An international multicenter study of blood culture practices. The International Collaborative Blood Culture Study Group.

An international study was organized to review blood culture practices in 67 medical centers, most of which were teaching hospitals with a total of over 58,000 active hospital beds. The number of blood cultures per admission was generally greater than 0.5 in the USA and less than 0.5 in other countries. Criteria varied for defining a septic episode, as well as for ascribing clinical importance to isolates of coagulase-negative staphylococci; however, septicemia rates tended to be lower in centers in which clinical evaluation was included among these criteria. Staphylococci were ranked first or second among etiologic agents of septicemia in the USA, whereas Escherichia coli was most frequently ranked first among European and Asian centers. All USA centers recommended collection of two blood cultures per septic episode and all but one recommended a maximum number of blood cultures per septic episode, whereas similar recommendations were less common in Europe and Asia. Collection of more than 10 ml per blood culture was more common in the USA than in Europe or Asia. A variety of broth-based systems were used, often in combination with lysis-centrifugation for special (fungal, mycobacterial) or, on occasion, routine purposes.