![]() However, all promote bacterial adhesion to abiotic surfaces and synthetic surfaces coated with host extracellular matrix components (such as fibrinogen, fibronectin collagen and laminin), and various host cells ( Table 4 Pietrocola et al., 2018 Foster, 2019). Due to the limited number of proteins expressed on the surface of the bacteria, a single MSCRAMM can carry out several functions. However, the precise number of CWA proteins expressed varies from strain to strain and within a species, and is dependent on growth conditions and growth phase (exponential vs. epidermidis, other S taphylococcus spp., Streptococcus spp. They have been described in great detail in S. The most prevalent CWA proteins are the microbial surface components recognizing adhesive matrix molecules (MSCRAMMs). The negative blood cultures in these cases may be as high as 70%. Aspergillus and other filamentous fungi will often have negative blood cultures but may be evident as abscesses in other body structures. 1, 3, 14, 19 This occurs most commonly in a setting of prior recent antibiotic therapy or when a very fastidious organism is responsible for IE. Thirty percent had central venous catheters.Ĭulture-negative endocarditis accounts for about 5% of cases. 26 In this series, predisposing factors, in addition to cardiac lesions, included immunosuppression from chemotherapy or following either bone marrow transplantation or solid organ transplantation, as well as intravenous hyperalimentation. In a recent series of adults and children from Brazil, Candida species accounted for 95 of 152 cases, and Aspergillus caused another 28 cases. Of the filamentous fungus, Aspergillus may also cause IE. 7, 19 Candida species are the most commonly isolated organisms. 3, 7, 16, 17įungal endocarditis in children is most commonly seen in infants. These cases usually present within the first 60 days after surgery or are associated with catheter placement in infants. 3, 4, 19 Staphylococcus aureus and coagulase-negative staphylococcus are primarily organisms seen following surgery and in neonatal IE. ![]() In older children who have acquired IE in a community setting and have not undergone a recent surgery, viridans streptococcus is the most likely organism in about 5% of patients, enterococcus is the cause. The changing nature of the gram-positive cocci infection reflects the changing settings in which IE now occurs. These rarely cause IE in adults and are extremely rare in children. The Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella (HACEK) group include gramnegative coccobacilli, primarily Haemophilus species, as well as Actinobacillus species and Eikenella species. 3, 4, 19 Gram-negative rods such as Pseudomonas are sometimes seen in burn and immunologically compromised patients, often in a hospital setting. Gram-negative endocarditis is rare, making up less than 5% of the cases. 3 Coagulase-negative staphylococci usually make up less than 10% of cases. 3 Staphylococcus aureus has increased significantly as a causative agent, representing 27–33% of the cases of IE. A recent review by the AHA shows that the alpha-hemolytic viridans group streptococcus account for approximately 32–43% of IE in childhood. Within this group, there has been a change in the percentage of various types of organisms found in IE over the past several decades. Gram-positive cocci remain by far the largest group of causative organisms for IE in children. ![]() STEPHEN PARIDON, in Pediatric Cardiology, 2006 Causative Organisms ![]()
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