Non-typhoidal Salmonella enteritidis prosthetic valve endocarditis.

In this case, we present a rare cause of prosthetic valve endocarditis. A man in his 80s presented to the emergency department with fever and diarrhoea. The patient underwent a transcatheter aortic valve replacement 17 years earlier. A negative PCR result in faeces for Salmonella and positive blood cultures with Salmonella gave rise to the suspicion of an intravascular Salmonella infection, which was confirmed with a positron emission tomography. Due to the low prevalence of Salmonella endocarditis, there is no consensus on the most effective treatment. Guidelines recommend early surgery and long-term antimicrobial treatment in endocarditis with Gram-negative bacteria. In this case, surgery was not deemed feasible given the patient his advanced age and multiple comorbidities. Despite treatment with intravenous antibiotics, the patient succumbed to progression of endocarditis 37 days after admission.

Metagenomic analysis of oral plaques and aortic valve tissues reveals oral bacteria associated with aortic stenosis.

OBJECTIVES: Bacteria derived from the oral cavity enter the bloodstream and cause the onset of various systemic diseases, including heart valve disease. However, information on the oral bacteria involved in aortic stenosis is limited. MATERIALS AND METHODS: We comprehensively analyzed the microbiota in aortic valve tissues collected from aortic stenosis patients using metagenomic sequencing and investigated the relationships between the valve microbiota, the oral microbiota, and oral cavity conditions. RESULTS: Metagenomic analysis revealed the presence of 629 bacterial species in five oral plaques and 15 aortic valve clinical specimens. Patients were classified into two groups (A and B) according to their aortic valve microbiota composition using principal coordinate analysis. Examination of the oral conditions of the patients showed no difference in the decayed/missing/filled teeth index. Bacteria in group B tend to be associated with severe disease, and the number of bacteria on the dorsum of the tongue and the positive rate of bleeding during probing were significantly higher in this group than in group A. The pathophysiology of aortic stenosis may be related to the presence of oral bacteria such as Streptococcus oralis and Streptococcus sanguinis following bacteremia. CONCLUSIONS: Systemic inflammation in severe periodontitis may be driven by the oral microbiota, supporting the indirect (inflammatory) association between oral bacteria and aortic stenosis. CLINICAL RELEVANCE: Appropriate oral hygiene management may contribute to the prevention and treatment of aortic stenosis.

Invasive Aortic Valve Endocarditis: Clinical and Tissue Findings From a Prospective Investigation.

BACKGROUND: Advanced aortic valve infective endocarditis (IE) with progression and destruction beyond the valve cusps-invasive IE-is incompletely characterized. This study aimed to characterize further the invasive disease extent, location, and stage and correlate macroscopic operative findings with microscopic disease patterns and progression. METHODS: A total of 43 patients with invasive aortic valve IE were prospectively enrolled from August 2017 to July 2018. Of these patients, 23 (53%) had prosthetic valve IE, 2 (5%) had allograft IE, and 18 (42%) had native aortic valve IE. Surgical findings and intraoperative photography were analyzed for invasion location, extent, and stage. Surgical samples were formalin fixed and analyzed histologically. The time course of disease and management were evaluated. RESULTS: Pathogens included Staphylococcus aureus in 17 patients (40%). Invasion predominantly affected the non-left coronary commissure (76%) and was circumferential in 15 patients (35%) (14 had prosthetic valves). Extraaortic cellulitis was present in 29 patients (67%), abscess in 13 (30%), abscess cavity in 29 (67%), and pseudoaneurysm in 8 (19%); 7 (16%) had fistulas. Histopathologic examination revealed acute inflammation, abscess formation, and lysis of connective tissue but not of myocardium or elastic tissue. Median time from onset of symptoms to antibiotics was 5 days, invasion confirmation 15 days, and surgery 37 days. Patients with S aureus had a 21-day shorter time course than patients non-S aureus. New or worsening heart block developed in 8 patients. CONCLUSIONS: Advanced invasive aortic valve IE demonstrates consistent gross patterns and stages correlating with histopathologic findings. Invasion results from a confluence of factors, including pathogen, time, and host immune response, and primarily affects the fibrous skeleton of the heart and expands to low-pressure regions.

Findings of prosthetic valve endocarditis in the balloon-expandable trans-catheter aortic valve: review of the literature and tips of management.

Prosthetic valve endocarditis after transcatheter aortic valve implantation (TAVI) is a rare complication associated with a high mortality rate. Nonetheless, the rapid expansion of TAVI in recent years has proportionally increased the number of patients exposed to the risk of developing transcatheter valve infection. A 71-year-old female with recent history of TAVI was diagnosed with prosthetic valve obstruction secondary to endocarditis. The characteristics of clinical presentation of endocarditis in the balloon-expandable transcatheter valve and the intra-operative findings are discussed with a review of the literature and tips of management.

Modified commando procedure in complicated infective endocarditis ─ a case series.

BACKGROUND: Complicated infective endocarditis (IE) with perivalvular abscess and destruction of intervalvular fibrous body (IFB) has high mortality risk and requires emergent or urgent surgery mostly. CASE PRESENTATION: We presented four patients with complicated infective endocarditis combined with perivalvular abscess and IFB destruction. Three patients had prosthetic valve endocarditis and one patient had native valve endocarditis. They all received modified Commando procedure successfully. No surgical mortality or re-exploration for bleeding. CONCLUSIONS: We suggest that modified Commando procedure may have some benefit in improving survival rate of patients with complicated IE and reducing complications.

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.

Infective endocarditis in patients with liver cirrhosis: a systematic review.

Liver cirrhosis is an increasing cause of mortality and morbidity in developed countries. Infective Endocarditis (IE) is an uncommon disease with notable morbidity and mortality. Even though cirrhosis is associated with immune dysfunction and increased occurrence of bacterial infection, IE is infrequently diagnosed in these patients. Thus, the purpose of this study was to systematically review all published cases of IE in patients with cirrhosis in the literature. A systematic review of PubMed, Scopus and Cochrane (through 23th April 2020) for studies providing epidemiological, clinical, microbiological as well as treatment data and outcomes of IE in patients with cirrhosis was performed. A total of 78 studies, containing data of 602 patients, were included. A prosthetic valve was present in 17.8%, while the most common causative pathogen was S. aureus in 26% followed by Streptococcus spp in 16.8%. Aortic valve was the most commonly infected site, followed by mitral valve. Diagnosis was set with a transthoracic ultrasound in 55.2%, while the diagnosis was set at autopsy in 16.7%. Fever and heart failure were the most common clinical presentations. Aminoglycosides, vancomycin, and cephalosporins were the antimicrobials most frequently used for treatment. Clinical cure was noted in 68.2%, while overall mortality was 41.4%. This systematic review thoroughly describes IE in patients with liver cirrhosis and provides information on epidemiology, clinical presentation, treatment and outcomes.

Infective endocarditis by Acinetobacter species: a systematic review.

A. baumannii - A. calcoaceticus complex infections are increasingly frequent, especially in intensive care units. Such infections are associated with a mortality that can be as high as 62%. On the other hand, infective endocarditis (IE) is an uncommon disease with notable morbidity and mortality. Even though IE is rarely caused by Acinetobacter species, these infections can be particularly problematic due to increasing antimicrobial resistance. The purpose of this study was to systemically review all published cases of IE by Acinetobacter species in the literature. A systematic review of PubMed, Scopus and Cochrane library (through 25 April 2020) for studies providing epidemiological, clinical, microbiological as well as treatment data and outcomes of IE by Acinetobacter species was performed. A total of 35 studies, containing data of 37 patients, were included. A prosthetic valve was present in 40.5%, while the most common causative pathogen was A. baumannii - A. calcoaceticus complex, followed by A. lwoffii. Aortic valve was the commonest infected site, followed by mitral valve. Diagnosis was set with transthoracic echocardiography in 48.6%, while the diagnosis was set at autopsy in 20%. Fever and sepsis were the commonest clinical presentations, followed by heart failure and embolic phenomena. Aminoglycosides, cephalosporins and carbapenems were the commonest antimicrobials used. Clinical cure was noted in 70.3%, while overall mortality was 32.4%. Development of heart failure was independently associated with mortality by IE. This systematic review thoroughly describes IE by Acinetobacter and provides information on epidemiology, clinical presentation, treatment and outcomes.

Ultrastructure of a late-stage bacterial endocarditis valve vegetation.

Infective endocarditis (IE) remains a severe illness with high mortality rate, despite advances in antibiotic therapy and cardiac surgery. If infectious bacteria and platelets are two key players of human IE vegetation developmental process, their interactions and respective roles in fully developed late-stage IE vegetations remain obscure. The objective of this study was to better understand the organization of the different components of the IE vegetation and to provide a detailed description of this vegetation ultrastructure. A late stage Staphylococcal endocarditic vegetation was provided from a 13 years teenager patient. After reception of the surgical piece, we carried out a histological study using routine methods, notably the hematoxylin-eosin-saffron staining. Labeling with the anti-CD 61 antibody was also carried out. In a second step, we used transmission electron microscopy to describe the different regions making up the vegetation. Our ultrastructural study revealed vegetation was clearly composed by three different regions and identified the specific location of the bacteria and platelets in the vegetation tissues. Histological analysis showed that platelets and Staphylococcus aureus were not co-localized. Electron microscopy study confirmed that S. aureus were found at distance from platelets, as well from immune cells, embedded in a biofilm and/or a necrotic area. These results reveal a development of a deep bacteria-only niche in vegetation, raising questions about medication access to these microorganisms. Vegetation composed of three regions: a region rich in bacteria incorporated into the necrotic tissue, the second region composed of fibrin filaments and the third region rich in platelets and free of bacteria.

Bacterial biofilms in infective endocarditis: an in vitro model to investigate emerging technologies of antimicrobial cardiovascular device coatings.

OBJECTIVE: In spite of the progress in antimicrobial and surgical therapy, infective endocarditis (IE) is still associated with a high morbidity and mortality. IE is characterized by bacterial biofilms of the endocardium, especially of the aortic and mitral valve leading to their destruction. About one quarter of patients with formal surgery indication cannot undergo surgery. This group of patients needs further options of therapy, but due to a lack of models for IE prospects of research are low. Therefore, the purpose of this project was to establish an in vitro model of infective endocarditis to allow growth of bacterial biofilms on porcine aortic valves, serving as baseline for further research. METHODS AND RESULTS: A pulsatile two-chamber circulation model was constructed that kept native porcine aortic valves under sterile, physiologic hemodynamic and temperature conditions. To create biofilms on porcine aortic valves the system was inoculated with Staphylococcus epidermidis PIA 8400. Aortic roots were incubated in the model for increasing periods of time (24 h and 40 h) and bacterial titration (1.5 × 104 CFU/mL and 1.5 × 105 CFU/mL) with 5 L cardiac output per minute. After incubation, tissue sections were analysed by fluorescence in situ hybridization (FISH) for direct visualization of the biofilms. Pilot tests for biofilm growth showed monospecies colonization consisting of cocci with time- and inocula-dependent increase after 24 h and 40 h (n = 4). In n = 3 experiments for 24 h, with the same inocula, FISH visualized biofilms with ribosome-containing, and thus metabolic active cocci, tissue infiltration and similar colonization pattern as observed by the FISH in human IE heart valves infected by S. epidermidis. CONCLUSION: These results demonstrate the establishment of a novel in vitro model for bacterial biofilm growth on porcine aortic roots mimicking IE. The model will allow to identify predilection sites of valves for bacterial adhesion and biofilm growth and it may serve as baseline for further research on IE therapy and prevention, e.g. the development of antimicrobial transcatheter approaches to IE.

Bacterial colonization of explanted non-endocarditis cardiac valves: evidence and characterization of the valvular microbiome.

Bacterial colonization has been already demonstrated in heart valve tissues of patients without cardiovascular infections. However, the evidence of a valvular microbiome is still scarce. The next-generation sequencing method was carried out on 34 specimens of aortic (n = 20) and mitral valves (n = 14) explanted from 34 patients having neither evidence nor history of infectious diseases, particularly infective endocarditis. While no bacteria were demonstrated using standard culture methods, bacterial deoxyribonucleic acid (DNA) sequences were found using next-generation sequencing in 15/34 (44%) cases. Escherichia coli was present in 6 specimens and was the most frequently identified bacterium. There was a trend towards a higher rate of bacterial DNA positivity in specimens of calcific valves than in those of non-calcific valves (10/17 vs 5/17, P = 0.17). Based on a quantitative test, E. coli accounted for 0.7% ± 1% in calcific valvular tissue and 0.3% ± 0.3% in non-calcific valvular tissue (P = 0.2), and for 11% ± 27% in the valvular tissue of diabetic patients and 0.3% ± 1% in the valvular tissue of non-diabetic patients (P = 0.08). Detection of bacterial DNA in non-endocarditis valvular tissues could be a relatively common finding. There could be an association between the valvular microbiome and certain models of valve degeneration and common metabolic disorders.

First Danish case of infective endocarditis caused by Enterococcus hirae.

Enterococcus hirae, a member of the Enterococcus genus, is known to cause infections, including infective endocarditis (IE), in animal species. In humans, E. hirae is an uncommon pathogen, but has been associated with severe and recurrent disease. Here, we report the first Danish case of E. hirae native aortic valve IE in a 62-year-old woman with no history of heart disease. She presented to the hospital with symptoms of gastroenteritis but no signs of heart disease. Nevertheless, blood culture revealed growth of E. hirae, and a transoesophageal echocardiography demonstrated a mobile mass adherent to the aortic valve, compatible with a vegetation. The patient was successfully treated for E. hirae native aortic valve IE with 4 weeks of intravenous benzylpenicillin in combination with gentamicin for the initial 2 weeks. To the best of our knowledge, this is the first documented case of E. hirae IE in Denmark and the sixth documented case worldwide.

Transcatheter Aortic Valve Replacement for Residual Lesion of the Aortic Valve Following "Healed" Infective Endocarditis.

OBJECTIVES: This study aimed to evaluate the safety and mid-term efficacy of transcatheter aortic valve replacement (TAVR) in the setting of aortic valve (AV) infective endocarditis (IE) with residual lesion despite successful antibiotic treatment. BACKGROUND: Patients with AV-IE presenting residual lesion despite successful antibiotic treatment are often rejected for cardiac surgery due to high-risk. The use of TAVR following IE is not recommended. METHODS: This was a multicenter retrospective study across 10 centers, gathering baseline, in-hospital, and 1-year follow-up characteristics of patients with healed AV-IE treated with TAVR. Matched comparison according to sex, EuroSCORE, chronic kidney disease, left ventricular function, prosthesis type, and valve-in-valve procedure was performed with a cohort of patients free of prior IE treated with TAVR (46 pairs). RESULTS: Among 2,920 patients treated with TAVR, 54 (1.8%) presented with prior AV-IE with residual valvular lesion and healed infection. They had a higher rate of multivalvular disease and greater surgical risk scores. A previous valvular prosthesis was more frequent than a native valve (50% vs. 7.5%; p < 0.001). The in-hospital and 1-year mortality rates were 5.6% and 11.1%, respectively, comparable to the control cohort. After matching, the 1-year III to IV aortic regurgitation rate was 27.9% (vs. 10%; p = 0.08) and was independently associated with higher mortality. There was only 1 case of IE relapse (1.8%); however, 18% of patients were complicated with sepsis, and 43% were readmitted due to heart failure. CONCLUSIONS: TAVR is a safe therapeutic alternative for residual valvular lesion after successfully healed AV-IE. At 1-year follow-up, the risk of IE relapse was low and mortality rate did not differ from TAVR patients free of prior IE, but one-fourth presented with significant aortic regurgitation and >50% required re-admission.