A general survey of antibiotic treatment of staphylococcal septicaemia and endocarditis.

The penicillinase-resistant penicillins (methicillin, oxacillin, nafcillin) have been the mainstay of antibiotic therapy for S. aureus septicaemia and endocarditis. In experimental rabbit S. aureus endocarditis, these three antibiotics were equally effective. There has been no prospective comparative clinical studies to determine the relative effectiveness of these antibiotics. In experimental rabbit S. aureus endocarditis, cephalothin and cefazolin are less effective than methicillin and nafcillin. The results of therapy with cephalosporins in patients with S. aureus endocarditis are variable. Clindamycin therapy of S. aureus endocarditis has been associated with clinical relapse. Vancomycin has been used to treat S. aureus septicaemia and endocarditis with good results. Fusidic acid has been used in combination with another effective drug in treating S. aureus septicaemia and endocarditis. Although the combination of a cell-wall acting antibiotic with an aminoglycoside has been shown to have an enhanced anti-staphylococcal activity in vitro and in animal studies, there is no evidence that such a combination reduces morbidity or mortality clinically. Rifampin in combination with a cell-wall acting antibiotic is antagonistic against S. aureus in vitro and in experimental endocarditis in rabbits. The use of such a combination has not shown consistent benefits clinically. The clinical importance of tolerance (MBC/MIC greater than or equal to 32) of cell-wall acting antibiotics to S. aureus is not clear. It appears not to be important in animal studies. Cephalosporins appear not to be effective in the treatment of methicillin-resistant S. aureus infections. The treatment of choice of sepsis and endocarditis due to such strains is vancomycin which is effective against all strains of methicillin-resistant S. aureus.(ABSTRACT TRUNCATED AT 250 WORDS)