Infections associated with cardiovascular implants
Cardiac prosthetic valve-associated infections are uncommon but considerably dangerous, with high mortality rates among patients reaching 30% (Darouiche, 2004). Microorganisms can join and develop biofilms on the surface of the heart valves, which induce the so-called prosthetic valve endocarditis (Darouiche, 2004; Donlan, 2001). Microorganisms responsible for this clinical entity are S. epidermidis, S. aureus, Streptococcus spp., Gram-negative bacilli, enterococci, and Candida sp. (Donlan, 2001).
Vascular grafts are implants that may lead to complications associated with infections (which may result from microbial biofilms developed on their surface). Arterio-venous, aortic, and femoro-popliteal grafts are the main types of vascular grafts. About 4-5% of implanted femoro-popliteal and, respectively, arterio-venous grafts become infected. Aortic allograft-associated infections are rare, with an infection rate of 2%, but 90% of these types of infections are fatal (Darouiche, 2004). Infra-inguinal arterial grafts are associated with an increased rate of amputation. The rate of amputation seems to be stabilized to 1-5%, in case of the best surgical techniques and antibiotic prophylaxis, but this therapy became difficult due to drug-resistant organisms (e.g., 30% of clinical S. aureus isolates are MRSA) (Guggenbichler et al., 2011).