Comparative study of treatment with penicillin, ceftriaxone, trovafloxacin, quinupristin–dalfopristin and vancomycin in experimental endocarditis due to penicillin- and ceftriaxone-resistant Streptococcus pneumoniae

Streptococcus pneumoniae is an infrequent cause of bacterial endocarditis, being responsible for 3% of adult cases. Recent studies reveal an alarming increase in the number of penicillin-resistant pneumococcal infections worldwide and cases of endocarditis caused by these bacteria have already been described. In the USA, for example, the levels of resistance are c. 44% and in France 42.8%. Spain, too, has one of the highest resistance rates. According to the study published by the pneumococcal reference laboratory of the Centro Nacional de Microbiología in Majadahonda (Spain), 49% of the strains studied revealed a diminished susceptibility to penicillin (MIC 0.06 mg/L), and most of these were also resistant to erythromycin, tetracyclines, chloramphenicol and thirdgeneration cephalosporins. Parenteral administration of penicillin has long been the treatment of choice for serious pneumococcal infections, but the existence of cases of endocarditis caused by penicillin-resistant strains of S. pneumoniae presents a new challenge. Other traditional antibiotics such as vanco-