Global Trends in Infective Endocarditis Epidemiology

Infective endocarditis

Infective endocarditis occurs worldwide, and is defined by infection of a native or prosthetic heart valve, the endocardial surface, or an indwelling cardiac device. The causes and epidemiology of the disease have evolved in recent decades with a doubling of the average patient age and an increased prevalence in patients with indwelling cardiac devices. The microbiology of the disease has also changed, and staphylococci, most often associated with health-care contact and invasive procedures, have overtaken streptococci as the most common cause of the disease. Although novel diagnostic and therapeutic strategies have emerged, 1 year mortality has not improved and remains at 30%, which is worse than for many cancers. Logistical barriers and an absence of randomised trials hinder clinical management, and longstanding controversies such as use of antibiotic prophylaxis remain unresolved. In this Seminar, we discuss clinical practice, controversies, and strategies needed to target this potentially devastating disease.

Cerebral imaging in infectious endocarditis: A clinical study

BACKGROUND

Because neurological failure is the most frequent extra-cardiac complication in Infectious Endocarditis (IE), a brain computerised tomography (CT) scan is usually performed. The benefits of magnetic resonance imaging (MRI) have not been clearly established. This study aims to clarify the prevalence and type of cerebral lesions in IE detected using MRI and to compare them with those detected using CT scans.

METHODS

In the Grenoble University Hospital, patients diagnosed with definite or possible endocarditis according to Duke's criteria were screened from 2010-2012. Brain CT and MRI were performed as soon as possible after diagnosis.

RESULTS

Of the 62 patients with IE who underwent at least one cerebral imaging within 3 weeks of diagnosis, Streptococcus (29) and Staphylococcus (14) were the main micro-organisms present. Twenty-eight (45%) patients underwent cardiac surgery. Eight (13%) died before discharge. Twenty (32%) had neurological symptoms. A brain CT-scan was performed on 53 (85%) patients and a MRI was performed on 43 (69%) patients. CT was pathological in 26 (49%) patients, whereas 32 (74%) MRI demonstrated abnormalities. The MRI lesions were classified as follows: ischaemia (48%), microbleeds (34%), haemorrhages (16%), abscesses (9%) and microbial aneurysms (4%). Of the 37 patients who underwent both MRI and CT examinations, ischaemia (48% vs 35%) and microbleeds (34%) demonstrated the difference between the two imaging methods.

CONCLUSION

Through the early diagnosis of cerebral damage, even in asymptomatic cases, MRI may have a role in the IE management, influence any surgical decision and assist in prognosis assessment.

Health Care-Associated Infective Endocarditis: a Growing Entity that Can Be Prevented

Infective endocarditis (IE) continues to be a serious disease with a poor prognosis and high mortality. Neither incidence rates nor mortality have decreased in recent decades. Because of this, it is important to prevent IE in patients at risk. In the past, prevention of IE has focused on antimicrobial prophylaxis, mainly for dental procedures. However, recent major changes in epidemiology, the most significant being the growing frequency and high mortality rate of health care-associated valve endocarditis (HAIE), mean that preventive strategies against IE must also change. Since intravascular catheters are the most common source of bacteremia among patients with HAIE, significant efforts must be made to minimize the risk of catheter-related bloodstream infections. Measures for preventing the infection of prosthetic valves and cardiac implantable devices at the time of implantation also need to be implemented.

Infective endocarditis in Rio de Janeiro, Brazil: a 5-year experience at two teaching hospitals

INTRODUCTION

Despite the recent advances in diagnosis and treatment, mortality rates due to infective endocarditis (IE) remain high if not aggressively treated with antibiotics, whether or not associated with surgery. Data on the prevalence, epidemiology and etiology of IE from developing countries remain scarce. The aim of this observational, prospective cohort study was to report a 5-year experience of IE at two teaching hospitals in Rio de Janeiro, Brazil.

MATERIAL AND METHODS

Demographical, anamnestic and microbiological characteristics of 71 IE patients were evaluated during the period of January 2009 to March 2013.

RESULTS

The mean age of the IE patients was 49.8 ± 2.4 years, of which 41 (57.7%) were males. The median time between the onset of symptoms and diagnosis of IE was 35.8 ± 4.8 days. A total of 31 (43.6%) cases of community-acquired infective endocarditis (CAIE) and 40 (56.3%) cases of healthcare-acquired infective endocarditis (HAIE) were observed. Staphylococcus aureus (30%) was the predominant cause of IE. Streptococcus spp. (45.1 %) was the predominant cause of the CAIE while S. aureus (32.5%) and Enterococcus spp. (27.2 %) were the main etiological agents of HAIE. For 64 (90.1 %) patients with native valve endocarditis, the mitral valve was the most commonly affected (48.3%). The main source of IE in this cohort was intravascular catheter. The tricuspid valve and renal chronic insufficiency were more frequent in patients with HAIE than CAIE (p = 0.001). The risk factors associated with in-hospital mortality rate (46.4%) in IE patients were: age over 45 (OR 3.4; 95% CI 1.03-11.24; p = 0.04) and chronic renal insufficiency (OR 38.3; 95% CI 3.2-449.4; p = 0.004).

CONCLUSIONS

At two main teaching hospitals in Brazil, Streptococcus spp. was the principal pathogen of CAIE while S. aureus and Enterococcus spp. were the most frequent causes of HAIE. IE remains a serious disease associated with high in-hospital mortality rate (46.6%); especially, in individuals over 45 years of age and with renal failure. Data suggest that early surgery may improve the outcome of IE patients.

Retrospective studies on pediatric infective endocarditis over 40 years in a mid-west area of China

OBJECTIVE

We have evaluated 106 pediatric cases of infective endocarditis (IE) to elucidate clinical manifestations and pathogenic microorganism profiling of IE in China.

METHODS

Clinical features, complications, pathogenic microorganisms, diagnosis and treatment of pediatric IE were reviewed in two groups of patients with IE from the different periods of time (group A, 34 cases obtained in the period from 2000 to 2011 and group B, 72 cases obtained in the period from 1964 to 1999).

RESULTS

A total of 106 pediatric patients with a definite diagnosis of IE based on the modified Duke criteria were enrolled and evaluated in this study. By comparing two groups of patients from different time periods, we found that the incidence of rheumatic heart disease was significantly reduced (from 19.4 to 5.9%), whereas congenital heart disease-associated IE had a tendency to increase (from 55.6 to 79.4%). Staphylococcus aureus was detected as the most common pathogenic microorganism, and its involvement tended to increase (from 32.0 to 58.5%), whereas the percentage of infections caused by Streptococcus viridans (8.0%) had not changed. It was interesting to note that the rate of vegetations detected was increased from 50.0 to 67.6% and the incidence of right-sided IE was also increased (from 35.0 to 60.9%). The most common valves involved in recent cases were tricuspid valves (increase from 30.0 to 47.8%), while mitral valve infection was reduced (from 60.0 to 39.1%). Penicillin was still the most commonly used antibiotic for the treatment of IE; the combination of penicillin plus cephalosporin has been recommended more and more recently.

CONCLUSIONS

Comparing pediatric IE patients during the past 40 years, we found that the role of rheumatic heart disease as a predisposing factor is diminishing. Pediatric IE is still predominantly caused by staphylococci. The most commonly involved valves are tricuspid valves instead of mitral valves. Gram-positive bacteria showed an increased resistance to penicillin when used alone, and the use of combination treatment with antibiotics is increasing in the area.

Viridans and bovis group streptococci that cause infective endocarditis in two regions with contrasting epidemiology

Viridans group (VGS) or bovis group streptococci (BGS) are the major causes for streptococcal infective endocarditis (IE). However, the causative isolates are not sufficiently characterized. Using multilocus sequence analysis we have examined VGS and BGS (VGS/BGS) isolates that caused IE in southern India and Germany, two distant geographic regions with a contrasting IE epidemiology. Other than in Germany, the majority of patients (68%) in Chennai, southern India had an underlying rheumatic heart disease (RHD). In accord with the high prevalence of RHD in the younger population and with the expansive age structure of India, the median age (24 years) of the VGS/BGS endocarditis patients was lower than in Germany (63 years), where RHD is rare and the age structure is contractive. Both in Germany and in southern India, the majority of cases were caused by mitis group streptococci, however, with considerable differences in the spectra of causative (sub)species. BGS endocarditis was more frequent in Germany. The spectrum of VGS/BGS that cause IE differs considerably between distant geographic regions in which different predisposing conditions prevail. Therefore, improved microbiological diagnosis in IE may facilitate determination of the optimal therapy.