From the Guidelines
Endocarditis is most commonly caused by bacterial infections, particularly Staphylococcus aureus, Streptococcus species, and Enterococcus species, as reported in the most recent study 1.
Common Causes of Endocarditis
The majority of cases of endocarditis are due to streptococcal and staphylococcal organisms, with Staphylococcus aureus being the most frequent organism in endocarditis resulting from intravenous drug abuse 1.
- Staphylococcus aureus is also a frequent cause of infective endocarditis in patients with insulin-dependent diabetes mellitus.
- Enterococcus faecalis and E. faecium account for 90% of enterococcal endocarditis, which is usually associated with malignancy or manipulation of the genitourinary or gastrointestinal tract.
- Gram-positive and Gram-negative bacilli are relatively uncommon causes of endocarditis.
- The HACEK group of organisms (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, and Kingella species) has become an important cause of endocarditis, causing large vegetations (greater than 1 cm) 1.
Risk Factors
Individuals with pre-existing heart valve abnormalities, prosthetic heart valves, or congenital heart defects are at higher risk of developing endocarditis 1.
- Intravenous drug users are particularly susceptible due to non-sterile injection practices.
- Less commonly, fungi such as Candida and Aspergillus can cause endocarditis, especially in immunocompromised patients or those with prolonged intravenous catheters.
- Healthcare-associated infections, including those from cardiac devices like pacemakers, are increasingly recognized causes of endocarditis.
Pathophysiology
The pathophysiology involves microorganisms adhering to damaged heart valves or endocardial surfaces, forming vegetations composed of platelets, fibrin, and microorganisms that can lead to valve destruction, heart failure, and embolic complications if not treated promptly with appropriate antibiotics 1.
Diagnosis and Treatment
The timely initiation of antimicrobial therapy and subsequent necessary interventions depend on the anticipated spectrum of pathogens and their virulence 1.
- Contemporary literature described frequently occurring microorganisms or microbial groups, such as coagulase-negative staphylococci, Staphylococcus aureus, Enterococcus sp., Gram-negative bacilli, Streptococcus sp., fungi, and bacteria of the HACEK group, as causal PVE agents.
- The routine application of molecular biological detection methods via microbial-specific polymerase chain reaction (PCR) or whole genome analyses in the diagnosis of PVE represents a significant step forward in the detection of pathogens and their virulence.
From the Research
Common Causes of Endocarditis
- Staphylococcus aureus is the leading cause of infectious endocarditis, as reported in 2, 3, 4
- The incidence of endocarditis caused by Staphylococcus aureus has remained high despite better diagnostic and therapeutic procedures over time 2
- Other common causes of endocarditis include:
- The epidemiology of endocarditis can vary depending on the population subgroup, with S. aureus being the most common pathogen in almost all subgroups, except in patients with implantable devices, prosthetic valves, or immunocompromised non-HIV, as well as in the sub-group from Asia 3
Risk Factors for Endocarditis
- Clinical risk factors for infective endocarditis in Staphylococcus aureus bacteremia include:
- Valve damage and inflammation can predispose to endocarditis, but by distinct mechanisms 6
- The presence of certain medical devices, such as prosthetic valves or implantable devices, can increase the risk of endocarditis 3, 5
Complications of Endocarditis
- Cardiac complications, such as cardiac failure and valve dysfunction, are common in patients with endocarditis 2
- Extracardiac complications, such as renal failure and central nervous system (CNS) events, can also occur 2
- The development of complications, such as CNS events, can be associated with an increased risk of mortality 2