Endocarditis, bacterial aminoglycosides

Bacterial endocarditis. An aminoglycoside, usually gentamicin, should comprise part of the antimicrobial combination for enterococcal, streptococcal or staphylococcal infection of the heart valves, and for the therapy of clinical endocarditis which fails to yield a positive blood culture. 

Aminoglycosides are most useful for bacteraemias (especially Gram-negative septicaemia) since their volume of distribution is relatively low. With the exception of patients with renal failure or endocarditis they should be administered once-daily. This is because they exhibit a dose-dependent pharmacodynamic effect. This means that bactericidal activity is determined more by the peak plasma concentration than by the time that the plasma concentration is above the minimum required to achieve bacterial killing. The converse is true of p-lactams, which exhibit t/me-cfepenofent bacterial killing. 

Aminoglycosides are parenteral antibiotics most widely used in the treatment of infections due to enteric gramnegative bacteria. However, aminoglycosides are often used in combination with cell wall-active agents such as beta-lactams or vancomycin for treatment of endocarditis. Aminoglycosides initially diffuse passively across the baae-rial outer membrane and are then actively transported into the cytoplasm. This active transport is inhibited in low pH or anaerobic conditions. Once inside the cytoplasm, aminoglycosides inhibit protein synthesis by binding to the bacterial... 

Leibovici L. Aminoglycoside-containing antibiotic combinations for the treatment of bacterial endocarditis an evidence-based approach. Int J Antimicrob Agents 2010 36(Suppl. 2) S46-9. 

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