S2-Leitlinie zur Diagnostik und Therapie der infekti�sen Endokarditis

Calculated initial parenteral treatment of bacterial infections: Bacterial endocarditis

This is the twelfth chapter of the guideline "Calculated initial parenteral treatment of bacterial infections in adults - update 2018" in the 2^nd updated version. The German guideline by the Paul-Ehrlich-Gesellschaft für Chemotherapie e.V. (PEG) has been translated to address an international audience. The bacterial endocarditis is characterised by a constant incidence but a shift in the patient population due to the use of prosthetic heart valves and foreign materials like pacemakers and the increasing application of invasive medical procedures. This is linked to a change in the predominant infecting organisms towards staphylococci. This chapter gives recommendations for the interdisciplinary management of infective endocarditis from the diagnostic workup over prevention to therapy with a focus on antibiotic therapy.

Advantages and Limitations of Direct PCR Amplification of Bacterial 16S-rDNA from Resected Heart Tissue or Swabs Followed by Direct Sequencing for Diagnosing Infective Endocarditis: A Retrospective Analysis in the Routine Clinical Setting

Infective endocarditis (IE) is a life-threatening disease that is associated with high morbidity and mortality. Its long-term prognosis strongly depends on a timely and optimized antibiotic treatment. Therefore, identification of the causative pathogen is crucial and currently based on blood cultures followed by characterization and susceptibility testing of the isolate. However, antibiotic treatment starting prior to blood sampling or IE caused by fastidious or intracellular microorganisms may cause negative culture results. Here we investigate the additional diagnostic value of broad-range PCR in combination with direct sequencing on resected heart tissue or swabs in patients with tissue or swab culture-negative IE in a routine clinical setting. Sensitivity, specificity, and positive and negative predictive values of broad-range PCR from diagnostic material in our patients were 33.3%, 76.9%, 90.9%, and 14.3%, respectively. We identified a total of 20 patients (21.5%) with tissue or culture-negative IE who profited by the additional application of broad-range PCR. We conclude that broad-range PCR on resected heart tissue or swabs is an important complementary diagnostic approach. It should be seen as an indispensable new tool for both the therapeutic and diagnostic management of culture-negative IE and we thus propose its possible inclusion in Duke's diagnostic classification scheme.

Dentigenous infectious foci - a risk factor of infective endocarditis

BACKGROUND

Dentigenous, infectious foci are frequently associated with the development of various diseases. The role of such foci in the evolution of endocarditis still remains unclear. This article presents the concluding results of an interdisciplinary study verifying the influence of dentigenous, infectious foci on the development of infective endocarditis.

MATERIAL/METHODS

The study subjects were 60 adult patients with history of infective endocarditis and coexistent acquired heart disease, along with the presence at least 2 odontogenic infectious foci (ie, 2 or more teeth with gangrenous pulp and periodontitis). The group had earlier been qualified for the procedure of heart valve replacement. Swabs of removed heart valve tissue with inflammatory lesions and blood were then examined microbiologically. Swabs of root canals and their periapical areas, of periodontal pockets, and of heart valves were also collected.

RESULTS

Microbial flora, cultured from intradental foci, blood and heart valves, fully corresponded in 14 patients. This was accompanied in almost all cases by more advanced periodontitis (2nd degree, Scandinavian classification), irrespective of the bacterial co-occurrence mentioned. In the remaining patients, such consistency was not found.

CONCLUSIONS

Among various dentigenous, infectious foci, the intradental foci appear to constitute a risk factor for infective endocarditis.

Congenital heart defects in adulthood

BACKGROUND

More than 90% of children with congenital heart defects now survive into adulthood; just a few decades ago, survival was rare, particularly among patients with complex defects. The new population of adults with congenital heart disease presents a special challenge to physicians from all of the involved specialties.

METHODS

Selective literature review.

RESULTS AND CONCLUSION

A complete cure of the congenital heart defect in childhood is exceptional, and most adult patients continue to suffer from residual problems and sequelae. Further surgery or catheter interventions may be needed. Potential late complications include arrhythmias, heart failure, pulmonary hypertension, endocarditis, and thromboembolic events. The management of these patients during pregnancy or non-cardiac surgery remains a challenge. If this evolving patient population is to receive the best possible care, the adequate provision of specialized medical services is a necessary, but not sufficient, condition: patients and their referring physicians will also need to be aware that these services are available, and then actually make use of them. Moreover, optimal communication among all of the involved physicians is essential.

[Infective endocarditis as cardiovascular emergency]

Infective endocarditis is an infection of cardiovascular structures which is typically caused by bacteria. Despite recent medical advances mortality reaches up to 26% which is even higher with mortality rates of up to 84% in complex cases leading to admission to intensive care units. The diagnosis is based on positive blood culture results with identical microorganisms and the demonstration of endocardial involvement. A rapid initiation of an adequate therapeutic regimen is important to prevent the patients from severe complications such as heart failure, uncontrolled infection or septic embolism. An early and targeted initiation of an antibiotic therapy after microbiologic testing is crucial for therapeutic success. The immediate cooperation of Cardiologists, Microbiologists, Infectious Disease Specialists and Cardiac Surgeons is highly recommended to allow an adequate medical and surgical treatment without delay in complex cases. Antibiotic treatment has to be continued postoperatively.

Differentiation of species of the Streptococcus bovis/equinus-complex by MALDI-TOF Mass Spectrometry in comparison to sodA sequence analyses

The Streptococcus bovis/equinus complex is a heterogeneous group within the group D streptococci with important clinical relevance regarding infective endocarditis, sepsis and colon carcinoma. The taxonomic identification of species and sub-species of this complex, by the standard methods remains difficult. In the present study, we compared the cluster analysis of 88 strains of species of the S. bovis/equinus complex by sequence analysis of the manganese-dependent superoxide dismutase gene (sodA) and by Matrix Assisted Laser Desorption/Ionization-Time Of Flight Mass Spectrometry (MALDI-TOF MS). We observed a high congruence of strain grouping by MALDI-TOF MS in comparison with sodA sequence analyses, demonstrating the accuracy and reliability of MALDI-TOF MS in comparison to DNA sequence-based method. By generating mass spectra for each species and sub-species, we were able to discriminate all members of the S. bovis/equinus complex. Furthermore, we demonstrated reliable identifications to the species level by MALDI-TOF MS, independently of cultivation conditions.

[Diagnosis and treatment of infective endocarditis. Current ESC guidelines]

To account for the current evidence in the field of infective endocarditis and to harmonize deviant national guidelines, in 2009 the European Society of Cardiology published novel recommendations on the prevention, diagnosis and treatment of infective endocarditis.The most important changes can be found concerning antimicrobial prophylaxis for endocarditis, the antimicrobial treatment of endocarditis caused by S. aureus and the indications for surgical treatment.Due to the weak evidence about prophylactic administration of antibiotics before procedures at risk for bacteraemia to prevent infective endocarditis, the novel guidelines recommend prophylaxis only in patients with the highest risk for infection and lethal course of endocarditis. These are patients with prosthetic valves or prosthetic material used for cardiac repair, patients with previous endocarditis and patients with congenital heart disease. A narrow definition of procedures at risk was proposed only including dental procedures requiring manipulation of the gingival or periapical region of teeth.For endocarditis caused by S. aureus an additional gentamicin administration was previously recommended but this is now seen only as optional due to its nephrotoxicity. In methicillin-resistant strains daptomycin is a possible alternative to vancomycin. In strains susceptible to methicillin, beta-lactamic antibiotics were definitively preferred than the usage of vancomycin due to better outcome. The current guidelines recommend definitive timing and risk constellations for surgical treatment of infective endocarditis. For example, cardiac shock due to valvular lesions refractory to medical treatment should give rise to an emergency intervention within 24 h. Other indication groups contain uncontrolled infection and prevention of embolism and indications were defined as urgent or elective depending on the clinical situation.

Interactions between endocarditis-derived Streptococcus gallolyticus subsp. gallolyticus isolates and human endothelial cells

Background

Streptococcus gallolyticus subsp. gallolyticus is an important causative agent of infective endocarditis (IE) but the knowledge on virulence factors is limited and the pathogenesis of the infection is poorly understood. In the present study, we established an experimental in vitro IE cell culture model using EA.hy926 and HUVEC cells to investigate the adhesion and invasion characteristics of 23 Streptococcus gallolyticus subsp. gallolyticus strains from different origins (human IE-derived isolates, other human clinical isolates, animal isolates). Adhesion to eight components of the extracellular matrix (ECM) and the ability to form biofilms in vitro was examined in order to reveal features of S. gallolyticus subsp. gallolyticus endothelial infection. In addition, the strains were analyzed for the presence of the three virulence factors gtf, pilB, and fimB by PCR.

Results

The adherence to and invasion characteristics of the examined S. gallolyticus subsp. gallolyticus strains to the endothelial cell line EA.hy926 differ significantly among themselves. In contrast, the usage of three different in vitro models (EA.hy926 cells, primary endothelial cells (HUVECs), mechanical stretched cells) revealed no differences regarding the adherence to and invasion characteristics of different strains. Adherence to the ECM proteins collagen I, II and IV revealed the highest values, followed by fibrinogen, tenascin and laminin. Moreover, a strong correlation was observed in binding to these proteins by the analyzed strains. All strains show the capability to adhere to polystyrole surfaces and form biofilms. We further confirmed the presence of the genes of two known virulence factors (fimB: all strains, gtf: 19 of 23 strains) and demonstrated the presence of the gene of one new putative virulence factor (pilB: 9 of 23 strains) by PCR.

Conclusion

Our study provides the first description of S. gallolyticus subsp. gallolyticus adhesion and invasion of human endothelial cells, revealing important initial information of strain variability, behaviour and characteristics of this as yet barely analyzed pathogen.

Infective endocarditis--prophylaxis, diagnostic criteria, and treatment

BACKGROUND

Despite important medical advances, infective endocarditis (IE) is still a disease with high morbidity and mortality. Its prophylaxis, diagnosis, and treatment are still a major challenge in clinical practice.

METHODS

Selective literature review based on the current German and European guidelines and a PubMed search from 2004 onward.

RESULTS

Essential requirements for the rapid diagnosis and specific treatment of IE are the echocardiographic demonstration of endocardial disease and the identification of the causative organism by blood culture. The modified Duke criteria have made the diagnosis more objective but are not a replacement for clinical judgement. It should be borne in mind, when the initial empirical treatment is chosen, that Staphylococcus aureus is currently the most common causative organism. If diagnostic criteria are met that suggest a methicillin-resistant S. aureus infection, then glycopeptide antibiotics are still the standard treatment. Newer agents such as daptomycin can be considered as an alternative, as suggested by recent studies and in view of the increasing frequency of impaired vancomycin susceptibility. Early surgical treatment should be considered for patients who are likely to encounter further complications along their clinical course. According to the current recommendations, antibiotics should be given for endocarditis prophylaxis only to patients about to undergo one of a small number of explicitly defined procedures, who would otherwise be at a high risk of major illness or death. The purpose of this restriction is to make prophylaxis more efficient.

CONCLUSION

IE remains a potentially lethal infectious disease that can be treated effectively only by physicians from multiple disciplines working in collaboration.

Heart valve surgery today: indications, operative technique, and selected aspects of postoperative care in acquired valvular heart disease

BACKGROUND

Surgery plays a central role in the management of acquired valvular heart disease. The optimal diagnostic evaluation, surgical treatment, and postoperative care of these patients are only possible through a cooperative effort of the primary care physician, the cardiologist, and the cardiac surgeon.

METHODS

The literature was selectively searched for information on surgical indications, operative techniques, and postoperative care in acquired valvular heart disease. Evidence-based guidelines and treatment recommendations were also taken into account.

RESULTS

A wide variety of techniques and implants are now available for the surgical treatment of acquired valvular heart disease. If they are used in evidence-based fashion, the perioperative mortality is low and the long-term outcome is favorable.

CONCLUSIONS

The volume of surgery for acquired valvular heart disease in Germany has increased substantially in recent years, from 25,495 cases in 2002 (corresponding to 26.5% of all heart operations in that year) to 33,412 in 2007 (36.5% of all heart operations). The causes for this include both demographic changes and the availability of new, less invasive surgical techniques that yield better results in elderly and/or multimorbid patients. Because of these new techniques, the indications for surgery have widened, while the results have remained favorable.

Lipopolysaccharide-binding protein: a new biomarker for infectious endocarditis?

BACKGROUND

Infectious endocarditis (IE) is a bacterial infection of the endocardium. Diagnosis is based on results obtained from echocardiography, blood cultures, and molecular genetic screening for bacteria and on data for inflammatory markers such as the leukocyte (WBC) count and the C-reactive protein (CRP) concentration. The aim of the present study was to evaluate lipopolysaccharide-binding protein (LBP) as a supportive biomarker for the diagnosis and therapeutic monitoring of IE.

METHODS

We measured LBP and CRP concentrations and WBC counts in 57 IE patients at hospital admission, 40 patients with noninfectious heart valve diseases (HVDs), and 55 healthy blood donors. The progression of these 3 markers and the influence of cardiac surgery on them were evaluated in 29 IE patients and 21 control patients.

RESULTS

Serum LBP concentrations were significantly higher in IE patients [mean (SD), 33.41 (32.10) mg/L] compared with HVD patients [6.67 (1.82) mg/L, P < 0.0001] and healthy control individuals [5.61 (1.20) mg/L]. The progression in the LBP concentration during therapy of IE patients correlated with the changes in the CRP concentration. The 2 markers were equally influenced by antibiotic treatment and surgical intervention.

CONCLUSIONS

Serial LBP measurement may provide an effective and useful tool for evaluating the response to therapy in IE patients. We found a strong correlation between LBP and CRP concentrations; LBP has a tendency to increase earlier in cases of reinfection.

[Therapy and prophylaxis of infective endocarditis]

Infective endocarditis is an infection of cardiovascular structures which is typically caused by bacteria. Despite recent medical advances mortality ranges from 20 to 25%. Without treatment, IE is a lethal disease. The mortality rate depends on several clinical factors including the causative microorganism, the time of diagnosis, and the initiation of an adequate therapeutic regimen. The diagnosis is based on positive blood culture results with identical microorganisms and the demonstration of endocardial involvement. Negative blood cultures represent a diagnostic challenge which may increase the importance of diagnostic tools such as serology and PCR. An early and targeted initiation of an antibiotic therapy after microbiologic testing is crucial for therapeutic success. The immediate cooperation of Cardiologists, Microbiologists, Infectious Disease Specialists and Cardiac Surgeons is highly recommended to allow an adequate medical and surgical treatment in complex cases.Prophylaxis appears reasonable due to the inherent high mortality. The efficacy of an antibiotic prophylaxis is, nevertheless, not rigorously proven. Even if a high efficacy is assumed, the number needed to treat is extremely high due to the low individual risk. Thus, current guidelines recommend an antibiotic prophylaxis only in patients with a high risk for an adverse outcome.

Infective endocarditis with negative blood cultures

Culture-negative endocarditis is important as it has a relatively poor prognosis. The principal reason for negative cultures is prior antibiotic therapy although fastidious organisms such as Bartonella spp. and Coxiella burnetii are also important. PCR may offer significant advantages in diagnosis but tests require standardisation. Modification of current diagnostic criteria is required. Empirical cover of MRSA needs to be considered.

[Acute febrile disease with splenomegaly and pancytopenia. A 66-year-old Greek patient with a prosthetic mitral valve]

We report on a 66-year-old patient originating from Greece and living in Germany with a prosthetic mitral valve because of a combined vitium following juvenile rheumatic fever. The patient fell ill with acute fever, splenomegaly, and pancytopenia. After unsuccessful antibiotic therapy because of presumed endocarditis or sepsis with unknown focus, visceral leishmaniasis was suspected because of recent travel to Greece. Subsequently, this diagnosis was confirmed by serology. Considering thrombocytopenia and concurrent anticoagulation after prosthetic mitral valve replacement, we avoided a bone marrow biopsy usually required for definite proof of leishmania infection. Instead, infection with Leishmania infantum was diagnosed by PCR of a peripheral blood sample. After treatment with liposomal amphotericin B the patient recovered fully.

Remodeling or reimplantation for valve-sparing aortic root surgery?

BACKGROUND

Valve-sparing operations are gaining increasing acceptance; however, there is an ongoing discussion about the technique-specific indications. We present our experience with a follow-up of 123 months.

METHODS

Between July 1993 and July 2005, 164 consecutive patients were operated on using the remodeling (group A, n = 96) or reimplantation technique (group B, n = 68). Fifty-seven patients presented with acute type A dissection. Aortic regurgitation was present in 84%. Follow-up was 54.7 +/- 28 in group A and 48.4 +/- 37.3 months in group B.

RESULTS

After urgent operations, 4 patients died in each group, but none died after elective surgery. Late mortality was 8% in group A and 4% in group B. Seven patients of group A and 1 in group B required reoperation. Echocardiographic follow-up of reoperation-free survivors showed that 3 patients (all group A, 1.3%) had aortic regurgitation of more than grade II. Root diameter, valve pressure gradient, and valve orifice area were comparable. No gross thromboembolic or bleeding events occurred.

CONCLUSIONS

Aortic valve-sparing operations can provide acceptable long-term results in both techniques. Particular care to the annulus in the remodeling technique and different prosthesis designs in the reimplantation technique may overcome the intrinsic problems of each procedure.

[Surgical therapy of infective endocarditis]

Therapy of infective endocarditis (IE) remains a particular challenge due to a relative high morbidity and mortality. Cardiac surgery is established as a cornerstone in therapy for native valve endocarditis (NVE) as well as for prosthetic valve endocarditis (PVE) and is required in 30% of patients with active IE. The basic aim of surgery in IE is the radical debridement of infected tissue and reconstruction of valve function either by reconstructive valve surgery or valve replacement. Indication for surgery depends on several clinical variables, the main indication remains heart failure due to severe heart valve defects or prosthetic valve dysfunction. Surgical therapy of NVE can be performed with good clinical results in the early and late follow-up. Surgical therapy of PVE is still associated with quite high mortality up to 80% in some risk groups. This indicates the particular importance of focus evaluation and antibiotic prophylaxis after primary surgery for infective endocarditis.

Aldose reductase structures: implications for mechanism and inhibition

During chronic hyperglycaemia, elevated vascular glucose level causes increased flux through the polyol pathway, which induces functional and morphological changes associated with secondary diabetic complications. Inhibitors of aldose reductase (ARIs) have been widely investigated as potential therapeutic agents, but to date only epalrestat is successfully marketed for treatment of diabetic neuropathy, in Japan. Promising compounds during in vitro studies or in trials with animal models have failed to proceed beyond clinical trials and to everyday use, due to a lack of efficacy or adverse side effects attributed to lack of inhibitor specificity and likely inhibition of the related aldehyde reductase (ALR1). Knowledge of the catalytic mechanism and structures of the current inhibitors complexed with ALR2 are means by which more specific and tightly bound inhibitors can be discovered. This review will provide an overview of the proposed catalytic mechanism and the current state of structure-based drug design.