Rapid progression of Staphylococcus lugdunensis mechanical prosthetic valve endocarditis

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.

The Role of the Coagulase-negative Staphylococci (CoNS) in Infective Endocarditis; A Narrative Review from 2000 to 2020

Coagulase-negative staphylococci (CoNS) are part of the microbiota of human skin and rarely linked with soft tissue infections. In recent years, CoNS species considered as one of the major nosocomial pathogens and can cause several infections such as catheter-acquired sepsis, skin infection, urinary tract infection, endophthalmitis, central nervous system shunt infection, surgical site infections, and foreign body infection. These microorganisms have a significant impact on human life and health and, as typical opportunists, cause peritonitis in individuals undergoing peritoneal dialysis. Moreover, it is revealed that these potential pathogens are mainly related to the use of indwelling or implanted in a foreign body and cause infective endocarditis (both native valve endocarditis and prosthetic valve endocarditis) in patients. In general, approximately eight percent of all cases of native valve endocarditis is associated with CoNS species, and these organisms cause death in 25% of all native valve endocarditis cases. Moreover, it is revealed that methicillin-resistant CoNS species cause 60 % of all prosthetic valve endocarditis cases. In this review, we describe the role of the CoNS species in infective endocarditis, and we explicated the reported cases of CoNS infective endocarditis in the literature from 2000 to 2020 to determine the role of CoNS in the process of infective endocarditis.

Infective endocarditis causing mitral valve stenosis - a rare but deadly complication: a case report

Background

Infective endocarditis rarely causes mitral valve stenosis. When present, it has the potential to cause severe hemodynamic decompensation and death. There are only 15 reported cases in the literature of mitral prosthetic valve bacterial endocarditis causing stenosis by obstruction. This case is even more unusual due to the mechanism by which functional mitral stenosis occurred.

Case presentation

We report a case of a 23-year-old white woman with a history of intravenous drug abuse who presented with acute heart failure. Transthoracic echocardiography failed to show valvular vegetation, but high clinical suspicion led to transesophageal imaging that demonstrated infiltrative prosthetic valve endocarditis causing severe mitral stenosis. Despite extensive efforts from a multidisciplinary team, she died as a result of her critical illness.

Conclusions

The discussion of this case highlights endocarditis physiology, the notable absence of stenosis in modified Duke criteria, and the utility of transesophageal echocardiography in clinching a diagnosis. It advances our knowledge of how endocarditis manifests, and serves as a valuable lesson for clinicians treating similar patients who present with stenosis but no regurgitation on transthoracic imaging, as a decision to forego a transesophageal echocardiography could cause this serious complication of endocarditis to be missed.

Electronic supplementary material

The online version of this article (doi:10.1186/s13256-017-1197-3) contains supplementary material, which is available to authorized users.

Staphylococcus lugdunensis endocarditis with destruction of the ventricular septum and multiple native valves

Staphylococcus lugdunensis (S. lugdunensis) is a coagulase negative staphylococcus (CoNS) that can cause destructive infective endocarditis. S. lugdunensis, unlike other CoNS, should be considered to be a pathogen. We report the first case of S. lugdunensis endocarditis causing ventricular septal defect and destruction of the aortic and mitral valves. A 53-year-old male with morbid obesity and COPD presented with intermittent fever and progressive shortness of breath for 2 weeks. Chest examination showed bilateral basal crepitations, and a grade 2 systolic murmur along the right sternal border. The leukocyte count was 26,000 cells/μl with 89% neutrophils. He was treated with intravenous vancomycin and ceftriaxone. Blood cultures grew Staphylococcus lugdunensis. Transthoracic echocardiogram, which was limited by body habitus, showed no definite valvular vegetations. Repeat transthoracic echocardiogram performed one week later revealed a large aortic valve vegetation Vancomycin was switched to daptomycin on day 4 because of difficulty achieving therapeutic levels of vancomycin and the development of renal insufficiency. Open heart surgery on day 10 revealed aortic valve and mitral valve vegetations with destruction, left ventricular outflow tract (LVOT) septal abscess and ventricular septal defect (VSD). Bio-prosthetic aortic and mitral valve replacement, LVOT and VSD repair were done. Intraoperative cultures grew Staphylococcus lugdunensis. The patient was discharged home with daptomycin to complete 6 weeks of treatment. S. lugdunensis can cause rapidly progressive endocarditis with valve and septal destruction. Early diagnosis and therapy are essential, with consideration of valve replacement.