Microbiological etiology in prosthetic valve endocarditis: A nationwide registry study

Antibiotic Prophylaxis for Genitourinary Procedures in Patients with Artificial Joint Replacement and Artificial Heart Valves

Prosthetic joint infection (PJI) and prosthetic valve endocarditis (PVE) are uncommon but serious complications. According to current best practice statements, prior to a genitourinary procedure, patients with prosthetic joints should receive antibiotic prophylaxis if they are within 2 years of arthroplasty, if they are high risk for infection due to their individual comorbidities, or if the procedure poses a high risk for bacteremia. Patients with prosthetic valves should not receive antibiotic prophylaxis for the sole purpose of prevention of endocarditis. Enterococcus species are the uropathogens most often associated with PJI and PVE. Antibiotic selection should take into account local resistance patterns.

Infective Endocarditis in Patients With Bicuspid Aortic Valves: Unique Clinical and Microbiologic Features

OBJECTIVE

Patients with bicuspid aortic valves (BAV) are at increased risk of infective endocarditis (IE). Information of the clinical presentation and the microbiology of BAV-associated IE, however, is limited. Therefore, our study aimed to characterise the clinical features native valve endocarditis (NVE) in the setting of BAV and compared them to patients with prosthetic valve endocarditis (PVE) following BAV replacement.

METHODS

Adult patients with BAV or history of BAV with aortic valve replacement (AVR) and a definite or possible IE diagnosis within the Mayo Clinic Enterprise (USA) from January 2008 to December 2021, were included. BAV was confirmed by trans-oesophageal echocardiography. IE was defined according to the modified Duke criteria and only an initial episode was included. Statistical analyses were performed to compare clinical characteristics, microbiology, and IE complications.

RESULTS

Overall, 161 patients with BAV and IE (NVE [n=60], 37.3%) and PVE [n=101, 62.7%) were included. Mean age±SD was 56.5±16.1 years, and 139 (86.3%) patients were males. PVE patients were older (p<0.01) and had a higher rate of hypertension (p<0.01), chronic heart failure (p<0.01), chronic kidney disease (p<0.01), and perivalvular abscess (p<0.01). BAV patients with NVE had a higher prevalence of isolated mitral valve IE (p<0.01), moderate to severe aortic valve regurgitation (p<0.01) and combined aortic with mitral valve IE (p<0.01). Streptococcus mitis was the most common pathogen in NVE (30.0%) while Staphylococcus aureus was the most common in PVE (15.8%).

CONCLUSIONS

Patients with BAV are at risk of both NVE and PVE. Each syndrome has unique clinical features, including microbiologic findings, that should be appreciated in IE diagnosis and management.

Three cases of Cutibacterium avidum prosthetic valve infective endocarditis at a single heart center

OBJECTIVE

To resolve an exceptional clustering of Cutibacterium avidum prosthetic valve infective endocarditis (IE) at a single heart center.

METHODS

During a period of 21 months, three patients experienced C. avidum bacteremia 24-128 days after aortic valve replacement. Operative procedures and electronic prescriptions of antimicrobials were surveyed, and bacterial isolates were genome sequenced.

RESULTS

The prosthetic valves were inserted by separate surgical teams. In one case, echocardiographic confirmation of IE was not achieved until 4 months after the first positive blood culture, but the causative agents were irrefutably documented in all cases by culture, or amplification of bacterial deoxyribonucleic acid, from removed prosthetic material. Whole-genome sequencing clustered isolates to a distinctive subgroup of the species but did not suggest inter-patient transmission of isolates.

CONCLUSIONS

Despite vigorous sampling of blood and tissue, detection of C. avidum was not unconditional, neither by culture nor polymerase chain reaction test. The causative agent is likely underreported and should be meticulously searched for in culture-negative prosthetic valve endocarditis.

Epidemiological and microbial trends of infective endocarditis in western Norway: a 7-year prospective observational study

BACKGROUND

In this prospective, observational study, we aimed to investigate epidemiologic and microbial trends of infective endocarditis in western Norway.

METHODS

Clinical and microbiological characteristics of 497 cases of infective endocarditis from 2016 through 2022 were investigated. Categorical data were analysed using Chi-squared tests. Survival data were analysed using multiple Cox regression and reported using hazard ratios.

RESULTS

The mean age was 67 years, and 74% were men. The annual incidence rates varied from 10.4 to 14.1 per 100,000 inhabitants per year. Infective endocarditis on native valves was observed in 257 (52%) of the cases, whereas infective endocarditis on prosthetic valves and/or cardiac implantable electronic devices was observed in 240 (48%) of the cases: infection on surgically implanted bioprostheses was observed in 124 (25%) of the patients, infection on transcatheter aortic valve implantation was observed in 47 (10%) patients, and infection on mechanical valves was observed in 34 (7%) cases. Infection related to cardiac implantable electronic devices was observed in a total of 50 (10%) cases. Staphylococcus aureus and viridans streptococci were the most common microbial causes, and isolated in 145 (29%) and 130 (26%) of the cases, respectively. Enterococcal endocarditis showed a rising trend during the study period and constituted 90 (18%) of our total cases of infective endocarditis, and 67%, 47%, and 26% of the cases associated with prosthetic material, transcatheter aortic valve implantation and cardiac implantable electronic devices, respectively. There was no significant difference in 90-day mortality rates between the native valve endocarditis group (12%) and the group with infective endocarditis on prosthetic valves or cardiac implants (14%), p = 0.522. In a model with gender, age, people who inject drugs, microbiology and type of valve affected, only advanced age was significantly associated with fatal outcome within 90 days.

CONCLUSIONS

The incidence of infective endocarditis, and particularly enterococcal endocarditis, increased during the study period. Enterococci appeared to have a particular affinity for prosthetic cardiac material. Advanced age was the only independent risk factor for death within 90 days.

Prosthetic Valve Endocarditis: A Retrospective Cohort Study Conducted at "Dr. Carol Davila" Central Military Emergency University Hospital in Bucharest

OBJECTIVE

To evaluate patients with prosthetic valves who developed infective endocarditis by comparing treatment outcomes in both early- and late-onset IE episodes following prosthetic valve replacement surgery. This study sought to conduct a comprehensive assessment of the efficacy of these methodologies. The insights derived from this assessment can be utilized to enhance the quality of care for individuals with infective endocarditis who have undergone prosthetic valve replacement surgery.

RESULTS

During the period of investigation (January 2017-December 2022), 78 patients diagnosed with infective endocarditis (IE) on a prosthetic valve were admitted to the Infectious Diseases Department of the "Dr. Carol Davila" Central Military Emergency University Hospital in Bucharest. In 28 patients (35.8%), the onset of PVE occurred within 12 months of surgery (early onset), whereas in 50 patients (64.2%), the onset occurred more than 12 months after surgery (late onset). The mortality rate was 35.9% (53.6% among the early onset patients and 26% among the late-onset patients). Among patients who received surgical and medical therapy, the mortality rate was 29.6%, whereas among those who received only medical therapy, a 39.2% mortality rate was reported. According to the extracted data, antibiotic therapy was successful in 72.6% of the patients. In contrast, a combination of surgical and drug-based approaches resulted in a cure in 76.1% of patients. The most common etiological agent was Staphylococcus aureus (38.5%), followed by Enterococcus faecalis (26.9%) and Streptococcus mitis (10.3%). The mortality rate of patients infected with S. aureus was 29.2%, indicating the severity of this infectious agent.

CONCLUSIONS

Prosthetic valve endocarditis (PVE) is a serious condition associated with a high mortality rate both in the short and long term. Regardless of the therapy used, the risk of death remains high.

Prosthetic valve infective endocarditis caused by Cutibacterium modestum: a case report

Background

While Cutibacterium acnes is well known for its potential to cause acne vulgaris, postsurgical infections, and other human infections, few reports have described Cutibacterium modestum infections. Thus, the clinical characteristics of C. modestum as an infectious disease are not well understood. Herein, we describe the characteristics of a case of prosthetic valve infective endocarditis caused by C. modestum.

Case summary

An 81-year-old man was admitted to our hospital with fever, general fatigue, and appetite loss. His past medical history included aortic valve replacement surgery and coronary artery bypass grafting for aortic valve stenosis and angina pectoris. Physical examination on admission revealed a body temperature of 39.0°C, blood pressure of 97/68 mmHg, and pulse rate of 101 b.p.m. Transthoracic echocardiography showed no prosthetic valve destruction or malfunction or obvious vegetation adhesion to the prosthetic or other valves. Bacteria initially identified as C. acnes were detected in two sets of anaerobic blood culture bottles collected upon admission. However, as the samples required 111 and 118 h to become blood culture-positive, the possibility of contaminating bacteria was high. Transoesophageal echocardiography revealed vegetation in the artificial valve. Repeated blood culture revealed the same bacteria; thus, contamination was ruled out, and the diagnosis of infective endocarditis was confirmed. Finally, 16S ribosomal RNA gene sequencing identified the detected bacteria as C. modestum rather than C. acnes.

Discussion

Including this case, only two cases of prosthetic valve infective endocarditis caused by C. modestum have been reported, the characteristics of which are still poorly understood.

Enhancing regenerative medicine: the crucial role of stem cell therapy

Stem cells offer new therapeutic avenues for the repair and replacement of damaged tissues and organs owing to their self-renewal and multipotent differentiation capabilities. In this paper, we conduct a systematic review of the characteristics of various types of stem cells and offer insights into their potential applications in both cellular and cell-free therapies. In addition, we provide a comprehensive summary of the technical routes of stem cell therapy and discuss in detail current challenges, including safety issues and differentiation control. Although some issues remain, stem cell therapy demonstrates excellent potential in the field of regenerative medicine and provides novel tactics and methodologies for managing a wider spectrum of illnesses and traumas.

Late Recurrence of Prosthetic Valve Endocarditis Due to Candida albicans

BACKGROUND Candida prosthetic valve endocarditis is a rare disease that is increasing in incidence with the rising rates of fungemia and increased use of intracardiac devices. Chronic antifungal prophylaxis is used after primary treatment to prevent recurrence, but the optimal duration of prophylaxis is currently unknown. This case report is of a woman with a history of mitral valve replacement due to Candida endocarditis presenting 2 years later with prosthetic valve and native aortic valve Candida albicans endocarditis. CASE REPORT A 32-year-old woman with a history of intravenous drug abuse, Staphylococcus and Candida endocarditis, and 2 mitral valve replacements 2 years ago on long-term oral fluconazole presented with fevers, weight loss, and dyspnea. She had stopped taking her oral antifungals prior to presentation. She was found to have vegetations on her prosthetic mitral valve and on her native aortic valve. She was started on ceftriaxone, vancomycin, and micafungin, and blood cultures grew C. albicans. She also developed a C. albicans metatarsal abscess and a splenic infarct. She underwent redo mitral valve replacement and aortic valve debridement successfully and was continued on intravenous micafungin for 8 weeks. CONCLUSIONS This case highlights the association between prosthetic valve endocarditis, intravenous drug abuse, and opportunistic fungal infections. Lifelong oral fluconazole can be considered for all patients with C. albicans prosthetic valve endocarditis, especially in the setting of the presence of other risk factors, such as intravenous drug abuse, as demonstrated in our case. Further studies are needed to determine differences in outcomes.

The 2023 Duke-International Society for Cardiovascular Infectious Diseases Criteria for Infective Endocarditis: Updating the Modified Duke Criteria

The microbiology, epidemiology, diagnostics, and treatment of infective endocarditis (IE) have changed significantly since the Duke Criteria were published in 1994 and modified in 2000. The International Society for Cardiovascular Infectious Diseases (ISCVID) convened a multidisciplinary Working Group to update the diagnostic criteria for IE. The resulting 2023 Duke-ISCVID IE Criteria propose significant changes, including new microbiology diagnostics (enzyme immunoassay for Bartonella species, polymerase chain reaction, amplicon/metagenomic sequencing, in situ hybridization), imaging (positron emission computed tomography with 18F-fluorodeoxyglucose, cardiac computed tomography), and inclusion of intraoperative inspection as a new Major Clinical Criterion. The list of "typical" microorganisms causing IE was expanded and includes pathogens to be considered as typical only in the presence of intracardiac prostheses. The requirements for timing and separate venipunctures for blood cultures were removed. Last, additional predisposing conditions (transcatheter valve implants, endovascular cardiac implantable electronic devices, prior IE) were clarified. These diagnostic criteria should be updated periodically by making the Duke-ISCVID Criteria available online as a "Living Document."

Alternative Nuclear Imaging Tools for Infection Imaging

Purpose of Review

Cardiovascular infections are serious disease associated with high morbidity and mortality. Their diagnosis is challenging, requiring a proper management for a prompt recognition of the clinical manifestations, and a multidisciplinary approach involving cardiologists, cardiothoracic surgeons, infectious diseases specialist, imagers, and microbiologists. Imaging plays a central role in the diagnostic workout, including molecular imaging techniques. In this setting, two different strategies might be used to image infections: the first is based on the use of agents targeting the microorganism responsible for the infection. Alternatively, we can target the components of the pathophysiological changes of the inflammatory process and/or the host response to the infectious pathogen can be considered. Understanding the strength and limitations of each strategy is crucial to select the most appropriate imaging tool.

Recent Findings

Currently, multislice computed tomography (MSCT) and nuclear imaging (¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography, and leucocyte scintigraphy) are part of the diagnostic strategies. The main role of nuclear medicine imaging (PET/CT and SPECT/CT) is the confirmation of valve/CIED involvement and/or associated perivalvular infection and the detection of distant septic embolism. Proper patients’ preparation, imaging acquisition, and reconstruction as well as imaging reading are crucial to maximize the diagnostic information.

Summary

In this manuscript, we described the use of molecular imaging techniques, in particular WBC imaging, in patients with infective endocarditis, cardiovascular implantable electronic device infections, and infections of composite aortic graft, underlying the strength and limitations of such approached as compared to the other imaging modalities.