Infective endocarditis: an ongoing global challenge

Aerococcus urinae endocarditis - A case report

Aerococcus urinae is a gram-positive coccus bacterium with a previously underestimated prevalence due to morphological similarities to other gram-positive cocci. Development of newer diagnostic technologies (such as matrix-assisted laser desorption ionization time-of-flight mass spectrometry MALDI-TOF) led to increased recognition of Aerococcus urinae as causative organism mainly for urinary tract infections. Its antibiotic susceptibility poses some challenges, with resistance to some drugs of choice for urinary tract infection. We report a case of a 69-year-old male with infective endocarditis of the mitral valve, who initially presented with fever and shoulder pain to the emergency department. The patient reported an episode of obstructive renal infection two weeks earlier, which was treated with trimethoprim-sulfamethoxazole. The unusual presentation with shoulder pain and a new heart murmur led to suspicion of endocarditis. Urine and blood cultures were positive for Aerococcus urinae, echocardiography revealed vegetations on the mitral valve with severe mitral insufficiency. After two weeks of antibiotic treatment, mitral valve replacement was performed, from which the patient recovered. Reports of Aerococcus urinae endocarditis are still limited in number. On the other side, Aerococcus urinae is an emerging bacterial uropathogen with greater relevance than previously believed. We review the case reports of Aerococcus urinae endocarditis and newest literature about its presentation, course, and clinical management.

Infective endocarditis in HIV-infected patients. Analysis of a national cohort

BACKGROUND

There is limited recent evidence about infective endocarditis (IE) in HIV-infected patients. Our aim was to compare IE according to HIV infection presence.

METHODS

Consecutive inclusion of IE patients at 46 Spanish hospitals between 2008 and 2021.

RESULTS

From 5667 patients, 99 were HIV-infected (1·7%; 50 intravenous drugs users). Compared to patients without HIV, HIV-infected patients were more frequently male (84% vs. 67%), had younger median age (46 vs. 69 years), and less comorbidities, except liver disease (52% vs. 9%) and intravenous drug use (51% vs. 1%). They had more common tricuspid location (36% vs. 5%) and community-acquired IE (82% vs. 63%), vascular (29% vs. 17%) and cutaneous (22% vs. 7%) foci of infection, and Staphylococcus aureus aetiology (46% vs. 22%). Vegetations (84% vs. 72%), vascular phenomena (17% vs. 9%), splenomegaly (30% vs. 11%), and embolisation (41% vs 21%) were also more common. Surgical indication and surgery were less frequent in HIV-infected patients (54% vs 67%, 28% vs 47%, respectively). Median CD4 count in HIV-infected patients was 318 cells/mm3. In-hospital mortality (23% vs. 26%) and one-year mortality (25% vs. 32%) were similar in both groups. HIV infection was not independently associated with in-hospital (odds ratio 1·1, 95% CI 0·6-1·9) nor one-year mortality (hazard ratio 0·8, 95% CI 0·4-1·3).

CONCLUSIONS

In the combined antiretroviral therapy era, less than 2% of IE patients have HIV infection. HIV-infected patients have a different clinical profile than those without HIV, but the presence of HIV does not seem to impact on IE prognosis.

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.

Conservative Versus Surgical Therapy in Patients With Infective Endocarditis and Surgical Indication-Meta-Analysis of Reconstructed Time-to-Event Data

BACKGROUND

Infective endocarditis represents a life-threatening disease with high mortality rates. A fraction of patients receives exclusively conservative antibiotic treatment due to their comorbidities and high operative risk, despite fulfilling criteria for surgical therapy. The aim of the present study is to compare outcomes in patients with infective endocarditis and indication for surgical therapy in those who underwent or did not undergo valve surgery.

METHODS AND RESULTS

Three databases were systematically assessed. A pooled analysis of Kaplan-Meier-derived reconstructed time-to-event data from studies with longer follow-up comparing conservative and surgical treatment was performed. A landmark analysis to further elucidate the effect of surgical intervention on mortality was carried out. Four studies with 3003 patients and median follow-up time of 7.6 months were included. Overall, patients with an indication for surgery who were surgically treated had a significantly lower risk of mortality compared with patients who received conservative treatment (hazard ratio [HR], 0.27 [95% CI, 0.24-0.31], P<0.001). The survival analysis in the first year showed superior survival for patients who underwent surgery when compared with those who did not at 1 month (87.6% versus 57.6%; HR, 0.31 [95% CI, 0.26-0.37], P<0.01), at 6 months (74.7% versus 34.6%) and at 12 months (73.3% versus 32.7%).

CONCLUSIONS

Based on the findings of this study-level meta-analysis, patients with infective endocarditis and formal indication for surgical intervention who underwent surgery are associated with a lower risk of short- and long-term mortality when compared with conservative treatment.

Patients with Artificial Heart Valves

BACKGROUND

In Germany, a total of 38 547 heart valve procedures were performed in 2022. With a growing number of patients undergoing the surgical and interventional implantation of heart valves, the incidence of prosthetic endocarditis is also rising.

METHODS

We summarize the current state of the prophylaxis, diagnosis, and treatment of prosthetic endocarditis in a selective review of the literature.

RESULTS

Prosthetic endocarditis accounts for 10-30% of all cases of endocarditis. As its echocardiographic and microbiologic findings are often less specific than those of native endocarditis, its diagnosis now increasingly relies on alternative imaging modalities such as F-18-FDG PET-CT. Anti-infective and surgical treatment are made more difficult by biofilm formation on the prosthetic valve and the frequent formation of perivalvular abscesses.

CONCLUSION

Increased awareness of this clinical entity in the outpatient setting will promote the earlier initiation of appropriate diagnostic studies. Proper diagnostic evaluation is an essential prerequisite for the early detection and timely treatment of prosthetic endocarditis, with the goal of preventing progressive destruction and thus improving the outcome. Preventive and educative measures should be intensified, and certified, multidisciplinary endocarditis teams should be established. Antibiotic prophylaxis is now given much more restrictively than in earlier years; the risk of infection must be weighed against the potential development of both individual and collective resistance to antibiotic drugs.

Risk factors of prolonged intensive care unit stay following cardiac surgery for infective endocarditis

INTRODUCTION

Prolonged intensive care unit (ICU) stay is common in serious patients undergoing cardiac surgery. Prolonged ICU stay is associated with increased mortality and worse prognosis. This study was conducted to determine the risk factors for prolonged ICU stay after cardiac surgery for infective endocarditis (IE) and we try to decrease the operative risk of mortality and morbidity of cardiac surgery for IE.

METHODS

The retrospective study of patients with IE undergoing cardiac surgery between January 2006 and November 2022 at our hospital was performed.

RESULTS

896 patients undergoing cardiac surgery were divided into group of ICU stay ≤ 3d (n = 416) and group p of ICU stay > 3d (n = 480). There were 48 operative deaths (5.4%). Univariable and multivariable analyses showed that factors are associated with prolonged ICU stay following cardiac surgery for IE, including male (P < .001), age (P < .001), weight (P = .009), vegetation length (P < .001), paravalvular leak (P < .001), aortic cross-clamp time (P < .001), cardiopulmonary bypass (CPB) time (P < .001), mechanical ventilation time (P < .001), hospitalized time postoperative (P = .032), creatinine of serum before surgery (P < .001), creatinine of serum 24h after surgery (P = .005), creatinine of serum 48h after surgery (P < .001), fluid balance on operation day (P < .001), postoperative acute kidney injury (P < .001), left ventricular end diastolic dimension (LVEDD) preoperative (P < .001), LVEDD postoperative (P < .001), chest drainage (P = .032), frozen plasma (P = .016), preoperative aortic insufficiency (P < .001), and packed red cells (P < .001).

CONCLUSIONS

In our study, shortness of ICU stay and optimization of pre-, peri-, and postoperative factors that can shorten ICU stay, therefore, contribute to a better postoperative outcome and leads to lower rates of mortality and morbidity.

Epidemiological Changes and Improvement in Outcomes of Infective Endocarditis in Europe in the Twenty-First Century: An International Collaboration on Endocarditis (ICE) Prospective Cohort Study (2000-2012)

INTRODUCTION

Infective endocarditis (IE) has undergone important changes in its epidemiology worldwide.

METHODS

The study aimed to compare IE epidemiological features and outcomes according to predefined European regions and between two different time periods in the twenty-first century.

RESULTS

IE cases from 13 European countries were included. Two periods were considered: 2000-2006 and 2008-2012. Two European regions were considered, according to the United Nations geoscheme for Europe: Southern (SE) and Northern-Central Europe (NCE). Comparisons were performed between regions and periods. A total of 4195 episodes of IE were included, 2113 from SE and 2082 from NCE; 2787 cases were included between 2000 and 2006 and 1408 between 2008 and 2012. Median (IQR) age was 63.7 (49-74) years and 69.4% were males. Native valve IE (NVE), prosthetic valve IE (PVE), and device-related IE were diagnosed in 68.3%, 23.9%, and 7.8% of cases, respectively; 52% underwent surgery and 19.3% died during hospitalization. NVE was more prevalent in NCE, whereas device-related IE was more frequent in SE. Higher age, acute presentation, hemodialysis, cancer, and diabetes mellitus all were more prevalent in the second period. NVE decreased and PVE and device-related IE both increased in the second period. Surgical treatment also increased from 48.7% to 58.4% (p < 0.01). In-hospital and 6-month mortality rates were comparable between regions and significantly decreased in the second period.

CONCLUSIONS

Despite an increased complexity of IE cases, prognosis improved in recent years with a significant decrease in 6-month mortality. Outcome did not differ according to the European region (SE versus NCE).

New Perspectives for Prosthetic Valve Endocarditis: Impact of Molecular Imaging by FISHseq Diagnostics

BACKGROUND

The microbial etiology of prosthetic valve infective endocarditis (PVE) can be difficult to identify. Our aim was to investigate the benefit of molecular imaging technique fluorescence in situ hybridization (FISH) combined with 16S rRNA-gene polymerase chain reaction (PCR) and sequencing (FISHseq) for the analysis of infected prosthetic heart valves.

METHODS

We retrospectively evaluated the diagnostic outcome of 113 prosthetic valves from 105 patients with suspected PVE, treated in 2003-2013 in the Department of Cardiac Surgery, Charité University Medicine Berlin. Each prosthetic valve underwent cultural diagnostics and was routinely examined by FISH combined with 16S rRNA gene PCR and sequencing. We compared classical microbiological culture outcomes (blood and valve cultures) with FISHseq results and evaluated the diagnostic impact of the molecular imaging technique.

RESULTS

Conventional microbiological diagnostic alone turned out to be insufficient, as 67% of preoperative blood cultures were noninformative (negative, inconclusive, or not obtained) and 67% of valve cultures remained negative. FISHseq improved the conventional cultural diagnostic methods in PVE in 30% of the cases and increased diagnostic accuracy. Of the valve culture-negative PVE cases, FISHseq succeeded in identifying the causative pathogen in 35%.

CONCLUSIONS

FISHseq improves PVE diagnostics, complementing conventional cultural methods. In addition to species identification, FISH provides information about the severity of PVE and state of the pathogens (eg, stage of biofilm formation, activity, and localization on and within the prosthetic material). As a molecular imaging technique, FISHseq enables the unambiguous discrimination of skin flora as contaminant or infectious agent.

Emerging issues on Staphylococcus aureus endocarditis and the role in therapy of daptomycin plus fosfomycin

INTRODUCTION

Methicillin-resistant and -susceptible Staphylococcus aureus (MRSA/MSSA) infections are a major global health-care problem. Bacteremia with S. aureus exhibits high rates of morbidity and mortality and can cause complicated infections such as infective endocarditis (IE). The emerging resistance profile of S. aureus is worrisome, and several international agencies have appealed for new treatment approaches to be developed.

AREAS COVERED

Daptomycin presents a rapid bactericidal effect against MRSA and has been considered at least as effective as vancomycin in treating MRSA bacteremia. However, therapy failure is often related to deep-seated infections, e.g. endocarditis, with high bacterial inocula and daptomycin regimens <10 mg/kg/day. Current antibiotic options for treating invasive S. aureus infections have limitations in monotherapy. Daptomycin in combination with other antibiotics, e.g. fosfomycin, may be effective in improving clinical outcomes in patients with MRSA IE.

EXPERT OPINION

Exploring therapeutic combinations has shown fosfomycin to have a unique mechanism of action and to be the most effective option in preventing the onset of resistance to and optimizing the efficacy of daptomycin, suggesting the synergistic combination of fosfomycin with daptomycin is a useful alternative treatment option for MSSA or MRSA IE.

Advances in Molecular Imaging in Infective Endocarditis

Infective endocarditis (IE) is a growing epidemiological challenge. Appropriate diagnosis remains difficult due to heterogenous etiopathogenesis and clinical presentation. The disease may be followed by increased mortality and numerous diverse complications. Developing molecular imaging modalities may provide additional insights into ongoing infection and support an accurate diagnosis. We present the current evidence for the diagnostic performance and indications for utilization in current guidelines of the hybrid modalities: single photon emission tomography with technetium99m-hexamethylpropyleneamine oxime-labeled autologous leukocytes (99mTc-HMPAO-SPECT/CT) along with positron emission tomography with fluorodeoxyglucose (18F-FDG PET/CT). The role of molecular imaging in IE diagnostic work-up has been constantly growing due to technical improvements and the increasing evidence supporting its added diagnostic and prognostic value. The various underlying molecular processes of 99mTc-HMPAO-SPECT/CT as well as 18F-FDG PET/CT translate to different imaging properties, which should be considered in clinical practice. Both techniques provide additional diagnostic value in the assessment of patients at risk of IE. Nuclear imaging should be considered in the IE diagnostic algorithm, not only for the insights gained into ongoing infection at a molecular level, but also for the determination of the optimal clinical therapeutic strategies.

Risk scores' performance and their impact on operative decision-making in left-sided endocarditis: a cohort study

The accuracy of contemporary risk scores in predicting perioperative mortality in infective endocarditis (IE) remains controversial. The aim is to evaluate the performance of existent mortality risk scores for cardiovascular surgery in IE and the impact on operability at high-risk thresholds. A single-center retrospective review of adult patients diagnosed with acute left-sided IE undergoing surgery from May 2014 to August 2019 (n = 142) was done. Individualized risk calculation was obtained according to the available mortality risk scores: EuroScore I and II, PALSUSE, Risk-E, Costa, De Feo-Cotrufo, AEPEI, STS-risk, STS-IE, APORTEI, and ICE-PCS scores. A cross-validation analysis was performed on the score with the best area under the curve (AUC). The 30-day survival was 96.5% (95%CI 91-98%). The score with worse area under the curve (AUC = 0.6) was the STS-IE score, while the higher was for the RISK-E score (AUC = 0.89). The AUC of the majority of risk scores suggested acceptable performance; however, statistically significant differences in expected versus observed mortalities were common. The cross-validation analysis showed that a large number of survivors (> 75%) would not have been operated if arbitrary high-risk threshold estimates had been used to deny surgery. The observed mortality in our cohort is significantly lower than is predicted by contemporary risk scores. Despite the reasonable numeric performance of the analyzed scores, their utility in judging the operability of a given patient remains questionable, as demonstrated in the cross-validation analysis. Future guidelines may advise that denial of surgery should only follow a highly experienced Endocarditis Team evaluation.

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).

Infective Endocarditis: Clinical Characteristics and Echocardiographic Findings

Purpose

Infective endocarditis (IE) remains a disease with high morbidity and mortality. The aim of this study was to determine the clinical characteristics and echocardiographic features of patients with IE.

Methods

We analyzed patients with either definitive or probable diagnosis of IE who were hospitalized in a teaching hospital in Mashhad, Iran between June 2011 and January 2020. Patients who survived were followed up by echocardiography for at least 6-month after hospital discharge.

Results

A total of 82 cases with IE were included of which 62 (75.6%) received definitive diagnosis. The mean age was 39.7 ± 18.7 years and 52 (63.4%) were male. The most common preexisting structural cardiac abnormality that predispose patients to IE were congenital heart diseases (28 %) of which bicuspid aortic valve was more common (n = 12, 14.6%), followed by ventricular septal defect (n = 9, 11%) and Tetralogy of Fallot (TOF) (n = 2, 2.4%). Three (3.6 %) cases had rheumatic heart disease and 12 (14.6 %) were injecting drug users. The most common causative pathogen was Staphylococcus aureus, detected in 7 (19.4%) cases. Follow-up echocardiography revealed right or left ventricular failure in 10 (12.1%) cases. Cardiac complications occurred in 41 (50%) cases and systemic complications in 63 (76.8%). All-cause mortality was 41.5% (n = 34) and 6 (18.1%) patients died due to cardiovascular complications.

Conclusions

The short- and long-term prognosis in IE was poor and the predictors for in-hospital and 1-year mortality were defined as heart failure and septic shock. Congenital heart disease and intravenous illicit drug using (IVDU) were the most common predisposing condition which may necessitate a revision in the IE prophylaxis recommendations.

Infective endocarditis treated in a secondary hospital: epidemiological, clinical, microbiological characteristics and prognosis, with special reference to patients transferred to a third level hospital

OBJECTIVE

To analyse the clinical and epidemiological characteristics and mortality-related factors of patients admitted to a secondary hospital with Infective Endocarditis (IE).

METHODS

Observational study of a cohort of patients who have been diagnosed with IE in a secondary hospital and evaluated in accordance with a pre-established protocol.

RESULTS

A total of 101 cases were evaluated (years 2000-2017), with an average age of 64 years and a male-to-female ratio of 2:1. 76% of the cases had an age-adjusted Charlson comorbidity index of >6, with 21% having had a dental procedure and 36% with a history of heart valve disease. The most common microorganism was methicillin-susceptible S. aureus (36%), with bacterial focus of unknown origin in 54%. The diagnostic delay time was 12 days in patients who were transferred, compared to 8 days in patients who were not transferred (p=0.07); the median surgery indication delay time was 5 days (IQR 13.5). The in-hospital mortality rate was 34.6% and the prognostic factors independently associated with mortality were: cerebrovascular events (OR 98.7%, 95% CI, 70.9-164.4); heart failure (OR 27.3, 95% CI, 10.2-149.1); and unsuitable antibiotic treatment (OR 7.2, 95% CI, 1.5-10.5). The mortality rate of the patients who were transferred and who therefore underwent surgery was 20% (5/25).

CONCLUSIONS

The onset of cerebrovascular events, heart failure and unsuitable antibiotic treatment are independently and significantly associated with in-hospital mortality. The mortality rate was higher than the published average (35%); the diagnostic delay was greater in patients for whom surgery was indicated.

The Diagnostic Value of 99mTc-HMPAO-Labelled White Blood Cell Scintigraphy and 18F-FDG PET/CT in Cardiac Device-Related Infective Endocarditis-A Systematic Review

(1) Background: Treatment of cardiac arrhythmias and conduction disorders with the implantation of a cardiac implantable electronic device (CIED) may lead to complications. Cardiac device-related infective endocarditis (CDRIE) stands out as being one of the most challenging in terms of its diagnosis and management. Developing molecular imaging modalities may provide additional insights into CDRIE diagnosis. (2) Methods: We performed a systematic literature review to critically appraise the evidence for the diagnostic performance of the following hybrid techniques: single photon emission tomography with technetium99m-hexamethylpropyleneamine oxime–labeled autologous leukocytes (99mTc-HMPAO-SPECT/CT) and positron emission tomography with fluorodeoxyglucose (18F-FDG PET/CT). An analysis was performed in accordance with PRISMA and GRADE criteria and included articles from PubMed, Embase and Cochrane databases. (3) Results: Initially, there were 2131 records identified which had been published between 1971–2021. Finally, 18 studies were included presenting original data on the diagnostic value of 99mTc-HMPAO-SPECT/CT or 18F-FDG PET/CT in CDRIE. Analysis showed that these molecular imaging modalities provide high diagnostic accuracy and their inclusion in diagnostic criteria improves CDRIE work-up. (4) Conclusions: 99mTc-HMPAO-SPECT/CT and 18F-FDG PET/CT provide high diagnostic value in the identification of patients at risk of CDRIE and should be considered for inclusion in the CDRIE diagnostic process.