Etiology and risk factors of 180 cases of native valve endocarditis. Report from a 5-year national prospective survey in Slovak Republic

Efficacy of Antibiotic Prophylactic Regimens for the Prevention of Bacterial Endocarditis of Oral Origin

Despite the controversy about the risk of individuals developing bacterial endocarditis of oral origin, numerous Expert Committees in different countries continue to publish prophylactic regimens for the prevention of bacterial endocarditis secondary to dental procedures. In this paper, we analyze the efficacy of antibiotic prophylaxis in the prevention of bacteremia following dental manipulations and in the prevention of bacterial endocarditis (in both animal models and human studies). Antibiotic prophylaxis guidelines remain consensus-based, and there is scientific evidence of the efficacy of amoxicillin in the prevention of bacteremia following dental procedures, although the results reported do not confirm the efficacy of other recommended antibiotics. The majority of studies on experimental models of bacterial endocarditis have verified the efficacy of antibiotics administered after the induction of bacteremia, confirming the efficacy of antibiotic prophylaxis in later stages in the development of bacterial endocarditis. There is no scientific evidence that prophylaxis with penicillin is effective in reducing bacterial endocarditis secondary to dental procedures in patients considered to be "at risk". It has been suggested that there is a high risk of severe allergic reactions secondary to prophylactically administered penicillins, but, in reality, very few cases have been reported in the literature. It has been demonstrated that antibiotic prophylaxis could contribute to the development of bacterial resistance, but only after the administration of several consecutive doses. Future research on bacterial endocarditis prophylactic protocols should involve the re-evaluation of the time and route of administration of antibiotic prophylaxis, and a search for alternative antimicrobials.

Detection of Identical Isolates of Enterococcus faecalis from the Blood and Oral Mucosa in a Patient with Infective Endocarditis

The detection of infective endocarditis (IE) of oral origin has been previously discussed. However, there are few reports confirming this infection using molecular biological techniques. We herein describe the case of a 67-year-old man who developed IE. Blood culture samples and strains obtained from the gingival and buccal mucosa showed 100% identity to Enterococcus faecalis JCM 5803 on sequencing of 16S rRNA gene fragments. A random amplification of polymorphic DNA (RAPD) analysis showed the same pattern for these samples, thus confirming the identity of E. faecalis isolates in the blood and oral mucosa. Our observations provide novel information regarding the level of identity between IE pathogens and oral bacteria.

Incidence, predisposing factors, and aetiology of infective endocarditis in the Czech Republic

OBJECTIVES

The aim of this study was to evaluate the incidence and epidemiological characteristics of infective endocarditis (IE) in the Czech Republic. These results represent the first data on the epidemiology of IE from the post-communist countries.

METHODS

This was a prospective multi-centre observational study monitoring the occurrence of IE in the catchment areas of 29 hospitals during a 12-month period. The total monitored territory involved a population of 3.9 million people (37.7% of the total Czech population). Patients were included in the study if they had a diagnosis of possible or definite endocarditis according to the modified Duke criteria.

RESULTS

One hundred and thirty-four episodes of IE in 132 patients were reported. Thus the crude incidence of IE was 3.4 cases/100,000 inhabitants/y. Vegetations were most frequently found on the aortic and mitral valves. The most frequent agent was Staphylococcus aureus (29.9%). The aetiology remained unexplained in 33.6% of cases, mainly because of previous antibiotic therapy. Surgical intervention during antibiotic therapy was performed in 36 patients (27.5%). Thirty-six patients died during hospitalization (in-hospital mortality rate 27.5%). The most common predisposing cardiac factors were remote cardiac surgery (19.4%) and degenerative valvular changes (11.9%). The most common extracardiac factors were pyogenic infections of skin and soft tissues (13.0%) and chronic haemodialysis (8.2%).

CONCLUSIONS

Our results document the changing epidemiological characteristics of IE, namely an increasing incidence of the disease and an increasing role of Staphylococcus aureus as a major pathogen. A shift was evident in predisposing factors for IE: almost 39% of IE episodes were associated with both cardiac and extracardiac modern medical procedures.

Surgery in current therapy for infective endocarditis

The introduction of the Duke criteria and transesophageal echocardiography has improved early recognition of infective endocarditis but patients are still at high risk for severe morbidity or death. Whether an exclusively antibiotic regimen is superior to surgical intervention is subject to ongoing debate. Current guidelines indicate when surgery is the preferred treatment, but decisions are often based on physician preferences. Surgery has shown to decrease the risk of short-term mortality in patients who present with specific symptoms or microorganisms; nevertheless even then it often remains unclear when surgery should be performed. In this review we i) systematically reviewed the current literature comparing medical to surgical therapy to evaluate if surgery is the preferred option, ii) performed a meta-analysis of studies reporting propensity matched analyses, and iii), briefly summarized the current indications for surgery.

Getting to the heart of the problem: serological and molecular techniques in the diagnosis of infective endocarditis

Infective endocarditis is diagnosed using the Duke criteria, which rely predominantly on cardiac imaging and recovery of a causative organism from the bloodstream. These criteria can be inconclusive, particularly when blood cultures remain sterile either due to the fastidious nature of the infecting organism or prior antibiotic therapy. Serology and, more recently, molecular techniques have been investigated as a solution to the problematic negative blood culture. The detection of elevated antibody levels has proved particularly useful in the diagnosis of those patients infected with organisms that cannot be cultured using standard laboratory methods, whilst molecular methods have been successfully used in the detection of both fastidious pathogens and those inhibited by prior antibiotic therapy. In view of recent and ongoing developments in the field of molecular diagnostics, these techniques will become increasingly important not only in the routine investigation of infectious disease, but specifically the diagnosis of endocarditis.

A systematic review of population-based studies of infective endocarditis

BACKGROUND

We sought to summarize and critically appraise the literature on the epidemiology of infective endocarditis (IE) in the general population.

METHODS

We retrieved population-based IE surveys by searching MEDLINE and EMBASE. Two reviewers independently extracted relevant data. We performed a metaregression to determine if temporal trends of IE characteristics exist.

RESULTS

Fifteen population-based investigations with 2,371 IE cases from seven countries (Denmark, France, Italy, the Netherlands, Sweden, United Kingdom, and United States) from 1969 to 2000 were eligible. Different case definitions and procedures were used to capture all IE cases, including census of existing diagnoses, record-linkage system, and direct contact survey. In the unadjusted regression, there was a decline in the proportion of IE patients with underlying rheumatic heart disease (RHD; 12%; 95% confidence interval [CI], - 21 to - 3%; p = 0.01) and an increase in the proportion of patients undergoing valve surgery (9%; 95% CI, 3 to 16%) per decade. After adjusting for country, the decline in IE cases with underlying RHD became nonsignificant, but the proportions of IE patients undergoing valve surgery increased 7% per decade (95% CI, - 4 to 14%; p = 0.06), and those with underlying prosthetic valve increased 7% per decade (95% CI, - 1 to 16%; p = 0.07). There were no significant temporal trends in the causative organisms.

CONCLUSION

Evidence from well-planned, representative IE epidemiologic surveys is scarce in many countries. Available studies suggest a changing distribution of underlying valvular heart disease in patients with IE and an increase in its surgical treatment.

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.

Escherichia coli native valve endocarditis

Among 36 cases of Escherichia coli native valve endocarditis (NVE) that met Duke criteria (31 cases in the literature between 1909 and 2002, and five cases seen in Paris, France), the urinary tract was the most common portal of entry. The majority (72.2%) of cases developed in elderly females. Overall, the proportion of patients aged > 70 years rose from 5.3% in 1982 to 22.9% in 2002. Persistent E. coli bacteraemia in the elderly in the absence of cardiac risk-factors may be a sign of NVE and should prompt an investigation by echocardiography.

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.

Bacterial endocarditis of oral etiology in an elderly population

The aim of this study was to analyze the prevalence and characteristics of bacterial endocarditis (BE) of oral origin in a group of elderly people. A retrospective study of 115 BE clinical records was performed, focusing on the demographic and predisposing features, as well as on the analytical and clinical variables. Twenty-two of the 115 cases were excluded as they were detected in intravenous drug users. Of the remaining 93 cases, 54.8% were diagnosed in patients older than 60 years of age (group A) and 45.2% in patients younger than 60 years (group B). There were 16 cases (17.2%) of oral origin; 4 BE cases mainly associated with tooth extractions were found in group A and 12 BE (most of them related with odontogenic abscesses) in group B. Within group A, 1 patient (25%) had not an underlying cardiac condition versus 5 cases (41.6%) in group B. Even though the prevalence of BE of oral origin in patients older than 60 is low, the high frequency of cardiopathies, poor oral health and high number of dental procedures shown by the old population makes them a risk group for BE of oral origin.

An update on infective endocarditis of dental origin

OBJECTIVES

The aim of this study was to analyse the prevalence of dental treatment and oral infections related to the development of infective endocarditis (IE).

METHODS

A retrospective study of 103 cases of IE diagnosed from 1997 to 1999 was conducted in Galicia, Spain.

RESULTS

According to the Duke's endocarditis criteria (1994), 87 cases (84.5%) were considered definite IE. A presumed oral portal of entry was recorded in 12 patients (13.7%). Oral infections were held responsible in six cases while the remaining six had received dental treatment in the previous three months (three tooth extractions, one scaling, one cleaning, one fillings). In eight cases of IE (66.6%) typical oral pathogenic microflora was identified, with Streptococcus viridans being the most frequent. In four patients no previous cardiac disease was recorded.

CONCLUSIONS

These results suggest that prevalence and characteristics of IE cases of dental origin did not change significantly in the last decades. The need for increased oral hygiene and improved dental care should be emphasized on preventing IE of dental origin. Continued education of physicians and dentists on the importance of the knowledge of current prophylactic protocols should also be considered.