and one (10.0%) with ACjoined. Patients were cured in 30 (93.3%), 16 (94.1%), and eight (80.0%) cases in the AC12, AC24 and ACjoined groups, respectively. Unplanned readmission occurred in eight (25.0%), six (35.3%), and two (20.0%) patients in the AC12, AC24 and ACjoined groups, respectively. The outcome of patients with E. faecalis IE treated with AC in OPAT programs relies on an optimization of the delivery of the combination. AC24 exhibit an unexpected rate of failures, however, ACjoined might be an effective alternative which clinical results should corroborate in further studies.

Ampicillin-Ceftriaxone vs Ampicillin-Gentamicin for Definitive Therapy of Enterococcus faecalis Infective Endocarditis: A Propensity Score-Matched, Retrospective Cohort Analysis

Background

Ampicillin-ceftriaxone (AC) has emerged as an alternative antibiotic regimen for enterococcal infective endocarditis (EIE) with reduced toxicity compared with ampicillin-gentamicin (AG), but evidence regarding its success in reducing EIE-associated death in the United States is limited.

Methods

We conducted a retrospective, propensity score–matched cohort analysis of EIE patients treated with AC or AG between 2010 and 2017 at 3 hospitals in Pittsburgh, Pennsylvania. We assessed all-cause 90-day mortality as the primary outcome and in-hospital mortality, length of hospital stay, hospital readmissions, adverse events, and relapse of bacteremia as the secondary outcomes.

Results

A total of 190 patients with EIE (100 treated with AC and 90 with AG) were included. Ninety-day mortality was significantly higher with AC than AG (21% vs 8%; P = .02). After propensity score matching, 56 patients in each group remained for the outcomes analysis. Documented aminoglycoside resistance, presence of annular or aortic abscess, and complete pacemaker removal were the significantly different variables between the 2 matched cohorts. We observed no statistically significant difference in 90-day mortality between the 2 treatment groups (11% vs 7%; P = .55). Adverse events were more common in patients treated with AG (25 vs 39; P = .0091), and more patients in the propensity score–matched AG cohort switched antibiotic regimens than in the AC group (10% vs 49%; P < .0001).

Conclusions

Patients treated with AC demonstrate no significant differences in mortality, treatment failure, or bacteremia relapse compared with AG in a propensity score–matched EIE cohort.

Enterococcus hirae bacteremia associated with acute pyelonephritis in a patient with alcoholic cirrhosis: a case report and literature review

BACKGROUND

Infections caused by Enterococcus hirae are common in animals, with instances of transmission to humans being rare. Further, few cases have been reported in humans because of the difficulty in identifying the bacteria. Herein, we report a case of pyelonephritis caused by E. hirae bacteremia and conduct a literature review on E. hirae bacteremia.

CASE PRESENTATION

A 57-year-old male patient with alcoholic cirrhosis and neurogenic bladder presented with fever and chills that had persisted for 3 days. Physical examination revealed tenderness of the right costovertebral angle. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) of the patient's blood and urine samples revealed the presence of E. hirae, and pyelonephritis was diagnosed. The patient was treated successfully with intravenous ampicillin followed by oral linezolid for a total of three weeks.

CONCLUSION

The literature review we conducted revealed that E. hirae bacteremia is frequently reported in urinary tract infections, biliary tract infections, and infective endocarditis and is more likely to occur in patients with diabetes, liver cirrhosis, and chronic kidney disease. However, mortality is not common because of the high antimicrobial susceptibility of E. hirae. With the advancements in MALDI-TOF MS, the number of reports of E. hirae infections has also increased, and clinicians need to consider E. hirae as a possible causative pathogen of urinary tract infections in patients with known risk factors.

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.

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.

Infective Endocarditis in Patients on Chronic Hemodialysis

BACKGROUND

Infective endocarditis (IE) is a common and serious complication in patients receiving chronic hemodialysis (HD).

OBJECTIVES

This study sought to investigate whether there are significant differences in complications, cardiac surgery, relapses, and mortality between IE cases in HD and non-HD patients.

METHODS

Prospective cohort study (International Collaboration on Endocarditis databases, encompassing 7,715 IE episodes from 2000 to 2006 and from 2008 to 2012). Descriptive analysis of baseline characteristics, epidemiological and etiological features, complications and outcomes, and their comparison between HD and non-HD patients was performed. Risk factors for major embolic events, cardiac surgery, relapses, and in-hospital and 6-month mortality were investigated in HD-patients using multivariable logistic regression.

RESULTS

A total of 6,691 patients were included and 553 (8.3%) received HD. North America had a higher HD-IE proportion than the other regions. The predominant microorganism was Staphylococcus aureus (47.8%), followed by enterococci (15.4%). Both in-hospital and 6-month mortality were significantly higher in HD versus non-HD-IE patients (30.4% vs. 17% and 39.8% vs. 20.7%, respectively; p < 0.001). Cardiac surgery was less frequently performed among HD patients (30.6% vs. 46.2%; p < 0.001), whereas relapses were higher (9.4% vs. 2.7%; p < 0.001). Risk factors for 6-month mortality included Charlson score (hazard ratio [HR]: 1.26; 95% confidence interval [CI]: 1.11 to 1.44; p = 0.001), CNS emboli and other emboli (HR: 3.11; 95% CI: 1.84 to 5.27; p < 0.001; and HR: 1.73; 95% CI: 1.02 to 2.93; p = 0.04, respectively), persistent bacteremia (HR: 1.79; 95% CI: 1.11 to 2.88; p = 0.02), and acute onset heart failure (HR: 2.37; 95% CI: 1.49 to 3.78; p < 0.001).

CONCLUSIONS

HD-IE is a health care-associated infection chiefly caused by S. aureus, with increasing rates of enterococcal IE. Mortality and relapses are very high and significantly larger than in non-HD-IE patients, whereas cardiac surgery is less frequently performed.

Outcomes and Risk Factors of Septic Shock in Patients With Infective Endocarditis: A Prospective Cohort Study

Background

Little is known about the characteristics and impact of septic shock (SS) on the outcomes of infective endocarditis (IE). We aimed to investigate the characteristics and outcomes of patients with IE presenting with SS and to compare them to those of IE patients with sepsis (Se) and those with neither Se nor SS (no-Se-SS).

Methods

This is a prospective cohort study of 4864 IE patients from 35 Spanish centers (2008 to 2018). Logistic regression analyses were performed to identify risk factors for SS and mortality.

Results

Septic shock and Se presented in 597 (12.3%) and 559 (11.5%) patients, respectively. Patients with SS were younger and presented significantly higher rates of diabetes, chronic renal and liver disease, transplantation, nosocomial acquisition, Staphylococcus aureus, IE complications, and in-hospital mortality (62.5%, 37.7% for Se and 18.2% for no-Se-SS, P < .001). Staphylococcus aureus (odds ratio [OR], 1.94; 95% confidence interval [CI], 1.34–2.81; P < .001), Gram negative (OR, 2.21; 95% CI, 1.25–3.91; P = .006), nosocomial acquisition (OR, 1.44; 95% CI, 1.07–1.94; P = .015), persistent bacteremia (OR, 1.82; 95% CI, 1.24–2.68; P = .002), acute renal failure (OR, 3.02; 95% CI, 2.28–4.01; P < .001), central nervous system emboli (OR, 1.48; 95% CI, 1.08–2.01; P = .013), and larger vegetation size (OR, 1.01; 95% CI, 1.00–1.02; P. = 020) were associated with a higher risk of developing SS. Charlson score, heart failure, persistent bacteremia, acute renal failure, mechanical ventilation, worsening of liver disease, S aureus, and receiving aminoglycosides within the first 24 hours were associated with higher in-hospital mortality, whereas male sex, native valve IE, and cardiac surgery were associated with lower mortality.

Conclusions

Septic shock is frequent and entails dismal prognosis. Early identification of patients at risk of developing SS and early assessment for cardiac surgery appear as key factors to improve outcomes.

Characteristics and outcome of acute heart failure in infective endocarditis: focus on cardiogenic shock

BACKGROUND

Studies investigating the impact of cardiogenic shock (CS) on endocarditis are lacking. We aimed to investigate the characteristics and outcomes of endocarditis patients presenting with acute heart failure (AHF), particularly of those developing CS.

METHODS

Prospectively collected cohort from 35 Spanish centers (2008-2018). Logistic regression analyses were performed to identify risk factors for developing CS and predictors of mortality.

RESULTS

Amongst 4,856 endocarditis patients, 1,652 (34%) had AHF and 244 (5%) CS. Compared to patients without AHF and AHF but no CS, patients with CS presented higher rates of surgery (40.5%, 52.5% and 68%,p<.001) and in-hospital mortality (16.3%,39.1%, and 52.5%). Compared to patients with septic shock, CS patients presented higher rates of surgery (42.5% vs. 68%, p<.001), and lower rates of in-hospital and 1-year mortality (62.3% vs. 52.5%,p.008;and 65.3% vs. 57.4%,p.030). Severe aortic and mitral regurgitation (OR 2.47, 95%CI 1.82-3.35 and OR 3.03, 95%CI 2.26-4.07, both p<.001), left-ventricle ejection fraction<60% (OR 1.72, 95%CI 1.22-2.40, p.002), heart block (OR 2.22, 95%CI 1.41-3.47, p.001), tachyarrhythmias (OR 5.07,95%CI 3.13-8.19, p<.001) and acute kidney failure (OR 2.29, 95%CI 1.73-3.03,p<.001) were associated to a higher likelihood of developing CS. Prosthetic endocarditis (OR 2.03, 95%CI 1.06-3.88, p.032), S. aureus (OR 3.10, 95%CI 1.16-8.30, p.024), tachyarrhythmias (OR 3.09,95%CI 1.50-10.13, p.005), and not performing cardiac surgery (OR 11.40, 95%CI 4.83-26.90, p<.001) were associated to a higher risk of mortality.

CONCLUSIONS

Acute heart failure is common among patients with endocarditis. Cardiogenic shock is associated to very high mortality and should be promptly identified and assessed for cardiac surgery.

Prospective Cohort Study of Infective Endocarditis in People Who Inject Drugs

BACKGROUND

Infective endocarditis (IE) in people who inject drugs (PWID) is an emergent public health problem.

OBJECTIVES

The purpose of this study was to investigate IE in PWID and compare it with IE in non-PWID patients.

METHODS

Two prospective cohort studies (ICE-PCS and ICE-Plus databases, encompassing 8,112 IE episodes from 2000 to 2006 and 2008 to 2012, with 64 and 34 sites and 28 and 18 countries, respectively). Outcomes were compared between PWID and non-PWID patients with IE. Logistic regression analyses were performed to investigate risk factors for 6-month mortality and relapses amongst PWID.

RESULTS

A total of 7,616 patients (591 PWID and 7,025 non-PWID) were included. PWID patients were significantly younger (median 37.0 years [interquartile range: 29.5 to 44.2 years] vs. 63.3 years [interquartile range: 49.3 to 74.0 years]; p < 0.001), male (72.5% vs. 67.4%; p = 0.007), and presented lower rates of comorbidities except for human immunodeficiency virus, liver disease, and higher rates of prior IE. Amongst IE cases in PWID, 313 (53%) episodes involved left-side valves and 204 (34.5%) were purely left-sided IE. PWID presented a larger proportion of native IE (90.2% vs. 64.4%; p < 0.001), whereas prosthetic-IE and cardiovascular implantable electronic device-IE were more frequent in non-PWID (9.3% vs. 27.0% and 0.5% vs. 8.6%; both p < 0.001). Staphylococcus aureus caused 65.9% and 26.8% of cases in PWID and non-PWID, respectively (p < 0.001). PWID presented higher rates of systemic emboli (51.1% vs. 22.5%; p < 0.001) and persistent bacteremia (14.7% vs. 9.3%; p < 0.001). Cardiac surgery was less frequently performed (39.5% vs. 47.8%; p < 0.001), and in-hospital and 6-month mortality were lower in PWID (10.8% vs. 18.2% and 14.4% vs. 22.2%; both p < 0.001), whereas relapses were more frequent in PWID (9.5% vs. 2.8%; p < 0.001). Prior IE, left-sided IE, polymicrobial etiology, intracardiac complications, and stroke were risk factors for 6-month mortality, whereas cardiac surgery was associated with lower mortality in the PWID population.

CONCLUSIONS

A notable proportion of cases in PWID involve left-sided valves, prosthetic valves, or are caused by microorganisms other than S. aureus.

Is Once-Daily High-Dose Ceftriaxone plus Ampicillin an Alternative for Enterococcus faecalis Infective Endocarditis in Outpatient Parenteral Antibiotic Therapy Programs?

Ceftriaxone administered as once-daily high-dose short infusion combined with ampicillin has been proposed for the treatment of Enterococcus faecalis infective endocarditis in outpatient parenteral antibiotic therapy programs (OPAT). This combination requires synergistic activity, but the attainment of ceftriaxone synergic concentration (Cs) with the regimen proposed for OPAT has not been studied. This phase II pharmacokinetic study enrolled healthy adult volunteers who underwent two sequential treatment phases. During phase A, volunteers received 2 g of ceftriaxone each 12 h during 24 h followed by a 7-day wash-out. Then the participants received phase B, which consisted of a single dose of 4 g of ceftriaxone. Throughout both phases, each volunteer underwent intensive pharmacokinetic (PK) sampling over 24 h. Ceftriaxone total and unbound concentrations were measured. Twelve participants were enrolled and completed both phases. Mean ceftriaxone total and free concentrations 24 h after the administration of 2 g each 12 h were 86.44 ± 25.90 mg/liter and 3.59 ± 1.35 mg/liter, respectively, and after the 4-g single dose were 34.60 ± 11.16 mg/liter and 1.40 ± 0.62 mg/liter, respectively. Only 3 (25%) patients in phase A maintained unbound plasma concentrations superior to the suggested Cs = 5 mg/liter during 24 h, and none (0%) in phase B. No grade 3 to 4 adverse events or laboratory abnormalities were observed. Ceftriaxone optimal exposure combined with ampicillin to achieve maximal synergistic activity against E. faecalis required for the treatment of infective endocarditis remains unknown. However, the administration of a single daily dose of 4 g of ceftriaxone implies a reduction in the time of exposure to the proposed Cs. (This study has been registered in the European Union Drug Regulating Authorities Clinical Trials [EudraCT] database under identifier 2017-003127-29.).

A review of current treatment strategies for infective endocarditis

INTRODUCTION

Infective endocarditis is one of the most difficult-to-treat infectious diseases.

AREAS COVERED

We restricted this review to the anti-infective treatment of the main bacteria responsible for infective endocarditis, i.e. staphylococci, streptococci, enterococci, and Gram-negative bacilli, including HACEK. Specific topics of major interest in treatment strategy are covered as well, including empirical treatment, oral switch, and treatment duration. We searched in the MEDLINE database to identify relevant studies, trials, reviews, or meta-analyses until May 2020.

EXPERT OPINION

The use of aminoglycosides for the treatment of endocarditis has been dramatically reduced over the last 20 years. It should be administered once daily, and no longer than 2 weeks. For staphylococcal endocarditis, recent data reinforced the role of anti-staphylococcal penicillins, for methicillin-susceptible isolates (alternative, cefazolin), and vancomycin for methicillin-resistant isolates (alternative, daptomycin). For staphylococcal prosthetic-valve endocarditis, these treatments will be reinforced by the addition of gentamicin during the first 2 weeks, and rifampin throughout the whole treatment duration, i.e. 6 weeks. The optimal duration of antibacterial treatment is 4 weeks for most native valve endocarditis, and 6 weeks for prosthetic-valve endocarditis. The oral switch is safe in patients stabilized after the initial intravenous course.