Comparative evaluation of different types of blood culture media for isolation of aerobes

Abstract

The possible advantage of hypertonic sucrose medium over isotonic medium for isolating aerobic organisms from blood was studied. Approximately 50 ml of medium and 5 ml of blood inoculum were present in each culture bottle. In the first phase of the study, supplemented peptone broth (SPB) was compared with brucella broth containing 10% sucrose (BB-10S). There were 194 significant clinical isolates in at least one of the two bottles in each set during a 7-month period; 160 (82%) of the isolates grew in SPB, whereas 191 (98%) grew in BB-10S (P less than 0.01). Of the 158 isolates that grew in both media, 13 (8%) appeared earlier in BB-10S, whereas none did so in SPB. In the second phase of the study, SPB with 10% sucrose (SPB-10S) was compared with BB-10S. There were 187 isolates during a 9-month period; 173 (93%) grew in SPB-10S compared with 179 (96%) for BB-10S. In this comparison there was no apparent difference in the time interval required for recovery of organisms. The two hypertonic sucrose media (SPB-10S and BB-10S) were comparable for isolating organisms under aerobic conditions and superior to the nonhypertonic medium (SPB).