[Laboratory control in diagnosis and treatment of infective endocarditis].

Infectious endocarditis is caused by a wide variety of microorganisms. Etiological diagnosis depends either on direct methods, directed to the detection and isolation of the causative organisms, or serological methods. Blood cultures remain as the best method for the diagnosis of bacterial endocarditis. Blood culture technology has changed due to the appearance of new automatic continuous monitoring systems which shorten the detection time. Endocarditis with a negative blood culture has decreased below 5% because of new blood culture systems, new serological methods and molecular technology. The control of antimicrobial therapy in endocarditis must be performed by expert laboratories. A minimal bactericidal concentration, serum levels of antimicrobials and the serum bactericidal test are the most useful parameters. Their execution requires the use of strict protocols and interpretation must be carried out with an expert in clinical microbiology and infectious diseases.