Late prosthetic valve endocarditis with Mycobacterium tuberculosis after the Bentall procedure

Four decades of experience of prosthetic valve endocarditis reflect a high variety of diverse pathogens

Prosthetic valve endocarditis (PVE) remains a serious condition with a high mortality rate. Precise identification of the PVE-associated pathogen/s and their virulence is essential for successful therapy, and patient survival. The commonly described PVE-associated pathogens are staphylococci, streptococci and enterococci, with Staphylococcus aureus being the most frequently diagnosed species. Furthermore, multi-drug resistance pathogens are increasing in prevalence, and continue to pose new challenges mandating a personalized approach. Blood cultures in combination with echocardiography are the most common methods to diagnose PVE, often being the only indication, it exists. In many cases, the diagnostic strategy recommended in the clinical guidelines does not identify the precise microbial agent and to frequently, false negative blood cultures are reported. Despite the fact that blood culture findings are not always a good indicator of the actual PVE agent in the valve tissue, only a minority of re-operated prostheses are subjected to microbiological diagnostic evaluation. In this review, we focus on the diversity and the complete spectrum of PVE-associated bacterial, fungal and viral pathogens in blood, and prosthetic heart valve, their possible virulence potential, and their challenges in making a microbial diagnosis. We are curious to understand if the unacceptable high mortality of PVE is associated with the high number of negative microbial findings in connection with a possible PVE. Herein, we discuss the possibilities and limits of the diagnostic methods conventionally used and make recommendations for enhanced pathogen identification. We also show possible virulence factors of the most common PVE-associated pathogens and their clinical effects. Based on blood culture, molecular biological diagnostics, and specific valve examination, better derivations for the antibiotic therapy as well as possible preventive intervention can be established in the future.

Endocarditis Caused by Candida parapsilosis Presenting With Severe Thrombocytopenia in a Patient With Tetralogy of Fallot

Infective endocarditis (IE) occurs more frequently in individuals living with congenital heart disease, often with high morbidity and mortality. Although gram-positive bacterial infections commonly cause IE, prosthetic valves are a known risk factor for fungal IE. We report a case of prosthetic pulmonary valve Candida parapsilosis IE in a 58-year-old male with repaired tetralogy of Fallot. He presented with fatigue, petechiae, and hematochezia. He had severe thrombocytopenia from idiopathic/immune thrombocytopenia purpura, which resolved with steroids and immunoglobulin. Treatment with antifungals as well as a surgical pulmonary valve replacement resulted in recovery without relapse at greater than a year.