Comparison of outcome in patients with culture-negative versus culture-positive active infective endocarditis

Understanding Bartonella-Associated Infective Endocarditis: Examining Heart Valve and Vegetation Appearance and the Role of Neutrophilic Leukocytes

BACKGROUND

The endocardium and cardiac valves undergo severe impact during infective endocarditis (IE), and the formation of vegetation places IE patients at a heightened risk of embolic complications and mortality. The relevant literature indicates that 50% of IE cases exhibit structurally normal cardiac valves, with no preceding history of heart valve disease. Gram-positive cocci emerge as the predominant causative microorganisms in IE, while Gram-negative Bartonella spp., persisting in the endothelium, follow pathogenic pathways distinct from those of typical IE-causing agents. Employing clinical as well as advanced microbiological and molecular assays facilitated the identification of causative pathogens, and various morphological methods were applied to evaluate heart valve damage, shedding light on the role of neutrophilic leukocytes in host defense. In this research, the immunohistochemical analysis of neutrophilic leukocyte activation markers such as myeloperoxidase, neutrophil elastase, calprotectin, and histone H3, was performed. A distinct difference in the expression patterns of these markers was observed when comparing Bartonella spp.-caused and non-Bartonella spp.-caused IE. The markers exhibited significantly higher expression in non-Bartonella spp.-caused IE compared to Bartonella spp.-caused IE, and they were more prevalent in vegetation than in the valvular leaflets. Notably, the expression of these markers in all IE cases significantly differed from that in control samples. Furthermore, we advocated the use of 16S rRNA Next-Generation Sequencing on excised heart valves as an effective diagnostic tool for IE, particularly in cases where blood cultures yielded negative results. The compelling results achieved in this study regarding the enigmatic nature of Bartonella spp. IE's pathophysiology contribute significantly to our understanding of the peculiarities of inflammation and immune responses.

Case report: Novel three-dimensional echocardiographic methods mapping aortic root pseudoaneurysm secondary to blood culture-negative endocarditis with bicuspid aortic valve involvement

Background

Infective endocarditis (IE), though uncommon, is a potentially lethal disease. Blood culture-negative endocarditis (BCNIE) accounts for 2.5%–31% of all cases of IE and can lead to life-threatening complications, including aortic root pseudoaneurysm. It is associated with considerable diagnostic and therapeutic dilemmas. TrueVue and TrueVue Glass include the latest two technologies applied in advanced three-dimensional echocardiography, which allow for novel photorealistic images of cardiac structures, and provide abundant previously unavailable diagnostic information. Herein, based on a series of novel three-dimensional echocardiographic methods, we report a case of BCNIE with aortic valve involvement, leading to aortic valve perforation and prolapse, and developing into a giant aortic root pseudoaneurysm.

Case summary

In this study, we presented a case of a 64-year-old man exhibiting symptoms of intermittent fever, asthenia, and dyspnea following light exertion. Physical examination, laboratory tests, and electrocardiograms were suspected of IE, though the results of blood cultures were exactly negative. Three-dimensional transthoracic echocardiography, as well as a series of novel advanced techniques, was adopted to clearly visualize the lesions of the aortic valve and aortic root. However, despite active medical treatment modalities, the patient eventually suffered from a sudden, unexpected death 5 days later.

Conclusion

BCNIE with aortic valve involvement and development into a giant aortic root pseudoaneurysm is a rare and serious clinical event. In addition, TrueVue and TrueVue Glass offer unprecedented photographic stereoscopic images, enhancing the diagnostic performance of such structural heart diseases.

Evaluation of Infective Endocarditis in Children: A 19-Year Retrospective Study in Taiwan

Background: Infective endocarditis (IE) is an important cause of morbidity and mortality in pediatric patients with heart disease. Little literature has explored differences in the presentation of endocarditis in children with and without heart disease. This study aimed to compare the clinical outcomes and determine the risk of in-hospital death in the study population. Methods: Data were retrospectively collected from 2001 to 2019 from the Chang Gung Research Database (CGRD), which is the largest collection of multi-institutional electronic medical records in Taiwan. Children aged 0–20 years with IE were enrolled. We extracted and analyzed the demographic and clinical features, complications, microbiological information, and outcomes of each patient. Results: Of the 208 patients with IE, 114 had heart disease and 94 did not. Compared to those without heart disease, more streptococcal infections (19.3% vs. 2.1%, p < 0.001) and cardiac complications (29.8% vs. 6.4%, p < 0.001) were observed in patients with heart disease. Although patients with heart disease underwent valve surgery more frequently (43.9% vs. 8.5%, p < 0.001) and had longer hospital stays (28.5 vs. 12.5, p = 0.021), their mortality was lower than that of those without heart disease (3.5% vs. 10.6%, p = 0.041). Thrombocytopenia was independent risk factor for in-hospital mortality in pediatric patients with IE (OR = 6.56, 95% CI: 1.43–40.37). Conclusion: Among pediatric patients diagnosed with IE, microbiological and clinical features differed between those with and without heart disease. Platelet counts can be used as a risk factor for in-hospital mortality in pediatric patients with IE.

Outcomes of culture-negative vs. culture-positive infective endocarditis: the ESC-EORP EURO-ENDO registry

AIM

Fatality of infective endocarditis (IE) is high worldwide, and its diagnosis remains a challenge. The objective of the present study was to compare the clinical characteristics and outcomes of patients with culture-positive (CPIE) vs. culture-negative IE (CNIE).

METHODS AND RESULTS

This was an ancillary analysis of the ESC-EORP EURO-ENDO registry. Overall, 3113 patients who were diagnosed with IE during the study period were included in the present study. Of these, 2590 (83.2%) had CPIE, whereas 523 (16.8%) had CNIE. As many as 1488 (48.1%) patients underwent cardiac surgery during the index hospitalization, 1259 (48.8%) with CPIE and 229 (44.5%) with CNIE. The CNIE was a predictor of 1-year mortality [hazard ratio (HR) 1.28, 95% confidence interval (CI) 1.04-1.56], whereas surgery was significantly associated with survival (HR 0.49, 95% CI 0.41-0.58). The 1-year mortality was significantly higher in CNIE than CPIE patients in the medical subgroup, but it was not significantly different in CNIE vs. CPIE patients who underwent surgery.

CONCLUSION

The present analysis of the EURO-ENDO registry confirms a higher long-term mortality in patients with CNIE compared with patients with CPIE. This difference was present in patients receiving medical therapy alone and not in those who underwent surgery, with surgery being associated with reduced mortality. Additional efforts are required both to improve the aetiological diagnosis of IE and identify CNIE cases early before progressive disease potentially contraindicates surgery.

Clinical Characteristics and Risk Factors for in-Hospital Mortality in 240 Cases of Infective Endocarditis in a Tertiary Hospital in China: A Retrospective Study

Purpose

This study aimed (i) to investigate the clinical characteristics and risk factors related to in-hospital mortality in patients with infective endocarditis (IE) and (ii) to compare the differences in three age groups.

Methods

A total of 240 IE cases diagnosed using the modified Duke criteria between January 2016 and December 2019 were included and retrospectively studied. Patients were stratified into three age groups: < 50 y, 50–65 y, and > 65 y.

Results

The mean age of the patients was 51 ± 14 y, and 154 patients (64.2%) were male. In addition, 136 (56.7%) patients with IE had no previous cardiac disease. Congenital heart disease (CHD, 21.3%) was the most common underlying heart disease, followed by rheumatic heart disease (RHD, 8.8%). Streptococcus was found in 55 (22.9%) patients and was the most common causative pathogen, comprising 52.9% of all positive blood cultures. Echocardiography showed the presence of vegetations in 88.3% of cases and the predominant involvement of the left heart valves. Fever and cardiac murmur were the most frequent presentations, with no significant differences among age groups. Compared with younger patients, elderly patients had a lower operation rate and higher in-hospital mortality. The independent risk factors of in-hospital mortality were age > 65 y, intracranial infection, splenic embolization, cerebral hemorrhage, NYHA class III–IV, and prosthetic valve infection.

Conclusion

CHD replaces RHD as the most common underlying heart disease in IE patients. Patients without previous cardiac disease are at increased risk of IE. Streptococcus is still the primary causative pathogen of IE. Elderly patients present with more comorbidities and complications, in addition to a more severe prognosis than younger patients. Age older than 65 y, intracranial infection, splenic embolization, cerebral hemorrhage, NYHA class III–IV, and prosthetic valve infection showed poorer in-hospital outcomes.

Early surgical intervention in culture-negative endocarditis of the aortic valve complicated by abscess in an infant: A case report

BACKGROUND

Surgical therapy of infective endocarditis (IE) involving aortic valves and mitral valves is widespread. However, there are few reports concerning patients with culture-negative endocarditis complicated by the appearance of comorbid valvular perforation and abscess. Therefore, real-time surveillance of changes in cardiac structure and function is critical for timely surgical management, especially in patients who do not respond to medical therapy.

CASE SUMMARY

Here, we report an atypical case in a 9-mo-old infant without congenital heart disease but with symptoms of intermittent fever and macular rashes. Physical examination, laboratory tests, and electrocardiograms suggested a diagnosis of IE, although the result of blood cultures was exactly negative. After treatment with antibiotic drugs, the patient got a transient recovery. On the 9^th day, we proceeded with continuous echocardiogram due to fever again and the results revealed aortic valve abscess with perforation, regurgitation, vegetation, and pericardial effusion. Intraoperative monitoring revealed aortic valve perforation, presence of apothegmatic cystic spaces below the left coronary cusp of the aortic valve, and severe aortic valve regurgitation. Aortic valve repair was performed by autologous pericardial patch plasty. The patient was discharged after 4 wk of treatment and no complications occurred after surgery.

CONCLUSION

Our case demonstrated the necessity of serial echocardiography monitoring for possible adverse symptoms of IE in pediatric patients.

Causes of infective endocarditis in the Western Cape, South Africa: a prospective cohort study using a set protocol for organism detection and central decision making by an endocarditis team

BACKGROUND

Blood culture negative infective endocarditis (BCNIE) poses both a diagnostic and therapeutic challenge. High rates of BCNIE reported in South Africa have been attributed to antibiotic use prior to blood culture sampling.

OBJECTIVES

To assess the impact of a systematic approach to organism detection and identify the causes of infective endocarditis (IE), in particular causes of BCNIE.

DESIGN

Prospective cohort study.

METHODS

The Tygerberg Endocarditis Cohort study prospectively enrolled patients with IE between November 2019 and February 2021. A set protocol for organism detection with management of patients by an endocarditis team was employed. This prospective cohort was compared with a retrospective cohort of patients with IE admitted between January 2017 and December 2018.

RESULTS

One hundred and forty patients with IE were included, with 75 and 65 patients in the retrospective and prospective cohorts, respectively. Baseline demographic characteristics were similar with a mean age of 39.6 years and male predominance (male sex=67.1%). The rate of BCNIE was lower in the prospective group (28/65 or 43.1%) compared with the retrospective group (47/75 or 62.7%; p=0.039). The BCNIE in-hospital mortality rate in the retrospective cohort was 23.4% compared with 14.2% in the prospective cohort (p=0.35). A cause was identified (including non-culture techniques) in 86.2% of patients in the prospective cohort, with Staphylococcus aureus (26.2%), Bartonella species (20%) and the viridans streptococci (15.3%) being most common.

CONCLUSION

The introduction of a set protocol for organism detection, managed by an endocarditis team, has identified Staphylococcusaureus as the most common cause of IE and identified non-culturable organisms, in particular Bartonella quintana, as an important cause of BCNIE. A reduction in in-hospital mortality in patients with BCNIE was observed, but did not reach statistical significance.

A case of endocarditis and spondylodiscitis associated with Mycobacterium tuberculosis

Tuberculosis (TB) is a global health problem, in which the majority of cases occur in population-dense developing countries. Despite advances in various diagnostic TB modalities, extrapulmonary TB remains a challenge due to complexities related to its diagnostic approach. Hereby, we present a rare case of endocarditis and spondylodiscitis associated with Mycobacterium tuberculosis (MTB). This case report highlighted the challenges faced in diagnosing blood culture-negative infective endocarditis (BCNIE). We also emphasized the importance of considering MTB as etiology of BCNIE, particularly in endemic TB areas.

Blood culture-negative infective endocarditis: a worse outcome? Results from a large multicentre retrospective Spanish cohort study

BACKGROUND

To assess the impact of blood cultures negative infective endocarditis (BCNIE) on in-hospital mortality.

METHODS

Prospective multicentre study with retrospective analysis of a Spanish cohort including adult patients with definite IE. Cardiac implantable devices infection were excluded. Comparisons between blood cultures positive and BCNIE groups were performed to analyse in-hospital mortality.

RESULTS

1001 cases were included of which 83 (8.3%) had BCNIE. Alternative microbiological diagnosis was achieved for 39 (47%) out 83 cases. The most frequent identifications were: Coxiella burnetii (11; 28.2%), Tropheryma whipplei (4; 10.3%), Streptococcus gallolyticus (4;10.3%) and Staphylococcus epidermidis (3; 7.7%). Surgery was performed more frequently in BCNIE group (57.8 vs. 36.9%, p < .001). All-cause in-hospital mortality rate was 26.7% without statistical difference between compared groups. BCNIE was not associated to worse mortality rate in Cox regression model (aHR = 1.37, 95% CI 0.90-2.07, p = .14). Absence of microbiological diagnosis was also not associated to worse in-hospital prognosis (aHR = 1.62, 95% CI 0.99-2.64, p = .06).

CONCLUSIONS

In our cohort, BCNIE was not associated to greater in-hospital mortality based in multivariate Cox regression models. The variables most frequently associated with mortality were indicated but not performed surgery (aHR = 2.48, 95% CI 1.73-3.56, p < .001), septic shock (aHR = 2.24, 95% CI 1.68-2.99, p < .001), age over 65 years (aHR = 1.88, 95% CI 1.40-2.52, p < .001) and complicated endocarditis (aHR = 1.79, 95% CI 1.36-2.37, p < .001).

Bartonella species as a cause of culture-negative endocarditis in South Africa

Previous reports have highlighted the high prevalence of blood culture negative endocarditis (BCNE) in South Africa. The Tygerberg Endocarditis Cohort (TEC) study is an ongoing prospective cohort study of patients with confirmed or suspected IE presenting to Tygerberg Academic Hospital, Cape Town, South Africa. Current analysis includes patients that presented between November 2019 and August 2020. Forty four (44) patients have been included in this ongoing study. Fourteen of the 44 patients (31.8%) had BCNE. Further analysis of the patients with BCNE identified Bartonella species as the most common causative organism (n=6; 43%). Other causes included Mycoplasma species (n=2). No cause could be identified in 4 of the 44 patients (9%). Bartonella quintana was identified with PCR of valvular tissue as the causative organism in 4 of the 5 patients that underwent urgent surgery. The patients with Bartonella IE (n=6) had an average age of 39 years with equal gender distribution. The common clinical features were clubbing (n=5; 83%), anemia (n=4; 66.6%), haematuria (n=3; 50%), acute on chronic severe regurgitant lesion (n=3; 50%) and acute severe regurgitant lesion (n=2; 33.3%).The aortic valve was involved in 5 of 6 patients. During a mean follow-up period of 251 days after diagnosis, no major adverse events occurred. Bartonella-associated IE is an important cause of BCNE in the Western Cape of South Africa. Imaging findings (in patients with BCNE) of significant valvular destruction with large vegetations on the aortic valve not affected by congenital or rheumatic valve disease should raise the suspicion of Bartonella-associated IE.

Culture-Negative Mycotic Aortic Aneurysms Probably Have a Less Severe Clinical Nature Than Culture-Positive Counterparts

BACKGROUND

Mycotic aortic aneurysm constitutes a potentially devastating disease that necessitates prompt suspicion and diagnosis. There is no exact consensus for treatment, but removal of infected tissues and prolonged use of antimicrobials based on the identified causative microorganisms seem widely acceptable and have been similarly practiced worldwide. However, some patients still show no identified microorganisms. In this study, we sought to determine whether there are any clinical significance or differences of note in culture-negative mycotic aortic aneurysms.

METHODS

Between October 2003 and August 2018, 71 patients were identified as treated for mycotic aortic aneurysms at a single tertiary institution. Review of medical records and imaging studies were completed to collect the following information: demographics, previous medical/surgical history regarding potential infection sources, laboratory and radiologic findings, clinical presentations, treatment method, and morbidity and mortality rates. For analysis, patients were categorized into two groups: the blood and/or tissue culture-positive (CP) group and the blood and/or tissue culture-negative (CN) group. The latter was further divided as CN with identified microorganism by molecular biologic methods [CN(+)] and CN with no identified microorganism [CN(-)].

RESULTS

More patients in the CP group were symptomatic than were in the CN(+) group (100% vs. 80%; P = 0.034). However, identification of causative microorganisms did not result in a difference in symptom status upon comparing the [CP + CN(+)] and [CN(-)] groups. Inflammatory markers were the most elevated in the CP group and least elevated in the CN(-) group. The aneurysm growth rate seemed slower in the CN(-) group than in the CN(+) and CP groups (1.3 vs. 3.4 vs. 9 mm/month respectively). Aneurysm rupture at initial presentation was more prevalent in the CP group (33.3%). ¹⁸F-Fluorodeoxyglucose-positron emission tomography showed increased uptake regardless of whether or not the microorganisms were identified. Early mortality and disease-specific mortality rates during the follow-up period were higher in the CP group but without statistical significance.

CONCLUSIONS

Compared with the CP group, the CN groups appeared clinically less severe, and also exhibited a relatively less devastating course as exhibited by the slower aneurysm expansion rate and smaller number of ruptured aneurysms at the initial presentation.

Culture-negative infective endocarditis (CNIE): impact on postoperative mortality

Introduction

Poor postoperative outcomes have been reported after surgery for infective endocarditis (IE). Whether the absence of positive cultures impacts the prognosis remains a matter of discussion. The aim of this study was to evaluate the impact of negative cultures on the prognosis of surgically treated IE.

Methods

This was a single-center, retrospective study. From January 2000 to June 2019, all patients who underwent valvular surgery for IE were included in the study. The primary endpoint was early postoperative mortality. A covariate balancing propensity score was developed to minimize the differences between the culture-positive IE (CPIE) and culture-negative IE (CNIE) cohorts. Using the estimated propensity scores as weights, an inverse probability treatment weighting (IPTW) model was built to generate a weighted cohort. Then, to adjust for confounding related to CPIE and CNIE, a doubly robust method that combines regression model with IPTW by propensity score was adopted to estimate the causal effect of the exposure on the outcome.

Results

During the study period, 327 consecutive patients underwent valvular repair/replacement with the use of cardiopulmonary bypass and cardioplegic cardiac arrest for IE. Their mean age was 61.4 ± 15.4 years, and 246 were males (75.2%). Native valve IE and prosthetic valve IE accounted for 87.5% and 12.5% of cases, respectively. Aortic (182/327, 55.7%) and mitral valves (166/327, 50.8%) were mostly involved; 20.5% of isolated mitral valve diseases were repaired (22/107 patients). The tricuspid valve was involved in 10 patients (3.3%), and the pulmonary valve in 1 patient (<1%). Fifty-nine patients had multiple-valve disease (18.0%). Blood cultures were negative in 136/327 (41.6 %). A higher postoperative mortality was registered in CNIE than in CPIE patients (19% vs 9%, respectively, p = 0.01). The doubly robust analysis after IPTW by propensity score showed CNIE to be associated with early postoperative mortality (odds ratio 2.10; 95% CI, 1.04–4.26, p = 0.04).

Conclusions

In our cohort, CNIE was associated with a higher early postoperative mortality in surgically treated IE patients after dedicated adjustment for confounding. In this perspective, any effort to improve preoperative microbiological diagnosis, thus allowing targeted therapeutic initiatives, might lead to overall better postoperative outcomes in surgically treated IE.

Factors Affecting Mortality in Patients with Blood-Culture Negative Infective Endocarditis

Infective endocarditis retains high morbidity and mortality rates despite recent advances in diagnostics, pharmacotherapy, and surgical intervention. Risk stratification in endocarditis patients, including blood-culture negative endocarditis, is crucial in deciding the optimal management strategy; however, the studies investigating risk stratification in these patients were lacking despite the difference with blood-culture positive endocarditis. The aim of this study is to identify risk factors associated with in-hospital mortality in blood-culture negative infective endocarditis patients. A retrospective cohort study was conducted at National Cardiovascular Center Harapan Kita, Jakarta in blood-culture negative infective endocarditis patients from 2013 to 2015. Patient characteristics, clinical parameters, echocardiographic parameters, and clinical complications were collected from medical records and hospital information systems. There were 146 patients that satisfy the inclusion and exclusion criteria out of 162 patients with blood-culture infective endocarditis. The in-hospital mortality rate was 13.5%. On bivariate analyses, factors that were related to in-hospital mortality include New York Heart Association (NYHA) class III and IV heart failure ( p  = 0.007), history of hypertension ( p  = 0.021), stroke during hospitalization ( p  < 0.001), the decline in renal function ( p  < 0.001), and surgery ( p  = 0.028). Variables that were independently associated with mortality upon multivariate analysis were heart failure NYHA functional class III and IV (OR 7.56, p  = 0.011), worsening kidney function (OR 10.23, p  < 0.001), and stroke during hospitalization (OR 8.92, p  = 0.001). Presence of heart failure with NYHA functional class III and IV, worsening kidney function, and stroke during hospitalization were independently associated with in-hospital mortality in blood-culture infective endocarditis patients.

Ruptured mitral valve abscess with mitral incompetence in culture negative infective endocarditis: case report

Introduction

Perivalvular abscess in native valve infective endocarditis (IE) is associated with significantly increased mortality.

Case description

Herein, we report a 29 year old Indian male who presented with culture negative IE with perivalvular abscess and severe mitral regurgitation requiring mitral valve replacement.

Discussion

Initial approach is very difficult in terms of when IE presents as culture negative. This case highlights the important role of echocardiography in the management of culture negative IE.

The diagnosis of microorganism involved in infective endocarditis (IE) by polymerase chain reaction (PCR) and real-time PCR: A systematic review

Broad-range bacterial rDNA polymerase chain reaction (PCR) followed by sequencing may be identified as the etiology of infective endocarditis (IE) from surgically removed valve tissue; therefore, we reviewed the value of molecular testing in identifying organisms' DNA in the studies conducted until 2016. We searched Google Scholar, Scopus, ScienceDirect, Cochrane, PubMed, and Medline electronic databases without any time limitations up to December 2016 for English studies reporting microorganisms involved in infective endocarditis microbiology using PCR and real-time PCR. Most studies were prospective. Eleven out of 12 studies used valve tissue samples and blood cultures while only 1 study used whole blood. Also, 10 studies used the molecular method of PCR while 2 studies used real-time PCR. Most studies used 16S rDNA gene as the target gene. The bacteria were identified as the most common microorganisms involved in infective endocarditis. Streptococcus spp. and Staphylococcus spp. were, by far, the most predominant bacteria detected. In all studies, PCR and real-time PCR identified more pathogens than blood and tissue cultures; moreover, the sensitivity and specificity of PCR and real-time PCR were more than cultures in most of the studies. The highest sensitivity and specificity were 96% and 100%, respectively. The gram positive bacteria were the most frequent cause of infective endocarditis. The molecular methods enjoy a greater sensitivity compared to the conventional blood culture methods; yet, they are applicable only to the valve tissue of the patients undergoing cardiac valve surgery.

Evaluation of empirical treatment for blood culture-negative endocarditis

OBJECTIVES

Much progress has been made in understanding the main causes of blood culture-negative endocarditis (BCNE). Few studies concerning BCNE treatment (due to previous antibiotics used or fastidious pathogens) are available. We performed this study to evaluate the effectiveness of our therapeutic protocol in BCNE, based on compliance with the protocol, outcome and 1 year mortality.

PATIENTS AND METHODS

We collected prospectively and analysed retrospectively cases of BCNE between 2002 and 2014, using a simplified and standardized protocol developed by our multidisciplinary team. We apply two kinds of protocols to treat BCNE, which include only four intravenous antimicrobial agents: amoxicillin, vancomycin, gentamicin and amphotericin B.

RESULTS

We had 177 patients with definite BCNE. There were 154 (87.0%) patients treated with both appropriate antimicrobial agents and appropriate duration of treatment. We analysed the causes of inappropriate treatment in 13 (7.3%) cases and inappropriate duration in 10 (5.6%) cases. The treatment changes were justified in all cases except one of discharge against medical advice. The fatality rate was 5.1% (nine cases) and all deaths occurred in the group of patients who were treated with appropriate treatment; however, four deaths were not attributable to empirical treatment failure. Concerning the other deaths, the lack of surgical management, in association with empirical treatment, could explain our protocol's failure, such as poorly tolerated surgery.

CONCLUSIONS

Our protocol is efficient and our mortality rate was low, compared with the literature review. This may result from a strategy that uses a sampling procedure and a standardized protocol at the same time.

Global and regional burden of infective endocarditis, 1990-2010: a systematic review of the literature

Infective endocarditis (IE) is a life-threatening disease associated with serious complications. The GBD 2010 (Global Burden of Disease, Injuries, and Risk Factors) study IE expert group conducted a systematic review of IE epidemiology literature to inform estimates of the burden on IE in 21 world regions in 1990 and 2010. The disease model of IE for the GBD 2010 study included IE death and 2 sequelae: stroke and valve surgery. Several medical and science databases were searched for IE epidemiology studies in GBD high-, low-, and middle-income regions published between 1980 and 2008. The epidemiologic parameters of interest were IE incidence, proportions of IE patients who developed stroke or underwent valve surgery, and case fatality. Literature searches yielded 1,975 unique papers, of which 115 published in 10 languages were included in the systematic review. Eligible studies were population-based (17%), multicenter hospital-based (11%), and single-center hospital-based studies (71%). Population-based studies were reported from only 6 world regions. Data were missing or sparse in many low- and middle-income regions. The crude incidence of IE ranged between 1.5 and 11.6 cases per 100,000 people and was reported from 10 countries. The overall mean proportion of IE patients that developed stroke was 0.158 ± 0.091, and the mean proportion of patients that underwent valve surgery was 0.324 ± 0.188. The mean case fatality risk was 0.211 ± 0.104. A systematic review for the GBD 2010 study provided IE epidemiology estimates for many world regions, but highlighted the lack of information about IE in low- and middle-income regions. More complete knowledge of the global burden of IE will require improved IE surveillance in all world regions.

Reassessment of blood culture-negative endocarditis: its profile is similar to that of blood culture-positive endocarditis

INTRODUCTION AND OBJECTIVES

Left-sided infective endocarditis with blood culture-negative has been associated with delayed diagnosis, a greater number of in-hospital complications and need for surgery, and consequently worse prognosis. The aim of our study was to review the current situation of culture-negative infective endocarditis.

METHODS

We analyzed 749 consecutive cases of left-sided infective endocarditis, in 3 tertiary hospitals from June 1996 to 2011 and divided them into 2 groups: group I (n=106), blood culture-negative episodes, and group II (n=643) blood culture-positive episodes. We used Duke criteria for diagnosis until 2002, and its modified version by Li et al. thereafter.

RESULTS

Age, sex, and comorbidity were similar in both groups. No differences were found in the proportion of patients who received antibiotic treatment before blood culture extraction between the 2 groups. The interval from symptom onset to diagnosis was similar in the 2 groups. The clinical course of both groups during hospitalization was similar. There were no differences in the development of heart failure, renal failure, or septic shock. The need for surgery (57.5% vs 55.5%; P=.697) and mortality (25.5% vs 30.6%; P=.282) were similar in the 2 groups.

CONCLUSIONS

Currently, previous antibiotic therapy is no longer more prevalent in patients with blood culture-negative endocarditis. This entity does not imply a delayed diagnosis and worse prognosis compared with blood culture-positive endocarditis. In-hospital clinical course, the need for surgery and mortality are similar to those in patients with blood culture-positive endocarditis. Full English text available from:www.revespcardiol.org.

23S rDNA real-time polymerase chain reaction of heart valves: a decisive tool in the diagnosis of infective endocarditis

AIMS

A new diagnostic strategy to improve the detection of pathogens in heart valves (HVs) from patients with infective endocarditis (IE) was evaluated.

METHODS AND RESULTS

Three hundred and fifty seven HVs surgically removed from 326 patients with proven IE or suspicious intra-operative findings, examined by 16S rDNA polymerase chain reaction (PCR) and culture were retrospectively analysed according to the predictive value of various PCR methods. Patients were classified into four categories: active IE, IE with ambiguous infective status, healed IE, and valve diseases but no IE. Retained samples of 200 HVs were analysed by real-time PCR targeting bacterial 23S rDNA, fungal 28S rDNA, and mycoplasmal tuf gene. 16S rDNA PCR revealed 80.6% sensitivity, 100% specificity, 100% positive predictive value, and 71% negative predictive value (NPV), compared with cultivation with 33.4, 96.6, 95.5, and 40.9%, respectively. The use of real-time PCR increased diagnostic sensitivity to 96.4%, and NPV to 92.5%. Bacterial load, C-reactive protein, and white blood cell counts (WBCs) decreased during antibiotic treatment. Bacterial load showed no correlation to C-reactive protein or WBCs, whereas C-reactive protein and WBCs were significantly correlated.

CONCLUSION

23S rDNA real-time PCR of surgically removed HVs improves the diagnosis of IE. Polymerase chain reaction analysis of explanted HVs allow the optimization of the antimicrobial therapy, especially in patients with culture-negative IE.

Excellent Prognosis of Culture Negative Endocarditis in Hemodialysis Patients: A Case Series

Despite improved diagnostic methods, antimicrobial agents and more sophisticated echocardiographic studies, the incidence of infective endocarditis remains high, especially in a uremic and end stage renal disease (ESRD) population. Culture negative endocarditis (CNE) patients with normal renal function have increased morbidity and mortality, but clinical features and outcome in hemodialysis patients remains unclear. This study reported five survival cases of CNE in hemodialysis patients. The prognosis of all dialysis-related CNE patients enrolled in this study was excellent.

Impact of prior antibiotic use in culture-negative endocarditis: review of 86 cases from southern Pakistan

BACKGROUND

A large number of patients treated at our hospital for endocarditis have negative cultures. Taking into consideration the fact that many of these patients receive antibiotics prior to referral, we decided to study culture-negative endocarditis in Pakistan.

METHODS

The medical records of all patients admitted to the Aga Khan University Hospital, Pakistan, for the period from 1988 to 2001, with an underlying diagnosis of infective endocarditis (IE) and negative cultures, were reviewed.

RESULTS

Of the 159 patients diagnosed with IE by revised Duke criteria, 86 (54.1%) had persistent negative cultures. More than half of these patients (52%) had received antibiotics before being referred to our center. Patients with culture-negative endocarditis were less likely to be classified as definite endocarditis by revised Duke criteria (p<0.001, 95% CI 0.07-0.3) or to have large vegetations (p=0.021, 95% CI 0.05-0.5), and more likely to have a mitral valve prolapse (p=0.003, 95% CI 1.6-2.3). Definite endocarditis (p=0.042, 95% CI 1.02-7.4), heart failure (p=0.008, 95% CI 1.4-12.7), renal failure (p=0.017, 95% CI 1.16-40.7), embolism (p=0.019, 95% CI 1.2-38.8), and neurological complications (p=0.02, 95% CI 1.16-9.2) were associated with an increased mortality.

CONCLUSION

Culture-negative endocarditis is very common among patients with IE in Pakistan. The presentation, laboratory findings, and complications are similar to those for culture-positive endocarditis. It is postulated that previous antibiotic treatment is the most common cause of culture-negative endocarditis in our hospital.

Characteristics and analysis of risk factors for mortality in infective endocarditis

OBJECTIVE

The aim of our study was to establish the etiology of and risk factors for infective endocarditis (IE) and determine the prognostic factors for adverse outcome during hospital admission in a Turkish population.

MATERIAL AND METHODS

Between January 2002 and January 2004, the clinical and laboratory features of 112 consecutive adult patients (>18 years) with diagnosis of IE who were referred to the infectious diseases clinics/departments of 17 teaching hospitals in Turkey were evaluated. Cases of IE were defined according to the modified Duke Criteria. Mortality was defined as death occurring within 30 days or during hospital stay period. Univariate and multivariate analyses were performed to predict the factors related to fatal outcome.

RESULTS

A total of 112 consecutive patients presented with 101 definite and 11 probable IE episodes were defined according to the modified Duke Criteria. The mean age was 45.2+/-19.9. Fifty percent of the patients were male. Ninety (60.4%) of the 112 patients had risk factors for IE and 48 (42.9%) of them had >or=2 risk factors. On the other hand, 49.1% of patients had cardiac risk factors. Blood cultures were positive in 94 (83.9%) cases. Staphylococci were the most common agents (50.0%), followed by streptococci (28.7%) and enterococci (16.0%). Native cardiac valves were detected in 93 (83%) of the episodes of suspected IE. Valvular involvement was present in 103 (92%) patients; the mitral valve, alone or in combination with other valves, was affected in 70 (62.5%) of the patients. Echocardiography detected vegetations in 105 patients (93.8%). The mortality rate was 28.6%. Three factors were independently associated with mortality: haemodialysis OR: 14.5 (95% CI: 1.5-138.2), mobile vegetation OR: 4.8 (95% CI: 1.5-15.4) and mental alteration OR: 4.1 (95% CI: 1.1-15.6).

CONCLUSION

Mortality is still high in IE. Our data indicate that patients with altered mental status, mobile vegetation, or on haemodialysis had poorer prognosis.

Prognostic stratification of patients with left-sided endocarditis determined at admission

BACKGROUND

The prognosis of patients with left-sided endocarditis remains poor despite the progress of surgical techniques. Identification of high-risk patients within the first days after admission to the hospital would permit a more aggressive therapeutic approach.

METHODS

We designed a prospective multicenter study to find out the clinical, microbiologic, and echocardiographic characteristics available within 72 hours of admission that might define the profile of high-risk patients. Of 444 episodes, 317 left-sided endocarditis cases were included and 76 variables were assessed. Events were surgery in the active phase of the disease and in-hospital death. A stepwise logistic regression analysis was undertaken to determine variables predictive of events.

RESULTS

Multivariate analysis of the clinical variables found to have statistical significance in the univariate analysis identified the following as predictive: patient referred from another hospital (odds ratio [OR]: 1.8; confidence interval [CI], 1.1-2.9), atrioventricular block (OR: 2.5; CI, 1.1-5.9), acute onset (OR: 1.7; CI, 1.1-2.9), and heart failure at admission (OR: 2.3; CI, 1.4-3.8). When the echocardiographic and microbiological variables statistically significant in the univariate analysis were introduced, the presence of heart failure at admission (OR: 2.9; CI, 1.8-4.8), periannular complications (OR: 1.8; CI, 1.1-3.1), and Staphylococcus aureus infection (OR: 2.0; CI, 1.1-3.8) retained prognostic power. Risk could be accurately stratified when combining the 3 variables with predictive power: 0 variables present: 25% of risk; 1 variable present: 38% to 49% of risk; 2 variables present: 56% to 66% of risk; and 3 variables present: 79% of risk.

CONCLUSIONS

The risk of patients with left-sided endocarditis can be accurately stratified with the assessment of variables easily available within 72 hours of admission to the hospital.

Presentation and outcome of infective endocarditis in Spain: a retrospective study

OBJECTIVE

To analyze cases of infective endocarditis in patients who attended the Hospital General de Castellón, Spain, between 1999 and 2004.

METHODS

This was a retrospective study. Demographic and clinical characteristics were assessed, variation in presentation over time was analyzed, and factors influencing outcome were determined.

RESULTS

A total of 54 cases in 48 patients were included; 33 (61%) were in men. The median patient age was 62 years. Infective endocarditis occurred on a native valve in 36 cases (67%), a mechanical prosthetic valve in 12 (22%), and a pacemaker in six (11%). The mitral valve was the most commonly affected site. Transthoracic and/or transesophageal echocardiography showed a vegetation in 45 (83%) cases, moderate or severe valvular regurgitation in 27 (50%), and intracardiac destructive lesions in five (9%). The outcome in 15 (28%) cases was death, and multivariate analysis disclosed significantly increased risk of death associated with older age, lower serum albumin, and higher white blood cell count.

CONCLUSIONS

This study confirmed the protean nature of infective endocarditis, and identified several factors predictive of mortality including advanced age, low serum albumin, and high white blood cell count.

Latent infective endocarditis: epidemiology and clinical characteristics of patients with unsuspected endocarditis detected after elective valve replacement

BACKGROUND

The diagnosis of infective endocarditis is usually made on the basis of clinical and laboratory criteria and may be confirmed by histologic examination or culture of excised valves. We tried to determine the incidence and significance of inflammatory changes in valves excised during operations for reasons other than infective endocarditis.

METHODS

The charts and histopathology of all patients undergoing valve replacement during a 10-year period (1993-2002) were reviewed. A total of 868 patients underwent a total of 970 valve replacements during this period, of whom 11 patients (1.3%) were for endocarditis, with the remaining 857 (98.7%) for other indications. All excised valves were cultured and examined histologically for the presence of inflammatory infiltrates, vegetations, and microorganisms.

RESULTS

In 8 of 857 patients (0.9%), the histologic examination unexpectedly demonstrated an infiltrate suggestive of endocarditis. Blood and valve cultures, and serologic tests for Mycoplasma, Chlamydia, Legionella, Q fever, Brucella, Rickettsiae, VDRL, and Bartonella were negative in all but 1 patient, who was found to have Q fever. All received a prolonged course of antibiotics. Six patients had an uneventful recovery; 1 had intramyocardial abscesses and expired during cardiac reoperation; and 1 had recurrent fever and dehiscence of the aortic and mitral valve prostheses and after two cardiac reoperations remains in severe heart failure.

CONCLUSIONS

The presence of an unexpected inflammatory infiltrate in heart valves excised for reasons other than endocarditis may occur in 0.9% of such operations; these infiltrates could indicate presence of endocarditis. A microbial origin should be sought, and patients should receive empiric antibiotic treatment for endocarditis.

Infective endocarditis: a five-year experience at a tertiary care hospital in Pakistan

OBJECTIVES

Infective endocarditis is common and data regarding its pattern and outcome from developing countries is sparse. We therefore examined the spectrum, demographics and clinical features of infective endocarditis and sought to determine the factors affecting its clinical outcome.

PATIENTS AND METHODS

Over a five-year period at our university hospital in Karachi, Pakistan, we identified 66 patients with infective endocarditis and compared their clinicoepidemiologic features and outcomes to subjects in the West.

RESULTS

The male:female ratio was 2:1; overall median age was 24 years (35.5 years for men and 13.5 years for women) (p < 0.001). Median duration of symptoms before presentation was 20.5 days. Major predisposing cardiac abnormalities included congenital (50%) and rheumatic (23%) lesions, and a history of heart surgery (17%). Causative organisms and valvular sites of infection were similar to those seen in developed countries. Blood culture-negative infective endocarditis was found in 48% of cases. Renal failure was more frequent among culture-positive patients (p = 0.055). Risk factors for mortality included neurologic (p = 0.003) and embolic (p = 0.02) complications, renal (p = 0.03) and left ventricular failure (p = 0.002), and a history of cardiac surgery (p = 0.026). Overall mortality was 27%.

CONCLUSIONS

Patients with infective endocarditis in Pakistan exhibit significant differences compared to their counterparts in the West, including younger age at presentation, incidence of predisposing cardiac conditions, and gender differences reflecting sociocultural bias. Neurologic and embolic complications, renal failure and heart failure predict a worse outcome.

[Infective endocarditis in patients with chronic liver disease: clinical and prognostic assessment]

INTRODUCTION AND OBJECTIVES

Chronic liver disease increases the susceptibility to bacterial infections and infective endocarditis. Our aim was to determine the clinical and microbiological features and the prognosis in patients with chronic liver disease who also had infective endocarditis.

PATIENTS AND METHOD

One hundred and seventy-four consecutive inpatients at our institution were recruited and followed. Thirty of them had chronic liver disease. Clinical, microbiological and echocardiographic variables were analyzed and, in some cases, histological variables were also recorded.

RESULTS

Patients with chronic liver disease were younger (36 11 vs 54 18 years; p < 0.01) and had a larger proportion of intravenous drug users (73 vs 16%; p < 0.01), HIV infection (47 vs 10%; p < 0.01), right valve involvement and spleen enlargement, but heart failure appeared less often (7 vs 34%; p = 0.003). Thirty percent of the patients with and 51% of patients without chronic liver disease underwent surgery for infective endocarditis. Total mortality among patients with and without chronic liver disease was 40% and 31%, respectively. After adjustment for age and for the incidence of congestive heart failure, chronic liver disease doubled mid-term mortality with a RR = 2.45 (p = 0.015).

CONCLUSIONS

Chronic liver disease has a significant impact on the prognosis in patients with infective endocarditis, and these patients should therefore be considered a high risk group.

Molecular diagnosis of culture negative infective endocarditis: clinical validation in a group of surgically treated patients

OBJECTIVE

To assess the clinical validity of polymerase chain reaction (PCR) based molecular methods in the microbiological diagnosis of culture negative infective endocarditis in a group of surgically treated patients.

DESIGN

Retrospective case-control study.

SETTING

Reference cardiovascular surgical centre. PATIENTS AND SAMPLES: 15 culture negative patients with infective endocarditis classified according to Duke criteria, with 17 heart valve samples; 13 age and sex matched control patients without infective endocarditis, with 13 valve samples.

INTERVENTIONS

Medical records were reviewed and clinical, demographic, and microbiological data collected, including results of molecular detection of bacteria and fungi from valve samples. The clinical validity of molecular diagnosis was assessed, along with the sensitivity and speed of the systems.

RESULTS

In the study group, 14 patients were PCR positive (93%). Organisms detected were streptococci (3), staphylococci (2), enterobacter (1), Tropheryma whippelii (1), Borrelia burgdorferi (1), Candida albicans (1), and Aspergillus species (2). Three cases were positive on universal bacterial detection but the pathogen could not be identified because of contaminating background. One case was negative. All but two positive cases showed clinical correlations. These two cases had no symptoms of infective endocarditis but there was agreement with the surgical findings. All control cases were PCR negative. Results were available within eight hours, and if sequencing was necessary, within 48 hours.

CONCLUSIONS

PCR based molecular detection of pathogens in valve samples from surgically treated culture negative infective endocarditis patients is fast, sensitive, and reliable. The technology, combined with thorough validation and clinical interpretation, may be a promising tool for routine testing of infective endocarditis.

Changing spectrum of infective endocarditis: review of 194 episodes over 20 years

A review of admission records identified 194 episodes of infective endocarditis (IE) from January 1980 to December 1999 at a community hospital in Tokyo. The cases were divided into decades, and the clinical picture and short-term outcomes were compared and analyzed. The mean age of patients in the 1990s was older (45.5 +/-13.2 vs 55.1+/-12.6 years, p<0.001), and prosthetic valve endocarditis was significantly more frequently seen (14.4% vs 31.8%, p=0.004). None had a history of intravenous drug abuse (IVDA). Patients on chronic hemodialysis comprised 5.8% of IE cases in the 90s. Overall, dental procedure or caries still remained the main presumed source of infection. Staphylococcal IE showed a tendency to increase, and methicillin-resistant staphylococcal IE was significantly prominent in the 90s (0% vs 10.4%, p=0.0006). The overall in-hospital mortality was similar between the 2 groups (13.6% vs 18.8%, NS). Multivariate analysis found neurological abnormality, renal insufficiency and staphylococcal IE as predictors of in-hospital mortality. The characteristics of IE in Japan have changed, even among non-IVDA patients, and it appears to occur in a more high-risk patient population, which may warrant a more aggressive therapeutic approach to its management and treatment.

Better prognosis of elderly patients with infectious endocarditis in the era of routine echocardiography and nonrestrictive indications for valve surgery

OBJECTIVE

It has been reported that endocarditis in the elderly may have a poor outcome. Our aim was to assess the different features and prognosis, if any, in the present time.

METHODS

Of 103 patients with proven endocarditis, 31 were 65 years or older and 72 were younger than 65 years. Degenerative heart disease was seen more frequently in the elderly (22.5% vs 2.7%, P =.003). Drug abuse and immunodeficiency virus infection were more common in the younger group, as was tricuspid endocarditis (26.3% vs 0%, P <.001). At clinical presentation cardiac failure (41.9 vs 19.4%, P =.02) and leukocytosis (61.2% vs 40.2%, P =.049) were seen more frequently in the elderly.

RESULTS

Despite other similar clinical features, it took longer to diagnose older patients (7.2 +/- 6.2 vs 3.2 +/- 3.5 days, P <.001). Enterococcus infected the aged more often (32.2% vs 13.1%, P =.001). During hospitalization, heart failure and embolization tended to be more common in the elderly and the younger group, respectively. There were no significant differences in the incidence of anatomic complications, the need for operation, and overall mortality.

CONCLUSION

Although a worse prognosis has been reported in elderly patients with infective endocarditis, the early use of transesophageal echocardiographic examinations and equal therapeutic options provides a similar outcome when compared with younger subjects.