[News on Bartonella infections]

The review specifies 25 Bartonella species known so far and describes epidemiology and pathogenesis of Bartonella infections which are classified using patient symptomatology including culture-negative endocarditis. Microbiological diagnosis and significant principles of antibiotic therapy of Bartonella infections are also stated.

Complexity and subtlety of infective endocarditis

Infective endocarditis (IE) is an uncommon clinical entity that, if unrecognized, leads to serious morbidity and mortality. Approximately 15,000 new cases of IE occur in the United States each year. Despite advances in early diagnosis, antimicrobial treatment, and surgical techniques, reported mortality from referral centers has changed little throughout several decades. Early recognition of IE requires understanding of its epidemiology, risk factors, clinical presentations, physical examination signs, microbiological associations, and electrocardiographic and chest radiographic findings. Once IE is suspected, further testing with blood cultures and echocardiography can confirm the diagnosis and lead to early treatment with bactericidal antibiotics and surgery when appropriate, thus reducing the morbidity and mortality of IE. Unrecognized and untreated, IE is invariably fatal. Early recognition of IE and an in-depth understanding of the clinical vagaries of IE are mandatory for all patient care providers.

Contribution of systematic serological testing in diagnosis of infective endocarditis

Despite progress with diagnostic criteria, the type and timing of laboratory tests used to diagnose infective endocarditis (IE) have not been standardized. This is especially true with serological testing. Patients with suspected IE were evaluated by a standard diagnostic protocol. This protocol mandated an evaluation of the patients according to the modified Duke criteria and used a battery of laboratory investigations, including three sets of blood cultures and systematic serological testing for Coxiella burnetii, Bartonella spp., Aspergillus spp., Legionella pneumophila, and rheumatoid factor. In addition, cardiac valvular materials obtained at surgery were subjected to a comprehensive diagnostic evaluation, including PCR aimed at documenting the presence of fastidious organisms. The study included 1,998 suspected cases of IE seen over a 9-year period from April 1994 to December 2004 in Marseilles, France. They were evaluated prospectively. A total of 427 (21.4%) patients were diagnosed as having definite endocarditis. Possible endocarditis was diagnosed in 261 (13%) cases. The etiologic diagnosis was established in 397 (93%) cases by blood cultures, serological tests, and examination of the materials obtained from cardiac valves, respectively, in 348 (81.5%), 34 (8%), and 15 (3.5%) definite cases of IE. Concomitant infection with streptococci and C. burnetii was seen in two cases. The results of serological and rheumatoid factor evaluation reclassified 38 (8.9%) possible cases of IE as definite cases. Systematic serological testing improved the performance of the modified Duke criteria and was instrumental in establishing the etiologic diagnosis in 8% (34/427) cases of IE.

Are the Duke criteria really useful for the early bedside diagnosis of infective endocarditis? Results of a prospective multicenter trial

BACKGROUND

To date, no studies have evaluated the usefulness of the Duke vs the modified Duke criteria for the early diagnosis of infective endocarditis (IE), nor is it known whether a probabilistic approach may be useful in establishing an early clinical diagnosis of IE. The aim of this study was (1) to assess and compare the clinical usefulness of the Duke vs the modified Duke criteria for the early diagnosis of IE, and (2) to evaluate the diagnostic utility of a probabilistic approach based on the echocardiographic criterion.

METHODS

From January 2000 to December 2001, 267 consecutive patients with suspected IE were enrolled in a prospective multicenter trial.

RESULTS

IE was diagnosed in 147 cases (55%) and rejected in 120 cases (45%). The Duke and the modified Duke criteria had a high similar sensitivity, specificity and accuracy. The time to diagnosis was 8.15 +/- 7.4 days for the Duke criteria and 8.18 +/- 7.1 days for the modified Duke criteria. The time to diagnosis based on a probabilistic approach was shorter than that based on the Duke and the modified Duke criteria (4.96 +/- 7.1 days, for all p < 0.001).

CONCLUSIONS

Although the Duke and the modified Duke criteria have a very similar sensitivity, specificity and accuracy, the delay in the time to diagnosis may be significant. A probabilistic approach based on clinical suspicion and echocardiographic evidence may be useful for decision-making, whilst awaiting case definition by means of the Duke criteria.

[S2 guideline for infectious endocarditis]

Microbe-induced (infectious) endocarditis is an endovascular infection, caused mainly by bacteria, of cardiovascular structures. The major predilection site are the native heart valves, but involvement of implanted intracardiac foreign material is increasingly being seen. The mortality rate of infectious endocarditis depends on clinical factors and the causal agent, but also on the time of the establishment of the diagnosis and the initiation of appropriate treatment. In Germany, the current mortality rate ranges up to 18%. Between January 2003 and July 2004, with the aim of improving patient care and thus the outcome of this condition, a guideline commission worked out recommendations for the diagnosis, treatment and management of the disease for the use of general practitioners and hospital physicians, in particular microbiologists, infectiologists, cardiologists and cardiac surgeons. The basis for this guideline was the systematic search through the literature of the European guideline. On the 16th and 28th of June 2004, the entire guideline was formerly approved in a nominal group process.

[Surgical treatment of active infective endocarditis: analysis of 20 years' experience]

OBJECTIVES

Changes in perioperative condition and outcomes of surgically treated patients with active infective endocarditis were evaluated during the last 20 years.

METHODS

Between 1983 and 2002, 132 patients with active infective endocarditis underwent surgery at Saitama Medical School. Changes in frequency, pathogens, clinical features, surgical results, and perioperative treatment were compared between four periods of 5 years.

RESULTS

The percentage of surgery for infective endocarditis remained almost the same among all cardiovascular procedures. Staphylococcal infective endocarditis increased significantly (p < 0.01), and prosthetic valve infective endocarditis and periannular abscess became more common. Surgery tended to be performed in severely ill patients significantly more frequently (p < 0.01). If all patients were included, hospital mortality did not decrease significantly, at 1.7% in stable patients, but 50% in critically ill patients. Intensive care unit stay became relatively longer. Recurrent infection was observed significantly more frequently in critically ill patients and in patients with prosthetic valve infective endocarditis. Patients were referred for surgery following diagnosis and underwent surgery at increasingly more appropriate timing. However, the diagnosis of infective endocarditis took 1.5 months to establish regardless of the patient's condition or the clinical outcome. Moreover, antibiotics were administered orally in around 90% and intravenously in nearly 70% of the patients without microbiological tests, and negative cultures remained very frequent.

CONCLUSIONS

Critically ill patients underwent surgery increasingly more frequently, and surgical outcomes remained unsatisfactory over the last 20 years. Early diagnosis and avoidance of premature antibiotic therapy may be important for future improvement.

[Management of patients with infectious endocarditis]

The paper presents clinical manifestations of infectious endocarditis (IE), its new clinical classification, diagnostic criteria, potentialities and limitations of echocardiography. General principles of management of patients with IE are considered. The management algorithm is given, which involves the initial assessment of these patients, empirical therapy, etiotropic chemotherapy (CT) regimens in streptococcal, staphylococcal, gram-negative, fungal endocarditis, and IE of unknown etiology. Possible complications due to IE (refractory heart failure, infection dissemination, thrombohemorrhagic syndrome, immune diseases, persistent fever) are described, which need supplementary treatment, particularly schemes for correction of hemostatic and immune disorders. Clinical and microbiological criteria are proposed for evaluating the efficiency of treatment for IE. The conditions showing a higher risk for the types of IE that require antibiotic prophylaxis and the criteria for choosing its regimen are given. New trends in the treatment of IE, such as shorter courses of antibacterial CT, stepwise antibacterial therapy (ABT), and parenteral ABT at home, are outlined.

Factors other than the Duke criteria associated with infective endocarditis among injection drug users

BACKGROUND

Modified Duke criteria were applied to consecutive injection drug users (IDUs) who were admitted to an inner-city hospital with a clinical suspicion of infective endocarditis, and the presence of any other clinical variables that were predictive of the presence of infective endocarditis was determined.

METHODS

Clinical data on consecutive IDUs who were hospitalized over 15 months in Vancouver were collected. Data included the admission history, and findings on physical examination and on initial laboratory investigations. Each subject's course in hospital was followed until discharge or death during the index hospitalization. Follow-up data collected included culture results, the interpretation of the echocardiogram and the discharge diagnosis. The modified Duke criteria were used for the diagnosis of infective endocarditis (definite, possible or rejected). Multiple logistic regression was used to determine what clinical variables (exclusive of the Duke criteria) available within 48 hours of presentation were independent predictors of infective endocarditis.

RESULTS

One hundred IDUs were enrolled. Fifty-one were female, and 58 were HIV-positive. Twenty-three met the modified Duke criteria for definite infective endocarditis, and 25 had possible infective endocarditis. IDUs with definite infective endocarditis were more commonly noted to have evidence of vascular phenomena (arterial embolism, septic pulmonary infarction, mycotic aneurysm, intracranial hemorrhage or Janeway lesions) (6 [26%]) than those who had possible endocarditis (1 [4%]). Those with definite infective endocarditis more often had multiple opacities on chest radiography (56% v. < 12%), and fewer had an obvious source of infection (52% v. 72% and 81% of possible and rejected infective endocarditis, respectively). Among febrile IDUs, definite endocarditis was highly associated with having no obvious source of infection (odds ratio 3.1 [95% confidence interval 1.1-8.7]) compared with febrile IDUs with an obvious source of infection. In similarly compared groups, the presence of hematuria, proteinuria or pyuria was also predictive of definite endocarditis (odds ratio 2.9 [95% CI 1.1-8.6]).

CONCLUSIONS

Among IDUs, the modified Duke criteria are useful for classifying cases with definite infective endocarditis and rejecting cases without infective endocarditis. The classification of possible infective endocarditis is suitable for this population.

Eustachian valve endocarditis: Is it worth searching for?

BACKGROUND

Only a few cases of eustachian valve endocarditis have been reported. Whether the eustachian valve is an uncommon site for a vegetation to be attached or whether the disease is missed because a systematic approach to this valve is not routinely performed in the search for vegetations is not known.

METHODS

Every patient suspected of having endocarditis undergoes a specific approach, which includes a systematic study of the eustachian valve. In 10 patients with large valves but without signs and symptoms of endocarditis, we identified 2 specific findings: width <3 mm and a regular oscillating movement. A blinded evaluation in the 10 control subjects and 30 patients with right-sided endocarditis, including the 5 with eustachian valve endocarditis, showed an agreement of 97% (39/40).

RESULTS

Five of 152 patients with right-sided endocarditis were found to have eustachian valve vegetations (3.3%). Patients were young (age range 22-34 years) and all had predisposing factors (3 intravenous drug abusers, 2 central venous lines), fever, and septic pulmonary embolism. Staphylococcus aureus was cultured in all cases. Tricuspid involvement was found in 4 patients, and only 1 patient had isolated eustachian valve endocarditis. All patients did well with culture-guided antibiotics.

CONCLUSIONS

Our results suggest that eustachian valve endocarditis may be more frequent than is believed. Thus a systematic interrogation of the eustachian valve should be included in the echocardiographic examination of a patient suspected of having endocarditis.

Clinical information determines the impact of transesophageal echocardiography on the diagnosis of infective endocarditis by the duke criteria

BACKGROUND

Although transesophageal echocardiography (TEE) is more sensitive than transthoracic echocardiography (TTE) in detecting echocardiographic evidence of infective endocarditis (IE), the impact of TEE on the clinical diagnosis of IE has not been clearly delineated.

METHODS AND RESULTS

We studied 112 patients with 114 suspected episodes of IE over a 6-year period who underwent both TTE and TEE during their diagnostic evaluation. Using the results of these studies along with clinical and microbiologic data, we attempted to determine the incremental value of TEE to the Duke Endocarditis Diagnostic Criteria. Patients were initially classified into a diagnostic category of the Duke criteria with TTE data, and then the diagnostic classification was reconsidered with TEE data. A diagnostic category reassignment occurred in 25 of 114 episodes of IE evaluated when TEE results were incorporated into the evaluation with the Duke criteria (22 patients were reclassified from possible IE to definite IE whereas 3 patients were reclassified from rejected to possible IE). Diagnostic reclassification occurred in 9 (11%) of the 80 episodes of suspected IE with native cardiac valves and 13 (34%) of 34 episodes with prosthetic cardiac valves. Most patients reclassified from possible IE to definite IE with TEE data (19 of 22) had an intermediate clinical likelihood of IE, whereas 92% of patients had negative TTE results. Pathologic examination of valvular tissue in 22 of the 114 episodes of suspected IE revealed that the positive predictive value of the Duke criteria with TEE data for diagnosis of IE was 85% in patients with native valves and 89% in patients with prosthetic valves.

CONCLUSIONS

When clinical evidence of IE is present, TEE improves the sensitivity of the Duke criteria to diagnose definite IE. TEE data appears to be especially useful for the diagnostic evaluation of patients with suspected IE who have prosthetic valves.

Value and limitations of the Duke criteria for the diagnosis of infective endocarditis

OBJECTIVES

The purpose of this study was to assess the value and limitations of Duke criteria for the diagnosis of infective endocarditis (IE).

BACKGROUND

Duke criteria have been shown to be more sensitive in diagnosing IE than the von Reyn criteria, but the diagnosis of IE remains difficult in some patients.

METHODS

Both classifications were applied in 93 consecutive patients with pathologically proven IE. Blood cultures, and transthoracic and transesophageal echocardiography were performed in all patients.

RESULTS

Sensitivities for the diagnosis of IE were 56% and 76% for von Reyn and Duke criteria, respectively. Fifty-two patients were correctly classified as "probable IE" by von Reyn and "definite IE" by Duke criteria (group 1). However, discrepancies were observed in 41 patients. Eleven patients (group 2) were misclassified as "rejected" by von Reyn, but were "definite IE" by Duke criteria; this difference could be explained by negative blood cultures and positive echocardiogram in all patients. In eight patients (group 3), the diagnosis of IE was "possible" by von Reyn but "definite" by Duke criteria. This difference was essentially explained by the failure of the von Reyn classification to consider echocardiographic abnormalities as major criteria. Twenty-two patients (group 4) were misclassified as possible IE using Duke criteria, being false negative of this classification. Echocardiographic major criteria were present in 19 patients, but blood cultures were negative in 21 patients. The cause of negative blood cultures was prior antibiotic therapy in 11 patients and Q-fever endocarditis diagnosed by positive serology in three cases.

CONCLUSIONS

Twenty-four percent of patients with proved IE remain misclassified as "possible IE" despite the use of Duke criteria, especially in cases of culture-negative and Q-fever IE. Increasing the diagnostic value of echographic criteria in patients with prior antibiotic therapy and typical echocardiographic findings and considering the serologic diagnosis of Q fever as a major criterion would further improve the clinical diagnosis of IE.

[Diagnostic criteria of infectious endocarditis]

Accurate diagnostic criteria for infective endocarditis are essential to epidemiological studies. The von Reyn's criteria have been widely used for more than a decade after they were published in 1981. In 1994, the Duke's criteria for the clinical diagnosis of infective endocarditis were published, incorporating echocardiographic findings. They are modeled after the Jones criteria for the identification of cases of rheumatic fever and include 2 major and 6 minor diagnostic criteria. They are about twice as specific as the former von Reyn's criteria, without loss of specificity, and should become a standard reference for diagnosing infective endocarditis.

Bacterial endocarditis: results of a survey in a children's hospital in France

OBJECTIVE

To identify and analyse the risk factors for infective endocarditis.

DESIGN

Retrospective survey over a 12-year period.

SETTING

Department of Paediatric Cardiology, Nancy, France.

SUBJECTS

43 children attending during 1970-1992 who were diagnosed with infective endocarditis in accordance with Von Reyn's classification.

RESULTS

45 episodes of infective endocarditis were recorded (2 children had 2 episodes). Congenital cardiac disease was the most frequent predisposing factor for infective endocarditis. The causes of bacteraemia found were frequently, but not exclusively, of dental origin (30.5%). Among the dental causes were: poor oral health, inappropriate treatments and lack of antibiotic prophylaxis.

CONCLUSIONS

Children diagnosed with a cardiac disorder should be examined by a dentist. Modern principles of antibiotic therapy and accepted dental procedures must be performed as soon as possible and parents informed of the current preventive recommendations.

The Duke criteria for diagnosing infective endocarditis are specific: analysis of 100 patients with acute fever or fever of unknown origin

The recently proposed Duke criteria were confirmed to be more sensitive than the former Beth Israel criteria for the diagnosis of infective endocarditis (IE). To assess the specificity of the Duke criteria, we reviewed the records of 100 patients admitted to two internal medicine wards because of acute fever or fever of unknown origin (FUO). IE was considered a possible diagnosis for all patients who had had at least two blood cultures performed and one transthoracic echocardiogram obtained. The diagnosis of IE was rejected in all cases in accordance with the Duke criteria (i.e., a firm alternate diagnosis [n = 23], resolution of symptoms with no antibiotics [n = 39], or both reasons [n = 38]). To calculate the specificity of the Duke criteria, all 100 cases were then reclassified according to these criteria as if the diagnosis of IE had not been rejected. Only one patient, who probably did not have IE, was reclassified as having clinically definite IE. The specificity of the Duke criteria could therefore be calculated to 0.99 (95% confidence interval, 0.97-1). Although the design of the study may have resulted in a slight overestimation of the specificity rate, we conclude that the Duke criteria are highly specific for ruling out IE in patients with acute fever or FUO who are at low risk for IE.

Negative predictive value of the Duke criteria for infective endocarditis

With use of new Duke criteria, 405 episodes of suspected endocarditis were previously classified as "definite," "possible," or "rejected" endocarditis. To determine the negative predictive value of the Duke clinical criteria for the classification of suspected endocarditis, chart review and follow-up were performed for the 52 episodes in which the diagnosis of endocarditis was rejected. Three of 52 episodes were reclassified to possible endocarditis; 49 episodes in 48 patients met the criteria for rejected endocarditis. Of these 49 episodes, 31 (63%) had a firm alternate diagnosis other than endocarditis, 17 (35%) had resolution of the clinical syndrome leading to the suspicion of endocarditis with < or = 4 days of antibiotics, and 1 patient had no evidence of endocarditis at surgery. Echocardiograms recorded in 3 patients with rejected endocarditis had evidence of oscillating valvular masses, and blood cultures were positive in 13 episodes; none of these patients had evidence of endocarditis at follow-up. Follow-up or outcome information was available in all 49 episodes. Excluding the 5 in-hospital deaths, mean duration (+/- SD) of follow-up was 39.9 +/- 28.8 months (range 0.5 to 108.0); in living patients, mean time to final follow-up was 56.2 +/- 25.2 months (range 25.0 to 108.0). One patient had possible infective endocarditis at autopsy. No patient in our series whose diagnosis of endocarditis had been rejected had proven endocarditis. Therefore, the negative predictive value of the Duke clinical criteria for endocarditis is at least 92%.

Criteria for the diagnosis of endocarditis and the role of echocardiography

When infective endocarditis is a diagnostic possibility, echocardiography permits noninvasive imaging of cardiac structures. As involvement of the endocardium is a sine qua non of endocarditis, echocardiography may assist in its diagnosis by demonstrating such involvement. The ability of echocardiography to detect the intracardiac manifestations of infective endocarditis has continued to improve, especially with the introduction of transesophageal imaging. This article will discuss some of the echocardiographic findings in endocarditis and elucidate the incorporation of these findings in the new Duke criteria for the diagnosis of endocarditis.

[Clinical aspects and diagnosis of infectious endocarditis]

The first step in the diagnosis of infective endocarditis is a high level of clinical suspicion. Only rarely are all the classic signs of infective endocarditis, namely fever, a new cardiac murmur, splenomegaly, anemia and embolic phenomena, found. Every organ system can be involved by embolic or immunologic complications. We have to look specially for manifestations in skin and mucosa, CNS, kidney, locomotor system and lungs. The clinical spectrum has changed over the last decades. More elderly patients, patients with prosthetic heart valves and i.v. drug users are affected. The traditional classification into acute and subacute infective endocarditis has been replaced by a classification based on the microbiological etiology or on the involved valve (native, prosthetic, left- or right sided). In particular, the clinical presentation of right-sided infective endocarditis differs from the left-sided one. A diagnosis of infective endocarditis has to be considered in every patient with unexplained fever or a multisystem disease. A definite diagnosis of infective endocarditis rests on a multidisciplinary approach that involves the clinician and the echocardiography and microbiology laboratories.

Infective endocarditis. Implications for care of the adult with congenital heart disease

Infective endocarditis (IE) remains a severe complication for the adult with congenital heart disease (CHD). The last four decades have witnessed a radical transformation in the spectrum of IE, including the advent of cardiac surgery and the postantibiotic era. Because of the devastation caused by this disease, prevention is the hallmark. A clear understanding of the pathogenesis, clinical features, and management of IE is essential for any practitioner caring for adults with CHD.

[Evolution of protracted septic endocarditis]

A study of 1000 cases of septic endocarditis served as a basis for an analysis of the natural history of the diseases (1939-1972): changes in its etiology, clinical course and therapy. The increasing frequency of hospital infection (endocarditis) is emphasized. The characteristics of Staphylococcal and fungal endocarditis are presented, those of the lesion developing on heart valve prostheses as well. The classification of septic endocarditis is analysed, the stages of its activeness are described (III, II, I) along with the clinical and laboratory signs. Schemes of etiotropic therapy are presented, as well as rational combinations of antibiotics. The role of surgery in the management of primary septic endocarditis is described, and the rationale of preventive employment of antibiotics is discussed.